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An illustrated guide to the fossil barnacles (Cirripedia) from the Crags (Plio-Pleistocene) of East Anglia
Proceedings of the Geologists’ Association 125 (2014) 215–226
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An illustrated guide to the fossil barnacles (Cirripedia) from the Crags (Plio-Pleistocene) of East Anglia Joe S.H. Collins a,b, Stephen K. Donovan c,*, Claire Mellish a a
Department of Earth Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD, UK 8, Shaw’s Cottages, Perry Rise, Forest Hill, London SE23 2QN, UK c Department of Geology, Naturalis Biodiversity Center, Leiden, The Netherlands b
A R T I C L E I N F O
A B S T R A C T
Article history: Received 5 November 2013 Received in revised form 27 January 2014 Accepted 29 January 2014 Available online 1 March 2014
The Plio-Pleistocene Crag deposits of East Anglia include a wealth of shelly remains, including barnacles, preserved variously as complete shells, their disarticulated plates and trace fossils. Herein, we present a field guide to these distinctive fossils, with diagnoses of all known taxa recorded from the Crags of East Anglia, supported by both line drawings and photographs. The known stratigraphic and geographic distribution within the study area are tabulated. Recognised species include the sessile barnacles Armatobalanus bisulcatus (Darwin), A. dolossus (Darwin), Balanus balanus (Linne´), B. crenatus Bruguie`re, B. inclusus Darwin, Concavus concavus (Bronn), Chirona hameri (Ascanius), Megabalanus tintinnabulum (Linne´), Conopea calceola (Ellis), Co. spongicola (Brown), Acasta undulata Darwin, Coronula barbara Darwin, Megatrema anglicum (G.B. Sowerby) and Verruca stroemia (Mu¨ller) (=14 species); two pedunculate forms, Scalpellum magnum Darwin and Lepas delicatula Withers; and the boring Rogerella isp. The greatest diversity of species is found in the Coralline Crag and Red Crag formations, both yielding 11 species, although only four are common to both. Barnacles are poorly represented in other Crag deposits. ß 2014 The Geologists’ Association. Published by Elsevier Ltd. All rights reserved.
Keywords: Pedunculate barnacles Sessile barnacles Rogerella Stratigraphy
1. Introduction The Crags of East Anglia are, locally, amongst the most fossiliferous Plio-Pleistocene deposits in northern Europe. Although best known for their benthic molluscs and tetrapods, they include a range of marine invertebrates that rarely receive detailed discussion. Amongst these groups, the commonest arthropods are the shells of barnacles which occur either infesting a range of substrates or as disarticulated plates. Indeed, the acorn barnacles are such a distinctive part of the East Anglian Crags that the presence of common Megabalanus tintinnabulum (Linne´) in the Pliocene or Pleistocene (Jackson and Donovan, 1994, p. 203) of Tobago, West Indies, in part led Charles Taylor Trechmann and others (Donovan, 2003, p. 351) to call these deposits the Tobago Crag (now Rockly Bay Formation; Donovan, 1989). Trechmann (1934, p. 483) described these West Indian deposits thus: ‘‘. . . the typical Tertiary red or brown nodular clay or Tobago ‘‘Crag’’ as it has been called, full of Balani’’ which form by far the greater part of the assemblage. The ‘Proceedings of the Geologists’ Association’ has previously published discussions of the palaeoecology and taphonomy of this
* Corresponding author at: Naturalis Biodiversity Center, Postbus 9517, 2300 RA Leiden, The Netherlands. Tel.: +31 71 568 7642. E-mail address: [email protected] (S.K. Donovan).
important group of Crag fossils (for example, Donovan, 1988; Collins, 1989); herein, we examine the systematics and identification of the barnacles from the Crags of East Anglia. This contribution has its origins in a paper published by Collins (1963a) at a time when high definition photographs were not available of the species involved; this was supplemented by a report of a field study (Collins, 1963b). Herein, we present an illustrated field guide to the barnacles of the Crags, enabling their easier identification, and discuss something of their occurrence based on our own palaeontological studies and accounts of extant members of the same species. Illustrations include photographs of specimens in the Natural History Museum, London (BMNH), and relevant drawings from Darwin (1851, 1854; reprinted 2009) and other relevant references. Of the 16 species of barnacles known from the Crags, 14 were sessile forms, comprised of those commonly known as acorn, sponge, coral, wart and whale barnacles (Fig. 1). There are also two pedunculate (stalked) forms allied to the goose barnacle. The shell (capitulum) of the barnacles involved rapidly breaks down into separate plates or valves after death. Of these, Scalpellum magnum Darwin has 14 plates, some of which have the same name as the sessile species. The second pedunculate species is Lepas delicatula Withers, which has five plates. Further, one trace fossil, Rogerella isp., represents the borings of acrothoracian barnacles.
0016-7878/$ – see front matter ß 2014 The Geologists’ Association. Published by Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.pgeola.2014.01.004
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Fig. 1. Features of the shell of the balanid barnacles (after Collins, 1963a, pl. 2). (A and B) Gross morphology of Balanus. (A) Lateral view; (B) section across the shell X-X (see A) showing the mode of imbrications of the compartments (six in this genus) (redrawn after Pilsbry, 1916, fig. 7). The rostrum and rostrolateral compartments (RL) are combined; it is customary to refer to this composite compartment simply as the ‘rostrum’. Key: a, alae; p, parietes; r, radii; C, carina; CL, carinolateral; L, lateral; R, rostrum; and RL, rostrolateral. (C–E) Redrawn after Darwin (1854, figs 2–4). (C) Compartment with two radii, serving either as a rostrolateral or as a rostrum combined with the rostrolaterals, as in Balanus. (D) Compartment with a radius and an ala, serving as a lateral or carinolateral compartment. (E) Compartment with two alae, serving as a carina (also as a rostrum in genera other than Balanus). F-M, redrawn, in part, after Darwin (1854, figs 5–7). (F–I) External (F and H) and interior views (G and I) of terga of various forms; (J–M) external (K and M) and interior views (J and L) of scuta of various forms. Key: bm, basal margin; cm, carinal margin; om, opercular margin; sm, scutal margin; tm, tergal margin; AdR, adductor ridge; AF, articular furrow; AM, (circular) pit for adductor muscle; Ap, apex; AR, articular ridge; DM, pit for lateral depressor muscle; and S, spur. (N and O) Sections, magnified many times, through parietes to show the arrangement of the septa and pores in two examples of shell construction, typical of Balanus crenatus Brugie`re (N) and Balanus balanus Linne´ (O).
2. The Cirripedia: morphology and methodology (Revised after Collins, 1963a, p. 13) The barnacles, or Cirripedia, form a predominant part of the arthropod assemblage throughout the Crag deposits. Whilst certain species of balanid are readily distinguishable, others may easily be confused, particularly those
that occur only as disarticulated plates. Specific determination may commonly be achieved by the recognition of either any one, or a combination of, a few major features. The general appearance of the balanid shell, whether smooth or ribbed, conical or cylindrical, and features such as the shape of the orifice and nature of the radii and alae, may, with practice, be
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Table 1 Stratigraphic distribution of Crag barnacles and a guide to the parts furnished with pores, where present (expanded after Collins, 1963a, Table 2; see also Reid, 1890, Table 9). The Wroxham Crag Formation was formerly called the Weybourne Crag; the Chillesford Crag is now the Chillesford Member of the Norwich Crag Formation (Bowen, 1999, Table 6). Only the Coralline Crag is considered entirely Pliocene (Curry et al., 1978, fig. 5). Extant
Cromer Forest Bed Fmn.
Wroxham Crag Fmn.
Chillesford Member
Norwich Crag Fmn.
Red Crag Fmn.
Coralline Crag Fmn.
X X X X X X X X
X
X X
X X X X
Pores Walls
Armatobalanus bisulcatus (Darwin) Armatobalanus dolosus (Darwin) Balanus balanus (Linne´) Balanus crenatus Bruguie`re Balanus inclusus Darwin Concavus concavus (Bronn) Chirona hameri (Ascanius) Megabalanus tintinnabulum (Linne´) Conopea calceola (Ellis) Conopea spongicola (Brown) Acasta undulata Darwin Coronula barbara Darwin Megatrema anglicum (Sowerby) Verruca stroemia (Mu¨ller) Scalpellum magnum Darwin Lepas delicatula Withers Rogerella isp.
