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A review of the Eviota zebrina complex, with descriptions of four new species (Teleostei, Gobiidae)
expand article infoLuke Tornabene, David W. Greenfield§|, Mark V. Erdmann|
‡ University of Washington, Seattle, United States of America
§ University of Hawaii, Pacific Grove, United States of America
| Research Associate, Department of Ichthyology, California Academy of Sciences, San Francisco, United States of America
¶ University of Auckland, Auckland, New Zealand
Open Access

Abstract

The Eviota zebrina complex includes eight species of closely-related dwarfgobies, four of which are herein described as new. The complex is named for Eviota zebrina Lachner & Karnella, 1978, an Indian Ocean species with the holotype from the Seychelles Islands and also known from the Maldives, which was once thought to range into the Gulf of Aqaba and the Red Sea eastward to the Great Barrier Reef of Australia. Our analysis supports the recognition of four genetically distinct, geographically non-overlapping, species within what was previously called E. zebrina, with E. zebrina being restricted to the Indian Ocean, E. marerubrum sp. nov. described from the Red Sea, E. longirostris sp. nov. described from western New Guinea, and E. pseudozebrina sp. nov. described from Fiji. The caudal fin of all four of these species is crossed by oblique black bars in preservative, but these black bars are absent from the four other species included in the complex. Two of the other species within the complex, E. tetha and E. gunawanae are morphologically similar to each other in having the AITO cephalic-sensory pore positioned far forward and opening anteriorly. Eviota tetha is known from lagoonal environments in Cenderawasih Bay and Raja Ampat, West Papua, and E. gunawanae is known only from deeper reefs (35–60 m) from Fakfak Regency, West Papua. The final two species are E. cometa which is known from Fiji and Tonga and possesses red bars crossing the caudal fin (but lost in preservative) and a 9/8 dorsal/anal-fin formula, and E. oculineata sp. nov., which is described as new from New Guinea and the Solomon Islands, and possesses an 8/7 dorsal/anal-fin formula and lacks red caudal bars. Eviota oculineata has been confused with E. cometa in the past.

Keywords

coral-reef fishes, dwarfgoby, Eviota cometa, gobies, ichthyology, taxonomy, systematics

Introduction

The genus Eviota, commonly known as dwarfgobies, contains 124 species (Greenfield 2021; Greenfield and Erdmann 2021), making it one of the most speciose genera of marine fishes. Several putatively widespread species of Eviota displaying morphological variation have recently been shown to be complexes of distinct species that are often distinguishable by a combination of genetic differences, subtle morphological characters, and/or differences in live coloration (Greenfield and Tornabene 2014; Tornabene et al. 2015, 2016). Another example of this phenomenon is demonstrated by the Eviota zebrina complex, a group containing eight genetic lineages based on mtDNA, including the nominal species Eviota zebrina Lachner & Karnella, 1978, E. cometa Jewett & Lachner, 1983, E. gunawanae Greenfield et al., 2019, E. tetha Greenfield & Erdmann, 2014, and several undescribed species (Greenfield et al. 2019). All species in this complex possess: (i) unbranched pectoral-fin rays; (ii) reduced fifth pelvic-fin rays (absent or rudimentary to ~ 15% length of fourth ray); (iii) pore patterns lacking only the IT pores, or both the IT and nasal pores Figure 1); (iv) fourth pelvic-fin ray with only 3–7 branches; (v) a red or dark brown lateral stripe on the body (stripe faint in E. pseudozebrina sp. nov.) that terminates in distinct black spot on the base of the caudal fin that is sometimes bordered with yellow in life (spot faint in E. tetha). The combination of the lateral stripe and black caudal spot are present only in two other species, E. sebreei Jordan & Seale, 1906 and E. punyit Tornabene et al., 2016, both of which differ from the E. zebrina complex in having a pore pattern lacking the PITO pore, and in having a fourth pelvic-fin ray with many more branches (11–15 vs. 3–7).

Figure 1. 

Head pore patterns relevant to the Eviota zebrina complex A complete pore pattern (pattern 1 of Lachner and Karnella 1980). Note that the IT pore and associated section of the lateralis canal are absent in pore pattern 2 and in all species of the E. zebrina complex. Figure modified from Tornabene et al. (2013) B pattern 2, found in all species of the E. zebrina complex except E. tetha and E. gunawanae. Photograph of CAS 246248, E. longirostris C pattern found in E. tetha and E. gunawanae. Photograph of CAS 246247, E. tetha. Note the absence of NA pores and the anterior-facing AITO pore. Pore abbreviations follow Lachner and Karnell (1980).

Eviota zebrina was described based on type material from the Seychelles Islands, with non-type specimens from the Red Sea and other Indian Ocean localities east to the Great Barrier Reef, Australia. Lachner and Karnella (1978) noted geographic variation in meristic characters and pigmentation patterns among populations but refrained from splitting the groups into named species. During their survey of the marine fishes of Fiji (1999–2003), Greenfield and Randall identified one of the dwarfgobies collected as Eviota zebrina, the first record of that species from Oceania at that time (Randall 2005). When Herler and Hilgers (2005) published color photographs of E. zebrina from the Red Sea that differed from the color of specimens from Fiji, it raised suspicions that the specimens from Fiji might be undescribed. In 2017 MVE collected specimens and DNA tissue of E. zebrina from the southern Lau Islands, Fiji, and in 2018 specimens and tissue of E. zebrina from the Maldives, an Indian Ocean location. Greenfield et al. (2019) included DNA sequences of E. zebrina from the Red Sea, the Maldives, Seychelles Islands, western New Guinea, and Fiji in a molecular phylogeny of this complex (Figure 2), spanning most of the known range of E. zebrina. These data showed that E. zebrina indeed represented a species complex, with specimens of Eviotazebrina” from the Red Sea, western New Guinea, and Fiji all representing lineages that are distinct from those in the Indian Ocean. We herein describe the specimens from Fiji as Eviota pseudozebrina sp. nov., those from western New Guinea as E. longirostris sp. nov., and the Red Sea specimens as E. marerubrum sp. nov.

Figure 2. 

Molecular phylogeny based on COI and Ptr sequences. Branch lengths are substitutions/site, node labels are Bayesian posterior probabilities. Blue branches indicate new species described here. Labels before species name refer to tissue numbers.

Eviota cometa is also a member of the E. zebrina complex, and based on the phylogenetic tree of Greenfield et al. (2019), there are two lineages putatively identified as E. cometa. Eviota cometa was described by Jewett and Lachner (1983) from specimens in Fiji (type locality) and many non-type specimens across the western and central Pacific Ocean. As was the case with E. zebrina, the authors noted that E. cometa displayed some morphological variation across its geographic range but refrained from recognizing morphotypes as distinct species. Specifically, Jewett and Lachner (1983) noted that there were two distinct counts in the dorsal- and anal-fin rays, 9/8 (as in the holotype) vs 8/7, but in some locations, including the type locality in Fiji, both counts were present, leading to the conclusion that this was intraspecific variation. No differences in live coloration were noted at the time of description. Recent live photographs of specimens of E. cometa have revealed the presence of two distinct color morphs, both of which occur near the type locality of Fiji, and correspond to the genetic lineages shown by Greenfield et al. (2019). We show here that these genetically distinct color morphs correspond to the groups of possessing two different fin-ray counts noted by Jewett and Lachner (1983). We describe the new species here as E. oculineata sp. nov. Lastly, we provide a detailed comparison of the eight known species in this complex and a taxonomic key to aid in their identification.

The addition of these four new species raises the total number of species in the genus to 127.

Materials and methods

Counts and measurements, descriptions of fin morphology and the cephalic sensory-canal pore patterns follow Lachner and Karnella (1980) and Jewett and Lachner (1983). Dorsal/anal fin-ray formula counts (e.g., 9/8) only include segmented rays. For counts of rays in dorsal, anal, and pectoral fins in the Description sections below, we list the holotype first followed by the range of counts for the entire type series, with the frequency of that count in square brackets.

