Chriolepis, GILBERT, 1892

Tornabene, Luke, Van Tassell, James L., Gilmore, Richard G., Robertson, David Ross, Young, Forrest & Baldwin, Carole C., 2016, Molecular phylogeny, analysis of character evolution, and submersible collections enable a new classification of a diverse group of gobies (Teleostei: Gobiidae: Nes subgroup), including nine new species and four new genera, Zoological Journal of the Linnean Society 177 (4), pp. 764-812 : 772-778

CHRIOLEPIS GILBERT, 1892

TYPE SPECIES: CHRIOLEPIS MINUTILLA GILBERT, 1892 (ORIGINAL SPELLING CHRIOLEPIS MINUTILLUS), BY MONOTYPY

PYCNOMMA RUTTER, 1904 TYPE SPECIES: PYCNOMMA SEMISQUAMATUM RUTTER, 1904, BY MONOTYPY

the polyphyly of Psilotris , the new genus Carrigobius is erected. Important distinguishing features that separate it from Psilotris and Cryptopsilotris are the blunt profile of the head and the presence of a branched fifth pelvic-fin ray in adults. This latter feature, as well as the presence of two anal-fin pterygiophores before the first haemal spine, distinguishes Diagnosis

Possesses all taxonomic characters present in most members of Gobiosomatini and Gobiosoma group (seven-first dorsal-fin spines, pterygiophore insertion pattern of 3 – 221110, 27 vertebrae – 11 precaudal and 16 caudal, hypurals 1 and 2 fused to some extent with hypurals 3 and 4 and the terminal vertebral element, one epural); pelvic fins well separated, lacking both anterior frenum and well-developed membrane connecting innermost rays; pelvic-fin rays 1 – 4 branched, never with flattened or fleshy tips; fifth pelvic-fin ray unbranched in some species, branched or variable in others; pelvic-fin rays extending posteriorly to anus, never reaching origin of anterior anal-fin rays; body with scales, modified basicaudal scales present; two anal-fin pterygiophores inserted before first haemal spine; papillae rows 5i and 5s separate; cephalic lateralis canals and pores absent in all but two species Chriolepis roosevelti (Ginsburg, 1939) , Chriolepis semisquamata (Rutter, 1904) ; second dorsal-fin rays I,8 – 11; anal-fin rays I,8 – 10. Colour patterns variable among species: uniformly drab, with cryptic mottling and spotting, or with prominent narrow black vertical bars on white body. All but one known species occur in the tropical eastern Pacific Ocean.

Remarks

Chriolepis received its first formal taxonomic treatment when Findley (1983) reviewed the Pacific members of the genus in an unpublished PhD dissertation. This review provided a robust overview of the diversity within the Pacific members of the group (including several apparently new species that have yet to be described). Findley also recognized that the genus could be divided into two sub- genera that were originally described by Ginsburg (1938) as Chriolepis chriolepis and Chriolepis eleotriculus . Findley (1983) made no formal inferences regarding the relationships to the Atlantic species of Chriolepis or Varicus ; however, he acknowledged that Chriolepis as currently described was not likely to be monophyletic and was probably a ‘catch-all’ genus for unrelated species. Our molecular phylogeny supports this. The Pacific members of Chriolepis have no close relatives in the Atlantic except for Pycnomma roosevelti (here as Chriolepis roosevelti ). Even with the exclusion of Atlantic taxa, the Pacific species of Chriolepis themselves are not monophyletic, and form two distinct groups that agree well with Findley’s (1983) subgeneric arrangement, with subgenus Chriolepis being represented here by Chriolepis dialepta Bussing, 1990 , and subgenus Eleotriculus represented by Chriolepis zebra Ginsburg, 1938 and Chriolepis cuneata Bussing, 1990 . Chriolepis minutilla is the type species of the genus, and Findley (1983) recognized many similarities between Chriolepis minutilla , Chriolepis dialepta , and Chriolepis lepidota Findley, 1975 , placing all three in the subgenus Chriolepis . We agree with this assessment and conclude that C. minutilla and C. lepidota are likely to be part of the clade containing C. dialepta . Chriolepis tagus Ginsburg, 1953 , known only from the holotype, is of uncertain affinity, but we provisionally retain it within Chriolepis pending future analysis of additional specimens.

