Phylogeny of the eelpout genus Lycodes (Pisces, Zoarcidae) as inferred from mitochondrial cytochrome b and 12S rDNA

MOLECULAR PHYLOGENETICS AND EVOLUTION Molecular Phylogenetics and Evolution 26 (2003) 369–388 www.elsevier.com/locate/ympev

Phylogeny of the eelpout genus Lycodes (Pisces, Zoarcidae) as inferred from mitochondrial cytochrome b and 12S rDNA Peter R. Møller* and Peter Gravlund Zoological Museum, University of Copenhagen, Universitetsparken 15, Copenhagen DK-2100, Denmark Received 9 July 2001; revised 10 January 2002

Abstract The bottom-dwelling and species-rich eelpout genus Lycodes Reinhardt has a great potential for the study of Arctic marine speciation. Subdivision of the genus has been based on single or few morphological characters (e.g., lateral line configuration) with contradicting results and phylogenetic approaches have not been attended. Here we present the first phylogenetic analysis of the genus employing DNA sequences of the mitochondrial genes cytochrome b and 12S rDNA (714 bp). The analysis with the two genes combined resulted in two equally parsimonious trees. In both cladograms most of the previously suggested subgroups are para- or polyphyletic, except for the so-called short-tailed Lycodes spp., with a short tail, a single mediolateral lateral line configuration and a shallow or filled otolith sulcus. The group of long-tailed Lycodes spp., with ventral or ventro-medio-lateral types of lateral line configuration and a deep otolith sulcus, appears to be paraphyletic, since Pacific and Atlantic species in this group are not each otherÕs closest relatives. Thus, the short-tailed species are placed in a derived clade, indicating a secondary shortening of the tail, and a ‘‘slope to shore’’ type of evolution. This is not in accordance with earlier assumptions of the more elongate, deeper living species being the more derived. The basal position of long-tailed Pacific species supports earlier theories of Pacific origin of the genus/ family. Small genetic differences between Arctic/Atlantic species indicate a rather recent radiation in these areas after the opening of the Bering Strait 3.0–3.5 million years ago. Ó 2002 Elsevier Science (USA). All rights reserved.

1. Introduction The eelpouts of the genus Lycodes Reinhardt, 1831 are the largest group of zoarcid fishes, including about 62 species (Anderson, 1994; Møller, 2000a,b, 2001a,b). Lycodes is currently the most species-rich genus of the Arctic Ocean and adjacent waters, providing a great potential for the study of Arctic marine speciation. The high diversity of the genus is probably caused by the absence of pelagic larval stages, and a relatively stationary lifestyle. All species produce few (< 2000) and large (up to 10 mm), benthic eggs, which is not dispersed far by ocean currents. Several species occur in high densities, suggesting great importance to the ecosystem (e.g., Møller and Jørgensen, 2000; Zemnukhov and Balanov, 1999). Monophyly of the genus is generally accepted, primarily based on one autapomorphic character, the * Corresponding author. Fax: +45-35321010. E-mail address: [email protected] (P.R. Møller).

submental crests, which are more or less pronounced cartilage extensions on the lower jaws (Anderson, 1994; Andriashev, 1954; Møller and Anderson, 2000). A morphology-based phylogenetic analysis of the family Zoarcidae placed Lycodes as the primitive sister-group to all other genera in the subfamily Lycodinae, based on the plesiomorph high parasphenoid wing, which is low in all other Lycodinae (Anderson, 1984, 1994). However, the resolution of the subfamily Lycodinae in AndersonÕs (1984) analysis was very poor due to missing entries and homoplasy, and no trees showing the potential sister-group of Lycodes were published in the 1994 paper. Thus, zoarcids are known to be affected by a high degree of homoplasy in morphological characters on both generic and species level, and Lycodes is no exception. Species identification of Lycodes is often difficult due to variability in morphology and phylogenetic approaches of the genus have not been attended, except by Møller (2001b), who analysed the Lycodes pallidus complex. An analysis of all 62 species of Lycodes with 23 morphological characters produced

1055-7903/02/$ - see front matter Ó 2002 Elsevier Science (USA). All rights reserved. doi:10.1016/S1055-7903(02)00362-7

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virtually no phylogenetic resolution and nor did analyses of the 18 species here considered for molecular studies (Møller, unpublished data). It can be concluded that much more basic work in finding additional (e.g., osteological) characters is needed before a satisfactory morphology-based phylogeny of the genus can be made. Subdivision of Lycodes has been based on single or few morphological characters, with contradicting results (Table 1). The first attempt was made by L€ utken (1880), who recognised three groups based on different types of lateral line configuration: (a) single ventral, (b) double, and (c) single mediolateral. This system was adopted by Jensen (1904), and further developed by Andriashev (1954, 1986) and Toyoshima (1985). Jensen (1904) found that L€ utkenÕs groups (a) and (b) formed a natural group (‘‘Vahlii-esmarkii group’’), corroborated by a relatively long tail in contrast to the relatively short tail found in group (c) (‘‘Reticulatus group’’). The subdivision into long-tailed and short-tailed groups has been followed in several regional studies and identification keys (e.g., Andriashev, 1986; McAllister et al., 1981; Møller and Jørgensen, 2000) and in descriptions of new species (e.g., McAllister, 1976; Møller, 2001a,b; Nielsen and Foss a, 1993). Several zoarcid genera described by Bleeker (1874), Jordan and Evermann (1898), and Popov (1931) were

implemented as subgenera of Lycodes by Shmidt (1950) (Table 1). In his paper about the species from Sea of Okhotsk he recognised five subgenera, based on the shape of submental crests (Bergeniana), emargination of pectoral fins (Furcimanus), and squamation (Lycodalepis, Lycias, and Lycodes s. str.), thus giving the lateral line configuration less weight. Anderson (1994) did not agree on most of ShmidtÕs subgenera, but suggested the previously separate genera Petroschmidtia Taranets and Andriashev and Lycodopsis Collett as subgenera. Aprodon Gilbert was considered a separate monotypic genus by some recent authors (e.g., Robins, 1980; Toyoshima, 1985), but was regarded a junior synonym of Lycodes, with strong affinity to the subgenus Lycodopsis by Anderson (1994). He also accepted Furcimanus, and suggested an unnamed group of deep-sea species as a possible subgenus (Table 1). Like other zoarcids, Lycodes is expected to have originated in the northern Pacific, based on the higher diversity found there compared to Arctic and Atlantic oceans (Briggs, 1974; Shmidt, 1950). Lycodes appear to have had a much more pronounced Arctic/Atlantic radiation than other Arctic genera in families with an expected Pacific origin (e.g., Pholididae (Yatsu, 1985); Cottoidea (Yabe, 1985); Agonidae (Kanayama, 1991); Sebastes (Rocha-Olivares et al., 1999); Pleuronectidae

Table 1 Overview of suggested subgenera and species groups of Lycodes in the literature Author

Area

Characters

Subgenus/group

L€ utken (1880)

Arctic, Atlantic

Lateral line configuration

Single ventral Double Single medio-lateral Lycodes

3 1 4 9

Lycias vahlii-esmarkii group

2 9

— —

Jordan and Evermann Arctic, Atlantic, Pacific (1898)

Squamation

Jensen (1904)

Arctic, Atlantic

Lateral line configuration and length of tail

Shmidt (1950)

Arctic, Pacific

Submental crests Pectoral fin Squamation

—

— —

Toyoshima (1985)

Arctic, Pacific

Lateral line configuration — — — — —

Anderson (1994)b

Arctic, Atlantic, Pacific

Møller (2001b)

Arctic, Atlantic, Pacific

a

Pelvic fin ‘‘spine’’ Pectoral fin Tooth loss, coloration Lateral line configuration, coloration, length of tail, meristics and squamation Lateral line configuration

reticulatus group Bergeniana Popov, 1931 Furcimanus Jordan and Evermann, 1898 Lycodalepis Bleeker, 1874 Lycias Jordan and Evermann, 1898 Lycodes s. str. Reinhardt, 1831 A, anterolateral B, anteroventral C, midlateral D, ventromidlateral E, ventral F, double Petroschmidtia Taranets and Andriashev, 1934 Furcimanus Jordan and Evermann, 1898 Lycodopsis Collett, 1879 Unnamed

Lycodes pallidus complex

ToyoshimaÕs group F, double with zero taxa in the study area, present elsewhere. b Anderson considered 57 species valid, of which 11 were placed in suggested subgenera.

Species

6 3 4 4 2 15 2 2 12 13 12 0a 2 3 2 4

5

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(Cooper and Chapleau, 1998)). As for many other North Pacific fish genera, the Arctic/Atlantic distribution of Lycodes is generally thought to represent an occupation of the area about 3.0–3.5 million years ago, following the opening of the Bering Strait (Anderson, 1982, 1994; Herman and Hubkins, 1980). The many Pliocene-Pleistocene glacial and interglacial periods, with repeated openings and closings of the Bering Strait, are thought to be the most important generators of vicariant events in the evolution of Arctic fishes (Anderson, 1982; Andriashev, 1939, 1949; Berg, 1934). Thus, a relatively recent radiation of Arctic and Atlantic species is expected, probably with younger and more derived species than in the Pacific. No fossil Lycodes exists to test biogeographic hypotheses, but cladograms will hopefully be a valuable alternative in the reconstruction of the historical biogeography of the genus. Sequence data of mitochondrial DNA (mtDNA) have become a widely used tool for addressing phylogenetic relationships at various levels among perciform fishes (e.g., Lydeard and Roe, 1997; Song et al., 1998; Wiley et al., 2000). However, molecular studies of zoarcids have hitherto been prevented by the rarity of many species and logistic problems with obtaining samples (Anderson, 1994). Six species (Austrolycus depressiceps (28S), Lycodes cortezianus (12S, 16S), Lycodes pacificus (12S, 16S), Lycodichthys dearborni (12S, 16S), Pachycara brachycephalum (12S, 16S), and Zoarces viviparus (12S)) of the about 220 zoarcid species have been included in molecular phylogenetic studies, all as outgroups in analyses of other taxa (Notothenioidei (Bargelloni et al., 1994; Lecointre et al., 1997); Blennioidei (Stepien et al., 1997)). The aims of the present study are: (1) to employ DNA sequence data of the mitochondrial genes cytochrome b and 12S rDNA in order to elucidate the phylogenetic relationships within the genus Lycodes; and (2) to employ the resulting topologies in a discussion of: (a) the evolution of morphological characters (lateral line configuration, length of tail, vertebral counts, squamation, submental crests, pectoral fin shape, dentition, otolith, and coloration); (b) previously suggested subgenera and species groups; and (c) the biogeography of the genus.

