A new species of Mantidactylus (subgenus Guibemantis) from Madagascar,with a comparative survey of internal femoral gland structure in the genus (Amphibia: Ranidae: Mantellinae)

A new species of Mantidactylus (subgenus Guibemantis) from the rainforests of eastern Madagascar is described. The new species is sympatric with the closely related M. depressiceps (Boulenger, 1882) and M. tornieri (Ahl, 1929) but differs by larger size, a more strongly developed prepollex, and by advertisement calls. Mantidactylus acuticeps Ahl, 1929 and Rhacophorus mocquardii Boulenger, 1896 are confirmed to be junior synonyms of M. depressiceps. The presence of distinct femoral glands in the new species was noted; a feature so far not reliably recognized in other members of the subgenus Guibemantis. Femoral gland structure was investigated in representatives of each of the subgenera included in Mantidactylus by dissecting and reflecting the femoral skin. Four femoral gland types were identified. Type 1: many small, single granules in an ill-delimited patch, grouped in rosettes at the patch edges; type 2: a group of moderately sized granules in a well-delimited patch; type 3: comprising two different structures: distal granules enclosing externally a distinct central depression, and smaller proximal granules or groups of granules; type 4: as type 3, but lacking the proximal granules. Mantidactylus rivicola Vences, Glaw and Andreone, 1997, M. cf. malagasius (Methuen and Hewitt, 1913) and M. ventrimaculatus (Angel, 1935) differed from all other species examined; their femoral glands comprise a reduced number of large granules with an indistinct central depression in external view. The presence of a distal granule group with external central depression (types 3 and 4 above) provides a probable synapomorphy for the subgenera Brygoomantis, Ochthomantis, Hylobatrachus, Chonomantis and Mantidactylus. In females of these subgenera rudimentary femoral glands are present, but they lack completely in females of the other groups.     

Sibling species in the marine pollution indicator genus Pontonema Leidy (Nematoda: Oncholaimidae), with a description of P. mediterranea sp. nov.

Species of the marine nematode genus Pontonema have been found to dominate the macrobenthos under abnormally high conditions of particulate organic enrichment. Populations from organically enriched habitats in six localities (Kiel fjord, Germany; the Garroch Head sewage-sludge dump ground in the Firth of Clyde, Scotland; Cornelian Bay, N.E. England; the Tyne estuary, N.E. England; Sete, N.W. Mediterranean, France; Blanes Bay, N.W. Mediterranean, Spain) have been compared. Multivariate analyses of 16 morphometric characters in males, and 13 in females, shows that each population is significantly different morphologically from every other population. However, there is morphological overlap between the populations, and it is considered pragmatic to recognize three species in this group, based on a few stable morphological characters: P. vulgare (Bastian, 1865) from the Baltic, P. alaeospicula Bett and Moore 1988 from the UK sites, and P. mediterranea sp. nov. from the Mediterranean. P. mediterranea sp. nov. is described. The species were not found to have established sympatry in this study, unlike many other opportunistic taxa from organically enriched habitats, and the significance of this is discussed.     

Larval development of the circular crab,Atelecyclus rotundatus (Olivi) (Crustacea: Brachyura: Atelecyclidae) reared in the laboratory

The complete larval development is described of laboratory-reared Atelecyclus rotundatus and the stages are compared with larvae of other cancrideans (= corystoideans). The results suggest that the subfamily Atelecyclinae requires reappraising and that present larval evidence does not support the currently accepted grouping of families in the Cancridea.