Incoltorrida madagassica Steffan, 1973

Perkins, Philip D. & Bergsten, Johannes, 2019, New Myxophagan water beetles from Madagascar (Coleoptera: Torridincolidae, Hydroscaphidae), Zootaxa 4657 (1), pp. 57-96 : 64-67

Incoltorrida madagassica Steffan

Figs. 5 , 6 (habitus); 14, 15, 19 (genitalia); 38 (map); 48, 49 (habitat)

Incoltorrida madagassica Steffan 1973: 635 .

Type material: Holotype (male) with labels: “ HOLOTYPUS [red]// Madagascar (65) Cap Ambalasandra H. BERTRAND , 29.III.60 //MUS. ROY. AFR. CENTR. caput fehlt! TO-ma-03. mikr prap: 03.01. = genital// Incoltorrida madagassica STEFFAN 1973 HOLOTYPUS male [red].” Now deposited, with permanent microslide of male genitalia, in MNHN; see remarks.

Material examined (52): Fianarantsoa, 20.7722S 47.1809E; Amoron’i Mania, 3km south of Ambalamanakana next to RN7, Ankazomivady forest , hygropetric rocks and marsh with vegetation, elev. 1700 m, 1 xi 2014, J. Bergsten, T. Ranarilalatiana & S. Holmgren ( MAD 14-02 ) (3 NHRS) . Toamasina: Analanjirofo: S. side of Nosy Mangabe, Masoala National Park , hygropetric rocks by the sea, 15.5056S, 49.7571E, sea level, 20.II.2018, MAD 18- 60 , J. Bergsten & T. Ranarilalatiana (49 NHRS, BMNH, MCZ, PBZT / MBC) .

Differential Diagnosis. Similar in some characters to I. magna ; differing therefrom by smaller size (ca. 2.31 vs. 2.62 mm), less convex elytra with a more gradual posterior declivity, slightly narrower elytral costae, smaller elytral serial punctures, more sinuate fifth elytral costa, and especially differing by having two carinae and a distinct impression between the carinae on the basal 1/2 of the pronotum. The elytron of I. madagassica has two transverse ridges, offset from one another, one linking costae #3 and #5 (located just behind the humeral umbo), and one linking costae #5 and #8 (located at the sinuation dip of costa #5). In I. magna these two ridges are located in the same plane, not offset from one another. The male genitalia of I. madagassica differ from that of I. magna in being less arcuate in lateral view, and shaped differently in ventral view ( Figs. 14, 15 , 19 , 21 ).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 2.31/1.29; head width 0.46; pronotum 0.50/0.96; elytra 1.51/1.29. Dorsum dark brown, venter brown to reddish brown, legs brown to reddish brown except tarsi and femoral-tibial articulations black.

Sides of frontoclypeal shield slightly arcuate toward midline at frontoclypeal suture, narrowest part slightly past midlength of shield, at frontoclypeal suture.

Short oblique carinae on the anterior 1/3 of the pronotum are well developed, but there is no indication of a midlongitudinal carina. Two short carinae and a distinct impression between carinae located on basal 1/2 of pronotum.

Elytron with eight costae; fourth costa interrupted by strong punctures; fifth costa strongly bisinuate; sixth and seventh costae very indistinct. Two transverse ridges, one linking costae #3 and #5 (located just behind the humeral umbo), and one linking costae #5 and #8 (located at the sinuation dip of costa #5).

Posterior 1/2 of metaventral tabella with closely spaced transverse grooves. Midlongitudinal groove in posterior 1/2 of metaventral tabella shallow, with ill-defined margins.

Midlongitudinal carina of first abdominal ventrite is strong and extends length of ventrite.

Male genitalia ( Figs. 14, 15 , 19 ) in lateral view slightly arcuate, aedeagal tips wide, apically rounded and with many pores (apparently without microsetae); in ventral view aedeagus nearly parallel-sided, with narrowed tips.

Remarks. In the original description, Steffan (1973) stated that the holotype was deposited in the MNHN. However, MNHN collection staff were unable to find the type. Search at other museums determined that the holotype was still with the paratypes, at the MRAC. Having permission of that museum, the holotype (fragmentary; Fig. 6 ) and the permanent slide mounted male genitalia were transferred to the MNHN.

In the original description ( Steffan 1973), it is noted by the author that the head of the holotype is missing (“caput fehlt”). However, both the head and the prothorax are missing ( Fig. 6 ). The two paratypes, both females, are from a different locality than the holotype (“Zentrales Hochland auf der Strecke Tananarie - Ambositra”). These paratypes are larger than the holotype and have some sculptural differences; they probably represent a different species.

The original description gives “Cap Ambalasandra” as the type locality. Multiple searches online gave only one record with that geographical name, in a table in a paper on geological deposits. That locality is very near where the Mananara River enters the Indian Ocean ( Fig. 38 ).

Thirty-three larvae were collected in association with adults at site MAD 18-60.

Figures

FIGURE 5. Incoltorrida madagassica Steffan, habitus views of non-type with attached Platycola epibionts.

FIGURE 6. Incoltorrida madagassica Steffan, fragmentary holotype and labels.

FIGURES 14–18. Incoltorrida spp.; (14) I. madagassica, male genitalia of holotype (after Steffan 1973, permanent slide mount). (15–17) male genitalia apex showing pores of I. madagassica and spines of I. benesculpta and I. quintacostata; (18) I. quintacostata, aedeagus of holotype.

FIGURES 19–20. (19) Incoltorrida madagassica, male genitalia of non-type; (20) Incoltorrida benesculpta, male genitalia of holotype.

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

FIGURES 38–39. Distribution maps. (38) Incoltorrida madagassica; (39) Hydroscapha species.