Research Article |
Corresponding author: Luke Tornabene ( luke.tornabene@gmail.com ) Academic editor: Kyle Piller
© 2020 Emily P. McFarland, Carole C. Baldwin, David Ross Robertson, Luiz A. Rocha, Luke Tornabene.
This is an open access article distributed under the terms of the CC0 Public Domain Dedication.
Citation:
McFarland EP, Baldwin CC, Robertson DR, Rocha LA, Tornabene L (2020) A new species of Chromis damselfish from the tropical western Atlantic (Teleostei, Pomacentridae). ZooKeys 1008: 107-138. https://doi.org/10.3897/zookeys.1008.58805
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Initially described in 1882, Chromis enchrysurus, the Yellowtail Reeffish, was redescribed in 1982 to account for an observed color morph that possesses a white tail instead of a yellow one, but morphological and geographic boundaries between the two color morphs were not well understood. Taking advantage of newly collected material from submersible studies of deep reefs and photographs from rebreather dives, this study sought to determine whether the white-tailed Chromis is actually a color morph of Chromis enchrysurus or a distinct species. Phylogenetic analyses of mitochondrial genes cytochrome b and cytochrome c oxidase subunit I separated Chromis enchrysurus and the white-tailed Chromis into two reciprocally monophyletic clades. A principal component analysis based on 27 morphological characters separated the two groups into clusters that correspond with caudal-fin coloration, which was either known or presumed based on the specimen’s collection site according to biogeographic data on species boundaries in the Greater Caribbean. Genetic, morphological, and biogeographic data all indicate that the white-tailed Chromis is a distinct species, herein described as Chromis vanbebberae sp. nov. The discovery of a new species within a conspicuous group such as damselfishes in a well-studied region of the world highlights the importance of deep-reef exploration in documenting undiscovered biodiversity.
Caribbean, coral reef, mesophotic, phylogenetics, rariphotic, systematics
Chromis enchrysurus Jordan & Gilbert, 1882 is a species of Pomacentridae found on reefs in the tropical and subtropical western Atlantic Ocean from 5–146 m depth (
Some of the confusion around the distribution and general biology of the species stems from the white-tailed form being restricted to deep reefs at or below the lower boundary of conventional SCUBA diving (~ 40 m). However, research on deep-reef fishes has significantly expanded in the last decade due to advances in technical diving and the use of manned submersibles and remote operated underwater vehicles (ROVs) (
To date, DROP researchers have made collections at five deep-reef sites spanning the eastern and western Caribbean and have documented various Chromis species at each site, including the white-tailed morph of C. enchrysurus. In addition, one of us (LAR) has recorded Chromis spp. from closed-circuit rebreather dives off oceanic islands and the coast of Brazil, south to São Paulo State. Through these observations and collections together with photographic records accumulated by
To determine the geographic range for both color morphs we used data from
Four fresh yellow-tailed specimens of Chromis enchrysurus were collected from Marathon Key, Florida by Frank Young (Dynasty Marine, Inc; https://dynastymarine.net). Eleven fresh white-tailed specimens were collected from Curaçao and Sint Eustatius during submersible expeditions carried out by DROP. An additional eleven samples collected by DROP from Curaçao were represented only from tissue samples (vouchers were not retained), but white fins were noted from these specimens at the time of collection. DROP specimens were collected by the ‘Curasub’ crewed submersible, which was equipped with a quinaldine ejection system that was used to anesthetize the fish. A suction tube terminating in a holding tank was used to collect and retain the fish once sedated. Collections took place periodically from 2010 to 2019.
For parts of the species range where no fresh specimens were available, specimens were examined from the University of Kansas (
Morphological data were collected from 15 specimens of white-tailed morphs and 32 specimens of yellow-tailed morphs following methods of
Morphological data were analyzed using a Principal Component Analysis (PCA) conducted in RStudio (RStudio Team 2015) after converting values to residuals via linear regression to correct for variation attributable to specimen size. All 28 morphometric variables except standard length were included in the PCA. Average values of a measurement for color morphs were used for specimens that were missing a specific measurement due to condition (12 specimens were missing at least one measurement for a total of 20 data points).
DNA was extracted from tissue preserved in 95% ethanol using the Qiagen DNAeasy Blood and Tissue Kit (Qiagen, Valencia, California). For USNM specimens, DNA was extracted using an automated phenol:chloroform protocol on the Autogenprep965 (Autogen, Holliston, MA) using the mouse tail tissue protocol (
The mitochondrial gene cytochrome b (cytb) was targeted using primers Fishcytb-F and Trucytb-R (
Sequences were trimmed, aligned, and concatenated in Geneious version 10.2.6 (
Substitution models and codon-partitioning schemes for each gene were selected using PartitionFinder2 (
Analysis of the geographic ranges of color morphs indicate little overlap between yellow- and white-tailed morphs (Fig.
Observations and hypothesized ranges of Chromis enchrysurus and Chromis vanbebberae. Open circles and triangles represent locations of specimens examined in this study. Solid circles or triangles represent records from visual observations, database searches, or the literature. Red triangle is Curaçao, the type locality of C. vanbebberae.
Sixty-eight percent of overall morphometric variation is explained by the first five principal components, of which 29.6% is explained by PC1 (Suppl. material
The individual gene trees and the concatenated tree all recovered the yellow-tailed Chromis and white-tailed Chromis as reciprocally monophyletic sister taxa. The posterior probability values supporting this relationship are 1.0 in the concatenated tree (Fig.
Bayesian phylogenetic analysis of concatenated dataset of pomacentrid species. Circles at nodes indicate posterior probability. Branches with less than 0.50 posterior probability are collapsed. Branch length units are expected number of substitutions per site. Blue and yellow coloring on branches refer to C. vanbebberae and C. enchrysurus, respectively.
Bayesian phylogenetic analysis of cytb dataset of pomacentrid species. Circles at nodes indicate posterior probability. Branches with less than 0.50 posterior probability are collapsed. Branch length units are expected number of substitutions per site. Blue and yellow coloring on branches refer to C. vanbebberae and C. enchrysurus, respectively.
Bayesian phylogenetic analysis of COI dataset of pomacentrid species. Circles at nodes indicate posterior probability. Branches with less than 0.50 posterior probability are collapsed. Branch length units are expected number of substitutions per site. Blue and yellow coloring on branches refer to C. vanbebberae and C. enchrysurus, respectively.
