Comprehensive DescriptionRead full entry
Species of the scorpionfish genus Trachyscorpia ZBK are deepwater, bottom dwelling, relatively large fishes, attaining at least 35 cm standard length. The genus was originally proposed for Scorpaena cristulata Goode & Bean, 1896 ZBK by Ginsburg (1953) who simultaneously included Scorpaena echinata Koehler, 1896 ZBK in the genus. Subsequently, Eschmeyer (1969) added Scorpaena capensis Gilchrist & von Bonde, 1924 ZBK to Trachyscorpia ZBK . Eschmeyer (1969) tentatively regarded T. cristulata and T. echinata as the subspecies, T. cristulata cristulata and T. c. echinata . He also separated the species of Trachyscorpia ZBK into two subgenera, Trachyscorpia (type species: T. cristulata ) and Mesoscorpia ZBK ( T. capensis ), the latter being his new subgenus.
The genus Trachyscorpia ZBK is characterized by the following combination of characters: occiput flat, lacking pit; first preopercular spine largest; head bones strongly ossified; suborbital ridge well developed, with usually 5 or more spines; palatine teeth present; dorsal-fin spines 12 or 13; vertebrae 25 or 26; pectoral-fin margin bilobed; lateral line complete, extending onto caudal-fin base; and scales on the body ctenoid (Eschmeyer, 1969; this study).
Trachyscorpia capensis was described as a new species of Scorpaena from the west coast of South Africa from three specimens (whereabouts of the syntypes currently unknown; e.g., Eschmeyer, 1998). Although the name T. capensis has been used in many publications since Eschmeyer (1969) (e.g., Eschmeyer, 1986; Ishida, 1990; Pakhorukov, 2001), T. capensis is permanently invalid because it was preoccupied by Scorpaena capensis Gmelin, 1789 ZBK , which is currently recognized as Sebastes capensis . Whitley (1970) proposed a replacement name, T. eschmeyeri ZBK , for Gilchrist and von Bonde’s Scorpaena capensis ZBK .
The species of Trachyscorpia ZBK from Australasian waters (mostly reported as T. capensis ) has been recognized as containing two sympatric morphotypes by several ichthyologists for a long time (e.g., Daley et al, 1997; A. Stewart and C. Paulin, pers. comm., 2004). Our further examinations of specimens from the region showed that the two morphotypes represent T. (M.) eschmeyeri ZBK and a distinct new species of Trachyscorpia (Mesoscorpia) ZBK . In addition, during examination of the Australasian specimens, another new species was found at the Australian National Fish Collection (CSIRO). This new species was collected from the South-West Indian Ridge, southwestern Indian Ocean (ca. 1,700 km south of the southern tip of Madagascar), and resembles the Australasian new species rather than T. (M.) eschmeyeri ZBK . The two new species are herein described in detail, along with a redefinition of the subgenus Mesoscorpia ZBK .