Volume 18, Issue 4 – 15 October 2012
Volume 18, Issue 4 – 15 October 2012
F. B. M. Vermeulen, W. H. Suijker and G. E. Collier: Laimosemion paryagi (Cyprinodontiformes: Aplocheiloidei: Rivulidae), a new species from the upper Mazaruni river drainage of Western Guyana, pp. 181-190
Laimosemion paryagi, new species, is described from the upper Mazaruni river system, a tributary of the Essequibo River. It is a member of the Laimosemion breviceps group former known as the Rivulus breviceps group, and shares a robust body and deep caudal peduncle with Laimosemion breviceps (Eigenmann, 1909) and Laimosemion lyricauda (Thomerson et al., 1991) and to a lesser degree with L. gransabanae (Lasso et al., 1992) and Laimosemion torrenticola (Vermeulen & Isbrücker, 2000). These species are all endemic to the Guiana Highlands in western Guyana and the neighbouring Gran Sabana in Eastern Venezuela. It is distinguished from other species in the L. breviceps group by morphology and its remarkable male color pattern of red blotches on a turquoise ground color on the flanks and in the unpaired fins and having a rounded caudal fin as opposed to one having extension or being spade shaped. Analysis of mitochondrial DNA sequence reveals that it is genetically distinct from all other members of this group and that inhabitants of the Guyana highlands diverged from each other early in the history of the genus, commensurate with the geological age of the Guiana Shield.
Laimosemion paryagi n. sp. (not preserved). Male from the terra typica. Photo by F. Vermeulen
Stefano Valdesalici: Nothobranchius kardashevi and Nothobranchius ivanovae (Cyprinodontiformes: Nothobranchiidae): two new annual killifishes from the Katuma River drainage, western Tanzania, pp. 191-198
Two new annual killifish species, Nothobranchius kardashevi, new species, and N. ivanovae, new species, are described based on specimens collected in ephemeral pools in the Katuma River drainage system, western Tanzania. Nothobranchius kardashevi, new species, belongs to the N. ugandensis species group and N. ivanovae to the N. taeniopygus species group. Both are distinguished from the respective other group members by a diagnostic combination of male colouration and morphological characters.
Nothobranchius kardashevi, adult male, about 35 mm SL, not preserved, Karira stream, western Tanzania. Photo by I. Ivanova
David Bierbach, Madlen Ziege, Claudia Zimmer, Rüdiger Riesch, Ingo Schlupp, Lenin Arias-Rodriguez and Martin Plath: Male Grijalva mosquitofish (Heterophallus milleri Radda, 1987) increase individual mating preferences in front of an audience, pp. 199-208
Socially influenced mate choice behavior is currently a growing field in the study of sexual selection and evolution. Here, we provide the first description of male Grijalva mosquitofish (Heterophallus milleri) courtship behavior, and further report on an unparalleled “audience effect” in that species. Lab-reared male Grijalva mosquitofish significantly increased their preference for an initially preferred female in a full contact design in the presence of another male. This is somewhat unexpected as previous studies found males of other members of the family Poeciliidae to interact more evenly with stimulus females when faced with an audience, and thus decreasing their preference for the initially preferred female. As those “audience effects” are assumed to represent male tactics to prevent sperm competition risk arising through male mate choice copying, we argue that male mate choice copying might not play a major role in the reproductive biology of H. milleri.
Videotaped courtship sequence of H. milleri. For a description see main text
John E. Randall and Rachel J. Arnold: Uranoscopus rosette, a new species of stargazer (Uranoscopidae: Trachinoidei) from the Red Sea, pp. 209-218
Uranoscopus rosette is described as a new species of stargazer (family Uranoscopidae) from 11 specimens, 92-216 mm SL, collected from the Gulf of Aqaba, Red Sea, and formerly misidentified as U. fuscomaculatus Kner, U. sulphureus Valenciennes, or U. dollfusi Brüss. It is distinct in having two narrowly separated dorsal fins with IV spines and 13 soft rays, no scales dorsally on body anterior to origin of second dorsal fin; 37-41 oblique scale rows midlaterally on side of body; a strong cleithral spine; supracleithrum without a distinct posterior spine; 5-7 short spines ventrally on preopercle; body depth at anal-fin origin 3.6-4.05 in SL; head width 2.5-2.8 in SL; lingual lure flat and broadly triangular at base with long cirri on edges, ending in a ribbon-like filament with short cirri; and a unique color pattern dorsally on the body of irregular rows of dark gray-brown spots, many rosette-like, the head densely dark-dotted dorsally.
Holotype of Uranoscopus rosette in life, Gulf of Aqaba, Red Sea, 15 m. Photo by J. E. Randall
Michelle R. Gaither and John E. Randall: On the validity of the cirrhitid fish genus Itycirrhitus, pp. 219-226
The hawkfish Cirrhitus wilhelmi Lavenberg & Yañez was described from Easter Island in 1972, reclassified in Amblycirrhitus by Pequeño (1989), and the range extended to the Pitcairn Islands by Randall (1999). Randall (2001) described the new genus Itycirrhitus for this species. The similarity in general morphology and color to the Hawaiian Cirrhitops fasciatus and C. mascarenensis, type locality Mauritius, prompted the present molecular study to determine the validity of Itycirrhitus. Combining mitochondrial cytochrome oxidase I (COI) and cytochrome b (cyt b) sequence data from specimens of I. wilhelmi with comparable data from the two species of Cirrhitops, we found high levels of divergence between the two genera (COI, d = 15%; cyt b, d = 20-21%) that are similar to comparisons between Itycirrhitus and other genera of the family (COI, d = 8-18%; cyt b, d = 12-20%). This level of divergence is typical of other generic comparisons within Cirrhitidae (COI, d = 15-20%; cyt b, d = 15-21%).
Itycirrhitus wilhelmi, Easter Island. Photo by J. E. Randall
Gerald R. Allen and Peter J. Unmack: A new species of Rainbowfish (Chilatherina: Melanotaeniidae), from the Sepik River System of Papua New Guinea, pp. 227-237
A new species of rainbowfish, Chilatherina pagwiensis, is described on the basis of 31 specimens, 20.5-76.1 mm SL, collected from a tributary of the Sepik River near Pagwi village, East Sepik Province, Papua New Guinea. Morphologically it is closely allied to C. campsi, an inhabitant of mainly hilly or mountainous terrain in the Markham, Ramu, and Sepik river systems of northern Papua New Guinea and the Purari system, south of the Central Dividing Range. Both species are characterised by the absence of vomerine and palatine teeth, and males and females are relatively slender (greatest body depth 23.7-32.3 % SL) compared to most other family members. However, the two species exhibit pronounced modal differences in soft dorsal and anal rays. Chilatherina pagwiensis usually has 10-12 soft dorsal rays compared to usual counts of 13-15 in C. campsi. Likewise, the former species most frequently has 20-21 soft anal rays compared to 21-26 (most frequently 22-23) in C. campsi. Analysis of genetic relationships based on mitochondrial cytochrome b sequences indicates a close relationship between C. pagwiensis and the ancestor to C. axelrodi and C. campsi. The mean p-distance of C. pagwiensis to its relatives was 2.8 and 3.8% respectively, which are similar to values recorded between other rainbowfish sister species.
Freshly collected specimen of Chilatherina pagwiensis, male paratype, 64.3 mm SL, Kuins Creek, East Sepik Province, Papua New Guinea. Photo by P. J. Unmack