Analysis of genetic variation between and within groups shows that for both genes assessed, there is substantially more genetic variation between the two color morphs than there is within each. Average pairwise genetic distance in cytb sequences (Table
Holotype. USNM 446947, 73.9 mm SL, CURASUB19-01, tissue no. CUR19001, 117 m, Substation Curaçao Downline, Bapor Kibra, Curaçao, 12.0832, -68.8991, C.C. Baldwin, L. Tornabene, B. Van Bebber, W.B. Ludt, 6 May 2019.
Paratypes. Curaçao: All collected at the type locality off Curaçao: USNM 414901, 33.4 mm SL, CURASUB12-15, tissue no. CUR12142, 123–160 m, A. Schrier, B. Brandt, C.C. Baldwin, A. Driskell, P. Mace, 10 Aug 2012; USNM 414902, 36.1 mm SL, CURASUB12-15, tissue no. CUR12141, 123–160 m, A. Schrier, B. Brandt, C.C. Baldwin, A. Driskell, P. Mace, 10 Aug 2012; USNM 413966, 24.7 mm SL, CURASUB13-03, tissue no. CUR13056, 53–189 m, C.C. Baldwin, A. Schrier, D.R. Robertson, C.I. Castilla, B. Brandt, 7 Feb 2013; USNM 413947, 23.4 mm SL, CURASUB13-02, tissue no. CUR13013, C.C. Baldwin, A. Schrier, D.R. Robertson, C.I. Castilla, B. Brandt, 6 Feb 2013; USNM 430030, 14.9 mm SL, tissue no. CUR13335, Substation Curaçao Crew, 9 July 2013; USNM 406206, 24.1 SL, CURASUB11-03, tissue no. CUR11206, 119–161 m, A. Schrier, M. van der Huls, C.C. Baldwin, D.R. Robertson, J. Oliver, 24 May 2011; CAS 247234, 90.7 mm SL, CURASUB19-02, tissue no. CUR19010, C.C. Baldwin, L. Tornabene, T. Christiaan, S. Yerrace, 7 May 2019; UW 200069, 98.4 mm SL, tissue no. CUR19003, 106 m, C.C. Baldwin, L. Tornabene, B. Van Bebber, W.B. Ludt, 6 May 2019; UW 200070, 97.1 mm SL, CURASUB19-02, tissue no. CUR19009, C.C. Baldwin, L. Tornabene, T. Christiaan, S. Yerrace, 7 May 2019; Sint Eustatius: USNM 442658, 13.9 mm SL, CURASUB17-17, tissue no. EUS17005, South and southeast of R/V Chapman mooring, SW of island, Kay Bay, St. Eustatius, 17.4599, -62.9817, C.C. Baldwin, L. Tornabene, B. Brandt, J. Casey, 15 April 2017. See Suppl. material
Curaçao, Netherland Antilles.
Dorsal rays XIII, 12–13; anal rays II, 12–13; pored lateral-line scales 15–18 (usually 17; one paratype with ten and no apparent scale loss or damage); gill rakers 7–8+16–18. Proportional measurements expressed as percent standard length, unless otherwise noted as percent head length (HL): head length 30.2–41.0 (mean 35.4); predorsal length 31.1–42.0 (mean 34.9); orbit diameter 11.5–17.4 (mean 14.6), 39.0 (35.4–48.5) % HL; upper jaw length 9.1 (6.0–14.4), 30.0 (22.3–34.8) % HL; snout length 7.8 (6.9–10.3), 26.0 (17.5–32.2) % HL; interorbital width 10.7 (8.6–12.8), 35.4 (21.1–37.4) % HL; body depth 41.6–57.8 (mean 51.8); caudal length 29.7–44.9 (mean 37.20); last dorsal spine 10.2–16.4 (mean 13); longest dorsal ray 21.1–26.5 (mean 23.3); longest anal ray 18.9–28 (mean 24.3); 1st pelvic soft ray 28.8–43.2 (mean 36.4). See Table
Body
deep, 55.2 (41.6–57.8), laterally compressed, width 19.4 (16.6–21.6), oval in shape; eyes large, 11.8 (11.5–17.4), interorbital width 10.7 (8.6–12.1). Mouth small, upper jaw length 9.1 (6.0–14.4), terminal, and oblique. Head large, 30.2 (30.2–41.0) and rounded with a convex forehead and short snout 7.8 (5.2–10.3), snout length shorter than orbit diameter (snout ~ 1.8 times in orbit). Preopercle mostly smooth with slight serration at ventral angle; opercle possesses one large spine on dorsal posterior side. Suborbital bones mostly joined to cheek, save for second and third, which flex away from cheek with preorbital. Vertebrae 25 plus urostyle (Fig.
Dorsal fin XIII, 12 (12–13); longest dorsal ray 23.8 (21.1–28.5); last (13th) dorsal spine 16.4 (10.3–16.4); spinous dorsal base 48.6 (35.5–50.2); soft dorsal base 18.9 (13.4–18.9); pre-dorsal length 33.2 (31.1–42.0). Anal fin II, 12 (12–13); longest anal-fin ray 23.4 (18.9–28.0); pre-anal length 64.1 (63.2–69.0). Pectoral fin 18 (17–20) and lacking free rays; longest pectoral ray 34.2 (31.1–38.1). Pelvic fin I, 5; with a very long first pelvic ray 40.9 (28.8–43.2); pre-pelvic length 35.2 (35.2–43.6). Caudal fin forked with length 41.0 (29.7–44.9).
Scales large, coarsely ctenoid, covering body and most of head, often densely clustered at base of dorsal and anal fins. Pored lateral-line scales 17 (15–18), total scales in lateral series 28 (26–28); one paratype (USNM 430030, 14.9 mm SL) with only 10 pored lateral-line scales, lateral line terminating below the 10th dorsal spine in all individuals, without apparent damage or scale loss. Scales above lateral line 4 (3–4). Scales below lateral line 10 (10–11). Circumpeduncular scales 14 (13–4). No obvious pored or pitted scales on caudal peduncle.
Live coloration
(Fig.
Coloration in freshly dead specimens
(Fig.
Coloration in preservation
(Fig.
(Fig.
