A New Species of the Scorpionfish Genus Maxillicosta from the Southeast Coast of Australia, with a Redescription of M. Whitleyi (Scorpaeniformes: Neosebastidae)

A new species of scorpionfish, Maxillicosta meridianus, is described on the basis of 24 specimens collected from southeastern Australia at depths of 10–137 m. This species has previously been identified as M. whitleyi, but differs in having the following characters: central portion of inner ridge on ventral mandibular surface located on inner edge of dentary or closer to inner edge than to central ridge, no short ridge between posterior portions of inner and central ridges; 0–6 spinous points on anterior margin of nasal spine; 5–13 spinous points on surface of preocular spine; no spines or distinct ridges on lateral margin of occipital pit between tympanic spine and origin of parietal spine base; no ossified scale behind front edge of occipital pit between tympanic spines; dorsal surface of occipital pit smooth, without spines; two (rarely one or three) spinous points at tip of upper opercular spine; posterior margin of maxilla extending slightly beyond a vertical through posterior margin of pupil; and caudal fin usually without distinct markings in preserved specimens. Additionally, the two species significantly differ in eight meristic and six morphometric features. Morphological changes with growth and geographic variation are also discussed.

Figure 1

Maxillicosta meridianus. (A) CSIRO B 1253, paratype, 40.8 mm SL; (B) NMV A 21820, paratype, 64.9 mm SL; (C) CSIRO A 4252, holotype, 77.6 mm SL.

Figure 2

Ventral view of right half of mandible in (A–B) Maxillicosta meridianus and (C) M. whitleyi. (A) CSIRO H 633-01, paratype, 51.1 mm SL; (B) CSIRO A 4252, holotype, 77.6 mm SL; (C) NMV A 16546, 62.7 mm SL. IE, inner edge of dentary; IR, inner ridge; CR, central ridge; LL, lower lip; OR, outer ridge; AR, accessory ridge. Bars = 2 mm.

Figure 3

Lateral view of left nasal spine showing typical condition in (A) Maxillicosta meridianus and (B) M. whitleyi. (A) CSIRO A 4252, holotype, 77.6 mm SL; (B) NMV A 16546, 62.7 mm SL. AM, anterior margin of nasal spine. Anterior to the left. Bars = 1 mm.

Figure 4

Dorsal view of occipital pit region in (A) Maxillicosta meridianus and (B) M. whitleyi. (A) CSIRO A 4252, holotype, 77.6 mm SL; (B) NMV A 16546, 62.7 mm SL. CS, coronal spine; OP, occipital pit; OS, ossified scale; PS; parietal spine; TS, tympanic spine. Anterior at the top. Bars = 2 mm.

Figure 5

Distribution of Maxillicosta meridianus (stars) and M. whitleyi (circles), based on specimens examined in this study.

Figure 6

Comparisons of (A) snout length, (B) upper-jaw length, (C) first anal-fin spine length, (D) second anal-fin spine length, (E) third anal-fin spine length, and (F) caudal-peduncle depth (% standard length) with standard length in Maxillicosta meridianus (closed circles) and M. whitleyi (open circles).

Figure 7

Caudal-fin pigment patterns in preserved specimens of (A) Maxillicosta meridianus and (B) M. whitleyi. (A) NMV A 2678, paratype, 53.7 mm SL; (B) AMS I. 26023-003, 57.6 mm SL.

Figure 8

Comparisons of (A) orbit diameter, (B) predorsal-fin length, (C) pelvic-fin spine length, and (D) caudal-fin ray length (% standard length) with standard length in Maxillicosta meridianus.

Figure 9

Maxillicosta meridianus, AMS I. 23469-005, 51.0 mm SL.

Contributor Notes

(HM) The Kagoshima University Museum, 1-21-30 Korimoto, Kagoshima 890-0065, Japan; (PRL) CSIRO Marine and Atmospheric Research, G.P.O. Box 1538, Hobart, Tasmania 7001, Australia; And (MFG) Ichthyology, Museum Victoria, G.P.O. Box 666E, Melbourne, Victoria 3001, Australia. E-mail: (HM) motomura@kaum.kagoshima-u.ac.jp. Send reprint requests to HM.

Received: 07 Mar 2005

Accepted: 15 Mar 2006