Taxonomy and distribution of Rouleina attrita and Rouleina maderensis (Pisces: Alepocephalidae). Taxonomy and distribution of Rouleina attrita and Rouleina maderensis (Pisces: Alepocephalidae)
Three Atlantic species of Xenodermichthys and Rouleina are recognized: X. copei, R. attrita, and R. maderensis. Bathytroctes mollis and B. aequatoris are considered junior synonyms of R. attrita. Anomalopterus megalops is considered incerta sedis. Diagnostic characters for R. attrita are: no photophores, convoluted testes, 43-48 lateral line scales, 43-46 preural vertebrae, papillae on body near lateral line, and maturation at a size around 250-300 rnm standard length. Diagnostic characters for R. maderensis are: photophores present, lobate testes, 50-56 lateral line scales, 47-50 preural vertebrae, papillae usually peripheral to photophores on fins and fin bases, and maturation at a size around 200-250 mm standard length. The two species are sharply segregated by depth: 91% of all R. maderensis were from bottom trawls made between 595 and 1,200m while 88% of allR. attrita were from bottom trawls fished between 1,400 and 2,100 m.