Chromis vanbebberae occurs on a variety of deep-reef habitats at depths between 49 and at least 178 m, including on rocky reef slopes, coral outcroppings, around sponges, boulders, and caves. In areas of colder water in southeastern Brazil (Espírito Santo, Rio de Janeiro and Sao Paulo states) they are seen in depths as shallow as 10 m. In Curaçao, individuals are often found near sporadic patches of rocks located on otherwise open sandy bottoms devoid of other structure, which they frequently co-occupy with the seabasses Serranus phoebe or S. notospilus. They are also frequently found around artificial substrates such as shipwrecks (e.g., the wreck Queen of Nassau in southeast Florida), tires, and derelict ropes and fishing gear. This species and C. insolata Cuvier & Valenciennes, 1830, are the two most common pomacentrids on lower-mesophotic and rariphotic reefs in the Caribbean. In Brazil, C. insolata is replaced by its southern mesophotic counterpart, C. jubauna Moura, 1995, and the latter often schools with C. vanbebberae on coastal reefs; however, C. vanbebberae is the only mesophotic Chromis recorded in Brazilian oceanic islands.
Where C. vanbebberae and C. enchrysurus overlap in southeastern Florida, the two species segregate by depth, with C. enchrysurus occurring from (~ 25–40 m), and C. vanbebberae occurring in deeper water (~ 60–90 m).
The species epithet vanbebberae, Latinized from Van Bebber, honors Barbara Van Bebber, one of the most accomplished submersible pilots in the Caribbean. Van Bebber was one of several skilled pilots of the ‘Curasub’ that assisted DROP with observations and collections of many new species, including this species. The common name “Whitetail Reeffish” (castañeta coliblanca in Spanish) refers to the caudal-fin coloration that distinguishes the species from Chromis enchrysurus, the Yellowtail Reeffish.
Chromis vanbebberae is easily distinguished from C. enchrysurus (Fig.
Chromis vanbebberae frequently co-occurs with C. insolata and C. scotti Emery, 1968, in the Caribbean, and with C. jubauna in Brazil. It can be distinguished from C. scotti in having an abrupt, diagonal dividing line between the dark dorsal portion of body and white ventral portion of the body (a diffuse horizontal dividing line in C. scotti), and in lacking the prominent iridescent light blue coloration that is present on most of the dorsal portion of the body of C. scotti (Fig.
Live coloration of Chromis scotti and C. insolata A C. scotti, adult, Roatan, Honduras B C. scotti, juvenile, Tobago C C. insolata, adult, Florida Keys D C. insolata, juvenile, Florida Keys E C. jubauna, adult, Laje de Santos Island, Brazil F C. jubauna, juvenile, Laje de Santos Island, Brazil. Photographs by Mickey Charteris (A), Alison and Carlos Estape (B–D), and Osmar Luiz Jr (E, F).
Genetic analyses support the hypothesis that yellow-tailed and white-tailed specimens represent distinct species. Bayesian phylogenetic analysis of both genes and of the concatenated sequences returned topologies splitting the two species into reciprocally monophyletic clades with high posterior probability values. Additionally, genetic distance analyses demonstrate that for both genes, sequence variation between species is greater than that within species. While the within-group genetic distance of C. vanbebberae cytb sequences is higher than the within-group distance of C. enchrysurus, both values are distinctly lower than the between-group variation for the vast majority of species in our analysis (Table
Average genetic distance in mitochondrial gene cytb between species of Chromis. The number of base differences per site from averaging over alls equence pairs between groups are shown. Average within-species p-distance are shown on the diagonal.
1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | ||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | C. enchrysurus | 0.008 | 0.057 | 0.122 | 0.136 | 0.119 | 0.124 | 0.140 | 0.146 | 0.121 | 0.143 | 0.169 | 0.161 | 0.128 | 0.158 | 0.129 | 0.132 | 0.141 | 0.129 | 0.117 | 0.177 | 0.149 | 0.114 | 0.142 | 0.116 | 0.131 | 0.178 | 0.161 | 0.195 | 0.140 | 0.141 | 0.157 | 0.132 | 0.157 | 0.156 | 0.139 | 0.141 | 0.159 | 0.151 | 0.163 | 0.146 | 0.079 |