Measurements were made to the nearest 0.1 mm using an ocular micrometer or dial calipers, and are presented as percentage of Standard Length (SL). Measurements of the holotype are listed first, followed by the range and average for all measured specimens of the type series in parenthesis. Lengths are given as standard length (SL), measured from the median anterior point of the upper lip to the base of the caudal fin (posterior end of the hypural plate); origin of the first dorsal fin is measured from the median anterior point of the upper lip to the anterior base of the first dorsal-fin spine; origin of the second dorsal fin is measured from the median anterior point of the upper lip to the anterior base of its spine; origin of the anal fin is measured from the median anterior point of the upper lip to the anterior base of its spine; body depth is measured at the center of the first dorsal fin; head length is taken from the upper lip to the posterior end of the opercular membrane; orbit diameter is the greatest fleshy diameter; snout length is measured from the median anterior point of the upper lip to the nearest fleshy edge of the orbit; upper jaw length is the distance from the anterior tip of the premaxilla to the end of the upper margin of the dentary where the maxilla joins; caudal-peduncle depth is the least depth, and caudal-peduncle length the horizontal distance between verticals at the rear base of the anal fin and the caudal-fin base; pelvic-fin length is measured from the base of the pelvic-fin spine to the tip of the longest pelvic-fin soft ray. Cyanine Blue 5R (acid blue 113) stain and an air jet were used to make the cephalic sensory-canal pores more obvious (Akihito et al. 1993, 2002; Saruwatari et al. 1997). A digital radiograph was taken of the holotype of Eviota cometa to confirm counts of dorsal- and anal-fin rays.

Sequences for the new species and additional specimens from the E. zebrina complex were sequenced in Greenfield et al. (2019) and our prior studies on Eviota (Tornabene et al. 2013, 2015, 2016; Greenfield et al. 2019). For those studies, we sequenced a segment of the mitochondrial gene cytochrome c oxidase subunit I (COI) using the primers GobyL6468 and GobyH7696 (Thacker 2003) or FishF-1 and FishR-1 (Ward et al. 2005), and the nuclear gene Protease III (Ptr) using the primers PtrF2 and PtrR2 (Yamada et al. 2009). The PCR conditions follow that of Tornabene et al. (2016). Additional sequences that were putatively identified as E. zebrina were added from BOLD or GenBank. Sequences were aligned in Geneious v.6.0.6 (Biomatters; www.geneious.com). The final alignment consisted of 1173 bp of COI, and 614 bp of Ptr. A phylogenetic analysis of the concatenated alignment was done using Bayesian Inference in the software MrBayes v.3.2 (Ronquist et al. 2012), partitioning by gene. Substitution models were chosen using PartitionFinder2 (Lanfear et al. 2016). The analysis was run for 106 generations, discarding the first 10% of trees as burn-in.

Taxonomic account

Eviota pseudozebrina Tornabene, Greenfield & Erdmann, 2021

Fijian zebra Dwarfgoby Figures 3, 4, 5

Eviota cf. zebrina: Greenfield et al. 2019: 64, fig. 9 (Fiji).

Material

Holotype. CAS 228614, 16.6 mm SL male, Fiji, N. Lau Group, Vanua Balavu Id., Bay of Islands, cove in Bay, 17°10.679'S, 179°01.558'W, 0–2.4 m, rock with green algae, rotenone, field number G03-40, 13 January 2003, D.W. Greenfield, R. Langston, & K. Longenecker. Paratypes. CAS 246310, 10 males, 14.0–18.3 mm SL, 11 females, 11.6–14.8 mm SL, taken with holotype. CAS 244078, male, 10.4 mm SL, Fiji, S. Lau Group, Matuku Lagoon, 19°09.115'S, 179°44.732'E, 3–5 m, clove oil & hand net, field number MVE-17-016, 14 May 2017, M.V. Erdmann. CAS 246250, 10.5 mm SL, Fiji, S. Lau Group, Matuku Lagoon, 19°09.115'S, 179°44.732'E, 3–5 m, tissue number EZ3, clove oil & hand net, field number MVE-17-016, 14 May 2017, M.V. Erdmann.

Non-type material

All from Fiji - CAS 219786 (3), Viti Levu Id., off Suva; 228677 (8), Vanua Balavu Id., Bay of Islands; 228731 (1), Vanau Balavu Id., Bay of Islands; 228732 (2), Vanua Balavu Id., Balavu Harbor; 228743 (1), Viti Levu Id., Vatunisogasoga Reef; 228744 (1), Mago Id., Lau Group; 229544 (1), Viti Levu Id., E. of Nananu Passage; 229568 (2), Yadua Id., Talai Harbor; 229580 (14), Yadua Id., Tali Harbor; 229608 (15), Viti Levu Id., Nananui-i-cake Id.

Diagnosis

A species of Eviota with a cephalic sensory-canal pore pattern lacking only the IT pore, pectoral-fin rays not branched, dorsal/anal-fin ray formula 9/8, 5th pelvic-fin ray 6–16% of 4th ray; dark rectangular to round spot on area of preural centrum followed by a dark vertical line over end of hypural plate; caudal fin crossed by six or seven dark vertical bars in preservation, naris long and black, body deep, 22–26% SL; usually 15 pectoral-fin rays. Color of body a translucent gray background and markings of white, brown, or black, with no red coloration.

Description

Dorsal-fin elements VI+I,9, first dorsal triangular in shape, first three spines filamentous, 2nd or 3rd longest, reaching to 6th soft ray of second dorsal fin in holotype when adpressed, all second dorsal-fin soft rays branched, last ray branched to base; anal-fin elements I,8 (7[1],8[9])), all soft rays branched, last ray branched to base; pectoral-fin rays 16 (14[1], 15 [11], 16 [5]), all unbranched, pointed, reaching to below second dorsal fin; 5th pelvic-fin ray ~ 16% (6–16) of length of 4th pelvic-fin ray; 4th ray with 7 (3–7) branches, four segments between consecutive branches of 4th pelvic-fin ray, pelvic-fin membrane reduced, no basal membrane; caudal fin with 11 branched and 17 segmented rays; lateral-line scales 24 (24[8], 25[2]); transverse scale rows 7; urogenital papilla of male smooth, long and narrow, expanded into a lateral horn at tip, extending past anal-fin spine; female papilla smooth, bulbous, with short finger-like projections on end; front of head rounded with an angle of ~ 60° from horizontal axis; mouth slanted obliquely upwards, forming an angle of ~ 60° to horizontal axis of body, lower jaw not projecting; maxilla extending posteriorly to rear of pupil; anterior tubular nares long, black, extending to center of upper lip; gill opening extending forward to below posteroventral edge of preoperculum; cephalic sensory-pore system missing only IT pore, cutaneous sensory papilla system similar to papilla pattern B-1 (of Lachner and Karnella 1980).

Measurements

In percent SL, value of holotype followed by range and mean of holotype and nine other paratypes in parentheses. Head length 28 (27–32, 29); origin of first dorsal fin 36 (33–37, 35); origin of second dorsal fin 57 (54–60, 57); origin of anal fin 59.9 (56–62, 59); caudal-peduncle length 24 (23–30, 25); caudal-peduncle depth 12 (10–13, 12); body depth 23 (23–26, 23); eye diameter 9 (8–10, 9); snout length 5 (4–5, 4); upper-jaw length 11 (females 9–11, 10, males 10–12, 11); pectoral-fin length 39 (31–39, 33); greatest pelvic-fin length 33 (27–36, 32).

Color in life

(Figure 3) Background color of head and body translucent gray. Body with eight yellow-white spots along vertebral column, separated by black areas. A faint, dusky brown lateral stripe positioned below vertebral column, starting over abdomen and continuing onto caudal peduncle. Abdomen dark brown to black with seven large, irregularly shaped bright white spots spaced over dark area. Ventral portion of flank with six short, faint, vertical brown bars connected to dusky lateral stripe, each bar separated from one another by a small, bright yellow-white iridescent spot. Dorsal midline with approximately 11–13 brown spots, starting on predorsal area and ending over caudal-fin base, spots formed from coalescing dark anterior scale margins. Caudal-fin base with group of large melanophores in advance of posterior end of hypural plate, followed by a dark brown vertical line over end of plate. Top of head with long white line in center extending from between eyes back to nape, a curved white line on each side of line, curved out and back to nape. A line of faint melanophores extending from 7 o’clock position of eye down across cheek. Reddish color of gill filaments shows through cheek, with two white spots at end of dark stripe from eye. Dark stripe extending onto snout from 3 o’clock position of eye, with another line medial to it, the two lines joining anteriorly to meet black tubular nares, diverging posteriorly to form a Y shape. Pupil of eye black with iridescent greenish-yellow hue, upper half of eye surface cream colored with scattered melanophores, lower half darker. Pectoral-fin base with single white spot and another on base of fin rays. The dark bars crossing the caudal fin in freshly dead specimens not as visible in life.

