Cymatognathus, Kimura & Johnson & Peristiwady & Matsuura, 2017

Kimura, Seishi, Johnson, G. David, Peristiwady, Teguh & Matsuura, Keiichi, 2017, A new genus and species of the family Symphysanodontidae, Cymatognathus aureolateralis (Actinopterygii: Perciformes) from Indonesia, Zootaxa 4277 (1), pp. 51-66 : 53

Genus Cymatognathus gen. nov.

( Figure 1A )

Type species. Cymatognathus aureolateralis sp. nov.

Diagnosis. A symphysanodontid distinguishable from the other genus in the family, Symphysanodon , by the following: posterior tip of coronoid process of dentary abruptly depressed so that teeth on anterior portion appear as an elevated patch, creating a wavy contour on lower jaw ( Figures 2 A, 3A); anterior tip of upper jaw not notched ( Figure 5 A); posterior nostril horizontally slit-like ( Figure 6 A).

Description. Characters given in familial and generic diagnoses are not repeated. Body oblong, deep, compressed; mouth large, oblique; posterior tip of upper jaw just reaching to vertical through mid-pupil, its upper and lower corners rounded; upper lip posteriorly covered by maxilla; upper jaw projecting slightly beyond lower jaw; teeth in both jaws forming bands, outer teeth larger than the inner; small but somewhat robust conical teeth on vomer, palatines, endopterygoids and ectopterygoids ( Figures 7 A, 8A); anterior nostril rounded with slightly elevated rim ( Figure 6 A); metapterygoid without posteroventral projection (see “Remarks” below; Figure 8 A); opercle with two flat, pointed spines, the upper broader than the lower; preopercle with almost smooth posterior margin; head and body almost completely covered by ctenoid scales; scales on head progressively smaller anteriorly; lateral line complete, gently curved anteriorly, running almost parallel to dorsal contour of body; dorsal fin with nine spines and ten soft rays, last spine and first soft ray subequal in length; anal fin with three spines and seven soft rays; caudal fin deeply forked with tips of both lobes filamentous; pectoral and pelvic fins long, posterior tips of pectoral and pelvic fins extending beyond level of anal-fin origin; hypurals 1, 2 and 5 autogenous, hypurals 3 and 4 represented by a single plate.

Etymology. The name “ Cymatognathus ” is derived from the Greek kymatos (wave) and gnathos (jaw) in reference to the characteristic wavy upper contour of the lower jaw.

Figures

FIGURE 1. A. Cymatognathus aureolateralis sp. nov., holotype, MZB 19251, 181 mm SL, Bitung, North Sulawesi, Indonesia. B. Symphysanodon katayamai, FRLM 11738, 155 mm SL, Shima, Mie, Japan. 1. Fresh specimens (photographed by T. Peristiwady for C. aureolateralis and S. Kimura for S. katayamai). 2. X-ray photographs.

FIGURE 2. Tooth patches on jaws. A. Cymatognathus aureolateralis sp. nov., paratype, FRLM 54552, 178 mm SL, Bitung, North Sulawesi, Indonesia. B. Symphysanodon katayamai, FRLM 11738, 155 mm SL, Shima, Mie, Japan. 1. Frontal view of both jaws. 2. Dorsal view of lower jaw. 3. Lateral view of both jaws. ETP = elevated tooth patch, LOT = outer tooth patch on lower jaw, UOT = outer tooth patch on upper jaw.

FIGURE 5. Dorsal view of upper jaw. A. Cymatognathus aureolateralis sp. nov., paratype, FRLM 54552, 178 mm SL, Bitung, North Sulawesi, Indonesia. B. Symphysanodon katayamai, FRLM 11738, 155 mm SL, Shima, Mie, Japan. Arrow indicates notch at anterior tip of upper jaw.

FIGURE 6. Lateral view of snout, showing nostrils. A. Cymatognathus aureolateralis sp. nov., paratype, FRLM 54552, 178 mm SL, Bitung, North Sulawesi, Indonesia. B. Symphysanodon katayamai, FRLM 11738, 155 mm SL, Shima, Mie, Japan. AN = anterior nostril, PN = posterior nostril.

FIGURE 7. Tooth patches of vomer (V), palatines (P), endopterygoids (ENP) and ectopterygoids (ECP), ventral view. A. Cymatognathus aureolateralis sp. nov., paratype, FRLM 54552, 178 mm SL, Bitung, North Sulawesi, Indonesia. B. Symphysanodon katayamai, FRLM 11738, 155 mm SL, Shima, Mie, Japan.

FIGURE 8. Right-side suspensorium. A. Cymatognathus aureolateralis sp. nov., paratype, FRLM 54552, 178 mm SL, Bitung, North Sulawesi, Indonesia (medial view). B. Symphysanodon andersoni, USNM 435866, 200 mm SL, Salalah, Dhofar, Oman (lateral view, mirror image). C. S. katayamai, FRLM 11738, 155.4 mm SL, Shima, Mie, Japan (medial view). ECP = ectopterygoid, ENP = endopterygoid, MP = metapterygoid, P = palatine, Q = quadrate, S = symplectic. Circle indicates posteroventral projection of metapterygoid.