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On the Occurrence of Javanella and Saida in the Pliocene of Leizhou Peninsula, Guangdong, China
On the Occurrence of Javanella and Saida in the Pliocene of Leizhou Peninsula, Guangdong, China YUN-SIAN GOU AND DE-QIONG ch3.N
Nmjing Institute of Geology and Pdaeontology, Academia Sinica, P. R. China
ABSTRACT The occurrence of Javanella kendengensis Kingma, first recorded in the Pliocene of Java, and Saida sp. in the Pliocene Wanglougang Formation from the Leizhou Peninsula, Guangdong, gives further evidence of the close relationship between the ostracod faunas from the North Continental Shelf of the South China Sea and those from the Indo-Malayan area, and the possible connection with Australasian ostracod faunas from the Late Cenozoic to Recent. The two samples under study were collected by Gou and He in 1963 from boreholes in Xuwen County in the Southern Part of the Leizhou Peninsula. In the present paper, Javanella kendengensis Kingma and Saida sp. are described and the distribution of these two genera is discussed. The marine Pliocene ostracod fauna from the North Continental Shelf of the South China Sea was reported by Gou, Chen, Guan, Zheng, Huang and et al. (1981, 1983). There are 51 genera and 107 species described mostly from boreholes in the sea basins, and 65 genera and 166 species described from boreholes in the Leizhou Peninsula and northern Hainan Island, Guangdong. However, the genera Javanella and Saida have never been found in this area previously. Based on the composition of ostracod genera and species, the aspects of the Pliocene ostracod faunas from the Leizhou Peninsula and northern Hainan Island, and from the sea basins of the North Continental Shelf of the South China Sea are the same. Javanella is a particular genus established by Kingma (1948) from the Upper Pliocene Klitik Formation of Pentuk, East Java, but Kingma did not indicate the holotype for the type species Javanella kendengensis Kingma. Later, Keij (1979) gave a brief review of.the type species of the genus from Kingma’s collection, and selected a lectotype for Javanella kendengensis Kingma, which contains only one left valve and one right valve. Recently, Javanella kendengensis Kingma was obtained from a core sample of the Pliocene Wanglougang Formation in Xuwen County of the southern Leizhou Peninsula. In this sample, Javanella kendengensis Kingma is associated with shallow water forms of Ostracoda such as Keijella hodgii (Brady), Neocytheretta faceta (Guan), Callistocythere guangdongensis Gou, Stigmatocythere dorsinoda Chen, S.bona Chen, Neomonoceratina delicata Ishizaki et Kato, Parakrithella pseudadonta (Hanai) and Loxoconcha sp. Keij suggests that Javanella is a distinct Indo-Malayan genus, however the occurrence of this genus in the Leizhou Peninsula indicates that its distribution is not limited to the Indo-Malayan area, and further proves the close relationship between the faunas from the North Continental 797
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Shelf of the South China Sea and those from the Indo-Malayan area of the same age. Saida was established by Hornibrook (1952) from New Zealand with the Recent form Saida truncala as its type species. This genus is characterised by its tiny carapace. Based on the available data, Saida has a wide range in space and time. Since Hornibrook noted the earliest appearance of this genus in the Middle Eocene (Bortonian) of New Zealand, it has been discovered successively in the Upper Cretaceous of Europe and in Australasia where a few specimens have been found. Saida nettgauensis was described by Griindel (1966) from the Albian of Germany. Loxoconcha elliptica, reported by Bonnema (1941) from the Upper Cretaceous of Holland, was assigned to Saida by Szczechura (1965). After reviewing the European S. elliptica (Bonnema) from the Upper Cretaceous and the Palaeocene, Herrig (1966, 1967, 1968) proposed four new species: S. exilis Herrig (Upper Turonian), S. media Herrig (Santonian to Upper Campanian), S. crassa Herrig (Lower Maastrichtian to Danian) and S. nana Herrig (Maastrichtian). The Australian Upper Cretaceous form S. rhomboidea was described by Neale (1975) from the Santonian Chalk of Western Australia. The European Tertiary forms of Saida contain four unnamed species respectively mentioned or described and figured by Deltel(l941) from the Palaeogene (Lutetian) of S. W. France, by Pietrzeniuk (1969) from the Upper Eocene of Poland, by Ascoli (1969) from the Upper Eocene of Italy and by Sissingh (1972) from the Upper Pliocene of Greece. In America, Cytherelloidea murdercreekensis Howe and Law (1936), appearing in the Tertiary of Mississippi and Alabama, (Sexton, 1951) is referred to Saida (Howe and Howe, 1973) based on its shape and its having a prominent oblique ventrolateral