Figure 3. 

Eviota pseudozebrina, live. A–C CAS 244078, 10.4 mm SL male, Fiji D Underwater photograph of fresh specimen from Fiji, reproduced with permission from Randall (2005).

Color in freshly dead specimen

(Figure 4). Generally pigmented as described for live specimens, but with the lateral stripe and ventral vertical bars on flank considerably darker than in life. Dark bars on caudal fin much darker in preservation than in life. A distinct vertical bar of melanophores extending ventrally from eye (positioned at ~ 7 o’clock) extending over cheek and jaws. Vertical bar on cheek present in life, but much lighter. Anterior scale margins over entire body with dark pigment, versus only some dorsal scales pigmented in live specimens.

Figure 4. 

Eviota pseudozebrina, fresh specimen, type series, CAS 246310.

Color in preservative

(Figure 5). Background color of head and body light cream. Scale anterior margins lined with melanophores, making scale pattern obvious. Side of head and jaws, pectoral-fin base and nape peppered with large melanophores. Tubular nares entirely black. Dark cluster of melanophores on lower jaw at rictus. Dark blotch at center of preoperculum at level of bottom of eye, another above it at level of pupil and dark blotch behind upper half of eye. Pupil of eye gray, iris black. Lower surface of abdomen dark brown. Series of dark brown spots extending from front of first dorsal fin back along fin bases to caudal-fin base. Similar series of dark spots along anal-fin base and onto caudal peduncle. Caudal-fin base with distinct rectangular-shaped dark brown spot in advance of posterior end of hypural plate, followed by a dark brown vertical line over end of plate. Caudal fin peppered with melanophores and crossed by seven dark brown bars. Filamentous spines of first dorsal fin dark brown, remainder of fin heavily peppered with melanophores. Second dorsal fin peppered with melanophores and crossed by 4 dark brown bars. Anal fin peppered with melanophores. Pectoral and pelvic fins lightly peppered with melanophores.

Figure 5. 

Eviota pseudozebrina, preserved holotype, CAS 228614, 16.6 mm SL male, Fiji.

Etymology

The specific epithet is an adjective combining the Greek pseudos (lie) and zebrina (New Latin meaning zebra-marked), referring to its similarity to Eviota zebrina.

Distribution and habitat

Definitively known only from Fiji, but specimens identified as E. zebrina are known from Wallis & Futuna and Tonga in Oceania; genetic analysis of specimens from these areas is required to verify if they in fact represent E. pseudozebrina. In our CAS collections, the largest samples were from habitats with rock and green algae (Greenfield and Randall 2016). Individuals collected by MVE were similarly from a lagoonal habitat with mixed sand, coral rubble, macroalgae and scattered live coral; in all cases specimens were collected from the intertidal to a maximum depth of 5 m.

Eviota longirostris Tornabene, Greenfield & Erdmann, 2021

Long-snout Dwarfgoby Figures 6, 7

Eviota cf. zebrina. Greenfield et al. 2019: 64, fig. 9 (West Papua).

Material

Holotype. MZB 26096, 17.6 mm SL female, Sariga, Kokas, Fakfak, West Papua, 02°36.367'S, 132°24.746'E, 5 m, clove oil & hand net, field number MVE-18-014, 8 March 2018, M.V. Erdmann. Paratypes. CAS 2246249, 5, taken with holotype. CAS 246249, 13.2 mm SL male, taken with holotype, tissue numbers EZ11-EZ15, preserved in 95% ethanol. CAS 246538, 15.0 mm SL male, 15.2 mm SL female, 02°38.527'S, 132°31.363'E, Fuum, Kokas, Fakfak, West Papua, 3 m, clove oil & hand net, field number MVE-18-018, 10 March 2018, M.V. Erdmann. CAS 246779 17.8 mm SL male, 03°54.784'S, 134°07.333'E, Bo’s Rainbow, Kaimana, West Papua, 2 m, clove oil & had net, field number MVE 19-026, 21 April 2019, M.V. Erdmann. CAS 246248, 2, tissue numbers EZ1 and EZ2, preserved in 95% ethanol, 5°34.288'S, 134°48.416'E, Wasir, northeast Aru, 1–5 m, clove oil & hand net, field number MVE-16-077, 6 Dec 2016, M.V. Erdmann.

Diagnosis

A species of Eviota with a cephalic sensory-canal pore pattern lacking only the IT pore, pectoral-fin rays not branched, dorsal/anal-fin formula 9/8, 5th pelvic-fin ray 0–16% of 4th ray; dark triangular spot on area of preural centrum followed by a narrow dark vertical line over end of hypural plate; caudal fin crossed by six dark vertical bars, naris long and black, body slender 17–20% SL; snout long, 4–6% SL, and usually 16 pectoral-fin rays.

Description

Dorsal-fin elements VI+I,9, first dorsal triangular in shape, second spine slightly elongated in males, all second dorsal-fin soft rays branched, last ray branched to base; anal-fin elements I, 8, all soft rays branched, last ray branched to base; pectoral-fin rays 16 (15[1], 16[5], 17[1]), all unbranched, pointed, reaching to below second dorsal fin; 5th pelvic-fin ray variable ~ 8% (0–16) of length of 4th pelvic-fin ray; 4th ray with 6 branches, 4 segments between consecutive branches of 4th pelvic-fin ray, pelvic-fin membrane well developed, no basal membrane; caudal fin with 11 branched and 17 segmented rays; lateral-line scales 24; transverse scale rows 7; urogenital papilla of male smooth, long and narrow, expanded into a lateral horn at tip; female papilla smooth, bulbous, with short finger-like projections on end; front of head rounded at an angle of ~ 60° from horizontal axis; mouth slanted obliquely upwards, forming an angle of ~ 60° to horizontal axis of body, lower jaw not projecting; maxilla extending posteriorly to front of pupil; anterior tubular nares black, extending past rear margin of upper lip; gill opening extending forward to below posteroventral edge of preoperculum; cephalic sensory-pore system missing only IT pore, cutaneous sensory papilla system similar to papilla pattern B-1 (of Lachner and Karnella 1980).

Measurements

In percent SL, value of holotype followed by range and mean of holotype and six other paratypes in parentheses. Head length 28 (28–32, 30); origin of first dorsal fin 36 (32–36, 34); origin of second dorsal fin 55 (52–58, 55); origin of anal fin 62 (54–62, 59); caudal-peduncle length 26 (23–31, 28); caudal-peduncle depth 13 (13–15, 14); body depth 20 (17–20, 19); eye diameter 9 (8–10, 9); snout length 6 (4–6, 5); upper-jaw length 9 (females 7–9, 8; males 9v12, 10.0); pectoral-fin length 37 (29–41, 34); greatest pelvic-fin length 36 (30–38, 33).