2. Materials and methods 2.1. Samples Specimens of 13 species of Lycodes and two species of Lycenchelys were collected during several bottom-trawl surveys in the North Atlantic (Canadian, Greenlandic, and Norwegian waters). Identification was mainly made using Andriashev (1986) and Møller and Jørgensen (2000). Tissue samples (gill arch or tail musculature)

371

were dissected, avoiding cross-contamination, and stored in DMSO or in 95% ethanol, at 5 °C. Vouchers were fixed in 4% formaldehyde and stored in 70% ethanol at the Zoological Museum, University of Copenhagen (ZMUC). In addition, tissue samples and vouchers of six northeastern Pacific species/subspecies were borrowed from the Natural History Museum, University of Kansas (KUNHM). A list of the specimens used in the molecular study is presented in Table 2. 2.2. Morphological data Morphological characters were obtained from 1361 specimens of 56 distinct species of Lycodes, including primary types of 36 species. Data for six species were taken from the literature. A list of the specimens examined is provided in Appendix A. Institutional abbreviations follow Leviton et al. (1985), with the addition of Marine Research Institute of Iceland (MRII) and Natural History Museum Torshavn, Faroe Islands (NHMT). Fin ray and vertebral counts were taken from radiographs. Otoliths (sagitta) were dissected and studied by scanning electron microscopy (SEM). Morphometric measurements were made with a dial calliper to nearest 0.1 mm. Listing all counts and measurements is outside the scope of the present paper. However, potentially phylogenetically informative characters and characters used in previous attempts to subdivide the genus are listed in Appendix B. 2.3. DNA extraction, PCR amplification, and sequencing DNA was extracted from gill arch or muscle tissue using QIAmp Tissue Kit from Qiagen following the supplierÕs protocol. A standard 50 ll double-stranded (ds) PCR was carried out using 1 ll of the extracted DNA as template. The conditions of the PCR was for the 12S: one initial cycle of denaturation (94 °C, 2 min), followed by 30 cycles (94 °C for 1 min, 52 °C for 1 min, 72 °C for 1 min) and finally one cycle (94 °C for 30 s, 52 °C for 30 s, 72 °C for 5 min). Primers for 12S: 12SA5ðLÞ0 AAA CTG GGA TTA GAT ACC CCA CTAT-30 and 12SB-3ðHÞ0 GAG GGT GAC GGG CGG TGT GT-50 (Palumbi, 1996). For the amplification of the cytochrome b fragment the following conditions were applied: one initial cycle of denaturation (94 °C, 2 min), followed by 30 cycles (94 °C for 1 min, 52 °C for 1 min, 72 °C for 1 min) and finally one cycle (94 °C for 30 s, 52 °C for 30 s, 72 °C for 5 min). Primers for cytochrome b: GLU-5ðLÞ0 -TGA CTT GAA GAA CCA C/TCG TTG-30 (Palumbi, 1996) and CB2-5ðHÞ0 -AAA CTG CAG CCC CTC AGA ATG ATA TTT GTC CTC A-30 (Kocher et al., 1989). The dsPCR was carried out on a Techne Gene E Thermal Cycler. The PCR products were visualised on a low-melting point agarose gel containing ethidium

372

Species

Museum No.

Lycenchelys muraena Lycenchelys sarsii Lycodes spp. L. adolfi L. concolor L. cortezianus L. diapterus beringi L. diapterus diapterus L. esmarkii L. eudipleurostictus L. gracilis L. luetkenii L. mcallisteri L. paamiuti L. pacificus L. palearis L. pallidus L. reticulatus L. rossi L. seminudus L. terraenovae L. vahlii

ZMUC P764754 ZMUC P764755 ZMUC P764762 KUNHM 29970 KUNHM 23239 KUNHM 28240 KUNHM 28260 ZMUC P765170 ZMUC P765127 ZMUC P763167 ZMUC P765162 ZMUC P765163 ZMUC P765128 KUNHM 29971 KUNHM 28187 ZMUC P764751 ZMUC P765102 ZMUC P763082 ZMUC P765177 ZMUC P765149 ZMUC P765179

GenBank Accession No.

T2344 T2160 T2369 T2162

T498 T375

Collection locality

Latitude

Longitude

Depth (m)

Date (yymmdd)

Cytochrome b

12S

AY158831 AY158815

AY159963 AY159964

Baffin Bay, NW Atlantic Baffin Bay, NW Atlantic

67°190 N 67°340 N

60°110 W 58°280 W

1141 461

991012 991010

AY158832 AY158830 AY158827 AY158828 AY158829 AY158833 AY158835 AY158825 AY158824 AY158823 AY158822 AY158821 AY158826 AY158820 AY158819 AY158818 AY158817 AY158816 AY158834

AY159965 AY159959 AY159956 AY159957 AY159958 AY159972 AY159967 AY159961 AY159970 AY159971 AY159968 AY159960 AY159955 AY159962 AY159966 AY159975 AY159973 AY159969 AY159974

Baffin Bay, NW Atlantic Bering Sea, N Pacific Off California, NE Pacific Bering Sea, N Pacific Off California, NE Pacific Denmark Strait, NE Atlatic Baffin Bay, NW Atlantic Off Svalbard, NE Atlantic Cumberland Sound, NW Atl. Cumberland Sound, NW Atl. Baffin Bay, NW Atlantic Monterey Bay, NE Pacific Bering Sea, N Pacific Baffin Bay, NW Atlantic Baffin Bay, NW Atlantic Off Svalbard, NE Atlantic Baffin Bay, NW Atlantic Davis Strait, NW Atlantic Baffin Bay, NW Atlantic

67°540 N 57°660 N 34°500 –35°860 N 52°660 N 35°860 N 65°290 N 66°170 N 78°080 N

59°490 W 169°330 W 121°530 W 172°680 W 121°530 W 31°550 W 59°210 W 14°000 E

1441

991011 920825 971024 970805 971024 980629 991008 950509 95???? 000412 991008 9402?? 920825 991014 991008 940821 970820 990926 970819

— —

697 708 234

—

—

—

65°500 N 66°170 N 32°530 N 51°510 N 68°230 N 66°200 N 80°190 N 71°050 N 64°160 N 71°300 N

66°200 W 59°210 W 117°170 W 178°040 W 64°200 W 60°350 W 16°050 E 57°000 W 57°420 W 56°230 W

572–668 708 — —

422 441 352 327 877 272

P.R. Møller, P. Gravlund / Molecular Phylogenetics and Evolution 26 (2003) 369–388

Table 2 List of species, museum number, GenBank number, geographic position, depth of capture, and collection date for the specimens used in this study

P.R. Møller, P. Gravlund / Molecular Phylogenetics and Evolution 26 (2003) 369–388

bromide. In cases of sharp but faint bands a subsample was taken from the gel, eluted in 100 ll 1 TE and a new dsPCR carried out using 1 ll of the resolved PCRproduct as template and applying the same PCR conditions as above except for a 1 °C raise in annealing temperature. The dsPCR products were then cleaned using QuiaAmp columns. The purified dsPCR products were used as templates (1 ll) for a 10 ll cyclic sequencing (cs) reaction using ABI prism DNA Sequencing Kit (dRhodamine Terminator Cycle Sequencing Ready Reactions). For the cs reaction we used the same primers, one in each csPCR, as for the initial dsPCR reaction. Cs PCR conditions for both cytochrome b and 12S: one initial cycle (96 °C, 2 min) followed by 34 cycles (96 °C, 20 s, X °C, 10 s, 60 °C, 2 min) and finally one cycle (96 °C, 20 s, X °C, 10 s, 60 °C, 7 min). Annealing temperatures (denoted X °C) were identical to the dsPCR annealing temperatures. After cyclic sequencing the products were purified using ethanol precipitation. The purified sequencing products were run on a Perkin– Elmer ABI Prism 377 DNA Sequencer in a 5% polyacrylamide gel. The chromatographs resulting from laser spectroscopy of the fluorescent labelled nucleotides (Shera et al., 1990) were aligned manually using the computer program Sequencher (Perkin–Elmer). Alignment was unambigous as no insertions/deletions was observed. 2.4. Phylogenetic analyses All phylogenetic analyses were executed using parsimony, implemented in PAUP* (Swofford, 1998). The closely related species Lycenchelys muraena and L. sarsii (subfamily Lycodinae, sensu Anderson, 1994) were designated as outgroup taxa. Using two species from a relatively closely related genus has been suggested to be superior to using taxa from different but more distantly related genera (Smith, 1994). For the resulting topologies the consistency index (CI) was calculated to estimate the levels of homoplasy (Kluge and Farris, 1969). The cytochrome b and 12S sequences were analysed both independently and combined. However, since both genes are mitochondrial, which is inherited as one locus and without recombination, and since the sequences always originate from the same specimen, the two genes can be assumed to have experienced the same branching history, favouring a combined analysis. It has, however, been argued that genes can have evolved under different evolutionary rates and constraints resulting in very different topologies (Bull et al., 1993; de Queiroz et al., 1995). In the case of different data sets leading to different topologies, an incongruence length difference test (ILD) (Farris et al., 1995) was applied using PAUP* (Swofford, 1998) and TreeRot.v2 (Sorensen, 1999). The analysis was carried out using 100 random replicates in each of 10 searches with random taxa input order.

373

In parsimony analysis only minimal-length trees were retained and zero length branches were collapsed. The heuristic search algorithm was used and employed 1000 random addition of taxa and tree bisection and reconnection (TBR) branch swapping. The robustness of the clades recovered in the phylogenetic hypotheses were evaluated using the Bremer support index (Bremer, 1994). Furthermore, the partitioned Bremer support (PBS) for each of the two data sets was calculated for the topology resulting from the combined analysis (Baker and DeSalle, 1997). The PBS was calculated using the program TreeRot.v2 and PAUP* and gives an indication of which part of the combined data set supports the specific clades.

