Tuesday, March 21, 2017

[Ichthyology • 2016] Cirrhilabrus hygroxerus • A New Species of Fairy Wrasse (Pisces: Labridae) from the Timor Sea, northern Australia

Cirrhilabrus hygroxerus 
Allen & Hammer. 2016
Monsoon Fairy-wrasse |   OceanScienceFoundation.org   DOI: 10.5281/zenodo.60551


A new species of labrid fish, Cirrhilabrus hygroxerus, is described from 19 type specimens, 38.4–56.1 mm SL, collected from the eastern Timor Sea, Northern Territory, Australia. The new taxon belongs to a species complex containing five other Indo-Pacific species, comprising C. humanni (western Lesser Sunda Islands of Indonesia and East Timor), C. joanallenae (western Sumatra), C. morrisoni (Hibernia Reef, western Timor Sea), C. naokoae (Nias Island, western Sumatra), and the widespread C. rubriventralis (Red Sea, western Indian Ocean, Maldives, and Sri Lanka). Members of this complex typically have a single row of scales on the cheek and share the unique combination in the terminal-phase (TP) male of an elevated anterior dorsal fin, rounded caudal fin, and large fan or club-shaped pelvic fins without filamentous extensions. The new species is most similar to C. humanni and C. morrisoni, and the three species have apparently allopatric distributions in the Timor Sea-western Sunda Islands region. These three species share a uniquely shaped dorsal fin characterized by the presence of an anterior elevated, spike-like pennant. The best means of separating these species are differences in the color patterns of the TP male, primarily on the head, upper body, and on the dorsal, anal, and pelvic fins. The new species is distinguished by a combination of a yellow-orange upper head, blackish upper body, mainly blackish dorsal fin, and scarlet-red pelvic and anal fins. The female of C. hygroxerus is most similar to that of C. morrisoni, sharing a yellowish head and yellow pectoral-fin base.

Key words: coral-reef fishes, taxonomy, systematics, Indo-Pacific Ocean, biogeography, marine biodiversity 

Figure 3. Cirrhilabrus hygroxerus, live holotype, NTM S.17975-001, male, 54.1 mm SL, eastern Timor Sea
Figure 4. Cirrhilabrus hygroxerus, live female paratype, NTM S.17975-004, 49.5 mm SL, eastern Timor Sea
photos: M.P. Hammer 

 Distribution and habitat. The new species is currently known only from a single reef area in the eastern Timor Sea (Fig. 6), approximately 200 km north of Darwin, Australia. It was collected and observed in depths of about 18–37 m. The habitat appears to be localized to sloping rubble bottoms with scattered, low outcrops of rock or coral and occasional large coral outcrop

Etymology. The species is named hygroxerus (from Greek hygros, meaning wet, and xeros, meaning dry), with reference to the monsoonal cycle of wet and dry seasons of northern tropical Australia. The name is also intended as an acknowledgment of Monsoon Aquatics, the aquarium fish company that supplied all of the type specimens and continues to be an excellent source of specimens for NTM. The species epithet should be considered a noun in apposition. 

Gerald R. Allen and Michael P. Hammer. 2016. Cirrhilabrus hygroxerus, A New Species of Fairy Wrasse (Pisces: Labridae) from the Timor Sea, northern Australia. Journal of the Ocean Science Foundation. 22, 41–52.  oceansciencefoundation.org/josf22d.html  DOI: 10.5281/zenodo.60551  http://www.oceansciencefoundation.org/josf/josf22d.pdf

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