Color in life

(Figure 6). Background color of head and body translucent gray. Body with black subcutaneous lateral stripe, stripe beginning over abdomen as a large irregular blotch, narrowing posteriorly and terminating over caudal-fin base, stripe interrupted along dorsal edge by a series of 6 or 7 short and narrow white dashes. Black blotch over abdomen with several distinct iridescent yellow-white spots over dark area. Ventral portion of flank with six evenly-spaced dark spots, starting above origin of anal and continuing onto caudal peduncle, each spot loosely connected by faint dark pigment to aforementioned black lateral stripe, and each separated from one another by small yellow-white iridescent spots. On dorsal portion of flank, anterior margins of scales strongly marked with melanophores, dark scale margins coalescing along dorsal midline to loosely form a series of 14 black spots extending from predorsal area to caudal peduncle. A bold black spot at caudal-fin base consisting of two parts, a posterior narrow line centered over posterior end of hypural plate, the anterior half a roundish spot that looks triangular in shape with one point against the line when preserved. Yellow spots dorsal and ventral dark marking on the caudal peduncle, positioned above and below the posterior end of the triangular blotch and the vertical line. Reddish color of gill filaments shows through cheek from eye to pectoral-fin base. Pectoral-fin base crossed posterioventrally by a white line extending onto rays, connecting to white spot above base. A narrow red line below eye at 6 o’clock position extending down across end of jaws; this color feature is usually prominent but can also be muted quickly. Snout bright white, top of head white, peppered with melanophores, a reddish horseshoe-shaped mark behind each eye with the opening towards the eye. Jaws, underside of head and belly translucent gray. Two red stripes at front of eye, one at 9 o’clock position the other at 10 o’clock, running forward to meet at anterior tubular naris to form a V. Eye with black pupil surrounded by a narrow gold ring, iris pinkish and crossed by reddish horizontal stripe at center of pupil, a similar stripe on iris below pupil. Upper half of iris reddish with irregular pink marks. All fin rays and spines with a reddish tinge, a distinct reddish area at caudal-fin base.

Figure 6. 

Underwater photograph of Eviota longirostris A paratype, CAS 246538, near type locality, West Papua, MVE-18-018 B specimen from type locality, West Papua, MVE-18-014.

Color in preservative

(Figure 7). Background color of head and body light yellow. Scale anterior margins outlined with melanophores, a narrow line of melanophores laterally over length of vertebral column. A bold black spot at caudal-fin base consisting of two parts, a posterior narrow line centered over posterior end of hypural plate, the anterior half triangular in shape with one point against the line. A series of 11 black spots extending along dorsal-fin bases onto caudal peduncle. Six postanal spots, two above anal fin. Side of head with a band of melanophores under eye at 6–8 o’clock positions extending down across jaws. Another dark band behind eye at 2 o’clock position above preoperculum. Side of head peppered with melanophores. Pectoral-fin base crossed by a narrow posteroventral line of melanophores. Top of head and nape crossed by four bands of melanophores, the first behind the eyes, the last at the first dorsal-fin base, each band with a central horizontal black line. First dorsal fin with narrow band of melanophores along its lower quarter, distal end of spines with melanophores. Second dorsal fin similar to first but basal dark band ~ 1/3–1/2 of fin and distal margin with dark band. Anal fin mostly black except at its base and distal margin. Pectoral and pelvic fins immaculate. Caudal fin crossed by six or seven vertical bands of melanophores with peppering at dorsal and ventral portions of fin.

Figure 7. 

A Eviota longirostris, preserved holotype, MZB 26096 B paratype, CAS 246538, 15.0 mm SL male.

Etymology

The specific epithet is an adjective derived from the Latin longus (long) and rostrum (snout), alluding to the relatively long snout of this species compared to others in the complex.

Distribution and habitat

Currently known only from the southern coastal region of West Papua, from southern Raja Ampat (based on photos only) to Fakfak, Kaimana, and the Aru Archipelago, although possibly more widespread including perhaps to Australia. Observed in shallow depths of 2–8 m on coastal reefs exposed to significant terrigenous influences (freshwater influx and sedimentation) and moderate to strong currents. Observed individually on coralline algae and dead coral substrates.

Eviota marerubrum Tornabene, Greenfield & Erdmann, 2021

Red Sea Dwarfgoby Figures 8, 9

Eviota cf. zebrina. Greenfield et al. (2019: 64, fig. 9 (Red Sea).

Eviota zebrina (non Lachner & Karnella). Atta et al. (2019: 8); Troyer et al. (2018: 8); Meadows et al. (2014: 3, figs 2, 3); Golani and Bogorodsky (2010: 47); Herler (2007: 85); Herler and Hilgers (2005: 114, fig. 8).

Material

Holotype. USNM 218035, 14.1 mm SL male, Bay at El Himeira, Egypt, Gulf of Aqaba, Red Sea, 21–27 m, 9 September 1969, V. Springer et al. Paratypes. USNM 447872 (collected with holotype), 105, Bay at El Himeira, Egypt, Gulf of Aqaba, Red Sea, 21–27 m, 9 September 1969, Victor Springer et al.; USNM 218034, 163, Bay at El Himeira, Egypt, Gulf of Aqaba, Red Sea, 9–12 m, 8 September 1969, V. Springer, G. Raz & L. Hughes-Gannes; UW 159939 (previously in USNM 218034), 2, Bay at El Himeira, Egypt, Gulf of Aqaba, Red Sea, 9–12 m, 8 September 1969, V. Springer, G. Raz & L. Hughes-Gannes; CAS 247198 (previously in USNM 218034), 2f, Bay at El Himeira, Egypt, Gulf of Aqaba, Red Sea, 9–12 m, 8 September 1969, V. Springer, G. Raz & L. Hughes-Gannes; USNM 218031, 23, Bay at El Himeira, Egypt, Gulf of Aqaba, Red Sea, 0–18 m, 16 July 1969, V. Springer, A. Amir, G. Raz & H. Harpaz.

Non-type material

CAS 239041, 1, preserved in 95% ethanol, Al Lith, Shi’b Habil reef, Station 24, exposed inner shelf, 8.1 m depth, 30 Jan 2015, D.J. Coker, J.D. DiBattista, T.H. Sinclair-Taylor, and M.L. Berumen; CAS 239042, 1, preserved in 95% ethanol, Al Lith, Marmar reef, Station 29, sheltered outer shelf, cave next to station, 10.3 m depth, 31 Jan 2015, D.J. Coker, J.D. DiBattista, T.H. Sinclair-Taylor, and M.L. Berumen; CAS 239043, 1, preserved in 95% ethanol, Thuwal, Abu Madafi reef, Station 31, exposed outer shelf, 14 m depth, 5 Feb 2015, D.J. Coker, J.D. DiBattista, T.H. Sinclair-Taylor, and M.L. Berumen. Examined by Lachner and Karnella (1978), all from the Red Sea: USNM 218030, 3 (13.0–16.5); USNM 218031, 23 (8.4–15.3); USNM 218032, 6 (8.1–11.4); USNM 218033, 6 (8.8–11.2); FMNH 83851, 2; FMNH 83850, 1; BPBM 13428, 1.

Diagnosis

A species of Eviota with a cephalic sensory-canal pore pattern lacking only the IT pore, AITO small and opening dorsally; pectoral-fin rays not branched; dorsal/anal-fin formula 8/7; 5th pelvic-fin ray 8–15% of 4th ray; small dark circular spot on area of preural centrum connected to a short, narrow dark vertical line over end of hypural plate; caudal fin of freshly dead specimens crossed by five or six dark vertical bars, naris long and reddish brown; eye with two distinct white horizontal stripes, one crossing through upper margin of eye, another crossing through lower margin of eye; body depth approximately 20–25% SL; usually 15 pectoral-fin rays.

Description

Fin-ray counts for dorsal, anal, and pectoral fins in the following description are based on specimens examined by Lachner and Karnella (1978) from the Red Sea. We reexamined ten specimens each from three of the lots from that study from Egypt, Northern Gulf of Aqaba, Red Sea, which were used to obtain morphometrics and to confirm meristic characters. The holotype was selected from one of those three lots (USNM 218035) and all other specimens in this lot are designated as paratypes and given a new catalog number, USNM 447872. Four specimens were removed from USNM 218034, two of which are now paratypes CAS 247198 and two are paratypes UW 159939. The remaining specimens in USNM 218034, and USNM 218031, are also designated as paratypes.

