Volume 17, Issue 2 – 26 April 2011

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James D. S. Knuckey, David A. Ebert and George H. Burgess: Etmopterus joungi n. sp., a new species of lanternshark (Squaliformes: Etmopteridae) from Taiwan, pp. 61-72

Abstract

A new species of deepwater lanternshark, Etmopterus joungi n. sp., is described from the deep waters off north-eastern Taiwan. The new species is similar to other species of the “Etmopterus pusillus group” in having concave, flattened dermal denticles that are scattered irregularly across the body, a lateral line that ends in an open groove, suprapelvic flank markings lacking a posterior branch and a relatively cylindrical body, but can be separated from its congeners based on the following characteristics: gill slit height, tooth morphology, fin size and shape, interdorsal space and suprapelvic flank markings. The new species has a shorter preoral length and the gill slit height does not vary much compared to other members of the “E. pusillus group.” The teeth in the lower jaw of E. joungi n. sp. are slender, with relatively oblique cusps compared to those of its congeners. The pectoral fins of E. joungi n. sp. are more squared posteriorly and the caudal fin is shorter than the other members of the “Etmopterus pusillus group.” The pectoral axil to first dorsal fin origin measurement of E. joungi n. sp. fits into the interdorsal space about three times. The new species possesses suprapelvic flank markings that are unique compared to its congeners. 

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Holotype, Etmopterus joungi n. sp. (CAS 227957), female, 456 mm TL (435 mm TL after preservation), CAS-227957. Photo by D. A. Ebert.

Sven O. Kullander: A review of Dicrossus foirni and Dicrossus warzeli, two species of cichlid fishes from the Amazon River basin in Brazil (Teleostei: Cichlidae), pp. 73-94

Abstract

Dicrossus warzeli and D. foirni were described with focus on within-species colour pattern variation and aquarium observations. Validity of the two species is confirmed on the basis of wild specimens of D. warzeli from the lower Rio Tapajós between Itaituba (São Luis do Tapajós) and Cururu, and of D. foirni from tributaries of the middle Rio Negro (Rio Marauiá and Rio Padauari). A phylogenetic assessment using colour pattern and fin shape shows that D. foirni and D. warzeli are sister species, and form the sister group of D. filamentosus from the Rio Negro and Rio Orinoco basins and D. maculatus from the central Amazon basin.

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Schematic representation of vertically (black numbers) and horizontally arranged markings in species of Dicrossus.

Rüdiger Riesch, Timothy J. Colston, Brandon L. Joachim and Ingo Schlupp: Natural history and life history of the Grijalva gambusia Heterophallus milleri Radda, 1987 (Teleostei: Poeciliidae), pp. 95-102

Abstract

We report on basic natural history and life history data of the Grijalva gambusia Heterophallus milleri (Poeciliidae) from a small creek in Tabasco, southern México. Basic biology of H. milleri is similar to that of other members of the tribe Gambusiini. Insects make up at least part of H. milleri’s diet, the tertiary sex ratio was female-skewed, female H. milleri produced small offspring, one clutch at a time, relied predominantly on yolk for embryo provisioning (MI: 0.73), and male size was normally distributed.

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Heterophallus milleri, male.  Photo by D. Bierbach

Douglass F. Hoese, Richard Winterbottom and Sally Reader: Trimma maiandros, a new species of pygmy goby (Gobiidae) from the Indo-west Pacific, pp. 103-110

Abstract

A new species of the genus Trimma is described. Trimma maiandros n. sp. is characterized by having reduced predorsal scales, usually not crossing the midline; a dark ring around the eye and a dark triangular shaped spot extending ventrally and posteriorly from the eye and dark lines forming a zigzag pattern on the upper half of body; a very shallow interorbital groove and shallow or no postorbital groove; scales present on the pectoral and pelvic fin bases but not on the cheeks or opercles; and an unbranched fifth pelvic fin ray that is 25-50% of the length of the fourth ray. Trimma maiandros n. sp. has been found from numerous localities from Cocos (Keeling) Islands in the Indian Ocean and from Japan, Marshall and Mariana Islands to Samoa and Australia in the Pacific. Considerable geogra­phical variation occurs in coloration and other morphological features, and more than one species may be represented.

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Freshly collected holotype of Trimma maiandros, AMS I.20784-050, 20.7 mm SL, male. Photo by D. Hoese.

Stefano Valdesalici and Giuseppe Amato: Nothobranchius oestergaardi (Cyprinodontiformes: Nothobranchiidae), a new annual killifish from Mweru Wantipa Lake drainage basin, northern Zambia, pp. 111-119

Abstract

A new species of an annual killifish, Nothobranchius oestergaardi, is described based on specimens collected from an ephemeral pool in the swamps of the seasonal Mwawe River in the drainage system of the Mweru Wantipa Lake basin, northern Zambia. The new species belongs to the Nothobranchius taeniopygus species group and is distinguished from the other members by a diagnostic combination of male colouration and morphological characters.

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Nothobranchius oestergaardi, wild adult male, from the type locality, not preserved. Photo by A. Persson