Neobidessus obtusoides Young, 1977

Scheers, Kevin & Thomaes, Arno, 2022, A preliminary checklist of the minute diving beetles of Belize (Coleoptera: Dytiscidae: Bidessini), Belgian Journal of Entomology 125, pp. 1-15 : 11-12

Neobidessus obtusoides Young, 1977

STUDIED MATERIAL. BELIZE DISTRICT: La Democracia , ditch next to road, 17°21'38,7"N, 88°32'42,1"W, 09. V.2015, Leg. K. Scheers & A. Thomaes (6 ex.) ; La Democracia, ditch next to road, 17°21'38,7"N, 88°32'42,1"W, 10. V.2015, Leg. K. Scheers & A. Thomaes (2 ex.); TOLEDO: Deep River Forest Reserve , pond savannah, 16°31'11,7"N, 88°42'3,8"W, 19.IV.2015, Leg. K. Scheers & A. Thomaes (13 ex.) ; Deep River Forest Reserve , pond savannah, 16°31'14,2"N, 88°42'5,6"W, 19.IV.2015, Leg. K. Scheers & A. Thomaes (8 ex.) ; Deep River Forest Reserve , pond savannah, 16°31'35,5"N, 88°42'23,6"W, 20.IV.2015, Leg. K. Scheers & A. Thomaes (1 ex.) ; Deep River Forest Reserve , pond savannah, 16°31'42,7"N, 88°42'31,6"W, 20.IV.2015, Leg. K. Scheers & A. Thomaes (2 ex.) ; Indian Creek, Lake of former Lodge , 16°18'45,1"N, 88°49'31,4"W, 29.IV.2015, Leg. K. Scheers & A. Thomaes (1 ex.) .

DISTRIBUTION. Belize (first record), Mexico ( YOUNG, 1977). In Belize this species was found in Belize district and the northern half of the Toledo district ( Fig. 2 I ).

HABITAT. N. obtusoides seems to be restricted to ponds, ditches etc. in the savannah of central and north Belize. In the Bladen Nature Reserve and the Deep River Forest Reserve the species was present in nearly all sampled ponds in the savannah ( Fig. 3 ) whilst completely absent in the forest and the transition vegetation in between. In all six sites where N. obtusiodes was present it co-occurred with the common Bidessonotus vicinus and in five out of the six also with Anodocheilus francescae .

NOTE. YOUNG (1977) mentioned that this species seems to be isolated in the central plateau of Mexico and noted that it may be only a subspecies of Neobidessus pullus (LeConte, 1855) . The male genitalia are, however, distinct, and in the specimens studied from Belize there does not seem to be any variation regarding the male genitalia. In Belize this species is present in two forms; the typical form in which the elytra are yellow with contrasting black vittae and another form which is uniformly brown. The occurrence of these two forms is also documented for N. pullus and discussed in more detail by YOUNG (1977).

Figures

Fig. 2. Distribution of Bidessini in Belize: A, Anodocheilus francescae Young, 1974; B, Anodocheilus guatemalensis (Zaitzev, 1910); C, Bidessodes elongatus (Sharp, 1882); D, Bidessonotus caraibus (Chevrolat, 1863); E, Bidessonotus mexicanus Régimbart, 1895; F, Bidessonotus mobilis J. Balfour-Browne, 1947; G, Bidessonotus pollostus Young, 1990; H, Bidessonotus vicinus Young, 1990; I, Neobidessus obtusoides Young, 1977; J, Neobidessus persimilis (Régimbart, 1895); K, Uvarus spretus (Sharp, 1882). Yellow dots indicate literature records and red dots studied material.

Fig. 3. Pond in the savannah of the Deep River Forest Reserve (Toledo), the typical habitat of Anodocheilus francescae and Neobidessus obtusoides. At this site both species co-occurred with Bidessonotus vicinus. © Kevin Scheers.