2 | C. vanbebberae | 0.057 | 0.022 | 0.128 | 0.143 | 0.124 | 0.136 | 0.156 | 0.144 | 0.135 | 0.154 | 0.172 | 0.182 | 0.147 | 0.171 | 0.157 | 0.141 | 0.146 | 0.138 | 0.125 | 0.166 | 0.154 | 0.124 | 0.141 | 0.138 | 0.150 | 0.167 | 0.182 | 0.225 | 0.156 | 0.134 | 0.160 | 0.145 | 0.160 | 0.175 | 0.149 | 0.161 | 0.167 | 0.159 | 0.147 | 0.150 | 0.074 |
3 | C. verater | 0.122 | 0.128 | 0.099 | 0.074 | 0.086 | 0.136 | 0.142 | 0.111 | 0.145 | 0.139 | 0.136 | 0.086 | 0.154 | 0.120 | 0.114 | 0.139 | 0.099 | 0.086 | 0.146 | 0.120 | 0.111 | 0.146 | 0.090 | 0.083 | 0.145 | 0.136 | 0.167 | 0.136 | 0.108 | 0.136 | 0.114 | 0.108 | 0.142 | 0.105 | 0.111 | 0.136 | 0.136 | 0.136 | 0.136 | 0.117 | |
4 | C. xanthura | 0.136 | 0.143 | 0.099 | 0.114 | 0.127 | 0.139 | 0.176 | 0.086 | 0.157 | 0.164 | 0.145 | 0.117 | 0.167 | 0.157 | 0.151 | 0.157 | 0.123 | 0.037 | 0.152 | 0.151 | 0.139 | 0.178 | 0.111 | 0.114 | 0.154 | 0.145 | 0.182 | 0.139 | 0.136 | 0.154 | 0.123 | 0.127 | 0.145 | 0.139 | 0.123 | 0.148 | 0.154 | 0.176 | 0.151 | 0.127 | |
5 | C. xanthochira | 0.119 | 0.124 | 0.074 | 0.114 | 0.025 | 0.142 | 0.130 | 0.114 | 0.154 | 0.157 | 0.164 | 0.096 | 0.164 | 0.133 | 0.123 | 0.145 | 0.105 | 0.105 | 0.168 | 0.136 | 0.114 | 0.127 | 0.080 | 0.093 | 0.170 | 0.164 | 0.198 | 0.142 | 0.068 | 0.179 | 0.093 | 0.130 | 0.160 | 0.108 | 0.117 | 0.167 | 0.136 | 0.164 | 0.157 | 0.120 | |
6 | C. weberi | 0.124 | 0.136 | 0.086 | 0.127 | 0.025 | 0.145 | 0.136 | 0.123 | 0.154 | 0.170 | 0.167 | 0.090 | 0.167 | 0.139 | 0.133 | 0.148 | 0.123 | 0.117 | 0.175 | 0.139 | 0.130 | 0.140 | 0.093 | 0.093 | 0.170 | 0.167 | 0.198 | 0.145 | 0.071 | 0.182 | 0.108 | 0.139 | 0.170 | 0.117 | 0.130 | 0.164 | 0.142 | 0.176 | 0.164 | 0.127 | |
7 | C. vanderbilti | 0.140 | 0.156 | 0.136 | 0.139 | 0.142 | 0.145 | 0.164 | 0.130 | 0.056 | 0.160 | 0.136 | 0.127 | 0.105 | 0.127 | 0.123 | 0.142 | 0.133 | 0.127 | 0.165 | 0.151 | 0.145 | 0.178 | 0.142 | 0.123 | 0.164 | 0.139 | 0.173 | 0.000 | 0.164 | 0.139 | 0.160 | 0.157 | 0.130 | 0.139 | 0.133 | 0.148 | 0.167 | 0.164 | 0.136 | 0.151 | |
8 | C. ternatensis | 0.146 | 0.144 | 0.142 | 0.176 | 0.130 | 0.136 | 0.164 | 0.154 | 0.136 | 0.176 | 0.157 | 0.157 | 0.179 | 0.157 | 0.160 | 0.093 | 0.145 | 0.157 | 0.171 | 0.160 | 0.160 | 0.175 | 0.133 | 0.160 | 0.173 | 0.160 | 0.194 | 0.164 | 0.136 | 0.176 | 0.170 | 0.167 | 0.154 | 0.157 | 0.157 | 0.170 | 0.043 | 0.173 | 0.173 | 0.145 | |
9 | C. opercularis | 0.121 | 0.135 | 0.111 | 0.086 | 0.114 | 0.123 | 0.130 | 0.154 | 0.148 | 0.179 | 0.173 | 0.120 | 0.145 | 0.127 | 0.123 | 0.148 | 0.108 | 0.080 | 0.165 | 0.154 | 0.130 | 0.124 | 0.123 | 0.117 | 0.164 | 0.170 | 0.188 | 0.130 | 0.139 | 0.179 | 0.142 | 0.145 | 0.167 | 0.133 | 0.139 | 0.157 | 0.151 | 0.160 | 0.167 | 0.123 | |
10 | C. nigura | 0.143 | 0.154 | 0.145 | 0.157 | 0.154 | 0.154 | 0.056 | 0.136 | 0.148 | 0.151 | 0.133 | 0.127 | 0.111 | 0.142 | 0.145 | 0.127 | 0.139 | 0.145 | 0.162 | 0.151 | 0.151 | 0.181 | 0.130 | 0.130 | 0.164 | 0.136 | 0.182 | 0.056 | 0.160 | 0.148 | 0.160 | 0.167 | 0.127 | 0.154 | 0.145 | 0.148 | 0.145 | 0.160 | 0.151 | 0.151 | |
11 | C. iomelas | 0.169 | 0.172 | 0.139 | 0.164 | 0.157 | 0.170 | 0.160 | 0.176 | 0.179 | 0.151 | 0.099 | 0.167 | 0.154 | 0.194 | 0.188 | 0.179 | 0.157 | 0.160 | 0.102 | 0.151 | 0.170 | 0.219 | 0.157 | 0.164 | 0.108 | 0.096 | 0.182 | 0.160 | 0.164 | 0.093 | 0.157 | 0.160 | 0.105 | 0.167 | 0.148 | 0.096 | 0.173 | 0.086 | 0.090 | 0.167 | |
12 | C. dimidiata | 0.161 | 0.182 | 0.136 | 0.145 | 0.164 | 0.167 | 0.136 | 0.157 | 0.173 | 0.133 | 0.099 | 0.154 | 0.154 | 0.173 | 0.167 | 0.160 | 0.160 | 0.139 | 0.105 | 0.148 | 0.164 | 0.213 | 0.139 | 0.151 | 0.108 | 0.003 | 0.179 | 0.136 | 0.173 | 0.105 | 0.148 | 0.160 | 0.009 | 0.157 | 0.136 | 0.105 | 0.154 | 0.114 | 0.096 | 0.160 | |
13 | C. chrysura | 0.128 | 0.147 | 0.086 | 0.117 | 0.096 | 0.090 | 0.127 | 0.157 | 0.120 | 0.127 | 0.167 | 0.154 | 0.148 | 0.133 | 0.127 | 0.148 | 0.083 | 0.105 | 0.146 | 0.117 | 0.096 | 0.162 | 0.096 | 0.003 | 0.145 | 0.157 | 0.188 | 0.127 | 0.114 | 0.157 | 0.099 | 0.139 | 0.154 | 0.090 | 0.130 | 0.148 | 0.139 | 0.154 | 0.154 | 0.133 | |
14 | C. acares | 0.158 | 0.171 | 0.154 | 0.167 | 0.164 | 0.167 | 0.105 | 0.179 | 0.145 | 0.111 | 0.154 | 0.154 | 0.148 | 0.182 | 0.160 | 0.170 | 0.142 | 0.160 | 0.162 | 0.154 | 0.148 | 0.184 | 0.170 | 0.145 | 0.160 | 0.151 | 0.160 | 0.105 | 0.167 | 0.160 | 0.179 | 0.127 | 0.154 | 0.139 | 0.157 | 0.157 | 0.167 | 0.154 | 0.176 | 0.139 | |