X X
X X
X X
X X X X X
X
X X X
X X X
X X X X
X X
X
X
X
sufficient evidence on which to base a specimen’s identification (for explanation of morphological terminology, see Fig. 1). Nevertheless, these features should not be relied upon entirely, since the appearance of the shell varies, as observations of living forms show, according to habitat. For example, cramped conditions give rise to distorted forms, whilst exposed individuals commonly develop thickened shells; the nature of the substrate may also influence form of growth. The nature of the opercular valves (terga and scuta) of balanids, when preserved, is generally sufficient to provide tolerable determination. They are seldom preserved in situ, but when these valves are not obvious, it is always sound practice to probe carefully into the orifice of the shell to see if they are among the infilling debris. However, in many cases the valves are lost completely and it is necessary to resort to an examination of the shell. The compartments (walls or parietes), basis and radii of the shell are sometimes composed of inner and outer laminae which are joined together by septa, forming a series of tubes or pores. The presence or absence of these pores and the construction of the septa provides a useful, albeit not always final, indication of the species (Table 1). The relative angle of the ala and radius to the paries (plural, parietes) is another important consideration. The balanids attach to the substrate by a basal plate, or basis; if an individual is lost from a substrate, it may still leave behind an attachment scar as evidence (Miller and Brown, 1979). Another aid to identification of Recent and fossil balanids is the use of interlaminate figures, a name introduced by Cornwall (1959, p. 401). Under a microscope, polished sections ‘‘cut at right angles to the line of growth . . . [show] figures [which] can be seen between the outer and inner laminae of the shell as lighter areas on the polished surface’’ (Cornwall, 1956, p. 646). These figures, first noticed by Alessandri (1895), were investigated by Gruvel (1905), and subjected to intense study by both Cornwall (1956, 1959, 1960) and Davadie (1963), who recognised their specific individuality. Although no intensive work on British taxa seems to have been attempted, figures of some of the species present in the Crags were illustrated by Davadie (1963) and these occurrences are noted in the text. For further discussion of the extant British barnacles, including some of the species discussed below, see Rainbow (1984) and Southward (2008). For simplicity, we have eschewed a full systematic presentation; rather, we provide brief
Basis
Radii
X X X X X
X X
X X X
X X X
X
X X X X X
X
descriptive diagnoses of all taxa supplemented by photographs and some illustrations from earlier sources. 3. Cirripede species of the Crags The stratigraphic distribution of the British Plio-Pleistocene members of the Cirripedia, together with a simple guide to the parts furnished with pores, is presented in Table 1. Disarticulated plates may be common locally, particularly in coarse-grained, reworked sands at the base of a bed or unit. It should be noted that some of the living species no longer inhabit British waters. Recorded ranges are given appropriate to British occurrences only; these are based on published records, information on specimen labels in the BMNH and personal observations of the authors. Upto-date information on certain of the localities in Suffolk may be gleaned from Dixon (2012). Species that the authors consider to abundant (‘common’) are so indicated below. 3.1. Armatobalanus bisulcatus (Darwin, 1854) (Figs. 2A–C and 3O–V) Description. Only basis porous. Shell subconical, ranging to c. 25.0 mm across basal diameter, weakly to strongly plicate in the lower half; upper margins of radii oblique and smooth; sutural edges smooth. Scuta narrow, with two to four longitudinal furrows; terga have a short, broad spur half the width of the valve. The subspecies Armatobalanus bisulcatus plicatus Darwin, 1854, is more regularly conical and has deep plications extending full height of walls; narrow radii have very oblique upper margins; in young specimens the diameter of the orifice is much reduced. For interlaminary figures, see Davadie (1963, pl. 42). Occurrence. Both subspecies occur in the Coralline Crag (Darwin, 1854, p. 26), Red Crag and Norwich Crag formations (Table 1). Coralline Crag at Gedgrave, Ramsholt (Fig. 2A), Boyton, Sutton (Fig. 2B and C); Red Crag at Sutton, Beggar’s Hollow, Walton-onthe-Naze, Shottisham; Norwich Crag, Bramerton. 3.2. Armatobalanus dolossus (Darwin, 1854) (Figs. 2F,G and 3G–J) Description. Only basis porous. Shell ranging to c. 0.6 mm across basal diameter, similar to A. bisulcatus, but rather more conical, orifice elongate oval in outline; radii with oblique upper margins.
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Fig. 2. (A–C) Armatobalanus bisulcatus (Darwin). (A) BMNH I.14823, syntype, Coralline Crag Formation, Ramsholt, Suffolk; attached to Talochlamys multistriata (Poli). (B and C) BMNH 59382, Coralline Crag Formation, Sutton, Suffolk. (D) Balanus inclusus Darwin, BMNH I.14836, syntype, Coralline Crag Formation, Gedgrave, Suffolk; scale bar represents 5 mm. (E) Balanus balanus (Linne´), BMNH T1011, glacial deposits, Garvel Park, Greenock, Scotland. (F and G) Armatobalanus dolossus (Darwin), BMNH I.794, Red
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Fig. 3. (A–F) Chirona hameri (Ascanius) (after Darwin, 1854, pl. 2, figs 1a, 1b, pl. 1, figs 7a–7d, respectively). (A) External view of lateral compartment; (B) internal view of carino-lateral compartment; (C and E) scutum, internal and external views; (D and F) tergum, internal and external views; (G–J) Armatobalanus dolossus (Darwin) (after Darwin, 1854, pl. 2, figs 3a–3d); (G) internal view of rostrum, much enlarged; (H) part of basal plate, much enlarged; (I) external view of scutum; (J) external view of tergum. (K–N) Megabalanus tintinnabulum (Linne´) (after Darwin, 1854, pl. 1, figs 1a–1d). (K) Shell, small specimen; (L) internal view of rostrum, 1; (M) internal view of scutum; (N) internal view of tergum. (O–V) Armatobalanus bisulcatus (Darwin) (after Darwin, 1854, pl. 2, figs 2a–2h). (O) Shell, 1.5; (P) A. b. plicatus, shell, 3; (Q) young shell, about 7; (R) external view of rostrum, 1.5; (S and U) scutum, external and internal views; (T and V) tergum, external and internal views. Presumed 1 except where stated otherwise.
Scuta smooth; grooved spur of terga narrower, one third width of valve and rather more elongate than that of A. bisulcatus. Margins of the basal plate bifurcated. For interlaminary figures, see Davadie (1963, pl. 50). Occurrence. Red Crag Formation and Norwich Crag Formation (=Mammaliferous Crag sensu Darwin, 1854, p. 28). Red Crag at Sutton, Beggar’s Hollow, Walton-on-the-Naze, Oakley; Norwich Crag at Postwick, Weybourne. 3.3. Balanus balanus (Linne´, 1758) (Figs. 2E and 4A–G) Description. Only walls porous. Shell subconical; generally ribbed longitudinally; orifice almost circular; summits of radii almost parallel to basis. Parietal pores distinctive, infilled apically,
usually rectangular towards the base with longitudinal ribs between the septa on the outer lamina; coarser ribs extend along upper surface of the inner lamina. ‘‘As the parietes rest on the basis, the circumference of the latter becomes marked in a very peculiar manner [Fig. 4C], by the basal edges of the parietal septa. Hence the basis of this species can be distinguished from that of every other sessile cirripede . . .’’ (Darwin, 1854, p. 22). Apex of tergum produced; a rather wide, grooved spur and concave sutural margin; scutum longitudinally striated. Balanus porcatus da Costa, 1778, is a junior synonym of B. balanus (see Pilsbry, 1916, p. 149). Occurrence. Red Crag Formation and Norwich Crag Formation, glacial deposits to Recent (Darwin, 1854, p. 21). Red Crag Formation at Sutton and Beggar’s Hollow; Norwich Crag Formation at Brammerton and Thorpe.
Crag Formation, Sutton; attached to Neptunea contraria (Linne´). (H) Balanus crenatus Bruguie`re, BMNH 44396, Norwich Crag Formation, Bramerton, Norfolk; attached to Nucella lapillus (Linne´). (I–L) Concavus concavus (Bronn), BMNH In.19079_05, Coralline Crag Formation, Suffolk, in lateral (I and J) and apertural views. Scale bars represent 10 mm except where quoted otherwise.
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Fig. 4. (A–G) Balanus balanus Linne´ (after Darwin, 1854, pl. 1, figs 5a–5g). (A) Shell, 1; (B) part of basal margin of wall, much enlarged; (C) part of basal plate, much enlarged; (D and E) scutum, external and internal views; (F and G) tergum, external and internal views. (H–N) Balanus crenatus Brugie`re (after Darwin, 1854, pl. 1, figs 6a–6g). (H) Shell, 2; (I) part of basal margin of wall, much enlarged; (J) portion of thick basal plate, much enlarged; (K and L) scutum, external and internal views; (M and N) tergum, external and internal views. (O–R) Balanus inclusus Darwin (after Darwin, 1854, pl. 2, figs 5a–5d). (O) Shell, about 3; (P) basis; (Q) elongated shell; (R) base of elongated shell with narrow, furrowed basis. Presumed 1 except where stated otherwise.
Fig. 5. Balanus concavus (Bronn) (after Darwin, 1854, pl. 1, figs 4a–4p). (A) Complete shell; (B) internal part of the carina (left), of the carino-lateral compartment and part of the lateral compartment, showing the raised borders (r) on the rostral side of the sutures; (C) shell with less prominent longitudinal ridges than (A); (D) smooth-shelled variety; (E and I) external views of scuta; (F, L and N) internal views of scuta; (G) internal view of tergum; (H, J, K and M) external views of terga; (O) detail of scutum at rostral corner (highly magnified). Presumed 1 except where stated otherwise.
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Fig. 6. (A–D) Chirona hameri (Ascanius), BMNH I.795, Red Crag Formation, Sutton, Suffolk, plates. (E and F) Megabalanus tintinnabulum (Linne´), BMNH 14734b (E) and a (F); Red Crag Formation, Sutton, Suffolk, plates in external (E) and internal (F) views. (G–N) Conopea calceola (Ellis), BMNH I.776, Norwich Crag Formation, specimen broken. (O and P) Coronula barbara Darwin, BMNH I.804, syntype, Red Crag Formation. (O) External view; (P) internal view. Scale bars represent 10 mm.
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3.4. Balanus crenatus Bruguie`re, 1789 (Figs. 2H and 4H–N) Description. Only walls porous. Shell highly variable from conical with ribbed walls, depressed and smooth, much elongated and conical, or club-shaped, according to population density and/or substrate; radii with oblique summits. Subrectangular pores are finely ridged between the septa along the outer lamina; on the inner lamina smooth along the outer surface, but ridged coincident with the septa on the inner surface. This is a distinctive distinguishing character from B. balanus. Scuta lack longitudinal striae and an adductor ridge; apices of both scuta and terga reflexed; the tergal spur is rounded. For interlaminary figures, see Davadie (1963, pl. 37). Common. Occurrence. Coralline Crag Formation (Darwin, 1854, p. 23), Red Crag Formation, Norwich Crag Formation to Recent. Coralline Crag at Sutton; Red Crag at Walton-on-the-Naze, Beggar’s Hollow; Norwich Crag at Easton Barents, Bramerton (Fig. 2H).
moderately prominent. For interlaminary figures, see Davadie (1963, pl. 26). Common. Occurrence. Common in the Coralline Crag Formation, Red Crag Formation, Norwich Crag Formation to Recent (Darwin, 1854, p. 17). Coralline Crag (Fig. 2I–L) at Ramsholt, Sudbourne; Red Crag at Sutton, Beggar’s Hollow, Walton-on-the-Naze; Norwich Crag at Covehithe. 3.7. Chirona hameri (Ascanius, 1767) (Figs. 3A–F and 6A–D) Description. No pores present. Shell smooth, large, ranging to 100.0 mm in height; shell rapidly disintegrates post-mortem into individual compartments (Fig. 6A–D); radii wide, regularly arched; scutum narrow, feebly striated longitudinally; tergum with narrow rounded spur. Occurrence. Darwin (1854, table on p. 6) recorded C. hameri from the Red Crag and Norwich Crag formations. Also found in glacial deposits to coasts of Yorkshire, round to Scotland and Ireland, to Recent. Red Crag at Sutton (Fig. 6A–D).
