Bellorchestia, Serejo & Lowry, 2008

Serejo, C. S. & Lowry, J. K., 2008, The Coastal Talitridae (Amphipoda: Talitroidea) of Southern and Western Australia, with Comments on Platorchestia platensis (Krøyer, 1845), Records of the Australian Museum 60 (2), pp. 161-206 : 169

Bellorchestia n.gen.

Talorchestia Dana, 1852: 851 .– Stebbing, 1906: 543 (partim.).– Stephensen, 1948: 7 (partim.).– Hurley, 1956: 359 (partim.).

Type species. Bellorchestia richardsoni n.sp.

Etymology. Bella means beautiful and refers to the general appearance of species in the genus, attached to the stem Orchestia from the Greek orchestes = dancer.

Diagnosis. Antenna 2 not geniculate and not sexually dimorphic. Mandible left lacinia mobilis 5-dentate. Maxillipedal palp dactylus present, reduced. Male gnathopods 1–2 subchelate; male gnathopod 2 basis narrow; propodus palm posterodistal corner defined by large protuberance; dactylus not attenuated distally. Pereopods 3–7 cuspidactylate. Pereopod 4 carpus significantly shorter than carpus of pereopod 3. Pereopods 6–7 sexually dimorphic, merus and carpus slightly more robust in terminal males. Pereopod 7 basis lateral sulcus present, slightly pronounced. Gills lobate and/or convoluted; gills 3–5 smaller than gills 2 and 6. Oostegites 2–5 setae with simple straight tips. Pleopods all well developed. Uropods 1–2 outer rami with marginal robust setae. Telson broader than long with more than 10 robust setae.

Species composition. Bellorchestia contains 7 species: B. chathamensis ( Hurley, 1956) ; B. kirki ( Hurley, 1956) ; B. marmorata ( Haswell, 1880) ; B. pravidactyla ( Haswell, 1880) ; B. quoyana (Milne Edwards, 1840) ; B. richardsoni n.sp.; B. spadix ( Hurley, 1956) and B. tumida (Thomson, 1885) .

Remarks. We have tentatively placed some of the remaining “ Talorchestia ” species from Tasmania and New Zealand into Bellorchestia . However, some diagnostic characters of Bellorchestia were not described in the respective literature. Re-examination of local material would clarify the identification of these taxa.

Bellorchestia is part of the so called sand-hopper group, which are large, strongly setose talitrids adapted for burrowing, also known as substrate modifiers ( Bousfield, 1982). Eleven genera are included in this group: Americorchestia Bousfield, 1991 , Atlantorchestoidea Serejo, 2004 , Bellorchestia n.gen., Deshayesorchestia Ruffo, 2004 , Megalorchestia Brandt, 1851 , Orchestoidea Nicolet, 1849 , Pseudorchestoidea Bousfield, 1982 , Sardorchestia Ruffo, 2004 , Talitrus Latreille, 1802 , Talorchestia Dana, 1852 (sensu stricto), and Trinorchestia Bousfield, 1982 . From these, Atlantorchestoidea , Orchestoidea , Pseudorchestoidea , and Talitrus have a 4-dentate left lacinia mobilis and male and female gnathopods 1 are simple. The remaining six genera are compared with Bellorchestia n.gen. in Table 2. Deshayesorchestia and Sardorchestia were briefly described recently based in a molecular analysis (Ruffo in Tafani et al., 2004). Important characters, such as state of the lacinia mobilis and pleopods, were not properly described, but other significant characters are pointed out in Table 2. Among other characters, the presence of robust setae on epistome and on ventral margins of peduncle of uropods 1–2 distinguish Bellorchestia n.gen. from the other related sand-hoppers.