15 | C. chromis | 0.129 | 0.157 | 0.120 | 0.157 | 0.133 | 0.139 | 0.127 | 0.157 | 0.127 | 0.142 | 0.194 | 0.173 | 0.133 | 0.182 | 0.049 | 0.139 | 0.145 | 0.133 | 0.194 | 0.170 | 0.167 | 0.156 | 0.130 | 0.130 | 0.191 | 0.176 | 0.188 | 0.127 | 0.154 | 0.170 | 0.167 | 0.170 | 0.173 | 0.139 | 0.136 | 0.170 | 0.151 | 0.176 | 0.157 | 0.151 | |
16 | C. limbata | 0.132 | 0.141 | 0.114 | 0.151 | 0.123 | 0.133 | 0.123 | 0.160 | 0.123 | 0.145 | 0.188 | 0.167 | 0.127 | 0.160 | 0.049 | 0.139 | 0.123 | 0.133 | 0.181 | 0.145 | 0.154 | 0.152 | 0.120 | 0.123 | 0.179 | 0.170 | 0.204 | 0.123 | 0.154 | 0.167 | 0.164 | 0.151 | 0.160 | 0.123 | 0.139 | 0.154 | 0.154 | 0.170 | 0.154 | 0.136 | |
17 | C. viridis | 0.141 | 0.146 | 0.139 | 0.157 | 0.145 | 0.148 | 0.142 | 0.093 | 0.148 | 0.127 | 0.179 | 0.160 | 0.148 | 0.170 | 0.139 | 0.139 | 0.136 | 0.148 | 0.165 | 0.127 | 0.142 | 0.175 | 0.154 | 0.151 | 0.170 | 0.160 | 0.170 | 0.142 | 0.154 | 0.148 | 0.160 | 0.148 | 0.154 | 0.145 | 0.136 | 0.148 | 0.111 | 0.170 | 0.160 | 0.136 | |
18 | C. ovalis | 0.129 | 0.138 | 0.099 | 0.123 | 0.105 | 0.123 | 0.133 | 0.145 | 0.108 | 0.139 | 0.157 | 0.160 | 0.083 | 0.142 | 0.145 | 0.123 | 0.136 | 0.117 | 0.156 | 0.127 | 0.077 | 0.140 | 0.108 | 0.080 | 0.154 | 0.160 | 0.204 | 0.133 | 0.123 | 0.164 | 0.108 | 0.136 | 0.154 | 0.062 | 0.133 | 0.160 | 0.136 | 0.154 | 0.157 | 0.127 | |
19 | C. anadema | 0.117 | 0.125 | 0.086 | 0.037 | 0.105 | 0.117 | 0.127 | 0.157 | 0.080 | 0.145 | 0.160 | 0.139 | 0.105 | 0.160 | 0.133 | 0.133 | 0.148 | 0.117 | 0.133 | 0.130 | 0.111 | 0.162 | 0.099 | 0.102 | 0.136 | 0.139 | 0.176 | 0.127 | 0.130 | 0.145 | 0.117 | 0.117 | 0.139 | 0.127 | 0.114 | 0.136 | 0.142 | 0.151 | 0.145 | 0.114 | |
20 | C. caudalis | 0.177 | 0.166 | 0.146 | 0.152 | 0.168 | 0.175 | 0.165 | 0.171 | 0.165 | 0.162 | 0.102 | 0.105 | 0.146 | 0.162 | 0.194 | 0.181 | 0.165 | 0.156 | 0.133 | 0.140 | 0.143 | 0.197 | 0.156 | 0.143 | 0.006 | 0.102 | 0.194 | 0.165 | 0.184 | 0.117 | 0.162 | 0.156 | 0.108 | 0.146 | 0.140 | 0.095 | 0.168 | 0.073 | 0.108 | 0.162 | |
21 | C. atrilobata | 0.149 | 0.154 | 0.120 | 0.151 | 0.136 | 0.139 | 0.151 | 0.160 | 0.154 | 0.151 | 0.151 | 0.148 | 0.117 | 0.154 | 0.170 | 0.145 | 0.127 | 0.127 | 0.130 | 0.140 | 0.117 | 0.184 | 0.157 | 0.120 | 0.142 | 0.148 | 0.179 | 0.151 | 0.151 | 0.154 | 0.154 | 0.114 | 0.148 | 0.130 | 0.142 | 0.160 | 0.154 | 0.145 | 0.154 | 0.160 | |
22 | C. randalli | 0.114 | 0.124 | 0.111 | 0.139 | 0.114 | 0.130 | 0.145 | 0.160 | 0.130 | 0.151 | 0.170 | 0.164 | 0.096 | 0.148 | 0.167 | 0.154 | 0.142 | 0.077 | 0.111 | 0.143 | 0.117 | 0.140 | 0.117 | 0.096 | 0.145 | 0.164 | 0.188 | 0.145 | 0.145 | 0.167 | 0.114 | 0.130 | 0.157 | 0.086 | 0.127 | 0.173 | 0.145 | 0.145 | 0.167 | 0.114 | |
23 | C. punctipinnis | 0.142 | 0.141 | 0.146 | 0.178 | 0.127 | 0.140 | 0.178 | 0.175 | 0.124 | 0.181 | 0.219 | 0.213 | 0.162 | 0.184 | 0.156 | 0.152 | 0.175 | 0.140 | 0.162 | 0.197 | 0.184 | 0.140 | 0.152 | 0.159 | 0.194 | 0.213 | 0.229 | 0.178 | 0.162 | 0.219 | 0.171 | 0.184 | 0.206 | 0.143 | 0.171 | 0.203 | 0.168 | 0.181 | 0.216 | 0.121 | |
24 | C. flavapicis | 0.116 | 0.138 | 0.090 | 0.111 | 0.080 | 0.093 | 0.142 | 0.133 | 0.123 | 0.130 | 0.157 | 0.139 | 0.096 | 0.170 | 0.130 | 0.120 | 0.154 | 0.108 | 0.099 | 0.156 | 0.157 | 0.117 | 0.152 | 0.093 | 0.151 | 0.142 | 0.191 | 0.142 | 0.117 | 0.164 | 0.117 | 0.142 | 0.142 | 0.108 | 0.117 | 0.160 | 0.127 | 0.160 | 0.151 | 0.123 | |
25 | C. bami | 0.131 | 0.150 | 0.083 | 0.114 | 0.093 | 0.093 | 0.123 | 0.160 | 0.117 | 0.130 | 0.164 | 0.151 | 0.003 | 0.145 | 0.130 | 0.123 | 0.151 | 0.080 | 0.102 | 0.143 | 0.120 | 0.096 | 0.159 | 0.093 | 0.142 | 0.154 | 0.185 | 0.123 | 0.111 | 0.154 | 0.099 | 0.136 | 0.151 | 0.086 | 0.127 | 0.145 | 0.136 | 0.151 | 0.151 | 0.130 | |
26 | C. fatuhivae | 0.178 | 0.167 | 0.145 | 0.154 | 0.170 | 0.170 | 0.164 | 0.173 | 0.164 | 0.164 | 0.108 | 0.108 | 0.145 | 0.160 | 0.191 | 0.179 | 0.170 | 0.154 | 0.136 | 0.006 | 0.142 | 0.145 | 0.194 | 0.151 | 0.142 | 0.111 | 0.188 | 0.164 | 0.185 | 0.120 | 0.164 | 0.154 | 0.111 | 0.145 | 0.142 | 0.105 | 0.170 | 0.080 | 0.114 | 0.157 | |
