Eviota jewettae, Greenfield, David W. & Winterbottom, Richard, 2012

Greenfield, David W. & Winterbottom, Richard, 2012, Two new dwarfgobies from the Southwestern Pacific Ocean (Teleostei: Gobiidae: Eviota), Zootaxa 3572, pp. 33-42 : 34-38

Eviota jewettae n. sp.

Jewett’s dwarfgoby Figs. 1–8 .

Eviota Raja Ampat sp. 2 and Eviota Palau sp. 6 Dimara, et al. 2010.

Holotype: ROM 84731, 12.1 mm female, Palau, Hatohobei State, Helen Reef, southern margin near east end, 02°47’56” N, 131°45’20”E, cave (ca 15 m wide, 4 m high) and surrounding area with sand/silt floor, floor at 27 m, 24–32 m, rotenone, field number RW08-33, R. Winterbottom, M. Westneat, J.Williams, W. Holleman, B. Hubley, M. Winterbottom, and C. McCord, 23 September 2008.

Paratypes: ROM 84721, 10.7 mm female, Palau, Hatohobei State, Helen Reef, outer reef along SE edge, 02°49’40”N, 131°47’18”E, steep drop-off slope (ca 85°) with small caves, overhangs, some sand and rubble, 20–30 m, rotenone, field number RW08-29, R. Winterbottom, M. Westneat, J.Williams, W. Holleman, B. Hubley, M. Winterbottom, and C. McCord, 22 September 2008; ROM 84725, 9.4 and 11.2 mm males, Palau, Hatohobei State, Helen Reef, south end 'embayment', 02°47’57”N, 131°45’18”E, vertical drop-off from reef top (no reef slope), 22–34 m, rotenone, field number RW08-30, R. Winterbottom, M. Westneat, J.Williams, W. Holleman, B. Hubley, M. Winterbottom, and C. McCord, 22 September 2008; ROM 84761, 10.1 mm male, Palau, Hatohobei State, Helen Reef, NW outer reef about 0.5 km S of northern large ship wreck, NW of N tip of island in lagoon, 02°58’38”N, 131°47’59”E, steep (80–85°) drop-off slope just past lip of reef slope, a few small caves (some with sand floor, most with rubble) and crevices, 7–33 m, rotenone, field number RW08-45, R. Winterbottom, M. Westneat, J.Williams, W. Holleman, B. Hubley, M. Winterbottom, and C. McCord, 27 September 2008; ROM 93605 (ex-ROM 84731) 40 specimens 6.5–11.8 mm (one cleared & stained) plus four males 11.4–12.4 mm, five females 10.9–11.8 mm in vials (measured; photograph of 11.8 mm female); AMS I.4607-001, four females 10.1–11.0 mm, one male 12.0 mm; CAS 234443, four females 10.0– 11.4 mm, one male 10.0 mm; USNM 406708, three females 9.9–10.9 mm, 2 males 10.0– 10.2 mm. The last four lots all taken with the holotype.

Non-types: Philippine Islands – USNM 235381, 10.8 mm female, Balicasag I., 9°31’14”N, 123°40’00”E, 0–24.4 m, field number SP 78-38. USNM 235380 (7) 10.1–12.1 mm, same data as USNM 235381; USNM 235382 (2) 11.6 (see Fig. 4 ) & 12.4 mm, S. tip of Cebu, Liloan Pt., 13.4–19.2 m, J. Libbey, JL-2; USNM 235385 (3) 10.5–12.4, near Moalboal, Cebu NW side Pescador I., 18.3–24.4 m, J. Libbey, JL-3; USNM 235384 (1) 10.9, E. coast of Cebu near Huisan Point, Caceres Reef, 24.4–30.5 m, J. Libbey, JL-7; USNM 235383 (1) 11.9 mm, Siquijor I., 25.9–30.5 m, J. Libbey, LK 79-16; CAS 52736 (2), 12.2–12.9 mm; ANSP 150918 (2), 11.0– 11.6 mm; AMNH 55056 (2), 10.9–12.4 mm; AMS I.23988-001 (2), 11.0– 11.3 mm. The last four lots were taken with USNM 235381.