3.5. Balanus inclusus Darwin, 1854 (Figs. 2D and 4O–R) 3.8. Megabalanus tintinnabulum (Linne´, 1758) (Figs. 3K–N and 6E,F) Description. Only basis porous. Shell conical, elongated along rostro-carinal axis with flat basis or with median groove for attachment to, for example, coralline algae. Walls moderately thick, common strongly ribbed internally. Radii broad and straight or slightly oblique. Scutum lacks adductor ridge; tergum has a rather narrow spur. Darwin (1851, p. 31) recognised two forms: either lateral walls much wider than carina, rostrum or carinolateral, or walls rough, longitudinally folded with summits of radii angular. Common. Occurrence. Coralline Crag Formation (Darwin, 1854, p. 31) and Red Crag Formation (Table 1). Coralline Crag at Gedgrave (Fig. 2D), Sutton, Boyton; Red Crag at Walton-on-the-Naze.
Description. Walls, basis and radii porous. Shell large, usually cylindrical or slightly conical, ribbed longitudinally. The orifice varies from trigonal to rhomboidal; parietal pores are rather large and rectangular. Radii are uncommonly transverse. Scuta triangular with deep concentric growth lines; the articular ridge is broad and reflexed; terga have a narrow median spur with straight margins projecting beyond the basal margin. For interlaminary figures, see Davadie (1963, pls. 2, 3). Uncommon. Occurrence. Red Crag Formation (Darwin, 1854, p. 14) to Recent. Red Crag at Sutton (Fig. 6E and F), Beggar’s Hollow, Butley, Waltonon-the-Naze.
3.6. Concavus concavus (Bronn, 1831) (Figs. 2I–L and 5)
3.9. Conopea calceola (Ellis, 1758) (Fig. 6G–N and 7A–D)
Description. A large shell, may exceed c. 40.0 mm in height by 20.0 mm in basal diameter, ranging from smooth to longitudinally rugged; walls and basis porous; orifice small, ranging from rhomboidal to subtrigonal; radii narrow and commonly oblique, alae less oblique. These two characters readily distinguish C. concavus from M. tintinnabulum. Scutum and tergum have apicobasal striae; the tergum has a deeply grooved spur projecting beyond the basal margin; the scutal adductor ridge may be very to
Description. Shell rather small, walls and basis porous, elongated along rostro-carinal axis; basis boat-shaped and commonly grooved for attachment to gorgonids, etc. No fossil opercular valves were available to Darwin. In Recent specimens the scutum has a small, deep pit for the internal depressor muscle. Uncommon. Occurrence. Coralline Crag Formation (Darwin, 1854, p. 15), Norwich Crag Formation (Fig. 6G–N) to Recent. Coralline Crag at Sutton.
Fig. 7. (A–D) Conopea calceola (Ellis) (after Darwin, 1854, pl. 1, figs 2a–2d). (A) Complete shell; (B) Spur of tergum; (C) scutum, internal view; (D) tergum, internal view; (E–I) Conopea spongicola (Brown) (after Darwin, 1854, pl. 1, figs 3a–3e). (E and H) Scutum, external and internal views; (F and I) tergum, external and internal views; (G) shell, lateral view, enlarged. (J–O) Acasta undulata Darwin (after Darwin, 1854, pl. 2, figs 6a–6f). (J) spinose rostrum, external view; (K) lateral compartment, smooth variety; (L) basal cup; (M and N) scutum, internal and external views; (O) tergum, external view. Presumed 1 except where stated otherwise.
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Fig. 8. Acasta undulata Darwin, BMNH I.788, Coralline Crag Formation, Sutton, Suffolk, mainly disarticulated plates. Scale bar represent 10 mm.
3.10. Conopea spongicola (Brown, 1827) (Fig. 7E–I) Description. Shell small, c. 0.8 mm along the rostro-carinal axis, sub-cylindrical; walls and basis porous; walls generally smooth; orifice toothed, trigonal. Radii and alae oblique. Scuta have fine apico-basal striae. Terga have narrow, produced apex without a longitudinal furrow and truncated spur. For interlaminary figures, see Davadie (1963, pl. 25). Occurrence. Coralline Crag Formation, Red Crag Formation to Recent of south-west England and Wales (Darwin, 1854, p. 16). Coralline Crag at Sutton; Red Crag at Little Oakley, Walton-on-theNaze. 3.11. Acasta undulata Darwin, 1854 (Figs. 7J–O and 8) Description. No complete specimens of this sponge-associated species were known to Darwin (1854, p. 34). Compartments are generally smooth, but may be studded with hook-like processes.
The rostrum is wide, with narrow, sharp-tipped radii; basis cupshaped, with a diameter of up to 15.0 mm. Scuta triangular with four or five sharp apico-basal furrows, the intervening ridges are striated; terga about half the width of the valve. Uncommon. Occurrence. Coralline Crag (Darwin, 1854, p. 34) and Red Crag formations. Coralline Crag at Sutton (Fig. 8); Red Crag at Oakley. 3.12. Coronula barbara Darwin, 1854 (Figs. 6O,P and 9A,B) Description. Walls porous. Shell crown-shaped, longitudinal ribs on the compartments are convex, prominent and crossed by more prominent growth ridges. The internal surface presents a complicated series of folds and cavities; for a more detailed description of these, see Darwin (1854, pp. 37–40). Opercular valves not articulated together. The species is commensal with whales. Uncommon. Occurrence. Red Crag Formation (Darwin, 1854, p. 38) (Fig. 6O and P) at Bawdsey, Sutton.
Fig. 9. (A and B) Whale barnacle Coronula barbara Darwin (after Darwin, 1854, pl. 2, figs 8b, a, respectively.). (A) Rostrum, internal view, 1; (B) rostrum, external view, 2. (C– E) Coral barnacle Megatrema anglicum (G.B. Sowerby) (after Darwin, 1854, pl. 2, figs 7a-7c). (C) Apertural view, 4; (D) scutum, internal view; (E) tergum, internal view; (F) wart barnacle Verruca stroemia (Mu¨ller) (after Darwin, 1854, pl. 2, fig. 9a), valves arrayed in association. Key: A, rostrum; B, carina; S, moveable scutum; S0 , scutum fixed; T, moveable tergum; T0 , tergum fixed. Presumed 1 except where stated otherwise.
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Fig. 10. (A) Megatrema anglicum (G.B. Sowerby), BMNH I.15948, Coralline Crag Formation, Ramsholt, Suffolk; embedded in the scleractinian coral Cryptangia woodi MilneEdwards and Haime and the bryozoan Cellepora sp. (B, C and M–P) Scalpellum magnum Darwin. (B and C) BMNH In35704, Coralline Crag Formation, Sudbourne, Suffolk, carina; (M and N) BMNH In.35707, Coralline Crag Formation, Sudbourne, Suffolk, upper latus; (O and P) BMNH In.35775, Coralline Crag Formation, Sutton, Suffolk, marginal carina; scale bar represents 5 mm. (D–L) Verruca stroemia (Mu¨ller), BMNH I.786, Coralline Crag Formation, Sutton, Suffolk, plates. (Q and R) Lepas delicatula Withers, BMNH In.37138, Coralline Crag Formation, Sudbourne, Suffolk, plates (see also Fig. 12); scale bar represents 3 mm. Scale bars represent 10 mm unless stated otherwise.
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Fig. 11. Scalpellum magnum Darwin (after Darwin, 1851, pl. 1, fig. 1a–n). (A) Restored capitulum and peduncle, 1; (B) carina, dorsal view; (C) right scutum; (D) right tergum; (E) upper latus; (F) carina, lateral view. (G–J) latus and external view of rostra, narrow (G and I) and broad (H and J). (K–N) Carinal latus in outside (K narrow, M broad) and inside views (L). Most images enlarged; compare with (A).
3.13. Megatrema anglicum (G.B. Sowerby, 1823) (Figs. 9C–E and 10A) Description. A coral-inhabiting species. Basal part porous. The exposed part of the shell is steeply conical in juveniles, becoming flat or low conical; plicated almost to a small, narrow, oval orifice. In fossil forms the basal part is conical, c. 0.06 mm in diameter, ‘‘. . . is almost wholly embedded, but in Recent specimens it is generally exerted’’ (Darwin, 1851, p. 36). Terga have an acute apex and the spur extends a little beyond the basal margin. Fairly common. Occurrence. Coralline Crag Formation to Recent (Darwin, 1854, p. 36). Coralline Crag at Ramsholt (Harper, 2012, fig. 1; Fig. 10A herein).
3.15. Scalpellum magnum Darwin, 1851 (Figs. 10B,C,M–P and 11) Description. No complete capitulum was known to Darwin (1851, p. 18) who presumed the number of valves present to be 14 and that the capitula length reached about 40.0 mm. The principal valves are as follows. Carina: tectum rounded in section, widening towards the rounded basal margin; the parietes extend at an obtuse angle to about one third of the entire length of the valve.