27 | C. fieldi | 0.161 | 0.182 | 0.136 | 0.145 | 0.164 | 0.167 | 0.139 | 0.160 | 0.170 | 0.136 | 0.096 | 0.003 | 0.157 | 0.151 | 0.176 | 0.170 | 0.160 | 0.160 | 0.139 | 0.102 | 0.148 | 0.164 | 0.213 | 0.142 | 0.154 | 0.111 | 0.179 | 0.139 | 0.173 | 0.108 | 0.148 | 0.160 | 0.012 | 0.157 | 0.136 | 0.102 | 0.157 | 0.111 | 0.093 | 0.160 | |
28 | C. lepidolepis | 0.195 | 0.225 | 0.167 | 0.182 | 0.198 | 0.198 | 0.173 | 0.194 | 0.188 | 0.182 | 0.182 | 0.179 | 0.188 | 0.160 | 0.188 | 0.204 | 0.170 | 0.204 | 0.176 | 0.194 | 0.179 | 0.188 | 0.229 | 0.191 | 0.185 | 0.188 | 0.179 | 0.173 | 0.213 | 0.179 | 0.198 | 0.188 | 0.185 | 0.188 | 0.179 | 0.182 | 0.191 | 0.198 | 0.201 | 0.182 | |
29 | C. delta | 0.140 | 0.156 | 0.136 | 0.139 | 0.142 | 0.145 | 0.000 | 0.164 | 0.130 | 0.056 | 0.160 | 0.136 | 0.127 | 0.105 | 0.127 | 0.123 | 0.142 | 0.133 | 0.127 | 0.165 | 0.151 | 0.145 | 0.178 | 0.142 | 0.123 | 0.164 | 0.139 | 0.173 | 0.164 | 0.139 | 0.160 | 0.157 | 0.130 | 0.139 | 0.133 | 0.148 | 0.167 | 0.164 | 0.136 | 0.151 | |
30 | C. xanthopterygia | 0.141 | 0.134 | 0.108 | 0.136 | 0.068 | 0.071 | 0.164 | 0.136 | 0.139 | 0.160 | 0.164 | 0.173 | 0.114 | 0.167 | 0.154 | 0.154 | 0.154 | 0.123 | 0.130 | 0.184 | 0.151 | 0.145 | 0.162 | 0.117 | 0.111 | 0.185 | 0.173 | 0.213 | 0.164 | 0.173 | 0.120 | 0.151 | 0.182 | 0.136 | 0.139 | 0.173 | 0.142 | 0.173 | 0.167 | 0.136 | |
31 | C. retrofasciata | 0.157 | 0.160 | 0.136 | 0.154 | 0.179 | 0.182 | 0.139 | 0.176 | 0.179 | 0.148 | 0.093 | 0.105 | 0.157 | 0.160 | 0.170 | 0.167 | 0.148 | 0.164 | 0.145 | 0.117 | 0.154 | 0.167 | 0.219 | 0.164 | 0.154 | 0.120 | 0.108 | 0.179 | 0.139 | 0.173 | 0.167 | 0.160 | 0.111 | 0.160 | 0.151 | 0.093 | 0.167 | 0.111 | 0.102 | 0.154 | |
32 | C. nitida | 0.132 | 0.145 | 0.114 | 0.123 | 0.093 | 0.108 | 0.160 | 0.170 | 0.142 | 0.160 | 0.157 | 0.148 | 0.099 | 0.179 | 0.167 | 0.164 | 0.160 | 0.108 | 0.117 | 0.162 | 0.154 | 0.114 | 0.171 | 0.117 | 0.099 | 0.164 | 0.148 | 0.198 | 0.160 | 0.120 | 0.167 | 0.145 | 0.151 | 0.120 | 0.139 | 0.167 | 0.160 | 0.167 | 0.145 | 0.139 | |
33 | C. multilineata | 0.157 | 0.160 | 0.108 | 0.127 | 0.130 | 0.139 | 0.157 | 0.167 | 0.145 | 0.167 | 0.160 | 0.160 | 0.139 | 0.127 | 0.170 | 0.151 | 0.148 | 0.136 | 0.117 | 0.156 | 0.114 | 0.130 | 0.184 | 0.142 | 0.136 | 0.154 | 0.160 | 0.188 | 0.157 | 0.151 | 0.160 | 0.145 | 0.160 | 0.133 | 0.127 | 0.151 | 0.157 | 0.148 | 0.167 | 0.145 | |
34 | C. margaritifer | 0.156 | 0.175 | 0.142 | 0.145 | 0.160 | 0.170 | 0.130 | 0.154 | 0.167 | 0.127 | 0.105 | 0.009 | 0.154 | 0.154 | 0.173 | 0.160 | 0.154 | 0.154 | 0.139 | 0.108 | 0.148 | 0.157 | 0.206 | 0.142 | 0.151 | 0.111 | 0.012 | 0.185 | 0.130 | 0.182 | 0.111 | 0.151 | 0.160 | 0.148 | 0.136 | 0.105 | 0.154 | 0.120 | 0.096 | 0.154 | |
35 | C. flavomaculata | 0.139 | 0.149 | 0.105 | 0.139 | 0.108 | 0.117 | 0.139 | 0.157 | 0.133 | 0.154 | 0.167 | 0.157 | 0.090 | 0.139 | 0.139 | 0.123 | 0.145 | 0.062 | 0.127 | 0.146 | 0.130 | 0.086 | 0.143 | 0.108 | 0.086 | 0.145 | 0.157 | 0.188 | 0.139 | 0.136 | 0.160 | 0.120 | 0.133 | 0.148 | 0.136 | 0.157 | 0.142 | 0.151 | 0.173 | 0.136 | |
36 | C. cyanea | 0.141 | 0.161 | 0.111 | 0.123 | 0.117 | 0.130 | 0.133 | 0.157 | 0.139 | 0.145 | 0.148 | 0.136 | 0.130 | 0.157 | 0.136 | 0.139 | 0.136 | 0.133 | 0.114 | 0.140 | 0.142 | 0.127 | 0.171 | 0.117 | 0.127 | 0.142 | 0.136 | 0.179 | 0.133 | 0.139 | 0.151 | 0.139 | 0.127 | 0.136 | 0.136 | 0.142 | 0.151 | 0.148 | 0.127 | 0.145 | |
37 | C. atripes | 0.159 | 0.167 | 0.136 | 0.148 | 0.167 | 0.164 | 0.148 | 0.170 | 0.157 | 0.148 | 0.096 | 0.105 | 0.148 | 0.157 | 0.170 | 0.154 | 0.148 | 0.160 | 0.136 | 0.095 | 0.160 | 0.173 | 0.203 | 0.160 | 0.145 | 0.105 | 0.102 | 0.182 | 0.148 | 0.173 | 0.093 | 0.167 | 0.151 | 0.105 | 0.157 | 0.142 | 0.157 | 0.105 | 0.090 | 0.157 | |
38 | C. atripectoralis | 0.151 | 0.159 | 0.136 | 0.154 | 0.136 | 0.142 | 0.167 | 0.043 | 0.151 | 0.145 | 0.173 | 0.154 | 0.139 | 0.167 | 0.151 | 0.154 | 0.111 | 0.136 | 0.142 | 0.168 | 0.154 | 0.145 | 0.168 | 0.127 | 0.136 | 0.170 | 0.157 | 0.191 | 0.167 | 0.142 | 0.167 | 0.160 | 0.157 | 0.154 | 0.142 | 0.151 | 0.157 | 0.157 | 0.176 | 0.136 | |
39 | C. amboinensis | 0.163 | 0.147 | 0.136 | 0.176 | 0.164 | 0.176 | 0.164 | 0.173 | 0.160 | 0.160 | 0.086 | 0.114 | 0.154 | 0.154 | 0.176 | 0.170 | 0.170 | 0.154 | 0.151 | 0.073 | 0.145 | 0.145 | 0.181 | 0.160 | 0.151 | 0.080 | 0.111 | 0.198 | 0.164 | 0.173 | 0.111 | 0.167 | 0.148 | 0.120 | 0.151 | 0.148 | 0.105 | 0.157 | 0.099 | 0.148 | |