Papua New Guinea — ROM 88146, 10.4 mm male, Eastern New Britain, Rabaul, Simpson Bay, S. side of Dawapia Rocks, 04°14’08” S, 152°10’02.3” E, 17.7 m, steep reef slope, caves and crevices, clove oil, field number RW11-04CR2, R. Winterbottom and W. Holleman, 20 November 2011; ROM 88160, 11.0 male, Eastern New Britain, Rabaul, Simpson Bay, S. side Dawapia Rocks, 04°14’10.7”S, 152°10’01.8”E, 13.4 m, overhang and small caves on steep reef slope, clove oil, field number RW11-06BR2, R. Winterbottom and W. Holleman, 21 November 2011; ROM 92164, 10.1 mm male, Eastern New Britain, Rabaul, S.E. side of Little Pigeon Island off Simpson Bay, 04°15’59.6”S, 152°19’38.9”E, 26.5 m, vertical wall with small and large caves and crevices, clove oil, field number RW11-11AW1, R. Winterbottom and W. Holleman, 24 November 2011. Indonesia – ROM 87458, 8.4 mm male, Raja Ampat, E. side Balbulol Island off Misool, 0 2°01’07.6”S, 130°42’12.3”E, 15.2–18.3 m, clove oil, field number RW10-52, R. Winterbottom and L. Katz, 3 February 2010

Diagnosis. The following combination of characters distinguish E. jewettae from congeners: cephalic sensorypore system lacking all pores 98% of the time; dorsal/anal fin-ray formula 8/8; pectoral-fin rays 15–16, ventralmost two rays unbranched with at least two (but up to four) lower rays branched at tips above this, remainder of rays unbranched; 4th pelvic-fin ray bifurcated with each branch about 60% of total length of the ray; unbranched 5th pelvic-fin ray 13–20% of 4th; dorsal-fin spines not filamentous, tubular anterior nares short, less than ½ pupil diameter in length; in life body translucent and crossed by five broad orange to red bands.

Description. Dorsal-fin rays VI-I,8; anal-fin rays I,8; pectoral-fin rays 16 (15–16), ventralmost two rays unbranched with at least two (but up to four) lower rays branched at tips above this, remainder of rays unbranched (easily broken); 4th pelvic-fin ray bifurcated with each branch about 60% of the total length of the ray, similar to Fig. 2 of E. lacrimae in Sunobe (1988); unbranched 5th pelvic-fin ray 13–20% of 4th pelvic-fin ray length; 11 branched caudal-fin rays; segmented caudal-fin rays 17; lateral scale rows 25 (24–25, usually 25); transverse scale rows 7; vertebrae 26; dorsal-fin spines not filamentous in males; 98% without pores in the cephalic sensory-pore system, but always lacking the POP, IT and NA pores; male genital papilla non-fimbriate.

Measurements (based on holotype and 9 paratypes, 10.9–12.4 mm). Head length 33.7 (30.8–34.2, 32.2); origin of first dorsal fin 38.3 (34.7–40.9, 37.3); origin of second dorsal fin 56.8 (53.8–63.2, 58.0); origin of anal fin 65.8 (56.5–65.8, 61.7); caudal-peduncle length 23.5 (21.6–26.6, 23.8); caudal-peduncle depth 12.3 (11.7–13.2, 12.4); body depth 20.6 (19.3–25.0, 21.5); eye diameter 11.5 (9.6–12.9, 11.0); snout length 6.2 (5.2–6.3, 5.6); upperjaw length 11.5 (10.8–13.7, 12.0).