process. There are two Australasian species of Saida found in Holocene to Recent sediments: one of them is S. torresi, reported by Brady (1880) from the Torres Straits of Australia, the other is S. truncala, recorded by Hornibrook (1952) from New Zealand. In the South China Sea Saida herrigi Keij is recorded from two localities, one of which is situated from 5'21": 111' 14'E to 6"40'N: 109'34' 30'' E in the South China Sea and is Holocene in age, and the other is situated off the Xisha-Zhongsha Islands where the specimens were collected from the surface of the bottom sediments (Cai and Tu, 1983). Recently, Saida sp., like Javanella kendengensis Kingma mentioned above, was found in the Pliocene Wanglougang Formation in another borehole in the Southern Leizhou Peninsula. Here it is associated with the shallow water forms Keijella hodgii (Brady), Parakrithella pseudadonta (Hanai), Cytheropteron uchioi Hanai, Stigmatocythere dorsinoda Chen, Albileberis asperata Guan, Pontocythere subjaponica (Hanai), Semicytherura miurensis (Hanai), Loxoconcha sinensis Brady, Neomonoceratina delicata Ishizaki et Kato, Hemicytherura cuneata Hanai, etc. The similarity of Saida sp., described in this present paper, to Saida herrigi Keij from the South China Sea and to S. rhomboidea Neale from the Australian Cretaceous seems further proof of the possible connection between the ostracod faunas from the North Continental Shelf of the South China Sea and those from the South Pacific and Australasia ranging from Late Cenozoic to Recent, although in these areas Tertiary species of Saida have not yet been found. Judging from the above data, the genus Saida is more widely dispersed than hitherto realised; PLATE1-All specimens described in this paper are kept in Nanjing Institute of Geology and Palaeontology, Academia Sinica. All figures are scanning electron micrographs of gold coated specimens (except Plate 2, figs. 1,2). Figs. 1-6. Juvunellu kendengensis Kingma. Fig. 1 . Lateral view of right valve, Plesiotype, Cat. No. 94397, x 100. Fig. 2. Internal view of right valve, Plesiotype, Cat. No. 94397, X 100. Fig. 3. Lateral view of left valve, Plesiotype, Cat. No. 94398, x 100. Fig. 4. Internal view of left valve, Plesiotype, Cat. No. 94398, x 100. Fig. 5. Hinge of right valve, Plesiotype, Cat. No. 94397, X200. Fig. 6. Hinge and adductor muscle scars of left valve, Plesiotype, Cat. No. 94398, X200. Figs. 7-11. Suidu sp. Fig. 7. Lateral view of right valve, Cat. No. 94402, ~ 2 0 0 .Fig. 8. Internal view of right valve, Cat. No. 94402, x200. Fig. 9. Hinge of right valve, Cat. No. 94402, X286. Figs. 10, 11. Detail of right hingement, Cat. No. 94402, x 1000.
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its species ranged either eastwards from Europe or northwards from Australia into the Indo-west Pacific. This genus is noticeably important for the study of primary dispersal routes and biogeographical distribution. Genus JAVANELLA Kingma KENDENGENSIS Kingma JAVANELLA (Pl. 1, figs. 1-6; P1. 2, figs. 1-4, 8, 9) Javunellu kendengensis Kingma, 1949, p. 89, P1. 10, fig. 6; Keij, 1979, p. 60,PI. 2, figs. 7, 8.
Description.-Carapace moderate in size, thin-shelled, elongate in lateral view, with posterior caudal process, which is situated somewhat below the middle of the posterior part. Posterior end bluntly acuminate in the middle. Anterior margin obliquely rounded. Dorsal margin nearly straight. Ventral margin sinuate, convex in the posterior part and concave in the anteior part. Surface of carapace smooth. Hinge in the right valve with a narrow, nearly smooth groove along the entire dorsal margin, and with a narrow elongate anti-slip tooth below the anterior end of the groove. Hinge in the left valve with a narrow elongate smooth bar fitting in the groove of the right valve. Marginal zone moderately wide with deep anterior and shallow posteroventral vestibule, marginal pore canals moderate in number, simple and branching. Normal pore canals sieve type. Central muscle scars consisting of slightly oblique row of four adductor muscle scars, a large frontal scar and two connecting large mandibular scars. Dimensions.-Right valve, Plesiotype, Cat. No. 94397, L - 570 pm, H - 260 pm; Left valve, Plesiotype, Cat. No. 94398, L - 590 pm, H - 240 pm. Remarks.