3. Results The variation of the analyzed sequences from the 19 taxa of Lycodes and two outgroup species are summarized in Table 3. The sequences were submitted to GenBank (Table 2). Table 4 shows the genetic distances calculated for the combined data set of 714 bp, as uncorrected paired nucleotide differences. The most similar pair of ingroup species is L. terraenovae and L. adolfi, which differ from one another by three substitutions (0.4%), and the least similar pair is L. esmarkii and L. cortezianus, which differ by 38 substitutions (5.3%). The results of each of the analyses are summarised in Fig. 1A–D and 2. Lycodes is monophyletic with respect to the Lycenchelys outgroups in all analyses, supported by high Bremer Support values; 14 in cytochrome b, 11 in 12S and 25 in combined analysis (Figs. 1A–B and 2). Ingroup clades in all trees are supported by varying Bremer Support values (from 1 to 8). Terminal branches are generally better supported than deeper nodes. The topology of the cytochrome b strict consensus tree is well resolved, with L. concolor as the earliest diverged species (Fig. 1A). The topology of the 12S strict consensus tree is poorly resolved and contains only three clades (Fig. 1B). Sister-group relationships of L. terraenovae + L. adolfi, and L. diapterus diapterus + L. diapterus beringi are in accordance with the cytochrome b tree, whereas the grouping of the two last-mentioned with L. cortezianus + L. pacificus contradicts the topology obtained using cytochrome b.

Table 3 Summary of gene sequence variability in the 19 taxa of Lycodes Base pairs

Variable sites

Phylogenetically informative

Cytochrome b 12S rDNA

320 394

52 (16.3%) 31 (7.8%)

34 (10.6%) 19 (4.8%)

Total

714

83 (11.6%)

53 (7.4%)

374

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Table 4 Pairwise numbers of nucleotide differences of combined cytochrome b + 12S rDNA analysis (lower half of the matrix) and cytochrome b analysis (upper half of the matrix) 1 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21.

Lycodes pallidus L. mcallisteri L. terraenovae L. adolfi L. rossi L. gracilis L. palearis L. diapterus diapterus L. concolor L. seminudus L. vahlii L. cortezianus L. diapterus beringi L. pacificus L. eudipleurostictus L. reticulatus L. paamiuti L. esmarkii L. luetkenii Lycenchelys sarsii Lycenchelys muraena

—

7 20 17 14 8 8 29 21 13 8 32 27 35 7 17 7 15 15 47 44

2 5 —

18 15 13 7 7 29 17 12 7 29 27 31 4 16 6 16 12 47 44

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

11 9

10 8 1

10 9 14 13

5 4 10 9 10

7 6 8 9 10 6

17 17 16 15 19 17 15

17 13 15 14 15 16 16 19

8 7 9 10 7 7 5 16 17

7 4 10 9 11 2 8 17 14 9

23 20 21 22 20 23 19 26 25 18 21

17 17 18 17 19 17 15 6 21 16 19 24

25 21 20 21 21 24 20 25 22 19 22 11 25

4 1 10 9 10 5 7 18 14 8 5 21 18 22

12 11 16 15 4 12 12 19 19 9 13 20 19 25 12

4 3 9 8 9 5 7 16 13 8 3 19 18 21 4 11

9 10 10 9 14 10 10 15 20 11 12 25 15 26 9 16 11

13 10 16 15 9 12 10 19 18 9 12 17 19 18 11 11 11 14

28 28 29 30 28 28 24 32 28 23 30 33 30 37 29 30 29 28 28 —

29 29 32 31 27 29 27 33 29 26 31 38 31 41 30 29 30 29 27 8

15

—

—

3 21 18 16 33 24 19 20 33 35 37 18 24 19 15 23 49 52

—

18 15 15 30 21 18 17 32 32 36 15 21 16 14 20 48 49

—

15 13 30 18 12 16 28 30 32 11 5 14 20 11 45 43

—

8 30 21 13 6 33 28 35 9 16 9 13 15 46 45

—

26 19 9 10 27 24 29 9 16 9 15 11 42 41

—

31 30 30 33 8 37 28 31 29 31 31 54 50

—

22 19 34 31 32 18 23 18 26 20 48 44

—

15 30 28 31 14 15 14 18 12 45 44

—

31 30 33 9 19 5 19 15 50 47

—

31 20 28 29 29 38 26 54 56

—

35 28 31 29 29 29 54 48

—

32 37 32 40 28 63 62

—

14 8 16 14 45 45

—

17 21 14 46 46

—

18 14 49 46

—

18 47 46

—

47 42

Cytochrome b 320 bp; 12S rDNA 394 bp.

The analysis of the combined cytochrome b and 12S data set resulted in two equally parsimonious trees (Figs. 1C–D). The two trees differ solely in the position of clade (B). In one tree (Fig. 1C), clade (B) appears as sister-group to L. gracilis among the rest of the long-tailed Atlantic species (clade FI ). In the other tree (Fig. 1D) it appears in a clade (G) as sister-group to the clade of short-tailed species (C). The exact phylogenetic positions of L. pallidus, L. gracilis, and L. palearis were not resolved with the present data set, as evidenced by the lack of Bremer support in the strict consensus tree (Fig. 2). However, in both most parsimonious trees (Fig. 1C–D) these species are found to be closer related to the clades of Atlantic long-tailed species (clade F) than to the clade with short-tailed species (C). Pacific/Arctic L. palearis is placed in a derived clade (F) together with Atlantic/Arctic species in both most parsimonious trees, indicating a closer relationship to Arctic/Atlantic species than to NE Pacific species (Fig. 1C–D). In Figs. 3–6 selected morphological characters and the distribution areas are traced on the strict consensus tree of the combined analysis (Fig. 2). The results are described and discussed in the next section.

4. Discussion 4.1. Discussion of the evolution of morphological characters and of previously suggested subgenera/species groups as revealed by the molecular cladograms In the following discussion, unless otherwise mentioned we refer to the trees of the combined cytochrome

b and 12S analysis (Figs. 1C–D and 2–6). It should be noted that these trees are gene trees based on mitochondrial genes and the results should be considered a first attempt to reconstruct the evolutionary history of Lycodes. Before any definite conclusions can be drawn further investigations utilising more sequence data from both mitochondrial and nuclear genes combined with more morphological data are needed. 4.1.1. Lateral line configuration It is evident that none of the lateral line groups (configurations) used in many papers (Table 1) appears monophyletic in the present analysis (Fig. 3). A ventral lateral line is indicated to be plesiomorphic in Lycodes, but all three types of ventral lateral line configuration (single, double, +1/2 mediolateal) seem to be homoplastic according to Fig. 3. The basal taxa L. concolor has a ventral + 1/2 mediolateral lateral line configuration, and appear to be distantly related to the other species (L. pallidus and L. paamiuti) with this kind of lateral line configuration (Fig. 3). This contradicts the a priori assumption of Møller (2001b) that five species with this kind of lateral line constitute a monophyletic group. Among the investigated species two clades (C and D) contain species with a single mediolateral configuration, indicating that the two East Pacific longtailed species L. cortezianus and L. pacificus are not closely related to the four Arctic short-tailed species with similar lateral line configuration (Fig. 3). Our results indicate that two independent reversals from a complicated (ventral) to a simple (mediolateral) lateral line occurred, during the evolution of Lycodes if we

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assume that the plesiomorphic state for a percid fish is a simple, mediolateral line. However, the topology of the cytochrome b tree (Fig. 1A) shows a rather different result, with all species having a single mediolateral line in the same clade. If this is followed, elongation of the tail and otolith sulcus deepening should have occurred secondarily in the common ancestor of L. cortezianus and L. pacificus. In both cases the position of L. cortezianus and L. pacificus within the ingroup clearly indicate that their former generic names Aprodon and Lycodopsis should be abandoned, as suggested by Anderson (1984, 1994). The two species with a ventro-medio-lateral configuration (Lycodes mcallisteri and L. palearis) are not sister species, according to the molecular data. The topology (Fig. 3) indicates that this configuration has evolved more than once and that the whole group of about 15 species as listed in Møller (2001a) is polyphyletic. L. mcallisteri appears to be closely related to L. eudipleurostictus, with which it occurs sympatrically in Baffin Bay, Eastern Arctic Canada (Fig. 2). The two species were not previously considered closely related because of their different lateral line configuration (Fig. 3) (Møller, 2001a). Furthermore, L. terraenovae (L. atlanticus in some papers) was considered most similar to L. esmarkii and L. eudipleurostictus on the basis of lateral line configuration (Fig. 3), squamation and head pores (Møller, 1997, 2000a). In the present study both genes agree that L. terraenovae is closest to L. adolfi, despite obvious differences in the above-mentioned characters. This relationship was actually suggested by Nielsen and Foss a (1993) after they had excluded other similar species on the basis of squamation and coloration. 4.1.2. Length of tail The phylogenetic significance of tail length is supported by the molecular data. Thus, the four included species with a short tail (preanal length > 45% SL) are monophyletic (clade C), and are placed in an unsolved polytomious clade (E) with the rest of the Arctic/Atlantic species and Pacific L. palearis (Fig. 2). However, in both most parsimonious trees, they form a sister clade to clade (F) of long-tailed species, with or without clade B (Fig. 1C–D). The fact that all deeper ancestral lineages to clade (C) have a long tail, indicate that short-tailed Lycodes evolved from a long-tailed ancestor, which is not in accordance with AndersonÕs (1994) interpretation of this character: A long tail is thought to be a homoplastic, derived state in the suborder Zoarcoidei, and within Zoarcidae a relatively short tail is regarded the plesiomorph state at the generic level. If the latter view is applied into our results, the short tail in some Lycodes must be interpreted as a reversal. Elongation of the tail was suggested to be an adaptation to a deep-sea environment, increasing the

