A Revision of the Hawaiian Lizardfishes of the Genus Synodus with Descriptions of Four New Species

Abstract

The Hawaiian lizard fishes of the genus Synodus are reviewed; 4 new species are described (bringing to 12 the number known from Hawaii), and the range of S. capricorn is Cressey and Randall is extended to the Northern Hemisphere. It is also determined that the name Synodus variegatus (Lacepede) properly applies to the species commonly known as S. englemani Schultz. Synodus dermatogenys Fowler is the oldest available name for the species that has been known as S. variegatus. Gill-raker counts are used as diagnostic characters for the first time with synodontids, and color slides and observations of fresh specimens revealed species-specific pigmentation patterns, many of which typically disappear with preservation. The key includes all known lizardfishes from Hawaii (genera Saurida, Synodus, Tra chinocephalus). Synodus amaranthus sp. nov. is similar to S. dermatogenys but differs in having barred pelvic fins; more gill rakers; and greater head length, orbit diameter, and pectoral fin length. SynodusJalcatus sp. nov. and S .janus sp. nov. have the high vertebral and lateral-line scale counts typical of S. ulae Schultz and S. capricornis, but have fewer gill rakers and different nasal flaps. Synodus lobeli sp. nov. is closest to S. indicus (Day), a species known only from the Indian Ocean and the Philippines, but has a shorter head, lower modal number of dorsal fin rays, and lacks the two dark marks found on the opercle of the latter species. Electrophoretic data are presented for the seven species (binotatus, dermatogenys, doaki, Jalcatus, ulae, usitatus, and variegatus) for which fresh or frozen material was available. Each of these species could be separated from all others on the basis of multiple fixed allelic differences, and this facilitated unambiguous identification of morphologically similar species. Discriminant function analysis, with functions derived for groups identified by electrophoretic phenotype, was used in the identification of specimens that could not be sampled electrophoretically.