-Four left valves and two right valves are present in our material. In the Treatise on Invertebrate Paleontology Part Q, Javanella was recognized as a synonym of Pellucistoma, but a review of the hinge structure shows that the former is quite different from the latter. In Pellucistorna, the hinge of the life valve consists of a long, anterior blade-like triangular tooth from which a long serrated bar extends backwards and terminates at the posterior cardinal angle; above this bar and parallel to it is a narrow, incised, line-like groove. The hinge in the right valve has an anterior socket and a crenulate groove. Examination of the hinges of Javanella and Nipponocythere shows that the right valve hinges in both genera are similar each to other, because in the latter an anti-slip tooth also occurs below the anterior end of the groove of the right valve. However, in Nipponocythere the posterior end of the bar of the left valve is roughly crenulated with a tooth in the posterior socket. The types of adductor scars,and frontal scar in these two genera are also similar to each other. It seems that, judging from the hinge structure and the muscle scar pattern, Javanella is rather closer to Nipponocythere than to Pellucistoma. The present specimens differ slightly from the lectotype of Javanella kendengensis in their rather larger size and more slender carapace. Occurrence.-Xuwen County; Wanglougang Formation. PLATE 2-Figs. 1-4, 8, 9. Javanella kendengemis Kingma. Fig. 1. Right valve seen from inside by transmitted light, Plesiotype, Cat. No. 94400, x 100. Fig. 2. Left valve seen from inside by transmitted light, Plesiotype, Cat. No. 94398, X 100. Fig. 3. A sieve-type normal pore canal on the anterior lateral surface of the left valve, Plesiotype, Cat. No. 94401, x4000. Fig. 4. Muscle scars of left valve, Plesiotype, Cat. No.: 94398, x 800. Fig. 8. Posterior part of left valve hinge, Plesiotype, Cat. No. 94399, ~ 6 0 0 . Fig. 9. Anterior part of right valve hinge, Plesiotype, Cat. No. 94397, x 600. Figs. 5-7-Saida sp. Fig. 5. Muscle scar pattern, Cat. No. 94402, x 1OOO. Fig. 6. Broader mural portion mrresponding vertically to the internal muscle scars, Cat. No. 94402, ~ 6 0 0 .Fig. 7. Detail of normal pore, x 2OOo.
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Genus SAIDAHornibrook SAIDAsp. (Pl. 1, figs. 7-1 1 ; P1. 2, figs. 5-7) Description.-Small, right valve more or less oval in lateral view. Dorsal margin long ahd slightly convex. Ventral margin long and straight, the front of the middle concave in inner view. Anterior end drawn out ventrally, with six distinct spines along the outer margin. Posterior one higher than the anterior and symmetrically rounded, with seven sharp spines along the posterior margin. The lateral part of the posteroventral area forms a semicircular protruding ala. The outer edge of the ala itself is defined by a smooth carina, which starting near the anteroventral area at one-quarter the height, runs posteriorly parallel to the venter then curves smoothly upwards to about one-half the height; the inner part of the ala merges gradually with the body of the valve dorso-anteriorly. A smooth, nearly straight carina is present in the posterodorsal area. A thin, smooth marginal rim forms a border all around the valve and is nearly straight along the venter. Surface covered with a meshwork of deep pits arranged in vague rows parallel to the margins. The rounded fossae on the lateral ala are much larger than the marginal fossae. The sunken sieve plates of the fossae and second-order reticulation are not visible. The smooth muri carry intramural pores (Pl. 2, fig. 7). On the central part, a broader mural portion corresponds vertically to the area of internal muscle scar (Pl. 2, fig. 6). The inside of the anterior rim has six or seven faint, short mural ribs which join with the anterior rim. The same occurs posteriorly. The lophodont hinge of the right valve (Pl. 1, figs. 9-1 1) consists of two terminal elongate teeth, subdivided into four or five cusps, and a long straight groove in between. The marginal zone is broken. Internal openings of normal pores are simple, rather large and widely spaced over entire valve (Pi. 1, fig, 8). The central muscle scar pattern is a vertical row of four elongate adductor scars set at midheight. Frontal scar not seen (Pl. 2, fig. 5). Dimensions.-Right valve, described specimen, Cat. No. 94402, L - 310 pm, H - 220 pm. Remarks.-Only a single right valve was found. This species of Saida differs from S. truncala Hornibrook, the type species, and S. torresi (Brady) in the presence of a poster0 dorsal carina, which is lacking in those two species. It is distinguished from S. herrigi Keij, from the South China Sea, by its lack of a low, irregular carina running obliquely forwards from the apex of the ala and by a different arrangement of fossae and muri (which are nearly horizontal in S. herrigi Keij). In general outline and alar shape, this unnamed species of Suidu is closer to Saida sp. (Sisingh, 1972) from the Pliocene Pigadia Formation of the South Aegean Island Arc, but is easily distinguished from the latter by the presence of a smooth, nearly straight carina in the posterodorsal area. This Saida sp. is also close to S. rhomboidea Neale, from the.upper Cretaceous of Gingin, Western Australia, but is easily distinguished by its smooth posterodorsal carina. Occurrence.-Xuwen County; Wanglougang Formation.
