FISHERY BULLETIN: VOL. 76. NO. 1 



and modified ringlike lateral line scales in the 

 adults. Photophores are present or absent: their 

 loss appears secondary. For example, in R. fune- 

 bris the size and arrangement of photophores are 

 identical to Xenodermichthys: in R. maderensis 

 the photophores are smaller; in R. harperi only 

 dark spots remain; and in R. attrita there are no 

 photophores. The purpose of this paper is to dis- 

 cuss the taxonomy and distribution of the two 

 known Atlantic species, R. attrita and R. 

 maderensis. 



METHODS 



Standard taxonomic measurements and counts 

 were made (Hubbs and Lagler 1958) with the fol- 

 lowing clarifications and additions. Caudal ver- 

 tebrae were distinguished from precaudal verte- 

 brae by the presence of a haemal arch and spine in 

 the former. On radiographs there is a sharp de- 

 marcation, characterized by a reduction in the 

 length of the pleural rib on the last precaudal 

 vertebra and/or the apparent intersection of the 

 last pleural rib with the first haemal spine. The 

 last caudal vertebra counted is that which articu- 

 lates with the parahypural, even if fused to a ural 

 centrum. The one or more ural centra are variable 

 in alepocephalids and were not counted. 



The high water content and postpreservation 

 shrinkage plus the damage inflicted on most 

 alepocephalids during capture, causes a notice- 

 able amount of variation in most measurements of 

 a species or even in repeated measurements of an 

 individual. The precision of alepocephalid 

 morphometries is therefore relatively low. In addi- 

 tion, most alepocephalid morphometries exhibit 

 definite allometry (Parr 1949, 1956, 1960). Before 

 the allometry of morphometries will be useful in 

 identifying larvae and small juveniles, more smal- 

 ler and less damaged specimens than are pre- 

 sently available will be needed. 



MATERIAL 



The following type-material of Rouleina was 

 examined from the U.S. National Museum of 

 Natural History, Washington, D.C. (USNM); 

 Museum National d'Histoire Naturelle, Paris 

 (MNHN); Zoological Museum, University of 

 Copenhagen (ZMUC); Zoological Museum, Berlin 

 (ZMB); and Museu Municipal do Funchal, 

 Madeira (MMF): Bathytroctes attrita, MNHN 



85-166 and 85-169; B. mollis, MNHN B-2219; B. 

 aequatoris, USNM 44085; B. harperi, USNM 

 92333; B. welshi, USNM 92332; Xenodermichthys 

 funebris, USNM 99b3A,Anomalopterus megalops, 

 USNM 170957; Aleposomus nudus, ZMB 17426; 

 A. lividus, ZMB 22398; R. danae, ZMUC P1778; 

 andR. maderensis, MMF 50, 2395, and 2396. 



Additional material was examined from the 

 British Museum (Natural History), London 

 (BMNH); University Museum, Tokyo (UMT); In- 

 stitute of Oceanographic Sciences, Wormley, En- 

 gland (lOS); Museum of Comparative Zoology, 

 Harvard (MCZ); Field Museum of Natural His- 

 tory, Chicago (FMNH); Rosenstiel School of Ma- 

 rine and Atmospheric Sciences, Miami (UMML); 

 Institut fiir Seefischerei, Hamburg (ISH); and 

 Virginia Institute Marine Science, Gloucester 

 Point (VIMS). These collections included four 

 specimens of R. guentheri cataloged as BMNH 

 1898.7.13.19 and UMT 5785, 5785', and 20983; 

 one specimen of R. danae, USNM 215490; 69 

 specimens of R. attrita, USNM 215479-215489 

 and 44085; ISH 123/73, 124/73, 950/73, 141/74, 

 163/74, 511/74, 512/74, 835/74, 844/74, 212/75, 

 234/75, and one uncatalogued; VIMS 3539, 3540, 

 3542, and 3543; FMNH 65711; UMML 22353; 

 MCZ 40609; and lOS Discovery 8512#1; and 35 

 specimens of R. maderensis, USNM 215471- 

 215478; ISH 130/75; VIMS 3541; MCZ 39349; 

 BMNH 1945.7.20.5; lOS Discovery 7431, 7432, 

 and 7436; and ZMUC Dana 1183^ 



RESULTS 



The species oi Rouleina separate conveniently 

 into two groups. The first group, which lacks 

 photophores or their remnants, contains i?. attrita 

 and/?, danae. Rouleina danae differs from/?, at- 

 trita by its reduced maxillary dentition and much 

 larger orbit (43.5% of head length (HL) vs. 24-29% 

 HL at about 100 mm standard length (SD). The 

 second gi'oup, which has photophores, contains/?. 

 maderensis and several Indo-Pacific species which 

 differ from it in having fewer anal fin rays (16-19 

 vs. 20-22). 



Although the two North Atlantic species,/?, at- 

 trita and /?. maderensis, are easily distinguished 

 with undamaged material, most specimens are 

 damaged and the two species are very similar in 

 gross morphology. The following key summarizes 

 characters which have been found useful to sepa- 

 rate these species. 



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