Eviota santanai, Greenfield, David W. & Erdmann, Mark V., 2013

Greenfield, David W. & Erdmann, Mark V., 2013, Eviota santanai, a new Dwarfgoby from Timor-Leste (Teleostei: Gobiidae), Zootaxa 3741 (4), pp. 593-600 : 594-599

Eviota santanai n. sp.

Santana’s Dwarfgoby Figs. 1–3 .

Eviota species 1 Allen & Erdmann 2013: 79.

Holotype: CAS 234966, 11.8 mm male, Tutuala, Timor-Leste, 08°21.723’S, 127° 04.488’E, 8 m, M.V. Erdmann, 16 August 2012.

Paratypes: USNM 410587, 12.8 mm male, taken with holotype; CAS 235688, 11.5 mm male, 10.7 mm female, Pulau Atauro, Timor-Leste, 08°13.281’S, 125° 36.830’E, 5 m, M.V. Erdmann, 23 August 2012.

Other material examined: Eviota latifasciata - BPBM 28959 paratypes, 10.8 & 11.7 mm, Gilbert Islands = ( Kiribati, Tungaru Islands); CAS 52737 paratype, 12.6 mm, Gilbert Islands; USNM 260079 paratypes, 10.1 & 12.7, Gilbert Islands; CAS 226268 (4), 10.4–12.2, Ponape; CAS 226295, 11.5 & 12.5, Ponape; CAS 226296, 12.0 & 12.8, Ponape; CAS 226297, 9.1 & 12.1, Ponape.

Diagnosis. The following combination of characters distinguishes E. santanai from congeners: the cephalic sensory-canal pore system lacks the IT and PITO pores, the AITO pore is not enlarged or paired, and the POP pores are small; some pectoral-fin rays are branched; the dorsal/anal formula is 8/8; and the body has six body bars with a black midcaudal peduncle spot centered on the last bar; no occipital spot; and color in life includes pinkishmauve bars that are red dorsally.

Description. Dorsal-fin rays VI-I,8; anal-fin rays I,8; dorsal and anal soft rays branched except first, the last ray branched to base; pectoral-fin rays 16, ends of many rays broken in all types, but some lower rays branched; pelvic fins joined by membrane only at extreme base; no pelvic frenum; pelvic-fin membrane reduced, pelvic-fin rays I,4, 4th pelvic-fin ray with 4–7 branches, 2 segments between branches; 5th pelvic-fin ray absent; 11 branched caudal-fin rays; segmented caudal-fin rays 17; lateral scale rows 24; transverse scale rows 7; no scales on head, nape, breast, or pectoral-fin base; midline of abdomen with cycloid scales; dorsal fin triangular in shape, and the dorsal-fin spines not filamentous; cephalic sensory-pore system lacking IT and PITO pores but AITO not enlarged as in Group IV; cutaneous papilla system not discernible because specimens are in poor condition; male genital papilla non-fimbriate, smooth and straight, with a blunt tip with a few short skin flaps on the end, not reaching anal-fin base; single small female with a short papilla with a few short flaps at end (difficult to observe because of condition); body slender, front of head rounded with an angle of about 70° from the horizontal axis; mouth oblique, forming an angle of about 45° to horizontal axis of body, lower jaw not projecting; maxilla extending to center of pupil; anterior tubular nares short, just extending to upper lip and light in color; gill opening extending forward to midway between edge of preoperculum and posterior end of opercular membrane; gill membranes attached anteriorly to isthmus, without a free fold.

Measurements (based on holotype and 2 paratypes, 11.5–12.8 mm). Head length 28.8 (28.8–29.6, 29.1); origin of first dorsal fin 37.3 (37.3–39.1, 37.9), above posterior end of pectoral-fin base; origin of second dorsal fin 57.6 (56.2–58.3, 57.4), slightly in advance of anal-fin origin; origin of anal fin 58.5 (58.5–63.3, 60.1); caudalpeduncle length 25.4 (21.3–25.4, 23.2); caudal-peduncle of moderate depth, 12.3 (11.7–13.0, 12.3); body depth slender 19.5 (19.5–21.7, 20.2); eye diameter 9.7 (9.7–10.9, 10.5); snout length 3.4 (3.4–3.9, 3.6); upper-jaw length 10.6 (10.6–12.6, 11.5).