REFERENCES 1969. First data on the ostracod biostratigraphy of the Possagus and Bredola sections (Palaeogene, NE Italy). Mem. Bur. Rech. Geol. Mineral., 69, 51-71. BRADY, G. s. 1880. Report on the Ostracoda dredged by H.M.S. ‘Challenger’during the years 1873-1876. Rep. Sci. Results Voyage ChaIlenger, 1, 1-179. CAI, H. M. and TU, x. 1983. Distribution of Foraminifera and Ostracoda from the surface of the bottom sediments off the Xisha-Zhongsha Islands, South China Sea. Nanhai Studia Marina Sinica, 4, 25-63. Science Press. CORYELL, H. N. and FIELDS, s. 1937. A Gatun Ostracode fauna from Cativa, Panama. Am. Museum Noi+tates. 956, 1-18. ASCOLI, P.
Pliocene Javanella and Saida of Guangdong, China 803 OOU, Y. S., CHEN, T. C., GUAN, S. Z., JIANG, Y. W., LIU, Z . Y.,LAI, X. H., WU, Q. J. and CHEN, C. Y. 1981. Ostracoda. In
Tertiary Palaeontology of North Continental Sherf of South China Sea, 138-187. Guangdong Science and Technology Press, Guangdong. OOU, Y. s.. ZHENG, s.-Y. and HUANG, B. R. 1983. Pliocene Ostracode Fauna of Leizhou Peninsula and Northern Hainan Island, Guangdong Province. Palaeontologia Sinica, Whole, No. 162, New Series B, 18, 1-117. HERRIG, E. 1966. Ostracoden aus der Weissen Schreibkreide (Unter-Maastricht) der Insel Riigen. Paliont. Abh., A, II,4, 693-1024. - 1967. Moglichkeiten einer Feinstratigraphie der hoheren Oberkreide in Nordostdeutschland mir Hilfe von Ostracoden. Ber. deurch. Ges. geol. Wiss., A, 12, 5.557-574. 1968. Zur Gattung Saida Hornibrook (Ostracoda, Crustacea) in der Oberkreide. Geologie, 17 (8), 964-981. HORNIBROOK, N. de B. 1952. Tertiary and Recent marine Ostracoda of New Zealand. New Zeal. Geol. Surv., Pal. Bull., 18, 1-82. HOWE, H. v. and LAURENCICH, L. 1958. Introduction to the Study of Cretaceous Ostracods, 536 pp. Louisiana State Univ. Press. HOWE, R. c . and HOWE, H. J. 1973. Ostracodes from the Shubuta Clay (Tertiary) of Mississippi. J. Paleont., 47 (4), 629-656. ISHIZAKI,K. 1971. Ostracodes from Aomori Bay, Aomori Prefecture, Northeast Honshu, Japan. Tohoku Univ., Sci. Rep., 2nd ser., (Geol.), 43(1), 59-79. KEIJ, A. J. 1975. Note on three Holocene Indo-Malaysian Ostracod species. Koninkl. Nederl. Akademie van Wetenschappe-Amsterdam, Proceedings, Ser. B, Palaeontology, 78(3), 231-241. - 1979. Brief review of type species of genera from the Kingma collection. In KRSTIC, N. (ed.). Taxonomy, Biostratigraphy and Distribution of Ostracodes, 59-62, Geological Society of Serbia, Belgrade. KINGMA, J. T. 1948. Contributions to the knowlerlge of the Young-C'aenozoic Ostracoda fvom the Malayan region, 118 pp. Kemink, Utrecht. MCKENZIE, K. G. 1973. Cenozoic Ostracoda. In HALLAM A. (ed.). Atlas of Palaeobiogeography, 477-487. MOORE, R. c . (ed.). 1961. Treatise on invertebrate paleontology, Part Q , Arthropoda 3. Crustacea, Ostracoda, Geol. SOC.America and Univ. Kansas Press, New York and Lawrence. NEALE, J. w . 1975. The ostracod fauna from the Santonian Chalk (Upper Cretaceous) of Gingin, Western Australia. Spec. Papers Pal. (Pal. Assoc.), (16), 1-81. SEXTON, J. v. 1951. The ostracode Cytherelloidea in North America. J. Paleont., 25(6), 808-816. SISSINGH, w . 1972. Late Cenozoic Ostracoda of the South Aegean Island Arc. Utrecht Micropal. Bull., (6), 10-187. SZCZECHURA, J. 1965. Cytheracea (Ostracoda) from the Uppermost Cretaceous and Lowermost Tertiary of Poland. Acta Palaeont. Polonica, 10(4), 451-564.
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DISCUSSION Whatley: Saida is a strange ostracod with respect to its distribution. It seems to have been widespread since the Cretaceous in Tethyan and Indo/Pacific Seas. However, since at least the Upper Oligocene, it has occurred in deep sea environments although it is never abundant there. Recently, we discovered Saida in the Atlantic in Recent sediments. There seems to be no simple explanation of its distribution.