3.14. Verruca stroemia (Mu¨ller, 1776) (Figs. 9F and 10D–L) Description. The wart barnacles are sessile forms composed of a rostrum and carina on each of which, on one side, is an articulated scutum and a tergum, respectively, while on the other side the scutum and tergum are immovably attached; this pattern can be on either side, arbitrarily. Margins ribbed, with the ribs extending as interlocking ‘spines’. Fairly common. Occurrence. Coralline Crag Formation, Red Crag Formation and interglacial deposits to Recent (Darwin, 1854, p. 42). Coralline Crag at Sutton (Fig. 10D–L); Red Crag at Walton-on-the-Naze.
Fig. 12. Lepas delicatula Withers (after Withers, 1953, pl. 58, figs 13a, b, 14a, b; see also Fig. 10Q, R herein). (A and D) BMNH In. 37138, holotype, outer (A) and side views of incomplete carina. (B and C) BMNH In. 37139, outer (B) and side views of basal part of carina. All 4.
Fig. 13. Scanning electron micrographs of the trace fossil Rogerella isp., probable spoor of acrothoracian barnacles (modified after Donovan, 1988, fig. 6), BMNH In.63653. (A) Wide, oval borings infilled with quartz grains (compare with Schlaudt and Young, 1960, pl. 119), 100. (B) Narrow, elongate, slit-like borings (compare with Bromley, 1970, fig. 4e (upper)), 64. (C) Enlargement of a clean, sock-shaped boring of the type shown in (A), 510. All specimens coated with 60% gold-palladium.
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Scuta: elongate trapezoid, length about four times the width; cross section slightly convex; the umbo is about one third to one quarter distant from the apex, a nearly straight occludent margin extends beyond the umbo; a ridge separates a short concave tergal margin from the sinuous lateral margin. Terga: triangular to crescent-shaped; the carinal margin is straight to slightly convex; occludent and scutal margins are slightly convex; a weak apico-basal ‘line’, dividing growth lines, runs parallel to the carinal margin. Upper latera: flat, subpentagonal, with straight tergal, carinal and scutal margins; the umbo is central with ridges extending to basal angles. Rostral latera flat, sub-triangular, rounded apically. The peduncle in this genus is invariably surrounded by numerous rows of small, overlapping, scale-like plates. According to Darwin (1854, p. 21), there is some variation in size between specimens from different localities. Fairly common. Occurrence. Lower part of the Coralline Crag Formation (Darwin, 1851, p. 18) (Fig. 10B and C); Red Crag Formation, Walton-on-theNaze. 3.16. Lepas delicatula Withers, 1953 (Figs. 10Q,R and 12) Description. This genus has five valves, of which only the carina was known to Withers (1953). Carina comparatively broad throughout, only a little constricted either side of the umbo; base broadly rounded; basal plate no wider than the widest part of the upper limb and directed inwards at a wide angle. Peduncle smooth. Occurrence. Only known from the type locality at Coralline Crag Formation at Sudbourne, Suffolk (Figs. 10Q,R and 12). 3.17. Trace fossil Rogerella isp. (Fig. 13) Description. Borings in shelly substrates produced by acrothoracian barnacles. The borings have a slot-like surface expression (aperture) and a sock-like section (Fig. 13C). Two morphologies are recognised, ‘wide’ (Fig. 13A) and ‘narrow’ (Fig. 13B). Occurrence. Only reported from Red Crag Formation at Waltonon-the-Naze (Donovan, 1988), but probably more widespread. Acknowledgement We thank Mr. Harry Taylor of the Photographic Unit of the Natural History Museum for providing the many images included herein. References Alessandri, G. de, 1895. Contribuzione allo studio dei Cirripedia fossili d’Italia. Bollettino della Societa` Geologica Italiana 13, 234–314. Ascanius, P., 1767. Icones rerum naturalium, quas in itinere Orientali depingi/ curavit P. Forska˚l; post mortem auctoris ad Regis mandatum æri incises edidit Carsten Niebuhr. Ex officina Mo¨lleri, Hauniæ 15 pp. Bowen, D.Q. (Ed.), 1999. A revised correlation of Quaternary deposits in the British Isles. Geological Society Special Report 23, 174 pp. Bromley, R.G., 1970. Borings as trace fossils and Entobia cretacea Portlock, as an example. In: Crimes, T.P., Harper, J.C. (Eds.), Trace Fossils Geological Journal Special Issue 3. , 49–90. Bronn, H.G., 1831. Italiens Tertia¨r-Gebilde und deren organische Einschlu¨sse. Karl Groos, Heidelberg xii + 176 pp.
Brown, T., 1827. Illustrations of the Conchology of Great Britain and Ireland, Drawn from Nature. Edinburgh and London, x + 237 pp. + 53 pls with descriptive letterpress. Bruguie`re, J.G., 1789. Histoire naturelle des Vers. Encyclopedia Methodique (Zoologie), Tome 1. Paris, xviii + 757 pp. Collins, J.S.H., 1963a. A guide to the identification of Crag (Plio/Pleistocene) acorn barnacles. Freelance Geological Association Journal 2 (3) 13–15. Collins, J.S.H., 1963b. A report of the cirripedes found in an exposure of the Red Crag at Beggar’s Hollow, Ipswich, Suffolk. Freelance Geological Association Journal 2 (3) 16–17. Collins, J.S.H., 1989. Some barnacles from the Red Crag at Beggar’s Hollow, Suffolk. Proceedings of the Geologists’ Association 100, 217. Cornwall, I., 1956. Identifying fossil and recent barnacles by the figures in the shell. Journal of Paleontology 30, 646–651. Cornwall, I., 1959. More shell figures and notes on barnacles. Canadian Journal of Zoology 37, 401–406. Cornwall, I., 1960. Barnacle shell figures and repairs. Canadian Journal of Zoology 38, 827–832. da Costa, E.M., 1778. Historia naturalis Testaceorum Brittaniae. Privately published, London, pp. 254. Curry, D., Adams, C.G., Boulter, M.C., Dilley, F.C., Eames, F.E., Funnell, B.M., Wells, M.K., 1978. A correlation of the Tertiary rocks in the British Isles. Geological Society Special Report 12, 78 pp. Darwin, C., 1851. A monograph on the fossil Lepadidae or, pedunculated cirripedes of Great Britain. Monograph of the Palaeontographical Society 5 (13) , vi + 88 pp. Darwin, C., 1854. A monograph of the fossil Balanidae and Verrucidae of Great Britain. Monograph of the Palaeontographical Society 8 (30) , 44 pp. Darwin, C., 2009. Monographs on the Fossil Lepadidae, Balanidae and Verrucidae. Cambridge University Press, Cambridge 86 + 44 + 2 pp. Davadie, C., 1963. Syste´matique et structure des balanes fosilles d’Europe et d’Afrique, 7e. E´ditions du Centre National de la Recherche Scientifique, Paris 146 pp. Dixon, R. (Ed.), 2012. A Celebration of Suffolk Geology: GeoSuffolk 10th Anniversary Volume. GeoSuffolk, Ipswich, viii + 475 pp. Donovan, S.K., 1988. Palaeoecology and taphonomy of barnacles from the PlioPleistocene Red Crag of East Anglia. Proceedings of the Geologists’ Association 99, 279–289. Donovan, S.K., 1989. Palaeoecology and significance of barnacles in the Pliocene Balanus Bed in Tobago, West Indies. Geological Journal 24, 239–250. Donovan, S.K., 2003. Charles Taylor Trechmann and the development of Caribbean geology between the wars. Proceedings of the Geologists’ Association 114, 345– 354. Ellis, J., 1758. An account of several rare species of barnacles. Philosophical Transactions of the Royal Society of London 50, 845–855. Gruvel, A., 1905. Monographie des Cirre`pedes ou The´ocostrace´s. Paris, 472 pp. Harper, E.M., 2012. Biotic interaction in the Suffolk crags. 231–241. In: Dixon, R. (Ed.), A Celebration of Suffolk Geology: GeoSuffolk 10th Anniversary Volume. GeoSuffolk, Ipswich, viii + 475 pp. Jackson, T.A., Donovan, S.K., 1994. Tobago. 193–207. In: Donovan, S.K., Jackson, T.A. (Eds.), Caribbean Geology: An Introduction. University of the West Indies Publishers’ Association, Kingston, iii + 289 pp. Linne´, C., 1758. Systema Naturae, Volume 1, Tenth ed. Holmiae, 824 pp. Miller III, W., Brown, N.A., 1979. The attachment scars of fossil balanids. Journal of Paleontology 53, 208–210. Mu¨ller, O.F., 1776. Zoologiae Danicae Prodromus, seu Animalium Daniae et Norvegiae, indigenarum characters, nomina, et synonyma imprimis popularium. Typis Hallageriis, Havniae xxxii + 282 pp. Pilsbry, H.A., 1916. The sessile barnacles (Cirripedia) contained in the collections of the U.S. National Museum; including a monograph of the American species. U.S. National Museum Bulletin 93, 1–366. Rainbow, P.S., 1984. An introduction to the biology of British littoral barnacles. Field Studies 6, 1–51. Reid, C., 1890. The Pliocene Deposits of Britain. Memoirs of the Geological Survey of the United Kingdom. Her Majesty’s Stationery Office, London viii + 326 pp. Schlaudt, C.M., Young, K., 1960. Acrothoracic barnacles from the Texas Permian and Cretaceous. Journal of Paleontology 34, 903–907. Southward, A.J., 2008. Barnacles. Synopses of the British Fauna (new series), vol. 57. , viii + 140 pp. Sowerby, G.B., 1820–1825. The Genera of Recent and Fossil Shells, for the use of students in Conchology and Geology/Commenced by James Sowerby . . . and continued by G.B. Sowerby . . . with . . . plates by James Sowerby and J.D.C. Sowerby. Four volumes. London, 267 pls with descriptive letterpress. Trechmann, C.T., 1934. Tertiary and Quaternary beds of Tobago, West Indies. Geological Magazine 71, 481–493. Withers, T.H., 1953. Catalogue of Fossil Cirripedia in the Department of Geology. Vol. 3. Tertiary. British Museum (Natural History), London xv + 396 pp.
