Volume 19, Issue 1 – 21 January 2013
Volume 19, Issue 1 – 21 January 2013
John E. Randall and Joseph D. DiBattista: A new species of damselfish (Pomacentridae) from the Indian Ocean, pp. 1-16
The pomacentrid fish Chromis dimidiata (Klunzinger, 1871), type locality Red Sea, formerly believed to be wide-ranging into the Indian Ocean, is restricted to the Red Sea. The Indian Ocean population is described as a new species, Chromis fieldi. It differs in having modally 17 pectoral rays and 17 lateral-line scales, compared to modally 16 pectoral rays and 15 lateral-line scales for C. dimidiata, and the demarcation of the dark brown anterior part of the body from the white posterior part is convex, compared to nearly straight in C. dimidiata, and not as sharply defined dorsally and ventrally. Phylogenetic comparisons based on mitochondrial DNA (mtDNA) cytochrome b sequences support morphological differentiation with evolutionary separation of C. dimidiata sampled in the central Red Sea and C. fieldi sampled in the Indian Ocean (d = 0.019). These two species differ from the related C. iomelas Jordan & Seale, 1906 of the western and central Pacific in having modally 12 dorsal and anal fin soft rays (vs. 13 for C. iomelas), the demarcation of dark brown and white distinctly anterior to the origin of the anal fin, and d = 0.085 to d = 0.087 for cytochrome b.
Holotype of Chromis fieldi, BPBM 20241, 57 mm, Mauritius. Photo by J. E. Randall
Matthew L. Wittenrich and Adeljean L.F.C. Ho: Social structure and reproductive behavior of the callionymid fish Callionymus bairdi (Gobiesociformes: Callionymidae): with notes on male alternative reproductive tactics, pp. 17-28
Despite the abundance and diversity of callionymids in marine environments, information on the social structure and mating systems of the group are rare. Most research has suggested that callionymids are non-territorial, polygynous spawners where male mating opportunities are controlled by dominance hierarchies, which in turn, are governed by body size. Here, we investigate the social structure and reproductive behavior of Callionymus bairdi through observations of wild and captive fish. Males greater than 8 cm SL held territories ranging in size from 6.81-10.9 m2, within which, females maintained territories of 0.182-1.41 m2. Subordinate males were found to move freely through the territories of larger males and compete for mating opportunities with females. The number of subordinate males and females living within territorial boundaries correlated strongly with the size of the territory. Male alternative reproductive tactics, including female mimicry and saboteur males, are discussed.
Callionymus bairdi positions prior to gamete release. A ventral view (A) of territory-holding male (♂ T-H) assuming a curved body position, while female (♀) remains straight. A dorsal (B1) and ventral view (B2) of both the territory-holding male (♂ T-H) and the saboteur male (♂ Sb) assuming a curved body position.
Jose Tavera and Arturo Acero P.: Description of a new species of Hypoplectrus (Perciformes: Serranidae) from the Southern Gulf of Mexico, pp. 29-38
Nine of the sixteen species of the western Atlantic genus Hypoplectrus (Serranidae) are currently recognized to be distributed in the Gulf of Mexico. Hypoplectrus atlahua n. sp. is only known from Tuxpan banks and Isla Lobos, Veracruz. It differs from the only other similarly colored species, H. nigricans (i.e black hamlet) in the number of gill rakers on the first arch, snout length, upper jaw length, pectoral and pelvic fins lengths, and coloration. It is a dark brown species, lacking nose spots, mask, caudal fin dark spots, peduncle saddle, and pectoral pigmentation, but has iridescent violet speckles and lines on cheeks and chest, and also a well-defined but rather small violet dot over the dorsal flat spine on the rear edge of the opercle.
Holotype, fresh specimens of Hypoplectrus atlahua n. sp.
Jacques Géry: Characiform fishes collected by H. Bleher on the road São Paulo-Corumba-Araguaia, December 2005, pp. 39-59
43 species, 28 preserved in alcohol (including 19 spp. photographed) and 15 species not preserved (some still in aquarium), all photographed. From the upper basins of the rios Tieté, Paraná, Paraguay, Tapajós, Xingú and Tocantins (the last three in the Serra do Roncador).
Knodus sp. 2 aff. moenkhausii. Station 16, Alto Rio das Mortes basin, road Cuiabá to Barra do Garça, km 52 after Primavera do Leste, near Reserva Indigena Sangradouro (no more existing). Photo by H. Bleher, 18.12.2005