Dorsal-fin elements VI+I,8 (7[1], 8[29], 9[2]), first dorsal triangular in shape, first or second spine elongated in some specimens of both sexes, ranging from slightly elongate (extending to first ray of second dorsal fin when depressed) in some smaller males and females of all sizes, to extremely elongate (extending to beyond last ray of second dorsal-fin when depressed) in largest males, all second dorsal-fin soft rays branched, last ray branched to base; anal-fin elements I, 7 (in all specimens examined), all soft rays branched, last ray branched to base; pectoral-fin rays 15 (14[3], 15[15], 16[7]), all unbranched, pointed, reaching to below second dorsal fin; 5th pelvic-fin ray variable ~ 10% (8–15%) of length of 4th pelvic-fin ray; 4th ray with 4–6 branches, 1–3 segments between consecutive branches of 4th pelvic-fin ray, pelvic-fin membrane not well developed, no basal membrane; caudal fin with 11 branched and 17 segmented rays (caudal fin broken in holotype and some paratypes, unable to count segmented rays); lateral-line scales 23 (22[2], 23[4], 24[2], 25[1], 26[1]); transverse scale rows 8 (7[6], 8[3]); urogenital papilla of male smooth, long and narrow, expanded into two lateral horns at tip; female papilla smooth, bulbous, with short finger-like projections on end; front of head sloping at an angle of ~ 50° up from horizontal axis; mouth slanted obliquely upwards, forming an angle of ~ 30° upwards from horizontal axis of body, lower jaw not projecting; maxilla extending posteriorly to posterior margin of pupil; anterior tubular nares reddish brown in life, extending past rear margin of upper lip; gill opening extending forward to below posteroventral edge of preoperculum; cephalic sensory-pore system missing only IT pore, AITO pore small and opening dorsally, cutaneous sensory papilla system similar to papilla pattern B-1 (of Lachner and Karnella 1980).

Measurements

In percent SL, value of holotype followed by range and mean of holotype and ten other paratypes in parentheses. Head length 28 (27–31, 29); origin of first dorsal fin 35 (33–38, 35); origin of second dorsal fin 53 (52–59, 55); origin of anal fin 58 (56–64, 60); caudal-peduncle length 26 (22–29, 26); caudal-peduncle depth 12 (10–13, 11); body depth 25 (20–25, 22); eye diameter 9 (9–11, 10); snout length 5 (4–5, 4); upper-jaw length 11 (females 9 or 10, 10; males 10–12, 10); pectoral-fin length 23 (21–29, 24); greatest pelvic-fin length 39 (27–39, 31).

Color in life

(Figure 8). Background color of head and body translucent gray. Body with broad red stripe extending from tip of snout to caudal peduncle, stripe interrupted by eight or nine iridescent white dashes evenly spaced along dorsal margin of stripe on body, dashes beginning above the operculum and terminating on caudal peduncle.

Figure 8. 

Eviota marerubrum, live. A, B Egypt (photograph J. Herler, with permission) C Israel (photograph R. Holzman, with permission).

Six short red bars extending ventrally from red lateral stripe, first bar just posterior to origin of anal fin, last bar at the posterior margin of caudal peduncle, each bar separated by a white (sometimes iridescent) space. Dorsal midline with 13 or 14 small evenly spaced red spots beginning on nape at a vertical above operculum and extending posteriorly to posterodorsal margin of caudal peduncle. Abdomen and side of body behind pectoral fin with six to eight iridescent white spots over red lateral stripe. Pectoral-fin base red with iridescent white spot in center. Pair of small dark spots at base of caudal fin, anterior spot centered just anterior to origin of caudal rays and circular in shape, posterior spot more vertically elongate, located on base of caudal rays.

Head pale gray ventrally, with red snout, nares, and nape. Eyes red with two horizontal white stripes on iris, above and below pupil. Short white stripe on head extending from behind eye, in line with upper stripe on iris, to operculum; white stripe sometimes broken into two small spots rather than continuous stripe. One or two iridescent white spots, slightly smaller than diameter of pupil, on side of head posterior to jaws. First three spines of the dorsal fin with evenly spaced red spots along entirety of spine. Second dorsal-fin rays each with two red spots evenly spaced along rays. Pectoral fins and pelvic fins white. Caudal fin pale with four faint red vertical bands.

Color in preservative

(Figure 9). Background color of head and body yellowish pale. Side of body without prominent markings except for a very narrow stripe line of single melanophores along lateral midline (present only in well-preserved specimens). Dorsal margin of body with 13 small evenly spaced dark spots beginning on nape at a vertical above operculum and extending posteriorly to posterodorsal margin of caudal peduncle. Dorsal and anal fins unpigmented in type series, however recently preserved specimens may have a dark band of melanophores at the base of first dorsal fin, and second dorsal and anal fins uniformly covered with small melanophores. Pelvic fins without pigment. Caudal fin with four faint brown vertical bands, band more pronounced in freshly preserved specimens.

Figure 9. 

Eviota marerubrum, preserved A holotype, USNM 218035 B freshly preserved specimen from Egypt, 16.5 mm SL (photograph J. Herler, with permission).

Etymology

The specific epithet is an adjective combining the Latin maris (sea) and ruber (red) referring to the type locality, the Red Sea.

Distribution and habitat

Currently known only from specimens examined from the Red Sea, ranging from the Gulf of Aqaba in the northern Red Sea to the central Red Sea off the coast of Saudi Arabia.

Eviota oculineata Tornabene, Greenfield & Erdmann, 2021

False-comet Dwarfgoby Figures 10, 11

Eviota cf. cometa Greenfield et al. 2019: 64, fig. 9 (New Guinea and Solomon Islands).

Eviota cometa (non Lachner & Karnella). Greenfield et al. (2019: fig. 8); Greenfield and Randall (2016: fig. 35); Allen and Erdmann (2012: 913); Randall (2005: 530); Suzuki et al. (2004: 131); Nakabo (2002: 1181).

Material

Holotype. CAS 247279, 10.9 mm SL male, tissue number COM5, preserved in 95% ethanol, 01°37.300'S, 138°43.395'E, Pulau Liki West, northern New Guinea, 30 m, clove oil & hand net, field number MVE-19-006, 12 Feb 2019, M.V. Erdmann. Paratypes. CAS 246244, 2, tissue numbers COM1 and COM2, preserved in 95% ethanol, 10°53.773'S, 150°44.637'E, Dumoulins, Milne Bay, Papua New Guinea, 20 m, clove oil & hand net, field number MVE-16-020, 23 May 2016, M.V. Erdmann. CAS 246245, 9.9 mm SL male, tissue number COM3, preserved in 95% ethanol, 09°19.954'S, 160°17.946'E, Shoal near Nugu Island, Florida Island Group, Solomon Islands, 35 m, 11 October 2016, M.V. Erdmann.

Non-type material

Fiji - CAS 228684, 2, field number G02-146, Naigani Island, patch reef, clear water, coral wall overhang with black coral, 17°34.611'S, 178°40.217'E, 5.4–9. 1 m, rotenone, 4 November 2002, Greenfield, et al.; CAS 238063, 2, field number JVE-10-11-2015, Mt. Mutiny Dive site, N.E. of Viti Levu, off Nanukuloa, rubbly reef, 17°20.76'S, 178°31.35'E, 12 m, clove oil, 11 October 2015, J.V. Eyre.

Diagnosis

A species of Eviota with a cephalic sensory-canal pore pattern lacking only the IT pore, AITO small and opening dorsally; pectoral-fin rays not branched; dorsal/anal-fin formula 8/7; 5th pelvic-fin ray 8–15% of 4th ray; large dark oval spot on area of preural centrum connected to a short, vertically elongate spot over end of hypural plate; caudal fin of freshly dead specimens without prominent vertical bars; naris long and reddish brown; side of body with prominent red lateral streak bordered dorsally by three to five elongate white dashes; eye with two distinct horizontal stripes, one white crossing through lower margin of pupil, one yellow crossing upper margin of pupil; body depth approximately 27–31% SL; usually 14 pectoral-fin rays.