Nmjing Institute of Geology and Pdaeontology, Academia Sinica, P. R. China
ABSTRACT The occurrence of Javanella kendengensis Kingma, first recorded in the Pliocene of Java, and Saida sp. in the Pliocene Wanglougang Formation from the Leizhou Peninsula, Guangdong, gives further evidence of the close relationship between the ostracod faunas from the North Continental Shelf of the South China Sea and those from the Indo-Malayan area, and the possible connection with Australasian ostracod faunas from the Late Cenozoic to Recent. The two samples under study were collected by Gou and He in 1963 from boreholes in Xuwen County in the Southern Part of the Leizhou Peninsula. In the present paper, Javanella kendengensis Kingma and Saida sp. are described and the distribution of these two genera is discussed. The marine Pliocene ostracod fauna from the North Continental Shelf of the South China Sea was reported by Gou, Chen, Guan, Zheng, Huang and et al. (1981, 1983). There are 51 genera and 107 species described mostly from boreholes in the sea basins, and 65 genera and 166 species described from boreholes in the Leizhou Peninsula and northern Hainan Island, Guangdong. However, the genera Javanella and Saida have never been found in this area previously. Based on the composition of ostracod genera and species, the aspects of the Pliocene ostracod faunas from the Leizhou Peninsula and northern Hainan Island, and from the sea basins of the North Continental Shelf of the South China Sea are the same. Javanella is a particular genus established by Kingma (1948) from the Upper Pliocene Klitik Formation of Pentuk, East Java, but Kingma did not indicate the holotype for the type species Javanella kendengensis Kingma. Later, Keij (1979) gave a brief review of.the type species of the genus from Kingma’s collection, and selected a lectotype for Javanella kendengensis Kingma, which contains only one left valve and one right valve. Recently, Javanella kendengensis Kingma was obtained from a core sample of the Pliocene Wanglougang Formation in Xuwen County of the southern Leizhou Peninsula. In this sample, Javanella kendengensis Kingma is associated with shallow water forms of Ostracoda such as Keijella hodgii (Brady), Neocytheretta faceta (Guan), Callistocythere guangdongensis Gou, Stigmatocythere dorsinoda Chen, S.bona Chen, Neomonoceratina delicata Ishizaki et Kato, Parakrithella pseudadonta (Hanai) and Loxoconcha sp. Keij suggests that Javanella is a distinct Indo-Malayan genus, however the occurrence of this genus in the Leizhou Peninsula indicates that its distribution is not limited to the Indo-Malayan area, and further proves the close relationship between the faunas from the North Continental 797
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Shelf of the South China Sea and those from the Indo-Malayan area of the same age. Saida was established by Hornibrook (1952) from New Zealand with the Recent form Saida truncala as its type species. This genus is characterised by its tiny carapace. Based on the available data, Saida has a wide range in space and time. Since Hornibrook noted the earliest appearance of this genus in the Middle Eocene (Bortonian) of New Zealand, it has been discovered successively in the Upper Cretaceous of Europe and in Australasia where a few specimens have been found. Saida nettgauensis was described by Griindel (1966) from the Albian of Germany. Loxoconcha elliptica, reported by Bonnema (1941) from the Upper Cretaceous of Holland, was assigned to Saida by Szczechura (1965). After reviewing the European S. elliptica (Bonnema) from the Upper Cretaceous and the Palaeocene, Herrig (1966, 1967, 1968) proposed four new species: S. exilis Herrig (Upper Turonian), S. media Herrig (Santonian to Upper Campanian), S. crassa Herrig (Lower Maastrichtian to Danian) and S. nana Herrig (Maastrichtian). The Australian Upper Cretaceous form S. rhomboidea was described by Neale (1975) from the Santonian Chalk of Western Australia. The European Tertiary forms of Saida contain four unnamed species respectively mentioned or described and figured by Deltel(l941) from the Palaeogene (Lutetian) of S. W. France, by Pietrzeniuk (1969) from the Upper Eocene of Poland, by Ascoli (1969) from the Upper Eocene of Italy and by Sissingh (1972) from the Upper Pliocene of Greece. In America, Cytherelloidea murdercreekensis Howe and Law (1936), appearing in the Tertiary of Mississippi and Alabama, (Sexton, 1951) is referred to Saida (Howe and Howe, 1973) based on its shape and its having a prominent oblique ventrolateral process. There are two Australasian species of Saida found in Holocene to Recent sediments: one of them is S. torresi, reported by Brady (1880) from the Torres Straits of Australia, the