Bidessus apicidens Biström & Sanfilippo, 1986

Bergsten, Johannes, Ranarilalatiana, Tolotra & Biström, Olof, 2020, A new species of Bidessus from Anjozorobe-Angavo and a review of Malagasy Bidessus (Coleoptera, Dytiscidae), European Journal of Taxonomy 720, pp. 1-18 : 3-5

Bidessus apicidens Biström & Sanfilippo, 1986

Figs 1A , 3A

Bidessus apicidens Biström & Sanfilippo, 1986: 46 .

Bidessus apicidens – Rocchi 1991: 85. — Nilsson 2001: 114. — Nilsson & Hajek 2020: 104.

Diagnostic characters

Head frontally not margined. Slightly posterior to frontal edge with a shallow, transverse depression, which medially is vague but still clearly discernible. Pronotum on disc with fine to very fine and sparse punctures (no clearly impunctate area). Pronotal striae at base strongly impressed; striae sinuate (not angled). Basal elytral striae quite long (length of stria almost half the length of elytra). Sutural lines in part vague; frontally and especially, posteriorly the lines are transformed to rows of punctures. Moreover, posteriorly, sutural row fades away; mixed with ordinary elytra punctures. Punctures on each side of elytral striae unequal; between sutural line and elytral stria punctures quite coarse, dense but somewhat irregularly distributed; outside elytral stria punctures distinctly finer and somewhat sparser. Last ventrite of female with a distinct, medial depression which is delimited by distinct, narrow and longitudinal keels. Female elytra outline posteriorly with a small but distinct, lateral expansion (unique character in Bidessus of Madagascar). Penis in lateral view quite slender, curved but medially slightly straightened. Penis apex not distinctly extended ( Fig. 3A ).

Length of body 1.7 mm.

Material examined

Paratype

MADAGASCAR • 1 ♀; “envir. de Moramanga” [around Moramanga]; “(Q. 1000 c.a)” [1000 m a.s.l.]; 21 Jul. 1970; N. Sanfilippo leg.; FMNH .

Distribution

Endemic species to Madagascar and only known from around Antsirabe and Moramanga ( Fig. 4D ). Collecting circumstances poorly known. Sampled at mid (1000 m a.s.l.) and high (1600 m a.s.l.) elevations. Only two specimens are so far known.

Figures

Fig. 1. Habitus photographs of Malagasy species of Bidessus Sharp, 1882. A. B. apicidens Bistr̂m & Sanfilippo, 1986, ♀, paratype, http://id.luomus.fi/GL.8408 (FMNH). B. B. cf. ceratus Guignot, 1941, http://id.luomus.fi/GC.2001 (FMNH). C. B. anjozorobe sp. nov., paratype (NHRS-JLKB000025034). D. B. cf. nero Gschwendtner, 1933 (NHRS-JLKB000025032).

Fig. 3. Male genitalia of the Malagasy species of Bidessus Sharp, 1882. For each subpanel from left to right penis in dorsal view, penis in lateral view and paramere in lateral view. A. B. apicidens Bistr̂m & Sanfilippo, 1986. B. B. cf. ceratus Guignot, 1941. C. B. anjozorobe sp. nov. D. B. cf. nero Gschwendtner, 1933. E. B. nesioticus Guignot, 1956. F. B. perexiguus Kolbe, 1883. G. B. longistriga Régimbart, 1895.

Fig. 4. Distribution maps of the Malagasy species of Bidessus Sharp, 1882. A. B. longistriga Régimbart, 1895. B. B. perexiguus Kolbe, 1883. C. B. cf. nero Gschwendtner, 1933 (circle), B. nesioticus Guignot, 1956 (square), B. anjozorobe sp. nov. (triangle). D. B. apicidens Biström & Sanfilippo, 1986 (square), B. cf. ceratus Guignot, 1941 (circle).