Contents lists available at ScienceDirect
Proceedings of the Geologists’ Association journal homepage: www.elsevier.com/locate/pgeola
An illustrated guide to the fossil barnacles (Cirripedia) from the Crags (Plio-Pleistocene) of East Anglia Joe S.H. Collins a,b, Stephen K. Donovan c,*, Claire Mellish a a
Department of Earth Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD, UK 8, Shaw’s Cottages, Perry Rise, Forest Hill, London SE23 2QN, UK c Department of Geology, Naturalis Biodiversity Center, Leiden, The Netherlands b
A R T I C L E I N F O
A B S T R A C T
Article history: Received 5 November 2013 Received in revised form 27 January 2014 Accepted 29 January 2014 Available online 1 March 2014
The Plio-Pleistocene Crag deposits of East Anglia include a wealth of shelly remains, including barnacles, preserved variously as complete shells, their disarticulated plates and trace fossils. Herein, we present a field guide to these distinctive fossils, with diagnoses of all known taxa recorded from the Crags of East Anglia, supported by both line drawings and photographs. The known stratigraphic and geographic distribution within the study area are tabulated. Recognised species include the sessile barnacles Armatobalanus bisulcatus (Darwin), A. dolossus (Darwin), Balanus balanus (Linne´), B. crenatus Bruguie`re, B. inclusus Darwin, Concavus concavus (Bronn), Chirona hameri (Ascanius), Megabalanus tintinnabulum (Linne´), Conopea calceola (Ellis), Co. spongicola (Brown), Acasta undulata Darwin, Coronula barbara Darwin, Megatrema anglicum (G.B. Sowerby) and Verruca stroemia (Mu¨ller) (=14 species); two pedunculate forms, Scalpellum magnum Darwin and Lepas delicatula Withers; and the boring Rogerella isp. The greatest diversity of species is found in the Coralline Crag and Red Crag formations, both yielding 11 species, although only four are common to both. Barnacles are poorly represented in other Crag deposits. ß 2014 The Geologists’ Association. Published by Elsevier Ltd. All rights reserved.
Keywords: Pedunculate barnacles Sessile barnacles Rogerella Stratigraphy
1. Introduction The Crags of East Anglia are, locally, amongst the most fossiliferous Plio-Pleistocene deposits in northern Europe. Although best known for their benthic molluscs and tetrapods, they include a range of marine invertebrates that rarely receive detailed discussion. Amongst these groups, the commonest arthropods are the shells of barnacles which occur either infesting a range of substrates or as disarticulated plates. Indeed, the acorn barnacles are such a distinctive part of the East Anglian Crags that the presence of common Megabalanus tintinnabulum (Linne´) in the Pliocene or Pleistocene (Jackson and Donovan, 1994, p. 203) of Tobago, West Indies, in part led Charles Taylor Trechmann and others (Donovan, 2003, p. 351) to call these deposits the Tobago Crag (now Rockly Bay Formation; Donovan, 1989). Trechmann (1934, p. 483) described these West Indian deposits thus: ‘‘. . . the typical Tertiary red or brown nodular clay or Tobago ‘‘Crag’’ as it has been called, full of Balani’’ which form by far the greater part of the assemblage. The ‘Proceedings of the Geologists’ Association’ has previously published discussions of the palaeoecology and taphonomy of this
* Corresponding author at: Naturalis Biodiversity Center, Postbus 9517, 2300 RA Leiden, The Netherlands. Tel.: +31 71 568 7642. E-mail address: [email protected] (S.K. Donovan).
important group of Crag fossils (for example, Donovan, 1988; Collins, 1989); herein, we examine the systematics and identification of the barnacles from the Crags of East Anglia. This contribution has its origins in a paper published by Collins (1963a) at a time when high definition photographs were not available of the species involved; this was supplemented by a report of a field study (Collins, 1963b). Herein, we present an illustrated field guide to the barnacles of the Crags, enabling their easier identification, and discuss something of their occurrence based on our own palaeontological studies and accounts of extant members of the same species. Illustrations include photographs of specimens in the Natural History Museum, London (BMNH), and relevant drawings from Darwin (1851, 1854; reprinted 2009) and other relevant references. Of the 16 species of barnacles known from the Crags, 14 were sessile forms, comprised of those commonly known as acorn, sponge, coral, wart and whale barnacles (Fig. 1). There are also two pedunculate (stalked) forms allied to the goose barnacle. The shell (capitulum) of the barnacles involved rapidly breaks down into separate plates or valves after death. Of these, Scalpellum magnum Darwin has 14 plates, some of which have the same name as the sessile species. The second pedunculate species is Lepas delicatula Withers, which has five plates. Further, one trace fossil, Rogerella isp., represents the borings of acrothoracian barnacles.
0016-7878/$ – see front matter ß 2014 The Geologists’ Association. Published by Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.pgeola.2014.01.004
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Fig. 1. Features of the shell of the balanid barnacles (after Collins, 1963a, pl. 2). (A and B) Gross morphology of Balanus. (A) Lateral view; (B) section across the shell X-X (see A) showing the mode of imbrications of the compartments (six in this genus) (redrawn after Pilsbry, 1916, fig. 7). The rostrum and rostrolateral compartments (RL) are combined; it is customary to refer to this composite compartment simply as the ‘rostrum’. Key: a, alae; p, parietes; r, radii; C, carina; CL, carinolateral; L, lateral; R, rostrum; and RL, rostrolateral. (C–E) Redrawn after Darwin (1854, figs 2–4). (C) Compartment with two radii, serving either as a rostrolateral or as a rostrum combined with the rostrolaterals, as in Balanus. (D) Compartment with a radius and an ala, serving as a lateral or carinolateral compartment. (E) Compartment with two alae, serving as a carina (also as a rostrum in genera other than Balanus). F-M, redrawn, in part, after Darwin (1854, figs 5–7). (F–I) External (F and H) and interior views (G and I) of terga of various forms; (J–M) external (K and M) and interior views (J and L) of scuta of various forms. Key: bm, basal margin; cm, carinal margin; om, opercular margin; sm, scutal margin; tm, tergal margin; AdR, adductor ridge; AF, articular furrow; AM, (circular) pit for adductor muscle; Ap, apex; AR, articular ridge; DM, pit for lateral depressor muscle; and S, spur. (N and O) Sections, magnified many times, through parietes to show the arrangement of the septa and pores in two examples of shell construction, typical of Balanus crenatus Brugie`re (N) and Balanus balanus Linne´ (O).
2. The Cirripedia: morphology and methodology (Revised after Collins, 1963a, p. 13) The barnacles, or Cirripedia, form a predominant part of the arthropod assemblage throughout the Crag deposits. Whilst certain species of balanid are readily distinguishable, others may easily be confused, particularly those
that occur only as disarticulated plates. Specific determination may commonly be achieved by the recognition of either any one, or a combination of, a few major features. The general appearance of the balanid shell, whether smooth or ribbed, conical or cylindrical, and features such as the shape of the orifice and nature of the radii and alae, may, with practice, be
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Table 1 Stratigraphic distribution of Crag barnacles and a guide to the parts furnished with pores, where present (expanded after Collins, 1963a, Table 2; see also Reid, 1890, Table 9). The Wroxham Crag Formation was formerly called the Weybourne Crag; the Chillesford Crag is now the Chillesford Member of the Norwich Crag Formation (Bowen, 1999, Table 6). Only the Coralline Crag is considered entirely Pliocene (Curry et al., 1978, fig. 5). Extant
Cromer Forest Bed Fmn.
Wroxham Crag Fmn.
Chillesford Member
Norwich Crag Fmn.
Red Crag Fmn.
Coralline Crag Fmn.
X X X X X X X X
X
X X
X X X X
Pores Walls
Armatobalanus bisulcatus (Darwin) Armatobalanus dolosus (Darwin) Balanus balanus (Linne´) Balanus crenatus Bruguie`re Balanus inclusus Darwin Concavus concavus (Bronn) Chirona hameri (Ascanius) Megabalanus tintinnabulum (Linne´) Conopea calceola (Ellis) Conopea spongicola (Brown) Acasta undulata Darwin Coronula barbara Darwin Megatrema anglicum (Sowerby) Verruca stroemia (Mu¨ller) Scalpellum magnum Darwin Lepas delicatula Withers Rogerella isp.