Nested between the two lineages of Chriolepis are the species of Pycnomma , a genus previously separated from Chriolepis by the presence of cephalic lateralis canals and pores; however, our analysis shows that the absence of cephalic lateralis canals may actually be a plesiomorphic condition across the Nes group, and that the presence of pores in Pycnomma *Spelling corrected to match gender of genus.

may represent independent apomorphic reversals. Rather than divide the clade containing the Pacific Chriolepis and Pycnomma into several genera, we synonymize Pycnomma with Chriolepis and restrict Chriolepis to the Pacific members of the group (except Chriolepis atrimela Bussing, 1997 ) plus the two species of Pycnomma .

Our genetic sampling did not include the Atlantic species Chriolepis benthonis Ginsburg, 1953 ; Chri- olepis bilix Hastings & Findley, 2013 ; Chriolepis prolata Hastings & Findley, 2015 ; or Chriolepis vespa Hastings & Bortone, 1981 ; however, these four species have several characters that differentiate them from each other and from most Pacific Chriolepis , and are herein assigned to either the genus Varicus (for Chriolepis vespa and Chriolepis benthonis ) or Pinnichthys gen. nov. (for Chriolepis bilix and Chriolepis prolata ). The Atlantic species previ- ously classified as Chriolepis have either one anal-fin pterygiophore inserted before the haemal spine, as in Chriolepis benthonis and Chriolepis vespa , or have papillae rows 5i and 5s connected and are heavily scaled, as in Chriolepis bilix and Chriolepis prolata Hastings & Findley, 2015 . The Pacific Chriolepis atrimela , a deep-reef species from the Galapagos Islands, is also assigned to Pinnichthys based on morphological features. Further discussion on the reassignment of Chriolepis atrimela and the other aforementioned Atlantic species of Chriolepis are given in the remarks sections for Varicus and Pinnichthys below.

The generic assignment of the Atlantic species Chriolepis fisheri is uncertain. This species lacks body scales except for two modified basicaudal scales on each side of the caudal peduncle, has one anal-fin pterygiophore inserted before the first haemal spine, and the connection of papillae rows 5i and 5s is unknown. Our molecular analysis includes two species that superficially agree with Chriolepis fisheri in that they possess only basicaudal scales. These species are recovered in two different lineages on the molecular phylogeny. One lineage from Belize and Fernando de Noronha, Brazil, is sister to Pinnichthys and possesses I,10 – 11 second dorsal-fin rays, I,9 – 11 anal-fin rays, and one anal-fin pterygiophore inserted before the haemal spine, all of which agree to some extent with the holotype of Chriolepis fisheri (I,10 second dorsal, I,9 anal). The second lineage is represented by two specimens from the Bahamas, and is nested among several species of Psilotris (labelled as Psilotris sp. / Chriolepis cf. fisheri in Fig. 5 ). These specimens have I,9 second dorsal-fin rays, I,8 analfin rays, and the one cleared-and-stained specimen has one anal-fin pterygiophore anterior to the haemal arch but two pterygiophores inserted in the subsequent interhaemal space. A survey of additional museum specimens labelled as Chriolepis fisheri from throughout the Caribbean has revealed a complex mix of specimens possessing a variety of combinations of second-dorsal and anal-fin counts, as well as pterygiophore insertion patterns, often co-occurring in the same locality ( Table S1). Furthermore, all of the Chriolepis fisheri material examined in this study comes from shallow reefs, whereas the holotype of Chriolepis fisheri was collected from a depth of 82 m. Therefore, it is possible that the true Chriolepis fisheri may be a more rare, deep-reef species, not represented by either of the two lineages in our tree. Based on this information, the status of Chriolepis fisheri is still unresolved, and an in-depth study of the various forms throughout the western Atlantic is needed to clarify this species (or group of species). Given the uncertainty regarding this species, rather than provisionally erect a new genus for the lineage that we tentatively decide is Chriolepis fisheri (thus preventing a polyphyletic Chriolepis ), all with the likelihood that this may very well change in the near future, we instead consider Chriolepis fisheri incertae sedis pending further investigation.