Description

Dorsal-fin elements VI+I,8, first dorsal triangular in shape, first or second spine elongated in some specimens of both sexes, ranging from slightly elongate (extending to first ray of second dorsal fin when depressed) in the smallest male, to extremely elongate (extending to beyond origin of last ray of second dorsal fin when depressed, as in holotype), all second dorsal-fin soft rays branched, last ray branched to base; anal-fin elements I, 7 (all soft rays branched, last ray branched to base; pectoral-fin rays 14 (14[3], 15[1]), all unbranched, pointed, reaching to below second dorsal fin; 5th pelvic-fin ray variable, ~ 10% (8–15%) of length of 4th pelvic-fin ray; 4th ray with four or five branches, one or two segments between consecutive branches of 4th pelvic-fin ray, pelvic-fin membrane not well developed, no basal membrane; caudal fin with 11 branched and 16 segmented rays; lateral-line scales 24 (22[1], 23[1], 24[1]), scales not countable on one specimen due to damage); transverse scale rows 7; urogenital papilla of male smooth, long and narrow, expanded into two lateral horns at tip; female papilla smooth, bulbous, with short finger-like projections on end; front of head sloping at an angle of ~ 60° up from horizontal axis; mouth slanted obliquely upwards, forming an angle of ~ 35° upwards from horizontal axis of body, lower jaw not projecting; maxilla extending posteriorly to center of pupil; anterior tubular nares extending past rear margin of upper lip; gill opening extending forward to below posteroventral edge of preoperculum; cephalic sensory-pore system missing only IT pore, AITO pore small and opening dorsally; cutaneous sensory papilla system similar to papilla pattern B-1 (of Lachner and Karnella 1980).

Measurements

In percent SL, value of holotype followed by range and mean of holotype and ten other paratypes in parentheses. Head length 27 (27–31, 28); origin of first dorsal fin 37 (35–37, 36); origin of second dorsal fin 57 (54–58, 56); origin of anal fin 59 (59–62, 60); caudal-peduncle length 25 (20–29, 25); caudal-peduncle depth 11 (11–13, 12); body depth 18 (18 or 19, 18); eye diameter 9 (8–10, 9); snout length 3 (3–6, 4); upper-jaw length 8 (females 9 or 10, 9; males 8 or 9, 9); pectoral-fin length 25 (22–29, 25); greatest pelvic-fin length 30 (28–33, 31).

Color in life

(Figure 10). Background color of head and body translucent gray. Body with broad red stripe extending from tip of snout to caudal peduncle, stripe interrupted by five iridescent white dashes evenly spaced along dorsal margin of stripe on body, dashes beginning above the operculum and terminating on caudal peduncle, with anterior three dashes sometimes merged as a continuous white stripe over abdomen.

Figure 10. 

Eviota oculineata, live, New Guinea.

Occasionally five short red bars extending ventrally from red lateral stripe, first bar just posterior to origin of anal fin, last bar at the posterior margin of caudal peduncle, each bar separated by a white (sometimes iridescent) space. Abdomen and side of body behind pectoral fin with two (sometimes three) iridescent white spots over red lateral stripe, first spot immediately above and posterior to axis of pectoral fin. Pectoral-fin base red with iridescent white spot in center. Pair of vertically elongate, broadly joined dark spots at base of caudal fin, anterior spot centered just anterior to origin of caudal rays, posterior spot located on base of caudal rays. Small yellow spot on base of caudal fin just dorsal to pair of dark spots.

Head pale gray ventrally, with red snout, nares, and nape. Eyes red with two horizontal stripes on iris, one yellow and passing through upper margin of pupil, one white and passing through lower margin pupil, dorsal margin of eye above stripe with yellow spots or mottling. Short white stripe on head behind eye, in line with upper stripe on iris, extending posteriorly to operculum; white stripe sometimes broken into two small spots rather than continuous stripe. One or two iridescent white spots, slightly smaller than diameter of pupil, on side of head posterior to jaws. First three spines of the dorsal fin with evenly spaced red spots along entirety of spine. Second dorsal-fin rays faintly tinged with red. Pectoral fins and pelvic fins white. Caudal fin lacking prominent vertical bands, lower half of caudal fin with faint red hue.

Color in preservative

(Figure 11). Based on holotype, preserved in 95% ethanol. Background color of head and body yellowish pale. Head without pigment except for a faint scattering of melanophores on nape. Abdomen uniformly covered with dark melanophores, remaining side of body lacking any pigmentation except for a row of scattered melanophores along the ventral midline of body, beginning at anal fin origin on continuing to middle of caudal peduncle. Pair of vertically elongate, broadly joined dark spots at base of caudal fin, anterior spot centered just anterior to origin of caudal rays, posterior spot located on base of caudal rays. Dorsal and anal fins with light scattering of chromatophores on inter-radial membranes and on rays of posterior half of fins. Caudal fin lacking pigmentation except for a faint horizontal streak of melanophores on five rays, the first of which is just below the lateral midline of the caudal fin, followed by the four subsequent ventral rays. Pectoral fin, pectoral-fin base, and pelvic fins without pigment.

Figure 11. 

Eviota oculineata, preserved holotype, CAS 247279.

Etymology

The specific epithet is an adjective combining the Latin oculi (eye) and linea (line, stripe) referring to the stripes through the eye, which distinguish this species from E. cometa.

Distribution

Currently known only from New Guinea and the Solomon Islands, but likely occurs in Fiji and the Banda Sea, Indonesia, and the Great Barrier Reef, Australia, based on live photographs as well as specimens previously identified as E. cometa that possess 8/7 counts in the dorsal/anal fins (Figure 12). The species seems to prefer outer reef slopes exposed to clear oceanic water in depths of 20–35 m and is frequently observed resting individually on coralline algae outcrops or live plate corals.

Figure 12. 

Eviota oculineata photographs from non-type specimens A Fiji (photograph R. Whitworth, with permission) B Fiji C Fiji (photograph J. Eyre, with permission) D Australia (photograph C. Goatley, with permission).

Remarks

When E. cometa was described, it was based on preserved material with no information on live coloration, with the holotype from Fiji. Specimens in the type series possessed both 8/7 and 9/8 dorsal/anal-fin formulas (Lachner and Karnella 1983). When Greenfield and Randall (2016) reviewed the dwarfgobies of Fiji they based their identification of preserved specimens as E. cometa on the description of the species by Lachner and Karnella (1983) and the underwater photographs identified as E. cometa in Suzuki et al. (2004), Randall (2005), and Allen and Erdmann (2012). In their review they provided two photographs (fig. 34 and fig. 35 of Greenfield and Randall 2016), one an underwater photograph by R. Whitworth taken in Fiji (Figure 12A) and a fresh specimen from CAS 222731 (Figure 13A). The underwater photograph (Figure 12A) was similar to the earlier underwater photos, showing only a clear caudal fin that was not crossed by oblique red bars, and eyes with white/yellow stripes, whereas the fin of the other fresh specimen (Figure 13A) had distinct red bars on the caudal (however, when preserved the red bars were not visible as dark bars as they are in E. pseudozebrina) and a solid red eye. This supported the idea that there were two species in Fiji, the type locality for E. cometa.

Figure 13. 

Eviota cometa A freshly dead specimen from Fiji B, C f reshly dead specimens from Vava’u, Kingdom of Tonga (photographs M. Gómez-Buckley, with permission) D, E live, Fiji (photograph E J. Eyre, with permission).

In 2017 MVE collected and photographed specimens (Figure 13D) from a silty lagoon in the Lau Archipelago, Fiji, that resembled the freshly dead specimen from Greenfield and Randall (2016, fig. 34) in that the eye was all red, different from the striped eyes in previous underwater photographs (e.g., Figures 10, 12; now E. oculineata). Similarly, photographs of specimens from Tonga of fish with red bars across the caudal fin and solid red eyes also appeared to be this same species (Figures 13B, C), and this was confirmed with DNA (Figure 2). Additionally, in 2020 Janet Eyre took an underwater photograph of a fish in Fiji with the same solid red eye color and red bars across the caudal fin (Figure 13E). These specimens with the red caudal-fin bars and solid red eyes have a dorsal/anal-fin formula of 9/8, the same as the holotype of E. cometa, whereas those individuals lacking the red bars and having striped eyes have a dorsal/anal-fin formula of 8/7 and are described here as E. oculineata.

The large collection of 30 E. cometa from Fiji, CAS 222731, came from a habitat of dead coral and silty sand, and the photographs taken by MVE (Figure 13D) and Janet Eyre (Figure 13E) were also both from protected, silty, patch reef habitat contrasting strongly with the clearer water, outer reef habitat where E. oculineata is found. Given the general preference of underwater photographers for clear water and healthy reefs, it is perhaps not surprising that the majority of underwater photographs in the literature appear to be E. oculineata and not the true E. cometa, given the latter species’ apparent proclivity for silty inshore reefs. Additional photographs of fishes originally identified as E. cometa from Lizard Island, Australia (Figure 12D) also appear to be E. oculineata, based on dorsal/anal fin-ray counts and coloration.