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functional effect of the sensory lateral line system in a dark environment (Marshall, 1971). McAllister (1976) stated that long-tailed Lycodes tend to inhabit cooler and deeper waters than short-tailed species. Depth range for short-tailed Lycodes is c. 0–1200 m versus 3– 3000 m for long-tailed species (Appendix B). However, several long-tailed species inhabit relatively shallow water, especially in the Arctic and NW Pacific. The short-tailed species do not inhabit warmer waters than long-tailed ones, in fact, almost half (8 of 17) of the short-tailed species are Arctic endemics versus only 20% (9 of 46) of the long-tailed species (Appendix B). Thus, the present analysis indicates that a short tail in Lycodes represents a (secondary) adaptation to relatively shallow Arctic waters. Evolution of shallow water taxa from deep water ancestors (slope to shore) was reported for the zoarcids of the Magellan province (Anderson, 1994, Fig. 17), Ogcocephalidae and Carapidae (Markle and Bradbury, 1986), gadoids (Howes, 1991), and Bythitidae (Cohen and McCosker, 1998). 4.1.3. Vertebral counts A long tail generally corresponds to a high count of caudal vertebrae, whereas a high number of precaudal vertebrae is found mainly among the species with a short tail (Appendix B). The position of the clade (C) with short-tailed species indicates a secondary loss of caudal vertebrae within Lycodes, which occurred five times at the generic level in Zoarcidae (Anderson, 1994). The high number of precaudal vertebrae in short-tailed species might be apomorphic for this group. However, a few homoplastic exceptions exist. L. luetkenii, for example, has few precaudal vertebrae for a short-tailed species, and L. vahlii has an unusually high precaudal vertebral count for a long-tailed Lycodes (Appendix B). In old literature many subspecies of Lycodes were defined, often on the basis of difference in vertebral counts (e.g., Jensen, 1904; Shmidt, 1950; Vladykov and Tremblay, 1936). In recent literature most described subspecies have been raised to species level or included in the general description of the original species (Anderson, 1994; Toyoshima, 1985). Until recently the NE Atlantic species L. gracilis was considered a subspecies of L. vahlii (e.g., Andriashev, 1986; Nash, 1986). In the present study the two species do not appear to be closely related (Fig. 2), supporting the recent resurrection of L. gracilis as a valid species based on several morphological characters (e.g., vertebral counts, color, squamation) (Carl, 2002). The present study indicates a sister-group relationship of the subspecies L. diapterus beringi and L. diapterus diapterus (Fig. 2). However, from Table 4 it is clear that they are not more similar than closely related, well separated species of Lycodes. They differ in vertebral counts (110–117 versus 119–121), coloration and other morphological characters (Andriashev, 1935;

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Fig. 1. Phylogeny of 18 species of Lycodes: (A) Cytochrome b, strict consensus of nine most parsimonious trees, tree length (TL) ¼ 120, CI ¼ 0.62; (B) 12S rDNA, strict consensus of 4724 most parsimonious trees, TL ¼ 64, CI ¼ 0.70; (C) Cytochrome b + 12S rDNA, first of two most parsimonious trees, TL ¼ 191, CI ¼ 0.62; (D) Cytochrome b + 12S rDNA, second of two most parsimonious trees TL ¼ 191, CI ¼ 0.62. Numbers on branches in (A) and (B) represent Bremer support index values.

Shmidt, 1950; Møller, unpublished data), and an extended morphological analysis should be carried out to clarify the taxonomy of the species complex.

4.1.4. Reduced squamation Occurs in several species in different clades, indicating that loss of scales has occurred several times during the

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Fig. 1. (continued)

evolution of Lycodes, as illustrated by the loss of abdominal scales (Fig. 5). In small species with a maximum length < 25 cm (e.g., L. adolfi and L. marisalbi), reduced squamation might represent a neotenic state, since juveniles (<60–90 mm) of larger, densely scaled species are

often more or less naked. Alternatively, reduced squamation might be related to low temperature (Andriashev, 1954), since naked or seminaked species of Lycodes are more frequent among Arctic species than among boreal congeners. Short-tailed species are

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Fig. 2. Phylogeny of 18 species of Lycodes. Cytochrome b + 12S rDNA, strict consensus of the two most parsimonious trees. Numbers on branches represent Partitioned Bremer support values given as cytochrome b/12S rDNA support.

generally less scaled (naked, or with naked abdomen and predorsal area) than long-tailed species, but several exceptions exist, e.g., naked abdomen and predorsal area in long-tailed L. pallidus and L. paamiuti (Fig. 5), and scaled predorsal area in short-tailed L. lavalaei and L. macrolepis (Appendix B). It appears that squamation is a very variable character, of little use in defining subgeneric groups within Lycodes. 4.1.5. Submental crests None of the sequenced species possess fused submental crests, leaving no basis for evaluation of the monophyly of the Bergeniana groups suggested by Popov (1931) and Shmidt (1950) (Table 1). The homology of the fused submental crests in about 15 NW Pacific species (see Appendix B) is not particularly certain and awaits further study (Anderson, 1994). Lycodes diapterus was reported to have fused submental crests (Toyoshima, 1985), which is not in accordance with our observations of free submental crests in the specimens examined for the present study. 4.1.6. Pectoral fin emargination Three of the sequenced taxa have an emarginate pectoral fin. They appear in two different clades; L. diapterus beringi and L. diapterus diapterus in a basal clade (D) with other long-tailed East Pacific species, and in L. eudipleurostictus in a derived clade (A) with

L. mcallisteri and other Arctic/Atlantic long-tailed species. Thus, the present results strongly indicate that the subgenus Furcimanus (Shmidt, 1950), based on pectoral fin emargination, is polyphyletic. Five additional species in the genus have an emarginate pectoral fin, of which L. diapterus, L. nakamurae, and L. pectoralis might be closely related (Anderson, 1994; Appendix B). The number of pectoral fin rays does not seem to be of phylogenetic importance, since high and low numbers are found in different clades (Appendix B). 4.1.7. Dentition Lycodes cortezianus and L. pacificus lack palatine teeth and L. pacificus lacks vomer teeth as well. Among the sequenced species these two species appear to be sister species, as suggested by Anderson (1994). Their close relation to L. diapterus is also supported by coloration, since all three species usually have a dark spot anteriorly in the dorsal fin. These characters are not unique for these species, and cannot justify a separate subgenus (Lycodopsis). Lack of palatine and vomer teeth is also seen in two NW Pacific species, L. albonotata and L. toyamensis, formerly placed in a separate genus Petroschmidtia (Matsubara and Iwai, 1951; Taranets and Andriashev, 1934; Toyoshima, 1985) or subgenus (Anderson, 1994). The two toothless NW Pacific species resemble L. cortezianus and L. pacificus in

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Fig. 3. Types of lateral line configuration in Lycodes indicated on cytochrome b + 12S rDNA, strict consensus tree. Symbols: White with black grid, mediolateral; black with white spots, ventro-medio-lateral; white, single ventral; white with black spots, ventral + 1/2 mediolateral; black, double ventral + mediolateral; horizontal stripes, equivocal. Figure generated using MacClade Version 3.0 (Maddison and Maddison, 1992).

having a long tail and a mediolateral lateral line, but differ by having high and fused submental crests, lack of pyloric caeca, and a unique pelvic fin spine (Appendix B). 4.1.8. Otoliths The morphology of the otolith sulcus was found to support the grouping of long-tailed and short-tailed species (Fig. 4). Otoliths of long-tailed species possess a deep sulcus (e.g., Lycodes brevipes, L. diapterus, and L. palearis (Morrow, 1979); L. gracilis (Carl, 2002); L. adolfi (Nielsen and Foss a, 1993); and L. mcallisteri (Møller, 2001a), whereas otoliths from short-tailed species have a more or less filled sulcus, e.g., L. luetkenii (Møller and Petersen, 1997). A filled sulcus is generally regarded as apomorphic in teleosts (Werner Schwarzh-

ans, personal communication), which is confirmed in the present study (Fig. 4). 4.1.9. Coloration All short-tailed species have some kind of stripes, marks or reticulations, whereas the long-tailed species are uniformly brownish, striped or spotted (Appendix B). The homology of different types of coloration is uncertain, and the phylogenetic significance of color seems to be very limited. Lycodes rossi and L. reticulatus are separated mainly by color (adult L. rossi with well-defined light stripes, versus reticulations in L. reticulatus), length of opercular lobe and depth of body (Andriashev, 1954, 1986; McAllister et al., 1981). Due to the weak morphological differentiation the validity of L. rossi was questioned by

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Fig. 4. Length of tail and otolith sulcus morphology in Lycodes indicated on cytochrome b + 12S rDNA strict consensus tree. Symbols: Black, long tail (preanal length < 45% SL), sulcus deep; white, short tail (preanal length > 45% SL), sulcus shallow/filled. Figure generated using MacClade Version 3.0 (Maddison and Maddison, 1992).

