A revision of Rhombodineutus Ochs in New Guinea (Coleoptera: Gyrinidae)

Abstract

Genus-group taxon Rhombodineutus Ochs, 1926 is related to Paracyclous Ochs (Indonesia) and Callistodineutus Ochs (Melanesia), classified under Dineutus MacLeay. It occurs in New Guinea and New Britain Island, inhabiting streams and rivers primarily at low and medium altitudes where the species may occur abundantly. Most species live in the forests and have a fairly restricted range, while D. pectoralis Régimbart has passed a niche shift and adapted to exposed and exploited land and spread widely, splitting into a considerable number of races, some of which were found at an elevation of 1500-2000 m. The morphological characters are reviewed and their differentiation examined as a background for the classification of the taxon and a revision of its species which have been placed in three groups, containing 8 species and 11 subspecies. One new species and four new subspecies are described. Keys are provided to the various groups of taxa.

Notes on Dineutus helleri Ochs, 1925, with new records for the Cyclops Mountains Whirligig Beetle, Dineutus h. stueberi Ochs, 1955 (Coleoptera, Gyrinidae)

“…Dineutus helleri stueberi is sympatric with another New Guinea endemic species, Dineutus t. tetracanthus Régimbart, 1906(Brinck 1983. However, we did not observe the latter species in the Cyclops Mountains.…”

“…Data from Brinck (1983) Ochs (1925Ochs ( , 1955, the redescription and identification key by Brinck (1983), as well as the study of reference specimens from the Torricelli Mountains in Papua New Guinea, housed in the Natural History Museum London. Diagnosis (adopted from Brinck 1983). Body length: ♂ 12.8-18.0 mm, ♀ 13.0-15.7 mm; habitus convex (Fig.…”

Morphological variation in Gyrinus sericeolimbatus Rég. in New Guinea and description of a new Gyrinus species (Coleoptera: Gyrinidae)

“…Other genera of Gyrinidae have been investigated carefully in New Guinea, and at least one species, Dineutus pectoralis RCg., has undergone a great differentiation at the subspecies level (Brinck, 1983). Other unstable species are known from other regions, e.g.…”

“…In the near future, these devclopnients may drastically change the distribution and genetic constitution o f many populations of G.sericeolirrrbatus and other gyrinids, owing t o new selection pressures and a probably increased gene flow betwccn formerly isolated populations (ef. Brinck. 1983).…”

Review of Mecyclothorax Sharp (Coleoptera: Carabidae: Moriomorphini) from Papua New Guinea, with Descriptions of Five New Species

“…Information for Zygoptera was extracted from the publications of Lieftinck (1932Lieftinck ( , 1933Lieftinck ( , 1935Lieftinck ( , 1937Lieftinck ( , 1938Lieftinck ( , 1949aLieftinck ( , 1949bLieftinck ( , 1955aLieftinck ( , 1955bLieftinck ( , 1956aLieftinck ( , 1956bLieftinck ( , 1957Lieftinck ( , 1958Lieftinck ( , 1959aLieftinck ( , 1959bLieftinck ( , 1960Lieftinck ( , 1963, information for Gyrinidae from the works of Brinck (1976Brinck ( , 1981Brinck ( , 1983Brinck ( , 1984, and information for Heteroptera primarily from the works of Andersen (1975Andersen ( , 1989aAndersen ( , 1989b, Lansbury (1966Lansbury ( , 1968aLansbury ( , 1972Lansbury ( , 1973Lansbury ( , 1993Lansbury ( , 1996, Polhemus & Polhemus (1985, 1986a, 1986b, 1987, 1993, 1994a, 1994b, 1995, 1996, 2000a. 2000b, 2000c, and Todd (1959).…”