X X
X X
X X
X X X X X
X
X X X
X X X
X X X X
X X
X
X
X
sufficient evidence on which to base a specimen’s identification (for explanation of morphological terminology, see Fig. 1). Nevertheless, these features should not be relied upon entirely, since the appearance of the shell varies, as observations of living forms show, according to habitat. For example, cramped conditions give rise to distorted forms, whilst exposed individuals commonly develop thickened shells; the nature of the substrate may also influence form of growth. The nature of the opercular valves (terga and scuta) of balanids, when preserved, is generally sufficient to provide tolerable determination. They are seldom preserved in situ, but when these valves are not obvious, it is always sound practice to probe carefully into the orifice of the shell to see if they are among the infilling debris. However, in many cases the valves are lost completely and it is necessary to resort to an examination of the shell. The compartments (walls or parietes), basis and radii of the shell are sometimes composed of inner and outer laminae which are joined together by septa, forming a series of tubes or pores. The presence or absence of these pores and the construction of the septa provides a useful, albeit not always final, indication of the species (Table 1). The relative angle of the ala and radius to the paries (plural, parietes) is another important consideration. The balanids attach to the substrate by a basal plate, or basis; if an individual is lost from a substrate, it may still leave behind an attachment scar as evidence (Miller and Brown, 1979). Another aid to identification of Recent and fossil balanids is the use of interlaminate figures, a name introduced by Cornwall (1959, p. 401). Under a microscope, polished sections ‘‘cut at right angles to the line of growth . . . [show] figures [which] can be seen between the outer and inner laminae of the shell as lighter areas on the polished surface’’ (Cornwall, 1956, p. 646). These figures, first noticed by Alessandri (1895), were investigated by Gruvel (1905), and subjected to intense study by both Cornwall (1956, 1959, 1960) and Davadie (1963), who recognised their specific individuality. Although no intensive work on British taxa seems to have been attempted, figures of some of the species present in the Crags were illustrated by Davadie (1963) and these occurrences are noted in the text. For further discussion of the extant British barnacles, including some of the species discussed below, see Rainbow (1984) and Southward (2008). For simplicity, we have eschewed a full systematic presentation; rather, we provide brief
Basis
Radii
X X X X X
X X
X X X
X X X
X
X X X X X
X
descriptive diagnoses of all taxa supplemented by photographs and some illustrations from earlier sources. 3. Cirripede species of the Crags The stratigraphic distribution of the British Plio-Pleistocene members of the Cirripedia, together with a simple guide to the parts furnished with pores, is presented in Table 1. Disarticulated plates may be common locally, particularly in coarse-grained, reworked sands at the base of a bed or unit. It should be noted that some of the living species no longer inhabit British waters. Recorded ranges are given appropriate to British occurrences only; these are based on published records, information on specimen labels in the BMNH and personal observations of the authors. Upto-date information on certain of the localities in Suffolk may be gleaned from Dixon (2012). Species that the authors consider to abundant (‘common’) are so indicated below. 3.1. Armatobalanus bisulcatus (Darwin, 1854) (Figs. 2A–C and 3O–V) Description. Only basis porous. Shell subconical, ranging to c. 25.0 mm across basal diameter, weakly to strongly plicate in the lower half; upper margins of radii oblique and smooth; sutural edges smooth. Scuta narrow, with two to four longitudinal furrows; terga have a short, broad spur half the width of the valve. The subspecies Armatobalanus bisulcatus plicatus Darwin, 1854, is more regularly conical and has deep plications extending full height of walls; narrow radii have very oblique upper margins; in young specimens the diameter of the orifice is much reduced. For interlaminary figures, see Davadie (1963, pl. 42). Occurrence. Both subspecies occur in the Coralline Crag (Darwin, 1854, p. 26), Red Crag and Norwich Crag formations (Table 1). Coralline Crag at Gedgrave, Ramsholt (Fig. 2A), Boyton, Sutton (Fig. 2B and C); Red Crag at Sutton, Beggar’s Hollow, Walton-onthe-Naze, Shottisham; Norwich Crag, Bramerton. 3.2. Armatobalanus dolossus (Darwin, 1854) (Figs. 2F,G and 3G–J) Description. Only basis porous. Shell ranging to c. 0.6 mm across basal diameter, similar to A. bisulcatus, but rather more conical, orifice elongate oval in outline; radii with oblique upper margins.
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Fig. 2. (A–C) Armatobalanus bisulcatus (Darwin). (A) BMNH I.14823, syntype, Coralline Crag Formation, Ramsholt, Suffolk; attached to Talochlamys multistriata (Poli). (B and C) BMNH 59382, Coralline Crag Formation, Sutton, Suffolk. (D) Balanus inclusus Darwin, BMNH I.14836, syntype, Coralline Crag Formation, Gedgrave, Suffolk; scale bar represents 5 mm. (E) Balanus balanus (Linne´), BMNH T1011, glacial deposits, Garvel Park, Greenock, Scotland. (F and G) Armatobalanus dolossus (Darwin), BMNH I.794, Red
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Fig. 3. (A–F) Chirona hameri (Ascanius) (after Darwin, 1854, pl. 2, figs 1a, 1b, pl. 1, figs 7a–7d, respectively). (A) External view of lateral compartment; (B) internal view of carino-lateral compartment; (C and E) scutum, internal and external views; (D and F) tergum, internal and external views; (G–J) Armatobalanus dolossus (Darwin) (after Darwin, 1854, pl. 2, figs 3a–3d); (G) internal view of rostrum, much enlarged; (H) part of basal plate, much enlarged; (I) external view of scutum; (J) external view of tergum. (K–N) Megabalanus tintinnabulum (Linne´) (after Darwin, 1854, pl. 1, figs 1a–1d). (K) Shell, small specimen; (L) internal view of rostrum, 1; (M) internal view of scutum; (N) internal view of tergum. (O–V) Armatobalanus bisulcatus (Darwin) (after Darwin, 1854, pl. 2, figs 2a–2h). (O) Shell, 1.5; (P) A. b. plicatus, shell, 3; (Q) young shell, about 7; (R) external view of rostrum, 1.5; (S and U) scutum, external and internal views; (T and V) tergum, external and internal views. Presumed 1 except where stated otherwise.
Scuta smooth; grooved spur of terga narrower, one third width of valve and rather more elongate than that of A. bisulcatus. Margins of the basal plate bifurcated. For interlaminary figures, see Davadie (1963, pl. 50). Occurrence. Red Crag Formation and Norwich Crag Formation (=Mammaliferous Crag sensu Darwin, 1854, p. 28). Red Crag at Sutton, Beggar’s Hollow, Walton-on-the-Naze, Oakley; Norwich Crag at Postwick, Weybourne. 3.3. Balanus balanus (Linne´, 1758) (Figs. 2E and 4A–G) Description. Only walls porous. Shell subconical; generally ribbed longitudinally; orifice almost circular; summits of radii almost parallel to basis. Parietal pores distinctive, infilled apically,
usually rectangular towards the base with longitudinal ribs between the septa on the outer lamina; coarser ribs extend along upper surface of the inner lamina. ‘‘As the parietes rest on the basis, the circumference of the latter becomes marked in a very peculiar manner [Fig. 4C], by the basal edges of the parietal septa. Hence the basis of this species can be distinguished from that of every other sessile cirripede . . .’’ (Darwin, 1854, p. 22). Apex of tergum produced; a rather wide, grooved spur and concave sutural margin; scutum longitudinally striated. Balanus porcatus da Costa, 1778, is a junior synonym of B. balanus (see Pilsbry, 1916, p. 149). Occurrence. Red Crag Formation and Norwich Crag Formation, glacial deposits to Recent (Darwin, 1854, p. 21). Red Crag Formation at Sutton and Beggar’s Hollow; Norwich Crag Formation at Brammerton and Thorpe.
Crag Formation, Sutton; attached to Neptunea contraria (Linne´). (H) Balanus crenatus Bruguie`re, BMNH 44396, Norwich Crag Formation, Bramerton, Norfolk; attached to Nucella lapillus (Linne´). (I–L) Concavus concavus (Bronn), BMNH In.19079_05, Coralline Crag Formation, Suffolk, in lateral (I and J) and apertural views. Scale bars represent 10 mm except where quoted otherwise.
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Fig. 4. (A–G) Balanus balanus Linne´ (after Darwin, 1854, pl. 1, figs 5a–5g). (A) Shell, 1; (B) part of basal margin of wall, much enlarged; (C) part of basal plate, much enlarged; (D and E) scutum, external and internal views; (F and G) tergum, external and internal views. (H–N) Balanus crenatus Brugie`re (after Darwin, 1854, pl. 1, figs 6a–6g). (H) Shell, 2; (I) part of basal margin of wall, much enlarged; (J) portion of thick basal plate, much enlarged; (K and L) scutum, external and internal views; (M and N) tergum, external and internal views. (O–R) Balanus inclusus Darwin (after Darwin, 1854, pl. 2, figs 5a–5d). (O) Shell, about 3; (P) basis; (Q) elongated shell; (R) base of elongated shell with narrow, furrowed basis. Presumed 1 except where stated otherwise.
Fig. 5. Balanus concavus (Bronn) (after Darwin, 1854, pl. 1, figs 4a–4p). (A) Complete shell; (B) internal part of the carina (left), of the carino-lateral compartment and part of the lateral compartment, showing the raised borders (r) on the rostral side of the sutures; (C) shell with less prominent longitudinal ridges than (A); (D) smooth-shelled variety; (E and I) external views of scuta; (F, L and N) internal views of scuta; (G) internal view of tergum; (H, J, K and M) external views of terga; (O) detail of scutum at rostral corner (highly magnified). Presumed 1 except where stated otherwise.
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Fig. 6. (A–D) Chirona hameri (Ascanius), BMNH I.795, Red Crag Formation, Sutton, Suffolk, plates. (E and F) Megabalanus tintinnabulum (Linne´), BMNH 14734b (E) and a (F); Red Crag Formation, Sutton, Suffolk, plates in external (E) and internal (F) views. (G–N) Conopea calceola (Ellis), BMNH I.776, Norwich Crag Formation, specimen broken. (O and P) Coronula barbara Darwin, BMNH I.804, syntype, Red Crag Formation. (O) External view; (P) internal view. Scale bars represent 10 mm.
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3.4. Balanus crenatus Bruguie`re, 1789 (Figs. 2H and 4H–N) Description. Only walls porous. Shell highly variable from conical with ribbed walls, depressed and smooth, much elongated and conical, or club-shaped, according to population density and/or substrate; radii with oblique summits. Subrectangular pores are finely ridged between the septa along the outer lamina; on the inner lamina smooth along the outer surface, but ridged coincident with the septa on the inner surface. This is a distinctive distinguishing character from B. balanus. Scuta lack longitudinal striae and an adductor ridge; apices of both scuta and terga reflexed; the tergal spur is rounded. For interlaminary figures, see Davadie (1963, pl. 37). Common. Occurrence. Coralline Crag Formation (Darwin, 1854, p. 23), Red Crag Formation, Norwich Crag Formation to Recent. Coralline Crag at Sutton; Red Crag at Walton-on-the-Naze, Beggar’s Hollow; Norwich Crag at Easton Barents, Bramerton (Fig. 2H).
moderately prominent. For interlaminary figures, see Davadie (1963, pl. 26). Common. Occurrence. Common in the Coralline Crag Formation, Red Crag Formation, Norwich Crag Formation to Recent (Darwin, 1854, p. 17). Coralline Crag (Fig. 2I–L) at Ramsholt, Sudbourne; Red Crag at Sutton, Beggar’s Hollow, Walton-on-the-Naze; Norwich Crag at Covehithe. 3.7. Chirona hameri (Ascanius, 1767) (Figs. 3A–F and 6A–D) Description. No pores present. Shell smooth, large, ranging to 100.0 mm in height; shell rapidly disintegrates post-mortem into individual compartments (Fig. 6A–D); radii wide, regularly arched; scutum narrow, feebly striated longitudinally; tergum with narrow rounded spur. Occurrence. Darwin (1854, table on p. 6) recorded C. hameri from the Red Crag and Norwich Crag formations. Also found in glacial deposits to coasts of Yorkshire, round to Scotland and Ireland, to Recent. Red Crag at Sutton (Fig. 6A–D).