McAllister et al. (1981). However, the genetic distance between the two species is the same (0.7%) as it is for some of the more morphologically distinct species (e.g., L. vahlii and L. paamiuti) (Table 4). The morphology of the two species should be studied in more detail. Except for L. seminudus, which has a speckled peritoneum with tiny black dots, short-tailed species have a light peritoneum (clade C). A speckled peritoneum is also seen in L. palearis and in a few other long-tailed species (Appendix B), most of which have a black or brown peritoneum. A dark peritoneum has been suggested to be an adaptation of deep-sea fishes to bioluminescent prey (McAllister, 1961). Thus, our results indicate that the light and speckled peritoneum in the above-mentioned species reflects a secondary loss of pigmentation. 4.2. Biogeography The present results with Pacific species in the basal clades support the assumed Pacific origin of the genus as

suggested by Shmidt (1950), Briggs (1974), and Anderson (1994) (Fig. 6). The lower level of genetic difference between related Arctic/Atlantic species (0.4–3.4%) than between NE Pacific species (2.8–5.2%) (Table 4) supports the hypothesis of a recent radiation of Arctic species after the opening of the Bering Strait, about 3.0– 3.5 million years ago. In codfishes (Gadidae), which is believed to have an Atlantic origin and to have invaded the Arctic from the Atlantic side (Cohen et al., 1990; Howes, 1991), the most genetically similar species are also found among Arctic species (Arctogadus glacialis, Boreogadus saida, Gadus spp., and Theragra chalcogramma) (Carr et al., 1999; Møller et al., 2002). From the present molecular data we cannot tell if Lycodes invaded the Arctic Ocean one or several times. Our two topologies indicate a single invasion from the Pacific into the Arctic/Atlantic Oceans, with a possible secondary back dispersal of L. palearis (Fig. 6). However, when all 62 species of Lycodes are taken into consideration (Appendix B), it is clear that several invasions is a more likely scenario. At least some of the radiation is

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Fig. 5. Squamation on abdomen in Lycodes, indicated on cytochrome b + 12S rDNA strict consensus tree. Figure generated using MacClade Version 3.0 (Maddison and Maddison, 1992).

expected to have happened in the NW Pacific, e.g., Sea of Okhotsk, where the highest diversity of Lycodes occurs (Shmidt, 1950). For example, about five species of short-tailed Lycodes are endemic to the NW Pacific, indicating that the short-tailed species might have branched off prior to the opening of the Bering Strait. During cold, glacial periods, Arctic species of Lycodes have either adapted to brackish water, e.g., L. jugoricus and L. marisalbi (Møller, 2000b); to relatively deep waters (e.g., most of the sequenced Arctic species); or have migrated to more southern areas. Only a few (L. esmarkii, L. gracilis, L. terraenovae, and L. vahlii), have been able to invade truly Atlantic waters (Carl, 2002; Møller and Jørgensen, 2000), and they do not form a monophyletic group (Fig. 6). The small genetic difference between these and Arctic species indicates that this has happened relatively recently (Table 4). Most species are limited to Arctic waters, mainly north of the ‘‘Shetland–Faroe-Iceland– Greenland–Canada’’ submerged ridge (Møller and Jørgensen, 2000). However, some of the Arctic species (e.g., L. polaris and L. reticulatus) occur further south

along the east coast of North America (to the Gulf of St. Lawrence), following the cold Labrador Current (Scott and Scott, 1988; Vladykov and Tremblay, 1936). A more detailed analysis of the biogeography of the genus must await the implementing of more ingroup taxa, especially from the NW Pacific, and additional lycodine outgroups into the data matrix.

Acknowledgments We thank K. Amaoka, M.E. Anderson, M. Aschan, A. Balanov, D. Balkwill, A. Balushkin, A. Bentley, O.A. Bergstad, O. Bjelland, M. Bruni, I. Byrkjedal, N. Chernova, J.S. Christiansen, B. Coad, B. Collette, G. Duhamel, V.V. Fedorov, S.E. Fevolden, J.D.M. Gordon, B. Gulliksen, R. Haedrich, L. Heilmann, S. Jewett, G. J onsson, O.A. Jørgensen, A. Klitgaard, G. Langhelle, S. Laframboise, D. McAllister, Y. Machida, N. Merrett, K. Nakaya, E. Nielsen, P. Pethon, S. Raredon, J. Reist, C. Renaud, K. Rhode, S.A. Schaefer, G.

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Fig. 6. Geographical distribution of sequenced species of Lycodes, indicated on cytochrome b + 12S rDNA, strict consensus tree. Arctic is defined as waters north of the Shetland–Faroe-Island–Greenland–Canada submerged ridge, and north of the Bering Strait. Figure generated using MacClade Version 3.0 (Maddison and Maddison, 1992).

Schultze, B. Sheiko, G. Shinohara, M. Treble, H.T. Valtysson, L. Van Guelpen, E.O. Wiley, and H. Wilkens, for loan and donation of specimens and radiographs; and H. Glenner, J. Nielsen, and M.E. Petersen for reading and commenting on the manuscript.

Appendix A. Species of Lycodes examined for morphological characters Lycodes adolfi Nielsen and Foss a, 1993. (36 specimens). Off Greenland: ZMUC P761186 (holotype), ZMUC P766; ZMUC P76324, ZMUC P76331-33, ZMUC P76819-20, ZMUC P76830, ZMUC P76118696, ZMUC P761321, ZMUC P761324-25, ZMUC P761328, ZMUC P762219, ZMUC P762534, ZMUC P762536-43, ZMUC P764762, MRII uncat.

Lycodes albolineatus Andriashev, 1955. (five specimens). Off Kamchatka: ZIN 34582 (holotype), ZIN 34581(2), ZIN 46306(2). Lycodes albonotatus Taranetz and Andriashev, 1934. (three specimens). Sea of Okhotsk: HUMZ 126170, HUMZ 126238, HUMZ 126459. Lycodes bathybius Shmidt (1950). (two specimens). Sea of Okhotsk: ZIN 24829 (holotype), ZIN 33079. Lycodes brevicauda Taranetz and Andriashev, 1935. (nine specimens). Sea of Okhotsk: ZIN 30190(6) (syntypes), BMNH 1970.2.12:1, ZIN 37961(2). Lycodes brevipes Bean, 1890. (13 specimens). Bering Sea: USNM 45362 (lectotype), NMC 61-0048, USNM 162712(6), USNM 119704(2), USNM 218833(2), USNM 283813 (skeleton), ZIN 26886 (syntype of Lycodes brevipes diapteroides Taranetz and Andriashev, 1937).

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Lycodes brunneofasciatus Suvorov, 1935. (four specimens). Off Kamchatka: ZIN 25074 (holotype), ZIN 34836(2), ZMUC P763903. Lycodes caudimaculatus Matsubara, 1936. (three specimens). Off Japan: HUMZ 57078, HUMZ 59333-34. Lycodes concolor Gill and Townsend, 1897. (16 specimens). Bering Sea: USNM 48764 (holotype), KUNHM 29970, ZIN 47120(12), ZMUC P762861-62. Lycodes cortezianus Gilbert, 1890. (eight specimens). Off California: USMN 46457 (lectotype), KUNHM 28239, ZIN 25870, USMN 188141(2), USMN 340199, USMN uncat. Lycodes diapterus Gilbert, 1892. (nine specimens). Off California: USNM 44385 (lectotype), KUNHM 28260, KUNHM 28240, USNM 46716, USNM 104390(2), USNM 125538, USNM 756265(2). Lycodes esmarkii Collett, 1875. (39 specimens). Off Norway: ZMUO J4496 and ZMUO J4498 (syntypes). Off Virginia: USNM 28848, USNM 33054. Off Greenland: ZMUC P762734, ZMUC P762737, ZMUC P764652-57, ZMUC P764658-59, ZMUC P764660-62, ZMUC P764663, ZMUC P764664-74, ZMUC P764675, ZMUC P764676, ZMUC P764690-92, ZMUC P764721, ZMUC P764723. Gulf of St. Lawrence, Canada: NMC 60-0163 (holotype of Lycodes vachoni Vladykov and Tremblay, 1936). Lycodes eudipleurostictus Jensen, 1902. (30 specimens). Norwegian Sea: Syntypes ZMUO J4505-06, ZMUO J4511, additional specimens: Beaufort Sea: NMC 74-0275(2), off Iceland: MRII uncat. (10), off Svalbard: ZMUC P764933, off Jan Mayen Isl.: ZMUC P764927-28, ZMUC P764930-32, ZMUC P761250, West Greenland: ZMUC P762815, ZMUC P762818-24. Lycodes fasciatus (Shmidt, 1904). (two specimens). Sea of Okhotsk: ZIN 41630(2). Lycodes frigidus Collett, 1878. (26 specimens). Greenland/Norwegian Sea: ZMUC 24 (syntype), ZMUB uncat. (3), ZMUC 31-33, ZMUC 102, ZMUC 104b, ZMUC 111, ZMUC 118, ZMUC 120, ZMUC P76317-18, ZMUC P76325, ZMUC P76327-30, ZMUC P76334, ZMUC P761230-33, ZMUC P761322, ZMUC P761411. Lycodes fulvus Toyoshima, 1985. Not examined, data from Toyoshima (1985). Lycodes gracilis Sars, 1867. (12 specimens). Off Norway: J4525 (holotype). Barents Sea: USNM 341939. E. Greenland: ZMUC P764925. Off Iceland: MRII uncat. (1) Svalbard: ZMUB 10469, ZMUC P763164-70. Lycodes heinemani Soldatov, 1916. (four specimens). Sea of Okhotsk: ZIN 19169(3) (syntypes), ZIN 36176. Lycodes hubbsi Matsubara, 1955. (three specimens). Sea of Okhotsk: USNM 117967, ZIN 48859. Off Japan: USNM 150364. Lycodes japonicus Matsubara and Iwai, 1951. (nine specimens). Sea of Japan: USNM 217443, USNM 150066(8).