Comparisons within the Eviota zebrina species complex

With the addition of the four species described here, the E. zebrina complex contains eight species: E. cometa, E. gunawanae, E. longirostris, E. marerubrum, E. oculineata, E. pseudozebrina, E. tetha, and E. zebrina. A combination of meristic features (e.g., counts of rays in the pectoral, dorsal, and anal fins), morphometric features (snout length, body depth), head pore patterns, and live and preserved coloration differentiate the species (Table 1). These characters are discussed in detail and are also presented in a taxonomic key below. We

Table 1.

Diagnostic characters for distinguishing species in the Eviota zebrina species complex. Counts for E. marerubrum and E. zebrina include data for specimens from the Red Sea and Seychelles, respectively, listed in Table 2 of Lachner and Karnella (1978), and morphometrics for E. zebrina are from 15 paratypes from CAS 40599. Data for E. cometa are from the holotype, tissue vouchers from the phylogeny, and Fiji specimens with 9/8 D2/A rays. Measurements are given in % SL.

E. longirostris E. zebrina E. pseudozebrina E. cometa E. oculineata E. marerubrum E. tetha E. gunawanae
Type locality Indonesia Seychelles Fiji Fiji Papua New Guinea Egypt Indonesia Indonesia
Pectoral rays - mode (range) 16 (15–17) 16 (15–17) 15 (14–16) 16 (16–17) 14 (14–15) 15 (14–16) 14 (14–15) 16 (16)
D2/A rays - mode 9/8 9/8 9/8 9/8 8/7 8/7 8/7 8/7
Length 5th pelvic-fin ray absent to 15.8% of 4th 6–14% of 4th 6–16% of 4th ~ 10% of 4th 8–15% of 4th 8–15% of 4th absent or rudimentary ~ 10% of 4th
AITO pore small, opens dorsally small, opens dorsally small, opens dorsally small, opens dorsally small, opens dorsally small, opens dorsally large, opens anteriorly large, opens anteriorly
IT pore absent absent absent absent absent absent absent absent
NA pores present present present present present present absent absent
Body depth - average (range) 18.7 (17.4–19.9) 19.2 (17.1–21.2) 23.2 (21.6–25.7) 21.1 (17.6–23.6) 28.4 (27.2–30.6) 22.3 (20.3–24.8) 19.6 (17.7–21.4) 19.6 (18.2–21.4)
Snout length - average (range) 5.3 (4.3–5.7) 3.4 (2.8–4.1) 4.3 (3.7–5.4) 3.7 (2.5–5.1) 4.3 (3.3–6.2) 4.3 (3.4–5.2) 4.5 (3.9–6.2) 4.4 (3.7–5.0)

Body coloration comparisons. All species in this group with the exception of E. tetha (Figure 14A) have large, prominent dark spots at the base of the caudal fin, which are often margined dorsally (and sometimes ventrally) by smaller yellow spots in life. The side of the body of most species in this group is characterized by a prominent red streak that ends at the base of the caudal fin; however E. longirostris (Figure 6) and E. pseudozebrina (Figure 3) lack red pigment and, instead, pigment on the side of the body is predominantly black or brown. Eviota pseudozebrina is the least colorful of all the species in the complex, with a translucent gray background and markings that are white, brown, or black. The upper half of the eye surface is cream colored with scattered melanophores, lower half darker. The overall coloration of E. longirostris is bolder with red markings on the head and eye and the spines and rays with a reddish tinge.

Figure 14. 

A E. tetha, Cendrawasih, West Papua B Eviota gunawanae, Fakfak, West Papua.

Five species have both a red body-stripe and the dark spot at the caudal-fin base: E. cometa, E. gunawanae, E. marerubrum, E. oculineata, and E. zebrina. Eviota gunawanae differs from the other four in having a solid white stripe on the mid-abdomen immediately posterior to the pectoral fin (Figure 14B), versus having a series of distinct white spots in this area (Figures 8, 10, 12, 13, 15). Above this region on the abdomen is a series of white stripes or dashes that extend from above the pectoral fin to the caudal fin base in all species in this complex. This series is made up of 3–6 elongate horizontal white dashes in E. oculineata (Figures 10, 12) versus being made up by eight or more short white dashes or spots in E. marerubrum (Figure 7), E. cometa (Figure 13), and E. zebrina (Figure 15). Eviota cometa differs from E. marerubrum, E. oculineata, and E. zebrina in having a large, prominent V-shaped white patch on the nape immediately posterior to the eyes (Figure 13D, E), whereas the other four species possess short horizontal white stripes in this region (Figures 8, 10, 12, 15).

Figure 15. 

Eviota zebrina A Seychelles (photograph J. Greenfield, with permission) B Maldives.

Eye coloration comparisons (Figure 16). As discussed by Greenfield (2017), eye coloration patterns in species of Eviota exhibit great variation and have been used in recognizing different species. Often dwelling in rock or coral crevices, dwarfgoby eyes are the body part that are most easily seen by other fishes, so it follows that eye coloration is a character that would be useful in species recognition and hence under selective pressure. Two of the species within the E. zebrina species complex differ from the others in lacking a reddish stripe crossing the center of the eye at the pupil. Eviota pseudozebrina is the most different by lacking any red in the eye, with the upper half of the eye gray and heavily peppered with melanophores, and the lower half dark (Figure 16F). From a lateral view, the entire iris of E. cometa is dark reddish, with the pupil surrounded by a white ring (Figure 16C). The dorsal side of the eye next to the interorbital area has a short white bar not visible laterally.

Figure 16. 

Eye coloration of the Eviota zebrina complex species A E. tetha, Kwatisore, West Papua; B gunawanae, Karas, West Papua C E. cometa, Lau Archipelago, Fiji D E. oculineata, Milne Bay, Papua New Guinea E E. longirostris, Fakfak, West Papua F E. pseudozebrina, Lau Archipelago, Fiji G E. marerubrum, Israel, Red Sea H E. zebrina, Laamu Atoll, Maldives (photograph G R. Holzman, with permission).

Eviota tetha (Figure 16A) and E. gunawanae (Figure 16B) both have a yellow bar crossing the eye above the pupil, a solid unbroken bar above that, a narrow white bar crossing below the pupil and a solid bar below that. Eviota tetha differs from E. gunawanae by having the bars red-orange, whereas they are darker, almost brown in E. gunawanae.

The remaining four species have a light bar crossing above and below the pupil, but from a lateral view only E. marerubrum (Figure 16G) has a solid red bar across the top of the eye, whereas the others have the upper bar broken by irregular light areas. The light bar above the pupil in Eviota oculineata (Figure 16D) is yellow, unlike the other two species where the bar is white. Eviota longirostris (Figure 16E) and E. zebrina (Figure 16) are similar but the bars in E. zebrina are bright red whereas they are a dark reddish color in E. longirostris.

Caudal fin markings (Figure 17). Several species have oblique dark bars crossing the caudal fin that are obvious in freshly dead or preserved specimens, but are faint or absent in underwater photographs of live fishes. Eviota zebrina from the Seychelles Islands has three or four distinctive oblique black bars crossing the caudal fin. There also is a dark mark extending out from the caudal spot over the hypural plate onto the lower portion of the fin. Eviota pseudozebrina has 7 black bars crossing the caudal fin and no dark spot at the lower part of the fin. Eviota longirostris has six or seven black bars crossing the caudal fin and no dark spot at the lower part of fin. Eviota marerubrum has four black bars crossing the fin with the lower portion of the bars enlarged forming spots. Eviota cometa has four or five red bars crossing the fin when fresh, but these are lost in preservative. Eviota oculineata, E. tetha, and E. gunawanae lack black bars on the caudal fin.

Figure 17. 

Comparison of caudal fin pigmentation in preserved specimens A Eviota zebrina paratype, CAS 040599 B E. pseudozebrina holotype, CAS 228614 C E. longirostris, paratype, CAS 246538.

