Hongeo, a new skate genus (Chondrichthyes: Rajidae), with redescription of the type species

Abstract

Hongeo gen. nov. is proposed following examinations of several individuals, including adult males, of the type species Raja koreana, previously described from a single adult female specimen from the southern coast of the Korean Peninsula. A number of external (including claspers, squamation, and ampullary and lateral line canal systems) and skeletal characters are newly described. The phylogenetic position of R. koreana among 26 nominal rajid supraspecific taxa plus 2 unnamed supraspecific taxa of Rajidae and 3 outgroups was estimated. According to a strict consensus tree of 20 equally parsimonious trees of 139 steps (CI = 0.626; RI = 0.850; RC = 0.532; HI = 0.374), Hongeo gen. nov. is defined by the two derived character states: rostral cartilage continuous with neurocranium and stout proximally, but very slender and uncalcified distally; and anterior fontanelle broad, extending forward onto the basal part of rostral cartilage slightly beyond the leading edge of nasal capsules. The new genus also differs from all other supraspecific taxa of Rajidae in the following combination of characters: dorsal surface of tail with a row of distinct thorns along midline in both sexes; most thorns directed anteriorly; a pair of longitudinally elongated black blotches having undulated contours on middle of dorsal surface of disc; three groups of outer buccal ampullae and tubules; three groups of nasal ampullae and tubules; hyoidean ampullae and tubules on ventral surface posteriorly extending past cloaca; rostral shaft narrow with filamentous cartilage at base; scapulocoracoid comparatively short and high with dorsoventrally elliptical anterior fenestra and expanded postventral fenestra; external margin of mesopterygium of pectoral fin slightly undulated, not sinuous, and not fused with pectoral radials; and clasper component eperon and pent present.