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Lycodes jenseni Taranetz and Andriashev, 1935. (42 specimens). Sea of Okhotsk: ZIN 24836 (holotype), USNM 150076(21), USNM 150077(19), ZIN 36937. Lycodes jugoricus Knipovich, 1906. (14 specimens). Laptev Sea: ZIN 30961 (neotype), ZIN 32911, ZIN 35053. Beaufort Sea: NMC 74-0259, NMC 77-0651, NMC 77-1101, NMC 77-1103, NMC 77-1211, NMC 771228(2), NMC 77-1235, NMC 77-1262, NMC 77-1274, NMC 81-873. Lycodes lavalaei Vladykov and Tremblay, 1936 (44 specimens). Off E. Canada: NMC 93-0110 (holotype), NMC 77-1501C, NMC 88-0316, NMC 88-0319(3), NMC 60-157, NMC 60-158, NMC 93-0110A, USNM 87672, USNM 165156, USNM 165158, USNM 16532327, USNM 341940(4), ZMH 265/1959, ZMH 266/ 1959(2), 39/1960(2), 19/1961, 24/1961, 25/1961(2), ZMH 1025/1982(2), ZMUC P762827-38. Lycodes l€uetkenii Collett, 1880. (16 specimens). Off Svalbard: ZMUO 4536 (holotype). Baffin Bay: CMNFI 1999-0021. Off Iceland: NHMR uncat. (2) Off Faeroes: NHMT uncat. (1) Kara Sea: ZIN 32749. Canada-West Greenland: ZMUC P76217, ZMUC P762812, ZMUC P762813-14, ZMUC P765162, ZMUC P761415, ZMUC P761416, ZMUC P761424. E. Greenland: ZMUC P761256, ZMUO 109/96. Lycodes macrochir Shmidt, 1950. Not examined, data from Shmidt (1950) and Toyoshima (1985). Lycodes macrolepis Taranetz and Andriashev, 1935. (four specimens). Sea of Okhotsk: ZIN 24837(3) (syntypes), ZIN 48105. Lycodes marisalbi Knipovich, 1906. (78 specimens). White Sea: ZIN 13500(4), ZIN 13501(3) and ZIN 13502 (paralectotypes). Beaufort Sea: AMNH 19834, NMC 59-0009(3), NMC 60-486, NMC 60-0491(2), NMC 75157, NMC 76-1248(2), NMC 77-976(26), NMC 771252B, NMC 77-1266(2), NMC 77-1434(5), NMC 771476C, NMC 77-1477A(5), NMC 77-1477B(5), NMC 77-1479A(5), NMC 77-1536(5), NMC 83-0030(4), NMC 83-0050. Lycodes matsubarai Toyoshima, 1985. (three specimens). Sea of Japan: HUMZ 120172, HUMZ 120227, HUMZ 120229. Lycodes mcallisteri Møller, 2001a. (nine specimens). Eastern Arctic Canada: ZMUC P764746 (holotype), CMNFI 2000-0055 (paratype), HUMZ 172115 (paratype), NMC 90-0223 (paratype), USNM 362128 (paratype), ZISP 52125 (paratype), ZMUC P765161 (paratype), ZMUC P765163 (paratype), ZMUC P765168 (paratype). Lycodes microlepidotus Shmidt, 1950. Not examined, data from Shmidt (1950). Lycodes microporus Toyoshima, 1983. (two specimens). Sea of Okhotsk: ZMUC P763906-07. Lycodes mucosus Richardson, 1855. (15 specimens). Arctic Canada: BMNH 1885.9.19.760 (holotype), NMC 60-15, NMC 62-0379(2), NMC 77-1463, NMC 90-215,

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NMC 93-0115. Bering Strait: USNM 27748 (holotype of L. coccineus Bean, 1881). Off NW Greenland: ZIN 40715, ZMUC P76631, ZMUC P76632, ZMUC uncat. Sea of Okhotsk: ZIN 24839(2), ZIN 24842 (syntypes of Lycodes knipowitschi panthera Shmidt, 1950). Lycodes multifasciatus Shmidt, 1950. (eight specimens). Sea of Japan: USNM 117933. Sea of Okhotsk: ZMUC P763908-09, ZMUC P763912-14. Bering Sea: ZIN 34866(2). Lycodes nakamurae Tanaka, 1914. (four specimens). Sea of Japan: USNM 111993, USNM 117935(3). Lycodes obscurus Toyoshima, 1985. (two specimens). Sea of Okhotsk: HUMZ 92885, HUMZ 92887. Lycodes ocellatus Toyoshima, 1985. (two specimens). Off Hokkaido: HUMZ 36844, HUMZ 36829. Lycodes ochotensis Taranetz and Andriashev, 1937. (two specimens). Sea of Okhotsk: ZIN 25271 (holotype), ZIN 46544. Lycodes paamiuti Møller, 2001b (173 specimens). Davis Strait: BMNH 1999.7.9:1-2(2), BSKU 47297, BSKU 47551, BSKU 80158, BSKU 80527, BSKU 80530(1), CNMFI 1999-0020(4), USNM 357279(2), ZIN 51961(2), ZMUC P761327, ZMUC P761364, ZMUC P761646, ZMUC P761664, ZMUC P761665-66, ZMUC P761667-68, ZMUC P762215, ZMUC P76269798, ZMUC P762699, ZMUC P762700, ZMUC P76270105, ZMUC P762707-17(11), ZMUC P762718, ZMUC P762719, ZMUC P762720, ZMUC P762721-22, ZMUC P762724 (holotype), ZMUC P762725-26, ZMUC P762727-28, ZMUC P762730-32. Denmark Strait: ISH 804-1964(2), ISH 807-1964(12), ISH147-1973(3), ISH 149-1973(3), ISH 6-1993(10), ISH 7-1993(5), ZMH 8421(7), ZMUC P763053-56(4), ZMUC P763057, ZMUC P763182, ZMUC P763184, ZMUC P763185-86, ZMUC P764086-90(5), ZMUC P764089, ZMUC P764091, ZMUC P764093-94(2), ZMUC P764094, ZMUC P764095. Greenland-Norwegian Seas: ISH 1271959, ISH 146-1959(13), ISH 76-1964, ISH 109-1965, ISH 8-1974(4), NHMT uncat. (10), ZMUB 3359(8), ZMUB 10769, ZMUC CN 65-68(4), ZMUC P761238, ZMUC P761244-45, ZMUC P761248, ZMUC P76471920, ZMUO IH 1-3/99(3). Lycodes pacificus Collett, 1879. (seven specimens). E. Pacific: USNM 27762, USNM 227178, USNM 339377(2), USNM uncat., ZMH 3747, KUNHM 29971. Lycodes palearis Gilbert, 1896. (three specimens). Bering Sea: USNM 048592 (syntype). Gulf of Alaska: NMC 61-92, KUNHM 28187. Lycodes pallidus Collett, 1879. (223 specimens). Norwegian Sea: ZMUO J4540-41 (syntypes). East Canada-West Greenland: NMC 60-448, NMC 62280(3), NMC 70-25 (9), NMC 75-1953, NMC 80-437(7), NMC 82-1064(3), NMC 90-0229, USNM 165166(2), USNM 165173, USNM 177622(3), USNM 177655, USNM 177656, ZMUC P762222, ZMUC P762258-59, ZMUC P764693-94, ZMUC P764695-96, ZMUC

P764697-98. Denmark Strait-Greenland and Norwegian Seas: MRII uncat., NHMT uncat.(4), ZMUB 1810(3), ZMUB 2566, ZMUB 2567, ZMUB 4208, ZMUB 10711, ZMUB 10770, ZMUB 10771-10780, ZMUC cn21-22, ZMUC c-f, 3-9, 11,13-14,16 and 22 (syntypes of Lycodes similis Jensen, 1904), ZMUC 241-243, ZMUC 244-246, ZMUC 248-251, ZMUC P76216, ZMUC P761235, ZMUC P761237, ZMUC P761239, ZMUC P761241, ZMUC P761243, ZMUC P761246, ZMUC P761247, ZMUC P761249, ZMUC P761323, ZMUC P761329, ZMUC P763033-34, ZMUC P763035-36, ZMUC P763117, ZMUC P763437-38, ZMUC P763178, ZMUC P764699, ZMUC P764700, ZMUC P764705-14, ZMUC P764724-41, ZMUC P764742-45. Svalbard - Barents Sea: ZMUC P763115, ZMUC P763439-42, ZMUC P763443-52, ZMUC P763453-71, ZMUC P763472-74, ZMUC P763475-81, ZMUC P763482-91, ZMUC P763492-96(5), ZMUC P763497, ZMUC P763498-99, ZMUC P764257-59(3), ZMUC P764701, ZMUC P764702, ZMUC P764703, ZMUC P764704. Kara Sea: ZMUC c, d, e, g, i, and l. Lycodes paucilepidotus Toyoshima, 1985. Not examined, data from Toyoshima, 1985. Lycodes pectoralis Toyoshima, 1985. (three specimens). Sea of Okhotsk: ZMUC P763904-05, ZM MGU p11714. Lycodes polaris (Sabine, 1824). (37 specimens). Kara Sea: ZIN 34152, ZMUO J4490(3) (syntypes of Lycodes agnostus Jensen, 1902), ZMUC P761253, ZMUC 3, 6, 11, 16, 20, 24, 25, 29. Beaufort Sea: NMC 67-301, NMC 69-115, NMC 77-1347, NMC 82-1059A, NMC 900221(2). Barents Sea: ZM MGU p4028, ZIN uncat.(3). E. Canada-West Greenland: USNM 177653, ZMUC 272, ZMUC P76878-81, ZMUC P761377, ZMUC P762256, ZMUC uncat. (2). Bering-Chukchi Seas: USNM 152295, USNM 152592, USNM 152593, USNM 315544. Lycodes raridens Taranetz and Andriashev, 1937. (16 specimens). Bering Sea: ZIN 25071(holotype), USMN 221103, USMN 218834, USMN 221106, NMC 790811(2). Sea of Okhotsk: ZIN 42270(4), ZIN 44549, ZIN 46563, ZIN 46565(3), ZIN 48111. Lycodes reticulatus Reinhardt, 1834. (94 specimens). Off West Greenland: ZMUC 17 and 21 (syntypes), ZMUC 8-9, ZMUC 29, ZMUC 277-278, ZMUC P76636, ZMUC P76644, ZMUC P76646, ZMUC P76653, ZMUC P76656-58, ZMUC P76869-75, ZMUC P761917, ZMUC P761417, ZMUC P762825-26, ZMUC uncat. (2). Off East Greenland: ZMUC Jrn 3032,ZMUC uncat. (2). Barents Sea: ZIN 32118(2), ZIN 32479(3), ZIN 50342, ZIN uncat. (2), ZMUC P76428187, ZMUC uncat. (9). E. Canada: NMC 93-0102 (holotype of Lycodes reticulatus laurentianus Vladykov and Tremblay, 1936), NMC 60-0159, NMC 70-302, NMC 90-0229, NMC 90-0230, USNM 39336, USNM 39337, USNM 165167, USNM 165169-71, USNM 177654(4),