Morphological characters. Eviota tetha and E. gunawanae are similar in morphology and both can be distinguished from the rest of the complex in lacking NA pores and in having the AITO pore enlarged and opening anteriorly, versus having a small AITO pore that opens dorsally. The remaining species in the complex have all pores present except the IT pore. The six species within the complex that lack only IT pores can be distinguished primarily on the basis of dorsal/anal-fin formula and coloration. Both E. oculineata and E. marerubrum have 8/7 dorsal-anal-fin formulas (as do E. tetha and E. gunawanae) and usually have fewer pectoral-fin rays (modally 14 or 15) whereas E. cometa, E. longirostris, E. pseudozebrina, and E. zebrina have 9/8 dorsal/anal-fin formulas and modally 15 (E. pseudozebrina) or 16 pectoral-fin rays (E. cometa, E. zebrina, E. longirostris). The species in the complex with 9/8 dorsal/anal-fin formulas vary interspecifically in some morphometric features. Specifically, snout length and body depth may be useful for distinguishing between E. cometa, E. longirostris, E. pseudozebrina, and E. zebrina (Figure 18).

Figure 18. 

Morphometric ranges for body depth (top) and snout length (bottom) for the species of the Eviota zebrina complex with 9/8 dorsal-anal-fin formulas. X’s are means, bars through boxes are medians.

Key to the species of the Eviota zebrina complex

Locations in parentheses only include type localities and other locations where we are confident in their occurrence based on a combination of live photographs, genetics, and specimens examined morphologically.

1 NA pores absent; AITO pore large, opening anteriorly; dorsal/anal-fin formula 8/7 2
NA pores present; AITO pore small, opening dorsally; dorsal/anal-fin formula 8/7 or 9/8 3
2 Pectoral-fin rays 16; 5th pelvic-fin ray ~10% of 4th; dark spot at the base of the caudal fin is larger and extends anteriorly as a partially overlapping paired spots Eviota gunawanae (West Papua)
Pectoral-fin rays 14 or 15; 5th pelvic-fin ray rudimentary or absent; dark spot at the base of the caudal fin is restricted to the posterior end of the hypural plate Eviota tetha (West Papua)
3 Dorsal/anal-fin formula 8/7 4
Dorsal/anal-fin formula 9/8 5
4 Eye with two horizontal white stripes; body depth 20–25% SL Eviota marerubrum sp. nov. (Red Sea)
Eye with two horizontal stripes, the upper yellow, the lower white, with yellow mottling along dorsal surface of eye; body depth 27–31% SL Eviota oculineata sp. nov. (New Guinea, Solomon Islands, Fiji, Australia)
5 Body markings predominantly red or reddish brown 6
Body markings predominantly dark brown to black 7
6 Eye without prominent horizontal stripes, only a narrow gold rim around pupil over red iris; caudal fin crossed by several red vertical bars when fresh that are lost in preservation E. cometa (Fiji, Tonga)
Eye with pair of horizontal stripes; caudal fin crossed by several black vertical bars that are usually retained in preservation Eviota zebrina (Maldives, Seychelles)
7 Body deep 22–26, 23% SL; anterior part of dark spot at caudal-fin base a distinct rectangular shape in advance of dark line over hypural plate; upper half of eye gray, heavily peppered with melanophores Eviota pseudozebrina sp. nov. (Fiji)
Body more slender, depth 17–20, 19% SL; anterior part of dark spot at caudal-fin base triangular with one point against posterior dark line; upper half of eye with irregular reddish areas with white areas peppered with melanophores Eviota longirostris sp. nov. (New Guinea)

Discussion

The combination of molecular data, live coloration, and re-examination of preserved specimens including type series have shown that the Eviota zebrina complex contains at least eight species. The integrative approach taken here was first used in this complex to recognize E. gunawanae as being distinct from E. tetha (Greenfield et al. 2019), and here we expanded our taxonomic scope within the complex to recognize E. longirostris, E. marerubrum, E. oculineata, and E. pseudozebrina as being distinct from E. zebrina and E. cometa, two species that they were previously confused when molecular data and color images of live specimens were unavailable.

We were unable to examine preserved specimens from throughout the range of the E. zebrina complex, nor would this be particularly informative given the importance of live coloration as a taxonomic character. We have also not photographed specimens or taken genetic samples throughout the E. zebrina complex range, so exact boundaries of species ranges given here are considered preliminary. Nevertheless, some preliminary biogeographic patterns can be observed, ranging from species pairs/groups that are predominantly allopatric to those that have ranges that overlap significantly. Eviota zebrina and E. marerubrum appear to be restricted to the Indian Ocean and Red Sea respectively, and form a clade with E. oculineata, which occurs from Australia and New Guinea east to Fiji, and E. cometa which is currently known from Fiji and Tonga (Figures 2, 19). Another large clade within this complex contains species entirely from the Central and Western Pacific (Figures 2, 20), including E. tetha, E. gunawanae, and E. longirostris, all from West Papua, and E. pseudozebrina, which is currently known only from Fiji. Interestingly, Fiji and West Papua are each home to at least three species in this complex, and are also the regions where the authors have the most live photos coupled with tissue samples. A search of museum records from 71 collections using Fishnet2 (accessed through the Fishnet2 Portal, www.fishnet2.org, 2020-11-12) showed that specimens identified as E. cometa or E. zebrina exist from many other localities including the Philippines, Australia, Thailand, China, Vietnam, Vanuatu, New Caledonia, Pohnpei, Japan, Kiribati, Palau, the Marshall Islands, Sri Lanka, and Mauritius. It is likely that increased sampling efforts in these areas will uncover additional undescribed species within this complex (and other complexes within Eviota) or expand the known ranges of existing species, and reveal a more complete picture of the patterns of diversification and evolution within dwarfgobies.

Figure 19. 

Distribution map of E. marerubrum, E. oculineata, E. zebrina, and E. cometa. Points represent localities of specimens examined in this study or verified photographs.

Figure 20. 

Distribution map of E. tetha, E. pseudozebrina, E. gunawanae, and E. longirostris. Points represent localities of specimens examined in this study or verified photographs.

Acknowledgements

Authors would like to thank R.C. Langston, K.R. Longenecker, K. Tang, and Captain B. Vasconcellos and the crew of the Moku Mokua Hine for assistance in the field. We are grateful to the late J. Seeto, G.R. South, and R.W. Tuxton of the University of the South Pacific, Fiji for facilitating our collecting in Fiji, and a special thanks to R.R. Thaman, also of U.S.P., for his unending assistance; without his help this project literally would not have been possible. MVE would like to thank the Fiji Department of Fisheries and Conservation International Fiji for hosting the 2017 Lau biodiversity survey that enabled us to obtain tissue samples and live color photographs of E. cometa, E. oculineata and E. pseudozebrina, and is particularly thankful to Roko Sau Joesefa Cinavilakeba, Susana Waqainabete-Tuisese and Semisi Meo, as well as the Captain and crew of the MV Sea Rakino for their excellent support during the 2017 survey, and to the Fijian Government and Lau Province village chiefs for permission to collect fishes. MVE also thanks G. Allen for his companionship during the numerous field surveys during which many of the new species were collected, and the owners, captains, and crews of the following vessels that supported collections: the MV Putiraja, the MV Silolona, the MY Rascal, S.Y. Wyuna, and the MV Chertan. We thank D. Catania, J. Fong, M. Hoang and L. Rocha of CAS, D. Pitassy and J. Williams of USNM, and K. Maslenikov of UW for assistance with specimens. J. DiBattista and colleagues kindly provided samples from Saudi Arabia. E. McFarland assisted with molecular work. We thank M. Gómez-Buckley, R. Buckley, K. Stone, T. Halafihi, the Vava’u Environmental Protection Association, and the Kingdom of Tonga Ministry of Fisheries for their support of fieldwork in Tonga. Finally, we thank M. Gómez-Buckley, E. Troyer, J. Eyre, R. Whitworth, R. Holzman, J. Herler, J. Greenfield, R. Winterbottom, and S. Raredon for photographs or radiographs. This research was supported by National Science Foundation grants INT97-29666 and DEB0-1027545, and Sea Grant Project R/FM-6PD, as well as grants to Conservation International by W.M. Brooks, the Paine Family Trust, the Henry Foundation, and D. Arnall.

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