40 | C. agilis | 0.146 | 0.150 | 0.136 | 0.151 | 0.157 | 0.164 | 0.136 | 0.173 | 0.167 | 0.151 | 0.090 | 0.096 | 0.154 | 0.176 | 0.157 | 0.154 | 0.160 | 0.157 | 0.145 | 0.108 | 0.154 | 0.167 | 0.216 | 0.151 | 0.151 | 0.114 | 0.093 | 0.201 | 0.136 | 0.167 | 0.102 | 0.145 | 0.167 | 0.096 | 0.173 | 0.127 | 0.090 | 0.176 | 0.099 | 0.160 | |
41 | C. alta | 0.079 | 0.074 | 0.117 | 0.127 | 0.120 | 0.127 | 0.151 | 0.145 | 0.123 | 0.151 | 0.167 | 0.160 | 0.133 | 0.139 | 0.151 | 0.136 | 0.136 | 0.127 | 0.114 | 0.162 | 0.160 | 0.114 | 0.121 | 0.123 | 0.130 | 0.157 | 0.160 | 0.182 | 0.151 | 0.136 | 0.154 | 0.139 | 0.145 | 0.154 | 0.136 | 0.145 | 0.157 | 0.136 | 0.148 | 0.160 |
Average genetic distance in mitochondrial gene COI between species of Chromis. The number of base differences per site from averaging over all sequence pairs between groups are shown. Average within-species divergences are shown on diagonal.
C. enchrysurus | C. insolata | C. vanbebberae | C. scotti | C. lubbocki | C. xanthura | C. randalli | C. sanctaehelenae | C. multilineata | C. alta | |
---|---|---|---|---|---|---|---|---|---|---|
C. enchrysurus | 0.007 | 0.070 | 0.036 | 0.065 | 0.110 | 0.118 | 0.143 | 0.104 | 0.145 | 0.057 |
C. insolata | 0.070 | 0.066 | 0.048 | 0.088 | 0.111 | 0.134 | 0.095 | 0.129 | 0.065 | |
C. vanbebberae | 0.036 | 0.066 | 0.004 | 0.058 | 0.105 | 0.106 | 0.138 | 0.100 | 0.142 | 0.051 |
C. scotti | 0.065 | 0.048 | 0.058 | 0.080 | 0.109 | 0.134 | 0.091 | 0.121 | 0.053 | |
C. lubbocki | 0.110 | 0.088 | 0.105 | 0.080 | 0.124 | 0.136 | 0.085 | 0.143 | 0.090 | |
C. xanthura | 0.118 | 0.111 | 0.106 | 0.109 | 0.124 | 0.156 | 0.108 | 0.143 | 0.109 | |
C. randalli | 0.143 | 0.134 | 0.138 | 0.134 | 0.136 | 0.156 | 0.138 | 0.144 | 0.139 | |
C. sanctaehelenae | 0.104 | 0.095 | 0.100 | 0.091 | 0.085 | 0.108 | 0.138 | 0.156 | 0.093 | |
C. multilineata | 0.145 | 0.129 | 0.142 | 0.121 | 0.143 | 0.143 | 0.144 | 0.156 | 0.131 | |
C. alta | 0.057 | 0.065 | 0.051 | 0.053 | 0.090 | 0.109 | 0.139 | 0.093 | 0.13 |
The genes used in this study are commonly used in phylogenetic and species-delimitation studies in fishes. Mitochondrial genes are especially useful in species identification and phylogenetic reconstruction due to their high number of copies compared to nuclear DNA, lack of recombination, and comparatively fast evolution (
Although the PCA does separate the two species on the basis of PC1, the morphometric differences are subtle and fail to perfectly separate the two species, especially when individuals are small (SL < 25 mm). While some characters have statistically significant differences between the two species (i.e., the length of soft dorsal base, length of last dorsal spine [p = 0.012], caudal fin length, etc.; see Morphometrics results above), these characters are not discrete, overlap substantially between species, and are not prominent when individuals are small. Collectively, this makes them largely impractical for diagnosing the two species. Coloration remains the most useful morphological character for distinguishing the species. The presence of sister species that are nearly morphologically identical and distinguished primarily by live coloration is increasingly observed in coral-reef fishes (
Data suggest that C. vanbebberae and C. enchrysurus occupy distinct geographic ranges with little overlap, which indicates that collection locality can help inform species identity with reasonable certainty when genetic analysis cannot be performed. Species-range estimates of C. enchrysurus and C. vanbebberae based on collections, visual observations, and genetic data from georeferenced specimens agree well with the findings of
A genetic break between sister species or populations occurring in the northern province of
Many of the recently described species from the Greater Caribbean are cryptobenthic fishes that are often overlooked in biodiversity surveys. However, pomacentrids are some of the most conspicuous fishes on corals reefs. They occur on shallow and deep coral reefs in every geographic region, where they are often the most abundant fishes on a given reef (
Morphometrics and meristics of Chromis vanbebberae and Chromis enchrysurus specimens examined. Morphometric values are as percentage of SL.
