Grammatonotus xanthostigma Anderson & Johnson, 2017, new species

Grammatonotus xanthostigma, new species

Yellowspot Groppo

(Figures 1–3; Tables 1 & 2)

Diagnosis. A species of Grammatonotus distinguishable from G. pelipel (described herein) and from all other previously described species of the genus, except G. brianne, by the following combination of characters: caudal fin rhomboid shaped with mid-caudal rays produced, lateral-line disjunct, anal-fin spines short (see Tables 1 & 2), and live coloration (see Figs. 1–3 and description of coloration below). It is distinguished from G. brianne by absence of scales on dentary (present in G. brianne), measurements of several body parts (see Table 2), and shape of caudal fin (compare Figs. 1–3 with Fig. 4). Caudal fin rhomboid shaped in both species, but posterior halves of dorsalmost and ventralmost borders of fin slightly concave in G. xanthostigma (gently rounded to convex in G. brianne). Also, G. xanthostigma with a bright yellow spot at upper base of pectoral fin (lacking in G. brianne).

G. xanthostigma G. pelipel

Description. The characters included in the combined description of G. xanthostigma and G. pelipel and those presented in the species diagnosis form part of the species description. Pectoral-fin rays 19. Branched caudal-fin rays 7 + 6. Procurrent caudal-fin rays 6 dorsally and ventrally. Pseudobranch with 11 to ca. 12 filaments. Total number of gillrakers on first arch 25 to 29. Lateral line disjunct with two most anterior tubed scales separated from the more posterior ones; number of tubed scales 15 to 18 (2 + 13, 2 +15, 2 + 16; counts of lateral-line scales made on both sides of each specimen). Midbody lateral scales 23 or 24. Epineural bones associated with first 12 or 13 vertebrae. One trisegmental pterygiophore associated with dorsal fin, and one with anal fin.

Coloration. Coloration based on digital photographs of two specimens (BPBM 41271, 60.2 mm SL, the holotype [Fig. 1], and USNM 432533, 61.0 mm SL, the paratype [Fig. 2]): Dorsally head and anterior two thirds of body rosy; rosy line along dorsum of caudal peduncle; ventrally head and area anterior to base of pectoral fin silvery to silvery pink; large blotch of grayish brown on posteroventral portion of opercle; mid-body and ventrum dull orange to yellow. Iris of eye with broad blue arch dorsally and narrow yellow stripe posteriorly; anteriorly adjacent to pupil, one specimen with narrow arch of yellow. Dorsal fin yellow proximally, bordered by light to dark purple distally (distal ends of dorsal spines and soft rays yellow). Anal fin purple with distal margin of yellow. Pectoral fin pale pink with bright yellow spot at upper base of fin. Pelvic fin purple. Anterior border of caudal fin outlined in rosy purple; caudal fin yellow, with some purplish near middle of distal end of fin; distal ends of produced mid-caudal rays bright yellow.

A digital photograph (Fig. 3) of another specimen (BPBM 41294, 57 mm SL) collected off Pohnpei in 137 meters on 16 July 2016 shows an individual with coloration closely resembling that described above. The major differences are in the pigmentation of the iris of the eye and in the absence of rosy purple outlining the anterior border of the caudal fin. We have not examined that specimen. The narrow purplish stripe (or partial stripe) evident along middle of body of two of the three specimens of G. xanthostigma (see Figs. 1 & 3) is most likely the manifestation of a blood vessel.

Distribution. This species is only known from specimens collected off Pohnpei Island, Senyavin Islands (part of the Caroline Islands group), western Pacific Ocean.

Material examined. Two specimens (60.2–61.0 mm SL) caught off Pohnpei Island (Gorgonian Buttress); Lat. 6.991784° N, Long. 158.137131° E.; depth 142 meters; collected by B. D. Greene, with hand net, 0 3 August 2015.

Holotype. BPBM 41271, 60.2 mm SL.

Paratype. USNM 432533 (out of BPBM 41271), 61.0 mm SL.

Etymology. The name xanthostigma is from the Greek — xanthos (yellow), stigma (spot) — in reference to the yellow spot at the upper base of the pectoral fin. The specific name of this new species is a noun in apposition to the generic name Grammatonotus.