Color in preservative of holotype ( Fig. 1 ). Background color of head and body pale yellowish. A few scattered small melanophores on top of the head directly behind the eyes, but no other dark pigment on the head. No dark markings on body, but a few melanophores on the gut show through the translucent sides of the abdomen. Caudal, pectoral and pelvic fins immaculate. A light peppering of small melanophores on basal and dorsal thirds of the first dorsal fin. A few scattered melanophores on the anterior portion of the second dorsal fin. Distal half of the anal fin with a peppering of melanophores.

Color in preservative of paratypes. A number of the paratypes from Palau show more dark pigmentation than is present in the holotype. There often is a concentration of melanophores along the anal-fin base that extends back along the caudal peduncle to the caudal-fin base. A few scattered melanophores may be present at the center of the pectoral-fin base. There may be a peppering of melanophores behind the eyes extending back across the nape to the dorsal-fin origin and then on the dorsum along the dorsal-fin bases. Most of the first dorsal-fin membranes heavily peppered with melanophores. A few specimens have a series of dark subcutaneous bars crossing the body. All have melanophores on the gut that show through the translucent sides of the abdomen ( Fig. 2 , ROM 93605).

Color in preservative of non-types. Specimens from Raja Ampat, Indonesia (ROM 87458) and Rabaul, New Britain, Papua New Guinea (ROM 88160 & 88146) have five strong subcutaneous body bars ( Fig 3 , ROM88160). Figure 4 is a drawing of a 11.6 mm male from the Philippines (USNM 235382) also exhibiting strong body bars.

Color of fresh paratype ( Fig. 5 , ROM 93605, Palau). Background color of head and body translucent white. Body crossed by five wide orange bars plus a narrow bar at the caudal-fin base: the first from the front of the first dorsal fin down behind the pectoral-fin base; the second at the posterior end of the first dorsal fin, curving down across the abdomen towards the anus; the third at the second element of the second dorsal fin extending down to the anal-fin origin; the fourth at the sixth element of the second dorsal fin extending down to the anal fin; the fifth across the caudal peduncle; the caudal-fin base crossed by a narrow bar that extends a short distance onto the caudal fin; some dark pigment on the ventral edge of the bars on the anal fin and caudal peduncle. Nape orange, crossed by three narrow white lines. Top of head, snout, nares, and operculum orange. Cheek under and behind eye with several round red-orange spots. A bar extending under center of eye down behind jaws to under head and another at the anteroventral portion of the eye extending down to the jaws. Top of head with scattered melanophores behind the eyes and some extending back behind the eyes. Eye with a black pupil surrounded by an orange iris that is ringed by dark pigment. Abdomen with a scattering of small melanophores on the gut showing through the translucent sides. Area around the anus dark. First two body bars extending up onto the first dorsal fin, black areas present on fin, more concentrated posteriorly. Second dorsal fin with body bars extending up onto basal third, scattered melanophores along it base and on distal margin. Anal fin with body bars extending onto it entire length. Caudal, pectoral and pelvic-fin rays orange.