Chromis vanbebberae | Chromis enchrysura | |||||
---|---|---|---|---|---|---|
Holotype USNM 446947 | Average | Range | Holotype |
Average | Range | |
standard length | 73.9 | 48.2 | 13.9–98.4 | 68 | 60.7 | 80.8–17.7 |
body depth | 55.2 | 51.1 | 41.6–57.7 | 50.9 | 50.2 | 53.9–44 |
body width | 19.4 | 19.1 | 16.5–21.6 | 17.8 | 17.5 | 19.2–13.8 |
head length | 30.2 | 35.4 | 30.2–41 | 31.3 | 31.6 | 36–29.8 |
snout length | 7.9 | 8.2 | 5.2–10.3 | 8.4 | 8.2 | 9.3–5.8 |
orbit diameter | 11.8 | 14.6 | 11.5–17.4 | 11.3 | 11.7 | 14.7–10 |
interorbit width | 10.7 | 10.6 | 8.6–12.1 | 10.6 | 10.6 | 14–9.2 |
caudal peduncle depth | 16.1 | 15.1 | 13.3–16.4 | 14.7 | 14 | 15.6–9.8 |
upper jaw length | 9.1 | 10 | 6.0–14.4 | 9.4 | 9.7 | 10.9–8 |
predorsal length | 33.2 | 34 | 28.6–42 | 35.6 | 33.7 | 38.3–28.2 |
spinous dorsal base | 48.6 | 44.1 | 35.5–50.2 | 45.9 | 46.7 | 50.8–36.6 |
soft dorsal base | 18.9 | 16.5 | 13.4–18.9 | 16.9 | 14.6 | 18–10.4 |
1st dorsal spine | 8.7 | 9.1 | 7.2–11.9 | 10.3 | 8.3 | 10.3–6.7 |
2nd dorsal spine | 12.9 | 14.3 | 11.4–17.5 | 14.9 | 12.6 | 16.2–10.6 |
3rd dorsal spine | 15.7 | 17.9 | 15.3–21.6 | 19.6 | 15.5 | 19.6–12.3 |
4th dorsal spine | 19.4 | 20.2 | 16.6–24.5 | 22.4 | 17.4 | 22.4–13.5 |
5th dorsal spine | 20.6 | 20.5 | 16.2–25.9 | 22.2 | 17.4 | 22.4–13.5 |
6th dorsal spine | 19.8 | 18.6 | 15.5–23.7 | 21.6 | 17 | 21.6–13.3 |
last dorsal spine | 16.4 | 13.8 | 10.3–17.4 | 14.1 | 12.3 | 16.1–9.3 |
longest dorsal ray | 23.8 | 23.2 | 21.1–28.5 | 21.3 | 19.1 | 23–16.1 |
preanal length | 64.1 | 67 | 63.2–69.7 | 64.7 | 66.5 | 69.9–63.1 |
1st anal spine | 9.3 | 8.7 | 5.8–11.6 | 9.9 | 8.1 | 9.9–5.5 |
2nd anal spine | 19.9 | 19.2 | 15.1–22.4 | 20.9 | 18.8 | 21.8–16 |
longest anal ray | 23.4 | 24.1 | 18.9–28 | 22.1 | 19.9 | 26.3–16.3 |
caudal length | 41 | 36.8 | 29.7–44.9 | 31.5 | 31.4 | 35.8–27.3 |
longest pectoral ray | 34.2 | 33.8 | 31.1–38.1 | 30.2 | 31.2 | 33.7–28.6 |
prepelvic length | 35.2 | 38.4 | 35.2–43.6 | 37.4 | 37.3 | 41.7–33.8 |
pelvic spine length | 22.2 | 20.3 | 18.7–22.4 | 22.7 | 20 | 31.2–17.2 |
1st pelvic soft ray | 40.9 | 35.4 | 28.8–43.2 | 36.3 | 23.4 | 36.8–30.8 |
dorsal rays | 12 | 12.73 | 12–13 | 12 | 12.22 | 11–15 |
anal rays | 12 | 12.57 | 12–13 | 12 | 12.06 | 11–13 |
pored lateral line scales | 17 | 16.54 | 15–17 | 17 | 17.16 | 16–18 |
upper gill rakers | 7 | 7.27 | 7–8 | 8 | 7.47 | 7–8 |
lower gill rakers | 17 | 16.93 | 16–18 | 16 | 16.84 | 16–18 |
We thank Katherine Maslenikov at UW for assistance with cataloging specimens, and both her and Sarah Yerrace (UW) for help with field work in Curaçao. We thank Frank Young at Dynasty Marine Inc. for acquiring specimens from the Florida Keys. Rob Robins at
Table S1. Material examined of Chromis vanbebberae and C. enchrysurus
Data type: Specimen list
Table S2. GenBank accession numbers for outgroup taxa
Data type: Accession numbers
Table S3. Contribution to overall variance by the first ten principle components
Data type: Principal component contributions
Table S4. Loadings for the first five components from the Principal Component Analysis
Data type: Principal component loadings
Explanation note: Values in blue contribute positively and those in red contribute negatively to a given component. The greater the absolute value of the contribution, the more intense the color. Only the first five of 28 components have been included.