Color in preservative of holotype: ( Fig. 1 ) Background color of head and body pale yellowish. Top of head with scattered irregular brown spots behind eyes, extending back to edge of preopercle. A few similar spots extending behind eye along top of cheek and preopercle, with a concentration towards the end of the preopercle. A small dark spot on lower portion of preopercle on left side of holotype (lacking in paratypes). Interorbital area, snout, and ventral surface of head lacking any dark pigment. Pectoral-fin base and sides of body lacking dark pigment except for a distinct black spot about half the size of the eye centered on the caudal peduncle. Pectoral and pelvic fins immaculate. Anal fin heavily pigmented, darker than other fins. Ventral half of caudal fin peppered with small dark spots with a few extending dorsally at center of fin. Distal portion of first dorsal-fin margin with small dark spots as is the second dorsal fin. Iris of eye black, pupil yellowish.

Live color: ( Fig. 2 ) Background color of head and body translucent white. Body with six internal pinkishmauve bars extending from backbone to ventral surface, the first two bars the widest, more triangular in shape, and most pronounced: first bar behind pectoral-fin base below nape and first four dorsal-fin spines; second bar below last two spines of first dorsal fin and space between the two dorsal fins; third bar below anterior half of second dorsal fin; fourth below second half of fin; fifth behind second dorsal fin; and sixth the narrowest and on the caudal peduncle with a distinct black spot on the midline. There is a crescent shaped red bar on the caudal-fin base. Each of these six internal bars have a red area over the backbone with two or three narrow red-orange bars extending up from them to the dorsal surface of body. These narrow red bars have some yellow pigment mixed with the red on the anterior half of the body. The translucent white area between these narrow dorsal bars has a very narrow vertical silvery-white line separating them. There also is a wider silvery-white bar separating the first two mauve bars ventrally. The nape is crossed by three yellow bars that are sprinkled with red. The area on top of the head and behind the eyes is bright red, with the red extending back along the backbone to under the first dorsal fin. The red also extends down onto the cheek and preoperculum. The red area on the top of the head with scattered silverywhite irregular spots that also are present on the top of the snout. Jaws with a tinge of red and area under the eye translucent white. The pupil of the eye is black and the iris red with yellow spokes radiating out from around the pupil and many small yellow spots dorsally. The operculum is yellow as is the pectoral-fin base, except that a silvery-white stripe runs across its center. Spines and rays of dorsal fins reddish.

Distribution. Known only from the northern coast of Timor-Leste.

Etymology. The specific epithet is named in honor of Connisso Antonino ("Nino Konis") Santana, a national hero in Timor-Leste's struggle for independence who was renowned for his environmental awareness. The type locality of this beautiful goby species is in Tutuala, just offshore of Santana's birthplace, and moreover is located within the Nino Konis Santana National Park.

Comparisons. In general live color pattern, E. santanai is most similar to E. latifasciata and also shares the same meristics. It does, however, differ in cephalic sensory-canal pore pattern. Whereas E. latifasciata belongs to Group II, only lacking the IT pore, E. santanai also lacks the PITO pore and the POP pores are very small. Other Eviota species that lack both the PITO and IT pores have the AITO pore enlarged or paired (Group IV), but this is not the case in E. santanai . There are only three species in Group IV that also have the same meristics as E. santanai : E. shimadai , E. lachdeberei , and E. partimaculata , but all of these have unbranched pectoral-fin rays (branched in E. santanai ). Eviota santanai also differs from E. latifasciata by lacking an occipital spot and having a pigment spot behind the eye that is lacking in E. latifasciata ( Fig. 3 ).