CRYPTOPSILOTRIS VAN TASSELL, TORNABENE & GILMORE GEN. NOV. TYPE SPECIES: CRYPTOPSILOTRIS BATRACHODES (B OHLKE €, 1963: 6, FIG. 2 , DESCRIBED AS PSILOTRIS BATRACHODES )

Diagnosis

Possesses all taxonomic characters present in most members of Gobiosomatini and Gobiosoma group [first dorsal-fin spines VII (rarely five or six), pterygiophore insertion pattern of 3 – 221110, 27 vertebrae – 11 precaudal and 16 caudal (occasionally 11 and 15 or 12 and 15), hypurals 1 and 2 fused to some extent with hypurals 3 and 4 and the terminal vertebral element, one epural); pelvic fins well separated, lacking both anterior frenum and welldeveloped membrane connecting innermost rays; pelvic-fin rays 1 – 4 branched, without flattened or fleshy tips; pelvic-fin rays extending posteriorly halfway to anus or slightly further, never reaching anus; body without scales (modified basicaudal scales absent); one anal-fin pterygiophore inserted before haemal spine (in anomalous cases where first haemal spine is on vertebra 13 rather than vertebra 12, two anal-fin pterygiophores inserted before haemal spine); papillae rows 5i and 5s not connected; cephalic lateralis canals and pores absent; second dorsal-fin rays I,8 – 9; anal-fin rays I,6 – 7; a broad dark diagonal brown band on head passing through eye and onto preopercle; dorsal surface of body uniformly dark brown in contrast to ventral two-thirds of body, which has dark spots or mottling on pale background; first dorsal fin with dark wide diagonal band, second dorsal fin with two dark wide diagonal bands, and caudal fin with crescent-shaped dark band. The one known species occurs in the western Atlantic Ocean.

Remarks

Greenfield (1993) and Smith & Baldwin (1999) noted that the species of Psilotris are quite dissimilar from one another, and probably do not represent a natural group. Psilotris batrachodes is the most distinctive of these species both in meristics (lowest anal-fin ray count) and in coloration, and indeed our molecular phylogeny shows this species as being a distinct lineage separate from other Psilotris species. For this reason, we erect the new genus Cryptopsilotris for this species.

Etymology

The genus name is formed from ‘ Psilotris ’, the genus the type species was formerly classified under, and the root ‘crypto-’, which is taken from the Greek ‘kruptos’ meaning hidden. The name is in reference to the cryptic coloration of the type species.

Figures

Figure 2. Anal-fin pterygiophore insertion patterns. (A) One anal-fin pterygiophore inserted anterior to first haemal spine (Varicus cephalocellatus paratype, USNM 427227); (B) rare pattern in which haemal spine on vertebra 12 is reduced, and first elongate haemal spine appears on vertebra 13, giving the appearance of two anal-pterygiophores inserted before first haemal spine. This pattern is considered homologous to pattern depicted in A, and occurs only in species in which the pattern from A is also observed (Varicus cephalocellatus paratype, USNM 427227); (C) two anal-fin pterygiophores inserted anterior to first haemal spine (Chriolepis lepidota holotype USNM 211456).

Figure 5. Bayesian phylogeny from MrBayes analysis of the Gobiosomatini. Tip labels follow classification recognized prior to this study. Red bars indicate new classification from this study (Table 2). Support values at nodes are Bayesian posterior probabilities. The “?” for Chriolepis cf. fisheri refers to the incertae sedis status of this species (see “Remarks” section for Chriolepis). Species from the eastern Pacific are denoted with “(P)”.