Volume 7, Issue 1, May 2003
Volume 7, Issue 1 – May 2003
John E. Randall: Thalassoma nigrofasciatum, a new species of labrid fish from the south-west Pacific, pp. 1-8
Thalassoma nigrofasciatum is described as a new species of Labridae from the Great Barrier Reef, vauatu, Lord Howe Island, Norfolk Island, Chesterfield Bank, New Caledoia, Loyalty Island, Fiji, and Tonga. It is typically found on exposed outer-reef areas from tide pools to dephts of at least 15 m. Previously identified as T. jansenii (Bleeker), it differs in colour and in having a deeper caudal peduncle and longer paired fins.
Holotype of Thalassoma nigrofasciatum, BPBM 14768, male, 131.8 mm, Lord Howe Island. Photo by J. E. Randall
Richard Winterbottom: A new species of Trimma (Gobiidae) from the western Indian Ocean, pp. 9-12
A new species of the genus Trimma is described. Trimma volcana is characterized by having large spots on the head and body, moderate to well-developed interorbital and postorbital trenches, scales present on the pectoral and pelvic fin bases but not on the cheecks, opercles, or midline of the nape, a posterior nostril which is adnate to the eye, and a fifth pelvic fin ray that is 80-9% of the fourth and is branched dichotomously twice. Trimma volcana has been found off Tanzania, Mozambique and the Comores Islands.
Left lateral view of a freshly collected specimen of Trimma volcana (13.6 mm SL female paratype, Mayotte, Comores, ROM 59762). Photo by R. Winterbottom
Richard Winterbottom and Cesar A. Villa: A new species of the Trimma caesiura complex (Gobiidae, Teleostei) from the north-eastern margin of the Australian Plate, with a redescription of the other nominal species in the complex, pp. 13-28
A new species of Trimma caesiura species complex, T. lantana, is described from the north-eastern margin of the Australasian plate and the Solomon Islands, and four other species of the complex are redescribed. This species complex is defined by the possession of a deep, steep-sided trench between and posterodorsal to the orbits. The new species differs from its congeners in the presence of two brick-red or brown, dark-edged, rounded blotches over the vertical limb of the preopercle, and smaller but similar blotches, on the cheek below the eye and on the dorsal surface of the snout. It differs further from T. caesiura in having an elongate spine in the first dorsal fin and ventrolateral white spots on the caudal peduncle, and in lacking thin white bars on the cheek. Trimma baudei has a club-like red bar over the vertical limb of the preopercle and a distinct dark bar over the bases of the pectoral fin rays (the latter diffuse or absent in T. lantana). Two other nominal species that appear to belong to this complex are redescribed here. Both T. mendelssohni and T. winterbottomi have more than a single branch in the fifth pelvic fin ray, usually more pectoral fin rays (a mean of 18 vs. 16), and a posterior nasal opening adnate to the anterior margin of the eye (vs. distinctly separate from the eye margin). The taxonomic status of two other species in this complex, T. corallinum and T. omanensis, is currently under review elsewhere, and these species are not considered further here.
Trimma caesiura, live, Palau. Photo by H. Nagano
Marta S. C. Soares, Luis Sousa and João Pedro Barreiros: Feeding habits fo the lizardfish Synodus saurus (Linnaeus, 1758) (Actinopterygii: Synodontidae), pp. 29-38
The feeding habits of the lizardfish Synodus saurus, were studie in the Azores archipelago, north-eastern Atlantic. Factors examined were diet composition, prey importance, season, fish size, feeding straegy and prey orientation in the oesophagus. The stomach contents of 308 specimens were collected and analyzed between March and November 2000. Synodus saurus is common in Azorean water. Though it prefers small grearious pelagic fish, it also feeds on epibenthic and benthic prey. We found the following prey in its diet: 9 families of teleostean fishes (Carangidae, clupeidae, Cynoglossidae, Gobiidae, Labridae, Myctophidae, Spaidae, Spyraenidae and Synodontidae), two families of crustaceans (Cymothoidae and Scyllaridae) and one of cephalopods (Loliginidae). The European pilchard, Sardina pilchardus was the commonest prey. The diet of the lizardfish varies with the season, showing the greatest diversity (given by the Shannon-Wiener index) im October. There is a significant correlation with the sea temperature. The size of the predator is not correlated to the size of its prey. However, we observed a ositive correlation between the size o the positive correlation between the size of the predator and the quantity of food in its stomach. The orientation of the prey in the oesophagus may partly depend on the predador’s size. However, analysis of the stomach contents provided no information on the selection of prey.
Camouflaged specimen of S. saurus. Photo by Peter Wirtz, ©imagDOP
Wilson J. E. M. Costa: Rivulus paracatuensis n. sp. (Cyprinodontiformes: Rivulidae):a new rivuline species from the Rio São Francisco basin, Brazil, pp. 39-43
Rivulus paracatuensis n. sp. is described from a small stream in the Rio Paracatú floodplains, Rio São Francisco basin, Minas Gerais, Brazil. It was previously misidentified as R. decoratus, the only other species of the genus occurring in the São Francisco basin, but described from Ibiraba, Bahia, which is about 1,000 km north of the Rio Paracatú. The new species is easily distinguished from R. decoratus by having more dorsal, caudal and pectoral fin rays, more vertebrae, more scales in the longitudinal series and more scale rows around the caudal peduncle, a wider basihyal, and a distinct male colour pattern.
Rivulus paracatuensis, MCP 29637, male, holotype, 22.5 mm SL; Brazil: Minas Gerais: Brasilândia de Minas. Photo by W. J. E. M. Costa