other is S. truncala, recorded by Hornibrook (1952) from New Zealand. In the South China Sea Saida herrigi Keij is recorded from two localities, one of which is situated from 5'21": 111' 14'E to 6"40'N: 109'34' 30'' E in the South China Sea and is Holocene in age, and the other is situated off the Xisha-Zhongsha Islands where the specimens were collected from the surface of the bottom sediments (Cai and Tu, 1983). Recently, Saida sp., like Javanella kendengensis Kingma mentioned above, was found in the Pliocene Wanglougang Formation in another borehole in the Southern Leizhou Peninsula. Here it is associated with the shallow water forms Keijella hodgii (Brady), Parakrithella pseudadonta (Hanai), Cytheropteron uchioi Hanai, Stigmatocythere dorsinoda Chen, Albileberis asperata Guan, Pontocythere subjaponica (Hanai), Semicytherura miurensis (Hanai), Loxoconcha sinensis Brady, Neomonoceratina delicata Ishizaki et Kato, Hemicytherura cuneata Hanai, etc. The similarity of Saida sp., described in this present paper, to Saida herrigi Keij from the South China Sea and to S. rhomboidea Neale from the Australian Cretaceous seems further proof of the possible connection between the ostracod faunas from the North Continental Shelf of the South China Sea and those from the South Pacific and Australasia ranging from Late Cenozoic to Recent, although in these areas Tertiary species of Saida have not yet been found. Judging from the above data, the genus Saida is more widely dispersed than hitherto realised; PLATE1-All specimens described in this paper are kept in Nanjing Institute of Geology and Palaeontology, Academia Sinica. All figures are scanning electron micrographs of gold coated specimens (except Plate 2, figs. 1,2). Figs. 1-6. Juvunellu kendengensis Kingma. Fig. 1 . Lateral view of right valve, Plesiotype, Cat. No. 94397, x 100. Fig. 2. Internal view of right valve, Plesiotype, Cat. No. 94397, X 100. Fig. 3. Lateral view of left valve, Plesiotype, Cat. No. 94398, x 100. Fig. 4. Internal view of left valve, Plesiotype, Cat. No. 94398, x 100. Fig. 5. Hinge of right valve, Plesiotype, Cat. No. 94397, X200. Fig. 6. Hinge and adductor muscle scars of left valve, Plesiotype, Cat. No. 94398, X200. Figs. 7-11. Suidu sp. Fig. 7. Lateral view of right valve, Cat. No. 94402, ~ 2 0 0 .Fig. 8. Internal view of right valve, Cat. No. 94402, x200. Fig. 9. Hinge of right valve, Cat. No. 94402, X286. Figs. 10, 11. Detail of right hingement, Cat. No. 94402, x 1000.
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its species ranged either eastwards from Europe or northwards from Australia into the Indo-west Pacific. This genus is noticeably important for the study of primary dispersal routes and biogeographical distribution. Genus JAVANELLA Kingma KENDENGENSIS Kingma JAVANELLA (Pl. 1, figs. 1-6; P1. 2, figs. 1-4, 8, 9) Javunellu kendengensis Kingma, 1949, p. 89, P1. 10, fig. 6; Keij, 1979, p. 60,PI. 2, figs. 7, 8.
Description.-Carapace moderate in size, thin-shelled, elongate in lateral view, with posterior caudal process, which is situated somewhat below the middle of the posterior part. Posterior end bluntly acuminate in the middle. Anterior margin obliquely rounded. Dorsal margin nearly straight. Ventral margin sinuate, convex in the posterior part and concave in the anteior part. Surface of carapace smooth. Hinge in the right valve with a narrow, nearly smooth groove along the entire dorsal margin, and with a narrow elongate anti-slip tooth below the anterior end of the groove. Hinge in the left valve with a narrow elongate smooth bar fitting in the groove of the right valve. Marginal zone moderately wide with deep anterior and shallow posteroventral vestibule, marginal pore canals moderate in number, simple and branching. Normal pore canals sieve type. Central muscle scars consisting of slightly oblique row of four adductor muscle scars, a large frontal scar and two connecting large mandibular scars. Dimensions.-Right valve, Plesiotype, Cat. No. 94397, L - 570 pm, H - 260 pm; Left valve, Plesiotype, Cat. No. 94398, L - 590 pm, H - 240 pm. Remarks.