3.5. Balanus inclusus Darwin, 1854 (Figs. 2D and 4O–R) 3.8. Megabalanus tintinnabulum (Linne´, 1758) (Figs. 3K–N and 6E,F) Description. Only basis porous. Shell conical, elongated along rostro-carinal axis with flat basis or with median groove for attachment to, for example, coralline algae. Walls moderately thick, common strongly ribbed internally. Radii broad and straight or slightly oblique. Scutum lacks adductor ridge; tergum has a rather narrow spur. Darwin (1851, p. 31) recognised two forms: either lateral walls much wider than carina, rostrum or carinolateral, or walls rough, longitudinally folded with summits of radii angular. Common. Occurrence. Coralline Crag Formation (Darwin, 1854, p. 31) and Red Crag Formation (Table 1). Coralline Crag at Gedgrave (Fig. 2D), Sutton, Boyton; Red Crag at Walton-on-the-Naze.
Description. Walls, basis and radii porous. Shell large, usually cylindrical or slightly conical, ribbed longitudinally. The orifice varies from trigonal to rhomboidal; parietal pores are rather large and rectangular. Radii are uncommonly transverse. Scuta triangular with deep concentric growth lines; the articular ridge is broad and reflexed; terga have a narrow median spur with straight margins projecting beyond the basal margin. For interlaminary figures, see Davadie (1963, pls. 2, 3). Uncommon. Occurrence. Red Crag Formation (Darwin, 1854, p. 14) to Recent. Red Crag at Sutton (Fig. 6E and F), Beggar’s Hollow, Butley, Waltonon-the-Naze.
3.6. Concavus concavus (Bronn, 1831) (Figs. 2I–L and 5)
3.9. Conopea calceola (Ellis, 1758) (Fig. 6G–N and 7A–D)
Description. A large shell, may exceed c. 40.0 mm in height by 20.0 mm in basal diameter, ranging from smooth to longitudinally rugged; walls and basis porous; orifice small, ranging from rhomboidal to subtrigonal; radii narrow and commonly oblique, alae less oblique. These two characters readily distinguish C. concavus from M. tintinnabulum. Scutum and tergum have apicobasal striae; the tergum has a deeply grooved spur projecting beyond the basal margin; the scutal adductor ridge may be very to
Description. Shell rather small, walls and basis porous, elongated along rostro-carinal axis; basis boat-shaped and commonly grooved for attachment to gorgonids, etc. No fossil opercular valves were available to Darwin. In Recent specimens the scutum has a small, deep pit for the internal depressor muscle. Uncommon. Occurrence. Coralline Crag Formation (Darwin, 1854, p. 15), Norwich Crag Formation (Fig. 6G–N) to Recent. Coralline Crag at Sutton.
Fig. 7. (A–D) Conopea calceola (Ellis) (after Darwin, 1854, pl. 1, figs 2a–2d). (A) Complete shell; (B) Spur of tergum; (C) scutum, internal view; (D) tergum, internal view; (E–I) Conopea spongicola (Brown) (after Darwin, 1854, pl. 1, figs 3a–3e). (E and H) Scutum, external and internal views; (F and I) tergum, external and internal views; (G) shell, lateral view, enlarged. (J–O) Acasta undulata Darwin (after Darwin, 1854, pl. 2, figs 6a–6f). (J) spinose rostrum, external view; (K) lateral compartment, smooth variety; (L) basal cup; (M and N) scutum, internal and external views; (O) tergum, external view. Presumed 1 except where stated otherwise.
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Fig. 8. Acasta undulata Darwin, BMNH I.788, Coralline Crag Formation, Sutton, Suffolk, mainly disarticulated plates. Scale bar represent 10 mm.
3.10. Conopea spongicola (Brown, 1827) (Fig. 7E–I) Description. Shell small, c. 0.8 mm along the rostro-carinal axis, sub-cylindrical; walls and basis porous; walls generally smooth; orifice toothed, trigonal. Radii and alae oblique. Scuta have fine apico-basal striae. Terga have narrow, produced apex without a longitudinal furrow and truncated spur. For interlaminary figures, see Davadie (1963, pl. 25). Occurrence. Coralline Crag Formation, Red Crag Formation to Recent of south-west England and Wales (Darwin, 1854, p. 16). Coralline Crag at Sutton; Red Crag at Little Oakley, Walton-on-theNaze. 3.11. Acasta undulata Darwin, 1854 (Figs. 7J–O and 8) Description. No complete specimens of this sponge-associated species were known to Darwin (1854, p. 34). Compartments are generally smooth, but may be studded with hook-like processes.
The rostrum is wide, with narrow, sharp-tipped radii; basis cupshaped, with a diameter of up to 15.0 mm. Scuta triangular with four or five sharp apico-basal furrows, the intervening ridges are striated; terga about half the width of the valve. Uncommon. Occurrence. Coralline Crag (Darwin, 1854, p. 34) and Red Crag formations. Coralline Crag at Sutton (Fig. 8); Red Crag at Oakley. 3.12. Coronula barbara Darwin, 1854 (Figs. 6O,P and 9A,B) Description. Walls porous. Shell crown-shaped, longitudinal ribs on the compartments are convex, prominent and crossed by more prominent growth ridges. The internal surface presents a complicated series of folds and cavities; for a more detailed description of these, see Darwin (1854, pp. 37–40). Opercular valves not articulated together. The species is commensal with whales. Uncommon. Occurrence. Red Crag Formation (Darwin, 1854, p. 38) (Fig. 6O and P) at Bawdsey, Sutton.
Fig. 9. (A and B) Whale barnacle Coronula barbara Darwin (after Darwin, 1854, pl. 2, figs 8b, a, respectively.). (A) Rostrum, internal view, 1; (B) rostrum, external view, 2. (C– E) Coral barnacle Megatrema anglicum (G.B. Sowerby) (after Darwin, 1854, pl. 2, figs 7a-7c). (C) Apertural view, 4; (D) scutum, internal view; (E) tergum, internal view; (F) wart barnacle Verruca stroemia (Mu¨ller) (after Darwin, 1854, pl. 2, fig. 9a), valves arrayed in association. Key: A, rostrum; B, carina; S, moveable scutum; S0 , scutum fixed; T, moveable tergum; T0 , tergum fixed. Presumed 1 except where stated otherwise.
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Fig. 10. (A) Megatrema anglicum (G.B. Sowerby), BMNH I.15948, Coralline Crag Formation, Ramsholt, Suffolk; embedded in the scleractinian coral Cryptangia woodi MilneEdwards and Haime and the bryozoan Cellepora sp. (B, C and M–P) Scalpellum magnum Darwin. (B and C) BMNH In35704, Coralline Crag Formation, Sudbourne, Suffolk, carina; (M and N) BMNH In.35707, Coralline Crag Formation, Sudbourne, Suffolk, upper latus; (O and P) BMNH In.35775, Coralline Crag Formation, Sutton, Suffolk, marginal carina; scale bar represents 5 mm. (D–L) Verruca stroemia (Mu¨ller), BMNH I.786, Coralline Crag Formation, Sutton, Suffolk, plates. (Q and R) Lepas delicatula Withers, BMNH In.37138, Coralline Crag Formation, Sudbourne, Suffolk, plates (see also Fig. 12); scale bar represents 3 mm. Scale bars represent 10 mm unless stated otherwise.
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Fig. 11. Scalpellum magnum Darwin (after Darwin, 1851, pl. 1, fig. 1a–n). (A) Restored capitulum and peduncle, 1; (B) carina, dorsal view; (C) right scutum; (D) right tergum; (E) upper latus; (F) carina, lateral view. (G–J) latus and external view of rostra, narrow (G and I) and broad (H and J). (K–N) Carinal latus in outside (K narrow, M broad) and inside views (L). Most images enlarged; compare with (A).
3.13. Megatrema anglicum (G.B. Sowerby, 1823) (Figs. 9C–E and 10A) Description. A coral-inhabiting species. Basal part porous. The exposed part of the shell is steeply conical in juveniles, becoming flat or low conical; plicated almost to a small, narrow, oval orifice. In fossil forms the basal part is conical, c. 0.06 mm in diameter, ‘‘. . . is almost wholly embedded, but in Recent specimens it is generally exerted’’ (Darwin, 1851, p. 36). Terga have an acute apex and the spur extends a little beyond the basal margin. Fairly common. Occurrence. Coralline Crag Formation to Recent (Darwin, 1854, p. 36). Coralline Crag at Ramsholt (Harper, 2012, fig. 1; Fig. 10A herein).
3.15. Scalpellum magnum Darwin, 1851 (Figs. 10B,C,M–P and 11) Description. No complete capitulum was known to Darwin (1851, p. 18) who presumed the number of valves present to be 14 and that the capitula length reached about 40.0 mm. The principal valves are as follows. Carina: tectum rounded in section, widening towards the rounded basal margin; the parietes extend at an obtuse angle to about one third of the entire length of the valve.