The holotype of Eviota latifasciata was originally described from Abaiang Atoll in the Gilbert Islands = ( Tungaru Islands, Kiribati) with paratypes from both Abaiang and Ponape in the Caroline Islands (Jewett & Lachner, 1983). Non-type material was listed from Christmas Island in the Indian Ocean and Kapingamarangi Atoll. Since that time E. latifasciata has also been reported by Allen & Erdmann (2012) from “ Christmas Island (Indian Ocean), Indonesia (Lesser Sunda Islands, Banda, Halmahera, and West Papua), Philippines (Palawan and Cebu), Papua New Guinea (Milne Bay), Palau, Ponape, and Gilbert Islands ( Kiribati). ” It was also reported from the Ryukyu Islands, Japan by Senou et al. (2004), and Tonga by Randall, et al. (2003). Yet photographs of live individuals from many of these locations show considerable variation (based on photographs provided by G.R. Allen), and as discussed by Allen, Brooks & Erdmann (2013), “Live colour patterns in particular (including eye colouration) are highly diagnostic for members of this genus...”. D.F. Hoese provided color photographs of specimens from the type series of E. latifasciata from the Gilbert Islands, the locality of the holotype, ( Fig. 4 ), another photograph of a specimen from the type locality ( Fig. 5 ), and G.R. Allen provided color photographs from Ponape in Micronesia to the northeast where some paratypes were taken ( Fig. 6 ). The color of the body bars are pinkish-mauve in E. santanai , whereas they are dark red in the Gilbert Island and Ponape specimens of E. latifasciata . The paratypes of E. latifasciata examined from the Gilbert Islands have a definite dark occipital spot even after having been preserved for 40 years ( Fig. 7 ), as does the comparative material from Ponape. The specimens of E. santanai collected in 2012 do not have an obvious occipital spot.

Recently E. dorsimaculata was described from the Marquesas Islands and was said to be most similar to E. latifasciata (Tornabene et al. 2013) . This species also belongs to Group II, only lacking the IT pore as does E. latifasciata , separating it from E. sanatanai . It also has a dark spot on the caudal peduncle that is above the lateral midline (centered on the midline in E. santanai ).

Remarks. The similarity of E. santanai to E. latifasciata presents another example of a species that is similar in color pattern to another species, but differs in the absence of a head pore. Greenfield and Randall (2010) noted that E. toshiyuki , known only from Japan, was very similar in color to E. zonura , known from Australia east to the Mariana Islands and Samoa, but differs in the absence of a head pore, and suggested that this might indicate that they were sister species. Earlier Lachner & Karnella (1980) suggested that cephalic sensory-canal pore systems might represent natural groupings of species, and continued to present new groupings in subsequent papers. These groupings have served useful in distinguishing the many different Eviota species from one another, particularly in dichotomous keys; however, in a recent paper Tornabene et al. (2013) demonstrated that pore patterns did not correlate with genetic relationships in the species they studied. Unexpectedly the correlation was with branching patterns in the pectoral-fin rays. Thus, the suspected sister species mentioned above that differed in pore patterns might actually be closely related.

Both the holotype and paratype specimens were collected from similar habitats consisting of shallow, wavewashed fringing reef crest in 5-8 m depth. Both sites were exposed to clear, relatively cool (25-27 ° C) water with reefs that quickly dropped off to over 200 m depth. The species was moreover observed at an additional four sites along the Timor-Leste coastline (recorded at a total of 6 of the 20 survey sites) and is thus considered relatively common (though cryptic and shy) in the region.

Figures

FIGURE 1. Color in preservative of holotype of E. santanai, CAS 234966, 11.8 mm. Photograph by D. W. Greenfield.

FIGURE 2. Underwater photograph of E. santanai. Photograph by M. V. Erdmann.

FIGURE 3. Head coloration of preserved specimens, with pigmentation differences indicated by arrows. A. Eviota santanai holotype, CAS 234966, 11.8 mm. B. Eviota latifasciata paratype, USNM 260079, 12.7 mm. Photograph by D. W. Greenfield.

FIGURE 4. Fresh specimen from the type series of E. latifasciata from Abaiang Atoll, Gilbert Islands, photograph by D. F. Hoese (DFH 73 - 36).

FIGURE 5. Fresh specimen of E. latifasciata from Abaiang Atoll, Gilbert Islands, AMS I. 18048 - 026 (DFH 73 - 45), photograph by D. F. Hoese.

FIGURE 7. Color in preservative of paratype of E. latifasciata, BPBM 28959, 11.7 mm, Abaiang Atoll, Gilbert Islands. Photograph by D. W. Greenfield.

FIGURE 6. C. Underwater photograph of E. latifasciata, Ponape, photograph by G. R. Allen. Note parasite on abdomen.