Gnatholepis pascuensis Randall and Greenfield, 2001

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 : 49-50

Gnatholepis pascuensis Randall and Greenfield, 2001

( Fig. 24 ; Tables 5–8)

Gnatholepis sp. nov. —DiSalvo et al. 1988: 461 (Easter Island).

Gnatholepis cauerensis pascuensis Randall and Greenfield, 2001: 11–12 , pl. IIE (Easter Island, off Tahai).— Randall et al. 2005: 47.

Gnatholepis pascuensis — Randall 2009: 179.

Diagnosis. A rather small Gnatholepis (up to 45 mm SL) with distinctive colour 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, very broad black cheek-bar and broad black eye-stripe (both as wide as pupil) crossing interorbital space; ctenoid body scales reaching rear corner of opercle, or to above pectoral fin base; nape midline scales always cycloid; few ctenoid scales present on opercle; distinct flap present at end of lower lip; 18–19 pectoral fin rays.

Material examined. EASTER ISLAND: Holotype BPBM 32850 , 34 mm SL, off Tahai, J. Randall and party, 13 February 1985; BPBM 6743 , 1 (30), offshore from Akapu, J. Randall and B. Baker, 3 February 1969; BPBM 32852 , 1 (41.5), off Tahai, J. Randall and party, 15 February 1985; BPBM 32853 , 1 (45), between Motu Tautara and Ara O Hara, J. Randall and party, 15 February 1985; BPBM 32851 , 2 (35–39), off E end Anakena, J. Randall and party, 14 February 1985.

Remarks. Randall and Greenfield (2001) created the name Gnatholepis cauerensis pascuensis based on one specimen (BPBM 32850). Randall (2009) subsequently elevated G. pascuensis to full species status and presented two additional lots as paratypes (BPBM 6743 and BPBM 32851–53). These specimens were not so designated in the original description (were given as “Other Material”) and therefore do not hold any type status. It is also unfortunate that Randall and Greenfield chose a specimen in poor condition for the holotype when there were three better specimens available (e.g. BPBM 32853, 32851).

We agree with Randall (2009) in assigning full species status to G. pascuensis . It has a high pectoral fin ray count (18–19). Although Randall (2009) reported one specimen with 17 rays on one side, the six specimens that we examined had 18–19 rays on both sides. Gnatholepis pascuensis also has a characteristic intense colour pattern of two rows of five elongate black blotches laterally, a very broad black cheek-bar and broad black eye-bar (nearly as wide as pupil) crossing the interorbital space ( Fig. 24 ). Some G. cauerensis specimens also have a broad cheek and eye-bar but have six lateral dark blotches and lower pectoral fin ray counts.

Gnatholepis cauerensis specimens from Rapa and Pitcairn have also 17–19 pectoral rays but are typically pale in colour and do not show any significant colour differences from other G. cauerensis .

Figures

FIGURE 24. Gnatholepis pascuensis, Easter Island. Photo by Jack Randall.