-Four left valves and two right valves are present in our material. In the Treatise on Invertebrate Paleontology Part Q, Javanella was recognized as a synonym of Pellucistoma, but a review of the hinge structure shows that the former is quite different from the latter. In Pellucistorna, the hinge of the life valve consists of a long, anterior blade-like triangular tooth from which a long serrated bar extends backwards and terminates at the posterior cardinal angle; above this bar and parallel to it is a narrow, incised, line-like groove. The hinge in the right valve has an anterior socket and a crenulate groove. Examination of the hinges of Javanella and Nipponocythere shows that the right valve hinges in both genera are similar each to other, because in the latter an anti-slip tooth also occurs below the anterior end of the groove of the right valve. However, in Nipponocythere the posterior end of the bar of the left valve is roughly crenulated with a tooth in the posterior socket. The types of adductor scars,and frontal scar in these two genera are also similar to each other. It seems that, judging from the hinge structure and the muscle scar pattern, Javanella is rather closer to Nipponocythere than to Pellucistoma. The present specimens differ slightly from the lectotype of Javanella kendengensis in their rather larger size and more slender carapace. Occurrence.-Xuwen County; Wanglougang Formation. PLATE 2-Figs. 1-4, 8, 9. Javanella kendengemis Kingma. Fig. 1. Right valve seen from inside by transmitted light, Plesiotype, Cat. No. 94400, x 100. Fig. 2. Left valve seen from inside by transmitted light, Plesiotype, Cat. No. 94398, X 100. Fig. 3. A sieve-type normal pore canal on the anterior lateral surface of the left valve, Plesiotype, Cat. No. 94401, x4000. Fig. 4. Muscle scars of left valve, Plesiotype, Cat. No.: 94398, x 800. Fig. 8. Posterior part of left valve hinge, Plesiotype, Cat. No. 94399, ~ 6 0 0 . Fig. 9. Anterior part of right valve hinge, Plesiotype, Cat. No. 94397, x 600. Figs. 5-7-Saida sp. Fig. 5. Muscle scar pattern, Cat. No. 94402, x 1OOO. Fig. 6. Broader mural portion mrresponding vertically to the internal muscle scars, Cat. No. 94402, ~ 6 0 0 .Fig. 7. Detail of normal pore, x 2OOo.
802 Y . 4 . Gou AND D.-Q. CHEN
Genus SAIDAHornibrook SAIDAsp. (Pl. 1, figs. 7-1 1 ; P1. 2, figs. 5-7) Description.-Small, right valve more or less oval in lateral view. Dorsal margin long ahd slightly convex. Ventral margin long and straight, the front of the middle concave in inner view. Anterior end drawn out ventrally, with six distinct spines along the outer margin. Posterior one higher than the anterior and symmetrically rounded, with seven sharp spines along the posterior margin. The lateral part of the posteroventral area forms a semicircular protruding ala. The outer edge of the ala itself is defined by a smooth carina, which starting near the anteroventral area at one-quarter the height, runs posteriorly parallel to the venter then curves smoothly upwards to about one-half the height; the inner part of the ala merges gradually with the body of the valve dorso-anteriorly. A smooth, nearly straight carina is present in the posterodorsal area. A thin, smooth marginal rim forms a border all around the valve and is nearly straight along the venter. Surface covered with a meshwork of deep pits arranged in vague rows parallel to the margins. The rounded fossae on the lateral ala are much larger than the marginal fossae. The sunken sieve plates of the fossae and second-order reticulation are not visible. The smooth muri carry intramural pores (Pl. 2, fig. 7). On the central part, a broader mural portion corresponds vertically to the area of internal muscle scar (Pl. 2, fig. 6). The inside of the anterior rim has six or seven faint, short mural ribs which join with the anterior rim. The same occurs posteriorly. The lophodont hinge of the right valve (Pl. 1, figs. 9-1 1) consists of two terminal elongate teeth, subdivided into four or five cusps, and a long straight groove in between. The marginal zone is broken. Internal openings of normal pores are simple, rather large and widely spaced over entire valve (Pi. 1, fig, 8). The central muscle scar pattern is a vertical row of four elongate adductor scars set at midheight. Frontal scar not seen (Pl. 2, fig. 5). Dimensions.-Right valve, described specimen, Cat. No. 94402, L - 310 pm, H - 220 pm. Remarks.-Only a single right valve was found. This species of Saida differs from S. truncala Hornibrook, the type species, and S. torresi (Brady) in the presence of a poster0 dorsal carina, which is lacking in those two species. It is distinguished from S. herrigi Keij, from the South China Sea, by its lack of a low, irregular carina running obliquely forwards from the apex of the ala and by a different arrangement of fossae and muri (which are nearly horizontal in S. herrigi Keij). In general outline and alar shape, this unnamed species of Suidu is closer to Saida sp. (Sisingh, 1972) from the Pliocene Pigadia Formation of the South Aegean Island Arc, but is easily distinguished from the latter by the presence of a smooth, nearly straight carina in the posterodorsal area. This Saida sp. is also close to S. rhomboidea Neale, from the.upper Cretaceous of Gingin, Western Australia, but is easily distinguished by its smooth posterodorsal carina. Occurrence.-Xuwen County; Wanglougang Formation.
