PROC. BIOL. SOC. WASH. 100(1), 1987, pp. 164-172 A NEW SPECIES OF NANNOSTOMUS (TELEOSTEI: LEBIASINIDAE) FROM NEAR PUERTO AYACUCHO, RIO ORINOCO DRAINAGE, VENEZUELA Justa M. Fernandez and Stanley H. Weitzman Abstract. —Nannostomus anduzei is described as a new, miniature species of the characiform family Lebiasinidae from near the Rio Orinoco, north of Puerto Ayacucho, Territorio Federal Amazonas. This species is distinguished from all other species o^ Nannostomus by its tiny adult size (to 16.2 mm SL), several reduced structures, and a distinctive live color pattern. Although the new fish is clearly a species of Nannostomus, its relationships among the other species are obscure. The new species of Nannostomus de-scribed below brings the number of known species to 15, nearly half of them having been described in the last 30 years. The re-lationships of the species of Nanno-stomus have been discussed by Gery (1977: 127-135) and Weitzman and Weitzman (1982:416-419). The species have been de-scribed in some detail by Weitzman (1966), Weitzman and Cobb (1975), and Weitzman (1978). Weitzman and Weitzman (1982: 417) remark that with only a few exceptions they were unable to accept cladistic hy-potheses of relationships among Nanno-stomus species based on 40 morphological characters extracted from Weitzman (1966: 8-53), Weitzman and Cobb (1975:6, 9-1 1, 25-33), and Weitzman (1978:2, 3, 7-9). They found a high degree of homoplasy and character lability causing them to distrust most phylogenetic hypotheses of relation-ships. Gery (1977:127-135), apparently partly based on Weitzman (1966:4-9) and Hoedeman (1950:22), recognized two gen-era and one subgenus of nannostomin le-biasinids. However, Weitzman and Cobb (1975:3-7) and Weitzman (1978:7-9) dis-cuss why most of the morphological char-acters used by Gery (1977), Weitzman (1966) and Hoedeman (1950) are of du-bious for generic diagnosis. Interestingly, Weitzman and Weitzman (1982:419) and Gery (1977:131) accepted different hypoth-eses of relationships among certain species of Nannostomus. Gery's hypotheses were based on unpublished karyotypic informa-tion sent to him by J. J. Scheel. The karyo-typic information was not cladistically ana-lyzed and appears to have the same limitations discussed by Weitzman and Fink (1983:394, 395) for similar data recorded for species of Paracheirodon Gery. We do not discuss here the many problems of re-lationships among the species and popula-tions o^ Nannostomus. We only summarize current opinions in order to demonstrate that a satisfactory study of the phylogenetic relationships of the species oi Nannostomus is lacking. Methods and Materials Data are recorded as described in Weitz-man (1966:3-6). All measurements other than standard length (SL) are expressed as a percentage of SL except subunits of the head which are recorded as a percentage of head length unless otherwise noted. Total vertebral counts, taken from radiographs and from cleared and Alizarin red and Al-cian blue stained specimens include all ver-tebrae of the Weberian apparatus counted
BioStor