3.14. Verruca stroemia (Mu¨ller, 1776) (Figs. 9F and 10D–L) Description. The wart barnacles are sessile forms composed of a rostrum and carina on each of which, on one side, is an articulated scutum and a tergum, respectively, while on the other side the scutum and tergum are immovably attached; this pattern can be on either side, arbitrarily. Margins ribbed, with the ribs extending as interlocking ‘spines’. Fairly common. Occurrence. Coralline Crag Formation, Red Crag Formation and interglacial deposits to Recent (Darwin, 1854, p. 42). Coralline Crag at Sutton (Fig. 10D–L); Red Crag at Walton-on-the-Naze.
Fig. 12. Lepas delicatula Withers (after Withers, 1953, pl. 58, figs 13a, b, 14a, b; see also Fig. 10Q, R herein). (A and D) BMNH In. 37138, holotype, outer (A) and side views of incomplete carina. (B and C) BMNH In. 37139, outer (B) and side views of basal part of carina. All 4.
Fig. 13. Scanning electron micrographs of the trace fossil Rogerella isp., probable spoor of acrothoracian barnacles (modified after Donovan, 1988, fig. 6), BMNH In.63653. (A) Wide, oval borings infilled with quartz grains (compare with Schlaudt and Young, 1960, pl. 119), 100. (B) Narrow, elongate, slit-like borings (compare with Bromley, 1970, fig. 4e (upper)), 64. (C) Enlargement of a clean, sock-shaped boring of the type shown in (A), 510. All specimens coated with 60% gold-palladium.
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Scuta: elongate trapezoid, length about four times the width; cross section slightly convex; the umbo is about one third to one quarter distant from the apex, a nearly straight occludent margin extends beyond the umbo; a ridge separates a short concave tergal margin from the sinuous lateral margin. Terga: triangular to crescent-shaped; the carinal margin is straight to slightly convex; occludent and scutal margins are slightly convex; a weak apico-basal ‘line’, dividing growth lines, runs parallel to the carinal margin. Upper latera: flat, subpentagonal, with straight tergal, carinal and scutal margins; the umbo is central with ridges extending to basal angles. Rostral latera flat, sub-triangular, rounded apically. The peduncle in this genus is invariably surrounded by numerous rows of small, overlapping, scale-like plates. According to Darwin (1854, p. 21), there is some variation in size between specimens from different localities. Fairly common. Occurrence. Lower part of the Coralline Crag Formation (Darwin, 1851, p. 18) (Fig. 10B and C); Red Crag Formation, Walton-on-theNaze. 3.16. Lepas delicatula Withers, 1953 (Figs. 10Q,R and 12) Description. This genus has five valves, of which only the carina was known to Withers (1953). Carina comparatively broad throughout, only a little constricted either side of the umbo; base broadly rounded; basal plate no wider than the widest part of the upper limb and directed inwards at a wide angle. Peduncle smooth. Occurrence. Only known from the type locality at Coralline Crag Formation at Sudbourne, Suffolk (Figs. 10Q,R and 12). 3.17. Trace fossil Rogerella isp. (Fig. 13) Description. Borings in shelly substrates produced by acrothoracian barnacles. The borings have a slot-like surface expression (aperture) and a sock-like section (Fig. 13C). Two morphologies are recognised, ‘wide’ (Fig. 13A) and ‘narrow’ (Fig. 13B). Occurrence. Only reported from Red Crag Formation at Waltonon-the-Naze (Donovan, 1988), but probably more widespread. Acknowledgement We thank Mr. Harry Taylor of the Photographic Unit of the Natural History Museum for providing the many images included herein. References Alessandri, G. de, 1895. Contribuzione allo studio dei Cirripedia fossili d’Italia. Bollettino della Societa` Geologica Italiana 13, 234–314. Ascanius, P., 1767. Icones rerum naturalium, quas in itinere Orientali depingi/ curavit P. Forska˚l; post mortem auctoris ad Regis mandatum æri incises edidit Carsten Niebuhr. Ex officina Mo¨lleri, Hauniæ 15 pp. Bowen, D.Q. (Ed.), 1999. A revised correlation of Quaternary deposits in the British Isles. Geological Society Special Report 23, 174 pp. Bromley, R.G., 1970. Borings as trace fossils and Entobia cretacea Portlock, as an example. In: Crimes, T.P., Harper, J.C. (Eds.), Trace Fossils Geological Journal Special Issue 3. , 49–90. Bronn, H.G., 1831. Italiens Tertia¨r-Gebilde und deren organische Einschlu¨sse. Karl Groos, Heidelberg xii + 176 pp.
Brown, T., 1827. Illustrations of the Conchology of Great Britain and Ireland, Drawn from Nature. Edinburgh and London, x + 237 pp. + 53 pls with descriptive letterpress. Bruguie`re, J.G., 1789. Histoire naturelle des Vers. Encyclopedia Methodique (Zoologie), Tome 1. Paris, xviii + 757 pp. Collins, J.S.H., 1963a. A guide to the identification of Crag (Plio/Pleistocene) acorn barnacles. Freelance Geological Association Journal 2 (3) 13–15. Collins, J.S.H., 1963b. A report of the cirripedes found in an exposure of the Red Crag at Beggar’s Hollow, Ipswich, Suffolk. Freelance Geological Association Journal 2 (3) 16–17. Collins, J.S.H., 1989. Some barnacles from the Red Crag at Beggar’s Hollow, Suffolk. Proceedings of the Geologists’ Association 100, 217. Cornwall, I., 1956. Identifying fossil and recent barnacles by the figures in the shell. Journal of Paleontology 30, 646–651. Cornwall, I., 1959. More shell figures and notes on barnacles. Canadian Journal of Zoology 37, 401–406. Cornwall, I., 1960. Barnacle shell figures and repairs. Canadian Journal of Zoology 38, 827–832. da Costa, E.M., 1778. Historia naturalis Testaceorum Brittaniae. Privately published, London, pp. 254. Curry, D., Adams, C.G., Boulter, M.C., Dilley, F.C., Eames, F.E., Funnell, B.M., Wells, M.K., 1978. A correlation of the Tertiary rocks in the British Isles. Geological Society Special Report 12, 78 pp. Darwin, C., 1851. A monograph on the fossil Lepadidae or, pedunculated cirripedes of Great Britain. Monograph of the Palaeontographical Society 5 (13) , vi + 88 pp. Darwin, C., 1854. A monograph of the fossil Balanidae and Verrucidae of Great Britain. Monograph of the Palaeontographical Society 8 (30) , 44 pp. Darwin, C., 2009. Monographs on the Fossil Lepadidae, Balanidae and Verrucidae. Cambridge University Press, Cambridge 86 + 44 + 2 pp. Davadie, C., 1963. Syste´matique et structure des balanes fosilles d’Europe et d’Afrique, 7e. E´ditions du Centre National de la Recherche Scientifique, Paris 146 pp. Dixon, R. (Ed.), 2012. A Celebration of Suffolk Geology: GeoSuffolk 10th Anniversary Volume. GeoSuffolk, Ipswich, viii + 475 pp. Donovan, S.K., 1988. Palaeoecology and taphonomy of barnacles from the PlioPleistocene Red Crag of East Anglia. Proceedings of the Geologists’ Association 99, 279–289. Donovan, S.K., 1989. Palaeoecology and significance of barnacles in the Pliocene Balanus Bed in Tobago, West Indies. Geological Journal 24, 239–250. Donovan, S.K., 2003. Charles Taylor Trechmann and the development of Caribbean geology between the wars. Proceedings of the Geologists’ Association 114, 345– 354. Ellis, J., 1758. An account of several rare species of barnacles. Philosophical Transactions of the Royal Society of London 50, 845–855. Gruvel, A., 1905. Monographie des Cirre`pedes ou The´ocostrace´s. Paris, 472 pp. Harper, E.M., 2012. Biotic interaction in the Suffolk crags. 231–241. In: Dixon, R. (Ed.), A Celebration of Suffolk Geology: GeoSuffolk 10th Anniversary Volume. GeoSuffolk, Ipswich, viii + 475 pp. Jackson, T.A., Donovan, S.K., 1994. Tobago. 193–207. In: Donovan, S.K., Jackson, T.A. (Eds.), Caribbean Geology: An Introduction. University of the West Indies Publishers’ Association, Kingston, iii + 289 pp. Linne´, C., 1758. Systema Naturae, Volume 1, Tenth ed. Holmiae, 824 pp. Miller III, W., Brown, N.A., 1979. The attachment scars of fossil balanids. Journal of Paleontology 53, 208–210. Mu¨ller, O.F., 1776. Zoologiae Danicae Prodromus, seu Animalium Daniae et Norvegiae, indigenarum characters, nomina, et synonyma imprimis popularium. Typis Hallageriis, Havniae xxxii + 282 pp. Pilsbry, H.A., 1916. The sessile barnacles (Cirripedia) contained in the collections of the U.S. National Museum; including a monograph of the American species. U.S. National Museum Bulletin 93, 1–366. Rainbow, P.S., 1984. An introduction to the biology of British littoral barnacles. Field Studies 6, 1–51. Reid, C., 1890. The Pliocene Deposits of Britain. Memoirs of the Geological Survey of the United Kingdom. Her Majesty’s Stationery Office, London viii + 326 pp. Schlaudt, C.M., Young, K., 1960. Acrothoracic barnacles from the Texas Permian and Cretaceous. Journal of Paleontology 34, 903–907. Southward, A.J., 2008. Barnacles. Synopses of the British Fauna (new series), vol. 57. , viii + 140 pp. Sowerby, G.B., 1820–1825. The Genera of Recent and Fossil Shells, for the use of students in Conchology and Geology/Commenced by James Sowerby . . . and continued by G.B. Sowerby . . . with . . . plates by James Sowerby and J.D.C. Sowerby. Four volumes. London, 267 pls with descriptive letterpress. Trechmann, C.T., 1934. Tertiary and Quaternary beds of Tobago, West Indies. Geological Magazine 71, 481–493. Withers, T.H., 1953. Catalogue of Fossil Cirripedia in the Department of Geology. Vol. 3. Tertiary. British Museum (Natural History), London xv + 396 pp.