REFERENCES 1969. First data on the ostracod biostratigraphy of the Possagus and Bredola sections (Palaeogene, NE Italy). Mem. Bur. Rech. Geol. Mineral., 69, 51-71. BRADY, G. s. 1880. Report on the Ostracoda dredged by H.M.S. ‘Challenger’during the years 1873-1876. Rep. Sci. Results Voyage ChaIlenger, 1, 1-179. CAI, H. M. and TU, x. 1983. Distribution of Foraminifera and Ostracoda from the surface of the bottom sediments off the Xisha-Zhongsha Islands, South China Sea. Nanhai Studia Marina Sinica, 4, 25-63. Science Press. CORYELL, H. N. and FIELDS, s. 1937. A Gatun Ostracode fauna from Cativa, Panama. Am. Museum Noi+tates. 956, 1-18. ASCOLI, P.
Pliocene Javanella and Saida of Guangdong, China 803 OOU, Y. S., CHEN, T. C., GUAN, S. Z., JIANG, Y. W., LIU, Z . Y.,LAI, X. H., WU, Q. J. and CHEN, C. Y. 1981. Ostracoda. In
Tertiary Palaeontology of North Continental Sherf of South China Sea, 138-187. Guangdong Science and Technology Press, Guangdong. OOU, Y. s.. ZHENG, s.-Y. and HUANG, B. R. 1983. Pliocene Ostracode Fauna of Leizhou Peninsula and Northern Hainan Island, Guangdong Province. Palaeontologia Sinica, Whole, No. 162, New Series B, 18, 1-117. HERRIG, E. 1966. Ostracoden aus der Weissen Schreibkreide (Unter-Maastricht) der Insel Riigen. Paliont. Abh., A, II,4, 693-1024. - 1967. Moglichkeiten einer Feinstratigraphie der hoheren Oberkreide in Nordostdeutschland mir Hilfe von Ostracoden. Ber. deurch. Ges. geol. Wiss., A, 12, 5.557-574. 1968. Zur Gattung Saida Hornibrook (Ostracoda, Crustacea) in der Oberkreide. Geologie, 17 (8), 964-981. HORNIBROOK, N. de B. 1952. Tertiary and Recent marine Ostracoda of New Zealand. New Zeal. Geol. Surv., Pal. Bull., 18, 1-82. HOWE, H. v. and LAURENCICH, L. 1958. Introduction to the Study of Cretaceous Ostracods, 536 pp. Louisiana State Univ. Press. HOWE, R. c . and HOWE, H. J. 1973. Ostracodes from the Shubuta Clay (Tertiary) of Mississippi. J. Paleont., 47 (4), 629-656. ISHIZAKI,K. 1971. Ostracodes from Aomori Bay, Aomori Prefecture, Northeast Honshu, Japan. Tohoku Univ., Sci. Rep., 2nd ser., (Geol.), 43(1), 59-79. KEIJ, A. J. 1975. Note on three Holocene Indo-Malaysian Ostracod species. Koninkl. Nederl. Akademie van Wetenschappe-Amsterdam, Proceedings, Ser. B, Palaeontology, 78(3), 231-241. - 1979. Brief review of type species of genera from the Kingma collection. In KRSTIC, N. (ed.). Taxonomy, Biostratigraphy and Distribution of Ostracodes, 59-62, Geological Society of Serbia, Belgrade. KINGMA, J. T. 1948. Contributions to the knowlerlge of the Young-C'aenozoic Ostracoda fvom the Malayan region, 118 pp. Kemink, Utrecht. MCKENZIE, K. G. 1973. Cenozoic Ostracoda. In HALLAM A. (ed.). Atlas of Palaeobiogeography, 477-487. MOORE, R. c . (ed.). 1961. Treatise on invertebrate paleontology, Part Q , Arthropoda 3. Crustacea, Ostracoda, Geol. SOC.America and Univ. Kansas Press, New York and Lawrence. NEALE, J. w . 1975. The ostracod fauna from the Santonian Chalk (Upper Cretaceous) of Gingin, Western Australia. Spec. Papers Pal. (Pal. Assoc.), (16), 1-81. SEXTON, J. v. 1951. The ostracode Cytherelloidea in North America. J. Paleont., 25(6), 808-816. SISSINGH, w . 1972. Late Cenozoic Ostracoda of the South Aegean Island Arc. Utrecht Micropal. Bull., (6), 10-187. SZCZECHURA, J. 1965. Cytheracea (Ostracoda) from the Uppermost Cretaceous and Lowermost Tertiary of Poland. Acta Palaeont. Polonica, 10(4), 451-564.
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DISCUSSION Whatley: Saida is a strange ostracod with respect to its distribution. It seems to have been widespread since the Cretaceous in Tethyan and Indo/Pacific Seas. However, since at least the Upper Oligocene, it has occurred in deep sea environments although it is never abundant there. Recently, we discovered Saida in the Atlantic in Recent sediments. There seems to be no simple explanation of its distribution.