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USNM 177657, USNM 177659, USNM 341940. Iceland: MRII uncat. (5). Jan Mayen Isl.: ZMUC P76311836. Svalbard: ZMUC P763162. Lycodes rossi Malmgren, 1864. (54 specimens). Svalbard: NRM 9398 (holotype). ZMUC P763074-3114, ZMUC P763116, ZMUC P763137-40. Kara Sea: ZIN 30684, ZIN 34151, ZM MGU P-4159, ZMUC jrn 1, ZMUC n, ZMUC p, ZMUC m (syntypes of Lycodes celatus Jensen, 1902). Lycodes sadoesis Toyoshima and Honma, 1980. (three specimens). Off Japan: NMC 79-697 (paratype), USNM 117935, USNM 117937. Lycodes sagittarius McAllister, 1976. (nine specimens). Beaufort Sea: NMC 74-282 (holotype), BMNH 1974.10.5.1 (only radiograph examined), NMC-74-275, NMC-74-282A, ROM 30520 (only radiograph examined), USNM 212282, ZMUC P761071. Kara Sea: ZIN 32050(2). Lycodes schmidti Gratzianov, 1907. (one specimen). Sea of Okhotsk: ZIN 46555. Lycodes seminudus Reinhardt, 1837. (61 specimens). West Greenland: ZMUC 15 (holotype), ZMUC P76799802, ZMUC P76803 (holotype of Lycodes nigricans Jensen, 1952), ZMUC P76804-07, ZMUC P76809-11, ZMUC P76813-14, ZMUC P76829, ZMUC P76882, ZMUC P762193, ZMUC P762384, ZMUC P762738-41, ZMUC uncat. (13). Beaufort Sea: NMC 77-1399, NMC 94-0035. Jan Mayen Isl.: ZMUC P763060-73. Svalbard: ZMUC P763153-61. Lycodes sigmatoides Lindberg and Krasynkova, 1975. (five specimens). Sea of Japan: ZIN 13165(3)(syntypes), ZIN 44719, ZMUC P763902. Lycodes soldatovi Taranetz and Andriashev, 1935. (three specimens). Sea of Okhotsk: ZIN 25190(2) (syntypes), ZMUC P764993-95. Lycodes squamiventer (Jensen, 1904). (30 specimens). Norwegian Sea: ZMUC 235 (lectotype), MRII uncat. (1), NMC 74-0395, RUSI 58504(4), ZIN 40718, ZIN 51938(2), ZMUB 1811(2) ZMUC 7-8, ZMUC 237-239, ZMUC P761234, ZMUC P761236, ZMUC P761240, ZMUC P761242, ZMUC P761330-33, ZMUC P76391011, ZMUC P764718, ZMUO J4546(2). Lycodes tanakae Jordan and Thompsom, 1914. (12 specimens). Sea of Japan: USNM 150205, ZIN 42283, ZIN 44550(2), ZIN 46333(3), ZIN 46335, ZIN 46338, ZIN 46547, ZIN 50184, ZMUC uncat. (1). Lycodes teraoi Katayama, 1943. (two specimens). Sea of Japan: USNM 117957(2). Lycodes terraenovae Collett, 1896. (115 specimens). Off Newfoundland: MOM-POI 295 (former syntype b, lectotype), MOM-POI 295 (former syntype a), MOMPOI 4651 (former syntype c), MOM-POI 3005 (former syntype d), ZMUB 3/87(2), ISH 103-1973(2), ISH 1041973, ISH 105-1973, ISH 106-1973, ISH 108-1973(2). West Greenland: P761252, P761326, P761347-48, P762490-515, Off E. USA: USNM 119446 (holotype

385

of Lycodes brunneus Fowler, 1944), USNM 119447, USNM 316579(3), VIMS 04190, VIMS 05242, VIMS 06455-56, VIMS 06469 (4), VIMS 06471(4), ZMUC CN 536 (holotype of Lycodes atlanticus Jensen, 1902, ZMUC CN 627. Rockall Trough: ISH 63-1974, ISH 667-1974, ISH 669-1974, ISH 705-1974, ISH 33081979, ISH 3339-1979, ISH 32-1981, ISH 14-1982. Off Mauritania: ISH 1192/1982, ZIN 46184(7), ZIN 46299. Off South Africa: ZIN 35812 (holotype of Lycodes agulhensis Andriashev, 1959), ZIN 42348, ZIN 42350, 43446, 45799-800, ZIN 46298, ZIN 40827(2), ZIN 42349(2), ZIN 43444(3), ZIN 46297(2), SAM 12101(3), SAM 12436-437, SAM 31616(2), SAM 31620(3). Lycodes toyamensis Katayama, 1941. (eight specimens). Sea of Japan: USMN 117937, USMN 148871, USMN 160719, USMN 161444, USMN 117935, USMN 177955(3). Lycodes turneri Bean, 1878. (nine specimens). Chukchi Sea: USNM 21529 (holotype), USNM 111621(2), USNM 152592, USNM 221069(2), ZIN 34839(3). Lycodes uschakovi Popov, 1931. (six specimens). Sea of Okhotsk: ZIN 29986 (holotype). Sea of Japan: ZIN 25269, ZIN 34845, 36935(3). Lycodes vahlii Reinhardt, 1831. (18 specimens). NW Atlantic: ZMUC 9 (holotype), NMC 62-0116, NMC 620118(2), NMC 62-123, NMC 63-0135(5), NMC 63148A, NMC 63-0151(2), NMC 63-0157(2), NMC 850266, NMC 85-0315, ZMUC P764722. Lycodes yamatoi Toyoshima, 1985. Not examined, data from Toyoshima (1985). Lycodes ygreknotatus Shmidt, 1950. Not examined, data from Shmidt (1950).

Appendix B. Character states 1. Submental crests (see Anderson, 1994, Fig. 4): absent (0), present (1). 2. Submental crests fusion: not united at symphysis (0), united at symphysis (1). 3. Lateral line configuration: mediolateral (0), ventromedio-lateral (1), single ventral (2), ventral + 1/2 mediolateral (3) (see Møller, 2001b, Fig. 4B), double ventral + complete mediolateral (4) (see Møller, 1997, Fig. 2), antero-lateral (5) (see Toyoshima, 1985, Fig. 36A), antero-lateral (6) (see Toyoshima, 1985, Fig. 36B) 4. Precaudal vertebrae (mean): 18–23 (0), 24–28 (1). 5. Caudal vertebrae (mean): 63–78 (0), 79–95 (1). 6. First dorsal fin ray associated with vertebra no. (mean): 0–5 (0), 6–9 (1). 7. Pectoral fin rays (mean): 14–17 (0), 18–21 (1), 22–24 (2). 8. Pterygiophores inserted anterior to haemal spine of first caudal vertebra: 0–2 (0), 3–4 (1).

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16. Head length (mean): < 20% SL (0), 20–25% SL (1), > 25% SL (2). 17. Otolith sulcus: deep (0), filled (shallow) (1). 18. Vertebra: asymmmetric (0), symmetric (1). 19. Pectoral fin: not emarginate (0), emarginate (1). 20. Spinules on gill-rakers of first gill arch: absent (0), present (1). 21. Pelvic fin spine: absent (0), present (1). 22. Peritoneum color: light (0), speckled (1), dark (2). 23. Body coloration: uniformly brownish (0), with stripes, marks or spots (1).

9. Predorsal squamation (see, e.g., Jensen, 1904, Figs. 1, 2, 12, and 13): naked (0), scaled (1). 10. Abdominal squamation (see, e.g., Jensen, 1904, plate 2): naked (0), scaled (1). 11. High of individual scales at midbody, above anal fin origin: < 0:4% SL (0), 0.4–0.7% SL (1), > 0:7% SL (2). 12. Palatine teeth rows: missing (0), one (1), two (2). 13. Vomer teeth: present (0), absent (1). 14. Preanal length (mean): > 45% SL (0), < 45% SL (1). 15. Gill slit length (mean): > 8% SL (0), < 8% SL (1).

Matrix of distribution, depth range, and morphological characters of all valid species of Lycodes. Arctic defined as waters north of the Shetland–Faroe-Island–Greenland–Canada submerged ridge, and north of the Bering Strait. Species in bold included in the molecular analysis. Data from literature: 1, Allen and Smith (1988); 2, This study; 3, Lindberg and Krasyukova (1975); 4, Toyoshima (1985); 5, Møller (2001b); 6, Shmidt (1950); 7, Carl (2002), 8, Miller and Lea (1972). Taxa/characters

Distribution

Depth range meter

1

2

3

4

5

6

7

8

9

10 11 12 13 14 15 16 17 18 19 20 21 22 23

Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes

Arctic NW Pacific NW Pacific NW Pacific NW Pacific N Pacific NW Pacific NW Pacific N Pacific NE Pacific N Pacific N Atlantic/Arctic Arctic NW Pacific Arctic NW Pacific NE Atlantic/Arctic NW Pacific NW Pacific NW Pacific NW Pacific Arctic NW Atlantic Arctic NW Pacific NW Pacific Arctic NW Pacific Arctic NW Atlantic NW Pacific N Pacific/Arctic NW Pacific NW Pacific NW Pacific NW Pacific NW Pacific Arctic NE Pacific N Pacific/Arctic Arctic NW Pacific NW Pacific Arctic N Pacific/Arctic Arctic Arctic NW Pacific Arctic NW Pacific

386–18802 242–3404 208–8004 445–5914;2 147–2402 25–9731 88–4904 200–5003;4 42–10251 73–8001 13–13001 151–10912 188–11872 126–4952 491–30002 68–1784 55–6607 68–1884 400–8904 225–245FM2 1342 3–902 24–5352 112–10982 200–3054 41–1472 3–3352 128–4804 298–6682 115–2106 400–13104 0–1802 74–3004 141–5604 340–4004 6004 165–2302 337–13372;5 10–3938 25–9251 11–17502;5 112–3304 143–4804 0–3002 25–1751 20–9302 42–3652 169–2354 357–6002 1502

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1

0 0 1 0 0 0 0 1 0 1 1 0 0 0 0 1 0 0 1 1 1 0 0 0 0 0 0 1 0 0 1 0 0 0 1 1 0 0 0 0 0 0 1 0 0 0 0 1 0 0

2 3 0 ? 0 2 2 2 3 0 2 4 4 1 2 1 2 0 4 6 1 0 0 0 1 0 1 1 1 1 2 0 1 2 2 2 1 3 0 1 3 0 2 0 0 0 0 5 1 1

0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 1 1 0 0 0 0 0 0 ? 0 1 0 0 0 0 0 0 0 1 0 1 0 1 1 1 1 0 0 1

1 1 1 1 0 1 1 1 1 1 1 1 1 1 1 0 1 0 1 0 0 0 0 0 0 0 1 1 1 ? 0 0 1 1 0 0 1 1 1 1 1 0 1 0 0 0 0 0 1 0

