Gnatholepis

Larson, Helen K. & Buckle, Duncan J., 2012, A revision of the goby genus Gnatholepis Bleeker (Teleostei, Gobiidae, Gobionellinae), with description of a new species, Zootaxa 3529 (1), pp. 1-69 : 13

Key to species of Gnatholepis

(may not always work, especially with small juveniles or faded preserved specimens)

1. No scales present on cheek or opercle; predorsal midline naked (few scales may cross nape close behind eyes); nape scales always cycloid; no enlarged canine teeth in lower jaw......................................................... 2

– Opercle and cheek scaled; predorsal with scales crossing midline; nape scales ctenoid and/or cycloid; enlarged canine or recurved teeth present in lower jaw........................................................................ 3

2. Second dorsal fin I,10, rarely I,11; anal rays I,11; no scales on pectoral fin base; males with small black spots on unpaired fins, and posteriormost 3–4 mid-lateral blotches darker than anterior spots (northern Australia)...................... G. argus

– Second dorsal fin I,11, rarely I,10; anal rays I,12; few embedded scales on pectoral fin base; males without dense black spots on fins and no large dark blotches on side of body (Queensland, Australia).............................. G. gymnocara

3. Anal fin with 1–4 irregular rows of oval black spots (fin also with red, blue and yellow markings when alive), and first dorsal fin with 2–4 dense black spots along fin base in both sexes, caudal fin in males with staggered rows of small dense black spots; each scale on anterodorsal half of body with black or blackish spot; breast scales reaching forward anterior to rear margin of preopercle or further forward to below mid-eye; nape scales often mostly ctenoid (Cocos-Keeling, Philippines, Taiwan, southern Japan, Indonesia, New Guinea to Vanuatu)............................................... G. ophthalmotaenia

– Anal fin without 1–4 rows of dense black spots, although fin may be heavily pigmented and irregular dusky spots may be formed, first dorsal fin without 3–4 dense black spots along base, caudal fin without rows of dense black spots (may be duskyspeckled or with brownish spots or streaks); scales on anterodorsal half of body may or may not bear dusky spots; breast scales reaching forward to rear margin of preopercle; nape scales ctenoid or cycloid...................................... 4

4. First dorsal fin rather tall, usually pointed, with third spine longest; black blotch usually present on upper part of first dorsal fin behind first and third spines; pelvic fins banded with light and dark pigment; pectoral rays 15 (data from only 3 specimens) ( Malaysia; Indonesia; Japan)..................................................................... G. yoshinoi

– First dorsal fin convex to almost square; no black blotch present on upper part of first dorsal fin; pelvic fins without dusky cross-bands; pectoral rays 15–19......................................................................... 5

5. Predorsal scales mostly ctenoid, often extending up to close behind eyes, may be cycloid toward midline and anteriorly; pectoral fin with many rows of fine dark and white speckles; when live, nape and body covered with irregular rows of small blackish to reddish spots, with five to six diffuse dusky blotches along the lower mid-side of the body; pectoral fin with rows of fine dark and white speckles; fifth D1 spine as long or nearly as long as 3 rd –4 th spines, giving fin rather square appearance when extended; head and body with stocky appearance (Indo-Pacific, from South Africa to Society Islands)........ G. anjerensis

– Predorsal scales always cycloid in midline, may be some ctenoid scales above opercle; pectoral fin may have dusky lines at base but not speckled with fine dark spots, if fine dark and light spots present then anal fin with dark streaks or distinct spots on membrane; when live, colour not as above; pectoral fin translucent and may have whitish or dusky speckling (fine dark and white speckles together in one species, G. knighti from Hawaii); fifth D1 spine usually shorter than 3 rd –4 th spines, giving fin rounded appearance when extended; body appears relatively slender............................................. 6

6. Pectoral fin covered with many rows of fine dark and white speckles; transverse black mark on upper part of eye usually split in two thin lines; anal fin plain dusky, often with one to several blackish rounded to oval spots posteriorly, or with dark streaks following membrane (Hawaii; Line Islands)......................................................... G. knighti

– Pectoral fin may have dusky lines at base but without fine dark and light speckles; transverse black mark on upper part of eye may be narrow or broad but not split; anal fin plain, without distinct dark spots or streaks............................ 7

7. 18–19 pectoral fin rays; distinctive pattern of two rows of five elongate dense black blotches on side of body, anteriormost three blotches largest, joined by faint broken yellowish brown lines in life, a very broad black cheek-bar and a broad black eyebar (both as wide as pupil) crossing the interorbital space (Easter Island)............................... G. pascuensis

– 15–17 pectoral fin rays; colour pattern not as above, with black cheek-bar and black marking on top of eye variable in intensity and width........................................................................................... 8

8. Distinctive vertical oval blackish to dark grey blotch across caudal fin base, oblique black curved or comma-shaped line on top of eye and body whitish with finely speckled dorsum; when alive, two broad ladder-like orange to reddish stripes along body; 7–9 predorsal scales, usually 8 (Red Sea to Persian Gulf).................................... G. caudimaculata n. sp.

– No distinctive vertical oval blackish to dark grey blotch across caudal fin base; black line on top of eye not curved or commashaped but relatively horizontal and may join its counterpart across interorbital space; 7–12 predorsal scales, usually 9–10..... 9

9. Predorsal scale count 7–12, modally 9, always cycloid in midline, may be some ctenoid scales above opercle; pectoral rays 14–19, modally 16; transverse black line on upper part of eye over centre to rear half of pupil, may partly cross mid-interorbital space, line joins mostly vertical to curved black line from cheek to past end of jaw; dorsal half of body with 2–3 rows of short lines or rows of spots (if lower half of body with rows of spots, then these paler than dorsal rows); fifth D1 spine shorter than 3 rd –4 th spines, giving fin rounded appearance when extended (Indo-Pacific, from South Africa to Pitcairn Island)..................................................................................................... G. cauerensis

–. Predorsal scale count 9–11, modally 10; all predorsal scales cycloid; pectoral rays 16–18, modally 17; transverse black line on upper part of eye joining the somewhat oblique to curved black line crossing cheek and ending well behind end of jaw; body