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[[ Genus Trachyscorpia Ginsburg ZBK ]]
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 .