Color of fresh non-type specimen ( Fig. 6 , ROM 88160, Rabaul, New Britain). Background color of head and body translucent white. Body crossed by five wide reddish bars with a concentration of melanophores on the dorsal and ventral margins of each bar: the first from the front of the first dorsal fin down behind the pectoral-fin base; the second at the posterior end of the first dorsal fin, curving down across the abdomen towards the anus; the third at the second element of the second dorsal fin extending down to the anal-fin origin; the fourth at the sixth element of the second dorsal fin extending down to the anal fin; the fifth across the caudal peduncle. Small red-orange marks at dorsal and ventral caudal-fin base connected with a fainter bar. Nape with indistinct light red blotches with scattered melanophores. Scale edges on dorsal half of body dark. Operculum with a light red blotch extending up behind eye. Cheek under and behind eye with several round reddish spots, a bar extending from below center of eye down behind jaws to ventral surface of head and another at the anteroventral portion of the eye extending down to the jaws. Jaws and snout reddish with scattered melanophores. Anterior tubular nares dusky. First dorsal fin dark red on basal half of first three elements, membranes between them black. A small clear area above this followed by similar coloration on the distal portion. A clear area along the basal portion of the next three elements extending up to meet the clear area at the middle of the anterior portion of the fin. Posterior half of fin with dark red spines and black pigment on the membranes. Basal one-quarter of spine of second dorsal fin clear, the remainder red. The lower half of the next rays are red from the third body bar extending up onto it, overlaid with black pigment, and the upper half has clear rays and reddish membranes peppered with small melanophores. The space between the third and fourth ray is clear, with the light area extending distally. The remainder of the fin is dark from the fourth body bar and is overlaid by a peppering of melanophores. Anal fin with body bars extending onto it entire length, and entire fin overlaid with a peppering of melanophores. Caudal, pectoral and pelvic-fin rays reddish and overlaid with a peppering of melanophores.

A photograph of three specimens of E. jewettae from Raja Ampat, Indonesia taken by G.R. Allen ( Fig. 7 ), shows some variation in the bands crossing the body. Figure 8 is an underwater photograph of a live E. jewettae taken at Waigeo Island, Indonesia.

Distribution. Known from Palau, Philippine Islands, Papua New Guinea and Raja Ampat, Indonesia. In Palau, the species is currently known only from Helen Reef, the southern-most of the South West Islands, and has not yet been found at the main island group to the north.

Etymology. This species is named for Susan L. Jewett who previously recognized this species as undescribed from specimens taken by the Smithsonian Philippine Expedition in 1978. During the 1970’s and 1980’s she, sometimes under the name Karnella, and E.A. Lachner described many Eviota species new to science and laid the foundation for the study of this genus.

Comparisons. Eviota jewettae is the only described species almost always completely lacking all cephalic sensory pores, although we are aware of some other possible undescribed species that also lack pores.

Remarks. Cutaneous papilla may be located at the location of pore sites and mistaken for pores, especially in the interorbital area. Stain and the use of an airjet are helpful in distinguishing between these.

As noted above, there are differences in the live and preserved coloration between the specimens from Palau and those from other locations to the south. In fresh material the Palau specimens have orange bars crossing the body and little dark pigmentation, whereas those from Indonesia and Papua New Guinea have reddish colored bars and much dark pigmentation. We do not have information on the fresh coloration of the USNM specimens from the Philippines, but the preserved material exhibits dark bars crossing the body as do those from Indonesia and Papua New Guinea. In one lot of 66 specimens from Palau, only a few showed any indication of dark barring. Because of these differences we have restricted the type material to Palau in the event that future DNA studies show them to be different.

Figures

FIGURE 1. Eviota jewettae, holotype preserved, ROM 84731. Photograph by D. W. Greenfield.

FIGURE 2. Eviota jewettae, paratypes preserved, ROM 93605. Photograph by D. W. Greenfield.

FIGURE 3. Eviota jewettae, ROM 88160, preserved specimen from Rabaul. Photograph by D. W. Greenfield.

FIGURE 4. Eviota jewettae, illustration of a 11.6 mm male from the Philippines (USNM 235382) also exhibiting strong body bars. Drawn by J. R. Schroeder

FIGURE 5. Eviota jewettae, ROM 93605, fresh specimen, 11.6 mm, Palau, Helen Reef. Photograph by R. Winterbottom.

FIGURE 6. Freshly collected specimen of Eviota jewettae (ROM 88160) from Rabaul, Eastern New Britain. Photograph by R. Winterbottom.

FIGURE 7. Freshly collected specimens of Eviota jewettae from Halmahera, Indonesia. Photograph by G. R. Allen.

FIGURE 8. Underwater photograph of Eviota jewettae from Waigeo Island, Indonesia. Photograph by G. R. Allen.