Incoltorrida magna, Perkins & Bergsten, 2019

Perkins, Philip D. & Bergsten, Johannes, 2019, New Myxophagan water beetles from Madagascar (Coleoptera: Torridincolidae, Hydroscaphidae), Zootaxa 4657 (1), pp. 57-96 : 76

Incoltorrida magna , new species

Figs. 3, 4 , 10 (habitus); 21 (genitalia); 36 (map); 40 (habitat)

Type Material. Holotype (male): Antsiranana, Diana: Antsaba: Galoko mountains , 3.4 km NW from Anstaba, S13.60931 E48.72129, aspirator, forceps, sieves: hygropetric rocks and pools, elev. 296 m, 28 xi 2012, elev. 296 m, 28 xi 2012, J. Bergsten, R. Bukontaite, J.H. Randriamihaja & T. Ranarilalatiana ( MAD12-31 ) ( NHRS) . Paratypes (36): Same data as holotype (1 NHRS) ; Antsiranana, Anjiabe Ambony: Ambilobe: Antsabe stairways-like cascade with vertical (!) steps, exposed, extremely hot day, N: -13.60930 E: 48.72120, elev. 303 m, 23 xi 2004, Balke et al. (P25 MD16 ) (35 BMNH, NHRS, MCZ, PBZT / MBC; 2 DNA extractions, #’s BMNH 670732 , BMNH 670733 ) .

Differential Diagnosis. This is the largest known Incoltorrida species: l/w ca. 2.62/1.58. The elytral serial punctures are very distinct, as is the transverse ridge that links costae #5 and #8. The pronotum lacks the basal ridges seen in I. quintacostata , I. benesculpta , and I. madagassica . It is much larger than I. marojejy (2.62 vs. 2.19); I. marojejy lacks the pronotal midlongitudinal carina that is present in I. magna , and the frons plate is shaped differently in the two species. The male genitalia ( Fig. 21 ) distinctively differ from that of the other species in the genus. See also the diagnosis of I. madagassica .

Description. Size: holotype (length/width, mm): body (length to elytral apices) 2.62/1.58; head width 0.50; pronotum 0.55/1.12; elytra 1.78/1.58. Dorsum dark brown to black, venter brown to reddish brown, legs brown to reddish brown except tarsi and femoral-tibial articulations black.

Frontoclypeal shield narrowest at anterior 1/3, with sides of frons slightly arcuate; apical 1/3 is slightly wider than area of frontoclypeal suture.

Short oblique carinae on anterior 1/3 of pronotum are well developed; a midlongitudinal carina is present, though not as developed as the oblique carinae; the area posterior to the carinae is transversely rounded and shows no indication of ridges or depressions, except for a basal impression in front of scutellum.

Elytra quite convex, declivity steep. Each elytron with eight wide and high costae; #4 continuous, not interrupted by punctures; #5 weakly bisinuate; #6 and #7 distinct, though crossed by transverse ridge that connects #5 and #8. Second transverse ridge links #3 and #5, in nearly same plane as the #5-#8 ridge.

Posterior 1/2 of metaventral tabella without distinctive, closely spaced transverse grooves; midlongitudinal groove in posterior 1/2 of metaventral tabella narrow and parallel-sided.

Midlongitudinal carina of first abdominal ventrite not especially strong and extends only 1/2 length of ventrite.

Male genitalia in lateral view distinctively arcuate; in ventral view widest at about apical 1/4, and then narrowed, with tips pointing slightly outward ( Fig. 21 ).

Etymology. Named in reference to the relatively large size.

Remarks. DNA sequences of partial CO1 (Acc. Nos. FJ819703 ( BMNH 670732) and FJ819702 ( BMNH 670733)) and partial 28S ( FJ 818159 ( BMNH 670732) and FJ818158 ( BMNH 670733)) published by Monaghan et al. (2009) are based on adult specimens, and are available in Genbank.

Figures

FIGURE 10. Incoltorrida magna, habitus views of holotype.

FIGURES 2–4. Dorsal morphology. (2) Incoltorrida quintacostata; (3–4) I. magna.

FIGURES 21–22. Incoltorrida, male genitalia of holotypes. (21) I. magna; (22) I. marojejy.