Dineutus (Rhombodineutus) tetracanthus tetracanthus Régimbart, 1906

Polhemus, Dan A., 2011, New distributional records for Gyrinidae (Insecta: Coleoptera) on New Guinea and nearby islands, with a checklist of the New Guinea species, Zootaxa 2900, pp. 51-68 : 61

Dineutus (Rhombodineutus) tetracanthus tetracanthus Régimbart, 1906

Fig. 5

Dineutes tetracanthus Régimbart, 1906: 21 .

Dineutus (Rhombodineutus) tetracanthus: Ochs, 1926: 70 .

Material examined. INDONESIA, Papua Prov. [= former Irian Jaya Prov.]: 7 males, 12 females, Wapoga River basin, Tirawiwa River and overflow channel at abandoned Wapoga Timber Company camp, 2.0 km. S. of PTFI Siewa exploration camp, 60 m. [200 ft.], 3°03'20"S, 136°23'31"E, water temp. 27° C., 10 April 1998, 08:30–11:30 hrs., CL 7094, D. A. Polhemus ( USNM); 2 females, Mamberamo River basin, Tiri River (trib. to Doorman River), 4.5 km. SW of Dabra, 80 m. [260 ft.], 3°17'30"S, 138°34'53"E, water temp. 25 °C., 12 September 2000, CL 7140, D. A. Polhemus ( USNM).

Discussion. This taxon has a rather broad distribution in the northwestern portion of the main body of New Guinea, occurring from the Bewani and Cyclops Mountains westward along the margins of the Mamberamo Basin to the Wapoga River Basin ( Fig. 5 ).

The Tiri River locality near Dabra at which this species was taken was a moderately swift, sand bottomed stream with pools 0.5–1.5 m. deep, alternating with shallow cobble riffles. The channel width varied from 2– 5 m., with the central portion of the channel unshaded, and the margins half shaded by undisturbed lowland rain forest. For a description of the Tirawiwa River locality listed below see the discussion under Dineutus (Rhombodineutus) heurni . At this latter site, Dineutus (Rhombodineutus) tetracanthus was syntopic with both Dineutus (Rhombodineutus) heurni and Dineutus (Rhombodineutus) sinuaticollis . Based on known collections, this subspecies occupies the Mamberamo Foreland area of freshwater endemism (Area 17) as defined by Polhemus & Allen (2007).

This species, in combination with Dineutus (Rhombodineutus) heurni and Dineutus (Rhombodineutus) sinuaticollis , was grouped under the composite listing of “ Rhombodinetus sp. undet.” from Station 50 in Polhemus (2000).

Figures

FIGURE 5. Distribution of certain Dineutus (Rhombodineutus) species and subspecies on New Guinea. Symbols with grey centers represent previous records; symbols with black centers represent new records presented in this paper.