1 0 1 1 1 1 0 0 0 0 1 1 0 1 1 ? 1 0 0 0 0 1 0 0 ? 0 1 0 0 ? 0 1 1 0 0 0 0 0 0 1 1 ? 0 0 0 0 0 1 1 1

1 1 1 2 1 1 2 1 1 1 1 2 1 1 1 1 1 1 1 0 1 1 1 2 1 1 1 1 2 1 0 0 1 1 0 0 1 1 1 1 1 1 1 0 1 1 1 0 0 1

0 1 0 0 0 1 1 1 1 0 1 1 1 0 0 ? 1 0 0 1 1 0 0 0 ? 0 0 0 0 ? 1 0 0 1 1 ? 1 0 1 1 0 ? 1 0 0 0 0 1 0 0

0 0 1 ? 0 1 0 1 0 0 1 1 1 1 1 0 01 0 1 0 0 0 1 0 0 1 0 1 1 1 0 0 1 1 0 1 1 0 1 1 0 0 0 0 0 0 0 0 1 1

0 1 1 ? 0 1 1 1 1 1 1 1 1 1 1 1 1 0 1 1 01 0 0 0 1 1 0 1 1 1 1 0 1 1 1 1 1 01 1 1 0 0 1 0 0 0 0 0 1 1

adolfi albolineatus albonotata bathybius brevicauda brevipes brunneofasciatus caudimaculatus concolor cortezianus diapterus esmarkii eudipleurostictus fasciatus frigidus fulvus4 gracilis heinemani hubbsi japonicus jenseni jugoricus lavalaei luetkenii macrochir4 macrolepis marisalbi matsubarai mcallisteri microlepidotus6 microporus mucosus multifasciatus nakamurae obscurus ocellatus ochotensis paamiuti pacificus palearis pallidus paucilepidotus4 pectoralis polaris raridens reticulatus rossi sadoensis sagittarius schmidti

0 0 1 ? 1 1 1 1 0 0 1 1 1 1 0 ? 1 ? 1 1 1 ? 0 0 ? 2 1 1 1 ? 1 0 1 ? 1 0 1 1 1 ? 1 ? 0 0 0 1 1 ? 1 1

1 1 0 1 1 1 2 1 2 1 1 1 1 12 1 1 1 1 1 1 1 2 1 1 1 1 1 1 2 ? 1 1 1 1 1 1 1 1 0 1 1 1 1 1 1 1 1 1 12 1

1 1 0 1 1 1 1 1 1 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 1 1 1 1 1 1 1 1 1 1 1

1 1 1 1 0 1 1 1 1 1 1 1 1 1 1 1 1 0 1 1 1 0 0 0 1 0 1 1 1 1 1 0 1 1 1 1 1 1 1 1 1 0 1 0 0 0 0 1 1 1

1 0 0 1 0 1 0 1 0 0 1 1 0 1 0 ? ? 0 1 1 1 0 1 0 ? 0 1 1 0 ? 1 0 1 ? ? 1 1 1 0 1 1 ? 1 0 0 0 0 0 1 0

1 1 0 0 2 1 0 0 1 1 0 1 1 0 1 0 1 1 0 1 0 1 1 2 1 1 1 0 1 0 0 1 0 0 0 1 0 1 1 1 1 1 0 1 1 2 2 1 1 1

0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 ? 0 0 0 ? ? 1 1 1 ? 0 0 ? 0 ? 0 1 0 ? ? ? ? 0 0 0 0 ? 0 1 1 1 1 ? 0 ?

1 1 1 1 0 1 1 1 1 1 1 1 1 1 1 ? 1 0 1 1 1 1 1 1 ? 1 1 1 1 ? 1 1 1 1 1 1 1 1 1 1 1 ? 1 1 0 0 0 1 1 0

0 0 0 0 0 0 0 0 0 0 1 0 1 0 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0 01 0 0 0 1 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0

0 0 1 ? 0 1 0 0 0 0 1 1 0 0 1 ? 0 ? 0 1 0 0 1 1 ? ? 01 01 1 ? 0 1 0 ? 0 ? ? 1 1 1 1 ? 0 1 1 1 1 ? 1 0

0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

2 2 2 2 0 1 2 2 2 2 2 2 2 1 2 2 2 0 2 2 0 0 0 0 0 1 1 2 2 0 2 0 1 2 2 2 2 2 2 1 2 0 2 0 0 0 0 2 2 0

0 1 1 0 1 1 1 1 0 0 01 1 1 1 0 1 1 1 1 1 1 1 1 1 0 1 1 1 1 1 0 1 1 1 0 1 0 0 0 1 01 1 0 1 1 1 1 1 0 1

P.R. Møller, P. Gravlund / Molecular Phylogenetics and Evolution 26 (2003) 369–388

387

Appendix B (continued) Taxa/characters

Distribution

Depth range meter

1

2

3

4

5

6

7

8

9

10 11 12 13 14 15 16 17 18 19 20 21 22 23

Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes Lycodes

Arctic NW Pacific NW Pacific Arctic NW Pacific NW Pacific Atlantic NW Pacific N Pacific/Arctic NW Pacific NW Atlantic/Arctic NW Pacific NW Pacific

50–12002 60–1202 300–4654 870–18002;5 125–5064;2 1504 150–26002 482–6504 25–1251 78–1483 39–7502 160–5604 1356

1 1 1 1 1 1 1 1 1 1 1 1 1

0 0 0 0 0 1 0 1 0 1 0 0 0

0 0 1 3 0 5 4 0 0 0 2 1 1

1 1 0 0 1 0 0 0 1 0 1 0 0

0 0 1 1 0 0 1 1 0 0 1 1 0

1 1 0 1 1 1 1 1 1 1 1 ? 0

1 1 2 1 1 0 2 1 1 1 1 1 1

0 1 1 0 0 0 1 0 0 0 1 ? 0

0 0 0 1 0 0 1 1 0 0 01 ? 1

0 0 1 1 0 0 1 1 0 0 1 1 1

seminudus sigmatoides soldatovi squamiventer tanakae teraoi terraenovae toyamensis turneri uschakovi vahlii yamatoi4 ygregnotatus6

References Allen, M.J., Smith, G.B., 1988. Atlas and zoogeography of common fishes in the Bering Sea and northeastern Pacific. NOAA Tech. Rept. NMFS 66, 1–151. Anderson, M.E., 1982. Revision of the fish genera Gymnelus Reinhardt and Gymnelopsis Soldatov (Zoarcidae), with two new species and comparative osteology of Gymnelus viridis. Natl. Mus. Can. Publ. Zool. 17, 1–76. Anderson, M.E., 1984. On the anatomy and phylogeny of the Zoarcidae (Teleostei: Perciformes). Unpublished Ph.D. Dissertation, College of William and Mary, Williamsburg. Anderson, M.E., 1994. Systematics and osteology of the Zoarcidae (Teleostei: Perciformes). J.L.B. Smith Inst. Ichthyol., Ichthyol. Bull. 60, 1–120. Andriashev, A.P., 1935. New data on the deep-water fishes of the Bering Sea. Dokl. Akad. Nauk SSSR 4, 105–108. Andriashev, A.P., 1939. Essay on the Zoogeography and Origin of the Fish Fauna of the Bering Sea and Adjacent Waters, University of Leningrad, USSR (in Russian). Andriashev, A.P., 1949. On the species composition and distribution of sculpins of the genus Triglops Reinh. in the northern seas. Akad. Nauk SSSR 1, 194–209. Andriashev, A.P., 1954. Fishes of the Northern seas of the USSR. Academy of Sciences of the Union of Soviet Socialist Republics, Moscow, Leningrad. (Translated from Russian by Israel program for scientific translations Jerusalem, 1964). Andriashev, A.P., 1986. Zoarcidae. In: Whitehead, P.J.P., Bauchot, M.-L., Hureau, J.-C., Nielsen, J., Tortonese, E. (Eds.), Fishes of the North-eastern Atlantic and the Mediterranean. UNESCO, Paris, pp. 1130–1150. Baker, R., DeSalle, R., 1997. On weighting and congruence. Syst. Biol. 46, 654–673. Bargelloni, L., Ritchie, P.A., Patarnello, T., Battaglia, B., Lambert, D.M., Meyer, A., 1994. Molecular evolution at subzero temperatures: mitochondrial and nuclear phylogenies of fishes from Antarctica (Suborder Notothenioidei), and the evolution of antifreeze glycopeptides. Mol. Biol. Evol. 11, 854–863. Berg, L.S., 1934. On the amphiboreal (discontinuous) distribution of marine fauna in the northern hemisphere. Izvest. Geogr. Obshch. 66, 69–78. Bleeker, P., 1874. Typi nonnuli generici piscium neglecti. Versl. Akad. Amstrdam. 2, 367–371. Bremer, K., 1994. Branch support and tree stability. Cladistics 10, 295– 304. Briggs, J.C., 1974. Marine Zoogeography. McGraw-Hill Series in Population Biology, New York. Bull, L.L., Huelsenbeck, J.P., Cunningham, C.W., Swofford, D.L., Waddell, P.J., 1993. Partitioning and combining data in phylogenetic analysis. Syst. Biol. 42, 384–397.

1 0 0 1 1 ? 0 2 ? 2 1 ? ?

1 1 1 1 1 1 1 0 1 1 1 12 ?

1 1 1 1 1 1 1 0 1 1 1 1 1

0 0 0 1 0 1 1 1 0 1 1 1 1

0 0 0 1 0 1 1 0 0 0 1 ? ?

2 1 1 1 1 1 1 1 1 1 0 0 1

1 1 0 0 1 ? 0 ? 1 ? 0 ? ?

1 1 0 1 0 1 1 1 1 1 1 ? ?

0 0 0 0 0 0 0 0 0 0 0 0 0

1 1 01 1 1 ? 1 0 1 ? 0 ? ?

0 0 0 0 0 0 0 1 0 0 0 0 0

1 0 2 2 2 0 2 2 0 0 2 2 2

01 1 0 0 1 0 0 01 1 1 1 1 1

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