Diastatotropis elegans Frieser, 1992

Diastatotropis elegans Frieser, 1992

( Figs 1–24 View FIGURES 1–3 View FIGURES 4–8 View FIGURES 9–14 View FIGURES 15–19 View FIGURES 20–24 )

Diastatotropis elegans Frieser, 1992: 47 (as ‘ Diastatotropis elegans Fairm. ’)

Diastatotropis elegans : Trýzna & Baňař (2016): 435 (key); Trýzna (2024): 340 (image list).

Type locality. ‘Madagascar’.

Type material. Holotype ( Figs 1–3 View FIGURES 1–3 ): ♀, labelled: ‘ Diastatotropis / elegans / Fm [Fairmaire] Madag [ Madagascar] [h] // xxx [sic] [h] // MUSEUM PARIS / Collection Léon Fairmaire / 1906 [p, typical blue acquisition label of MNHN] // HOLOTYPUS / DIASTATOTROPIS / ELEGANS Frieser, 1992 / designated: Frieser (1992) / labelled: Trýzna & Kment, 2024 [p, red rectangular label] ( MNHN) .

Other material examined. 1 ♂, 4 ♀♀: N Madagascar, Montagne d’Ambre N.P., nr. Joffreville , circ. Mille Arbre, S 12°31′17″; E 49°10′31″, 1061 m, 7.–16.i.2015, M. Trýzna leg. (♀ in Figs 15–19 View FIGURES 15–19 ; MTDC; 1 ♀ in NMPC, 1 ♀ in CMNC) GoogleMaps ; 1 ♂, 3 ♀♀: N Madagascar, Montagne d’Ambre Nat. Park , circ. Mille Arbres, S 12°31′08.860″; E 49°10′30.352″, 1086 m, 10.–19.i.2016, M. Trýzna leg. ( MTDC) GoogleMaps ; 4 ♂♂, 1 ♀: N Madagascar, Montagne d’Ambre N.P., circ. Mille Arbre , S 12°31′10″; E 49°10′31″, 1069 m, 4.–8.xii.2019, M. Trýzna leg. (♂ in Figs 4–8 View FIGURES 4–8 ; MTDC; 1 ♂ in NMPC, 1 ♂ in CMNC) GoogleMaps ; 2 ♂♂: Amber Geb., XI./XII., Karl Jordan Coll., B.M. 1940-109. ( BMNH) ; 1 ♂ (without pronotum and head): Amber Geb. , Karl Jordan Coll., B.M. 1940-109. ( BMNH) ; 1 ♀: Diego Suarez , Karl Jordan Coll., B.M. 1940-109. ( BMNH) ; 1 ♀: Diego Suarez , Karl Jordan Coll., B.M. 1940-109., Diastatotropis elegans Fairm. , ubi?? [= where??] ( BMNH) ; 2 ♂♂, 1 ♀: Muséum Paris , Madagascar, coll. Sicard, 1930 [typical blue acquisition label of MNHN] ( MNHN) .

Diagnosis. Small to medium-sized (ca. 7–11 mm), elongate species. Rostrum with two distinct lateral longitudinal carinae, reaching to line of central part of antennal scrobes anteriorly and to anterior margin of eyes posteriorly, and one short central longitudinal carina reaching only to middle of rostrum. Antennal club slender and cylindrical. Terminal segment elongate-oval, distinctly longer than wide. Antennomere 10 as long as wide. Entire body brown. Pronotum with longitudinal stripe in central part continuing to pronotal declivity, stripe can be narrowed or completely interrupted in central part, and has four spots: one pair on lateral part of pronotum just above lateral carina and the second pair on lateral part of pronotal declivity. Sub-basal tubercles of elytra high and conspicuous. Elytral interstriae flat, each elytron with large transverse yellow spot behind sub-basal tubercle, reaching from interstriae 1 to 9 and four small yellow spots on interstriae 2 and 8 on median and preapical part. Pygidium with longitudinal yellow stripe in proximal part.

Redescription. Coloration of the cuticle blackish to black, mandibles black, antennomeres and legs dark brown.

Vestiture. Head ( Figs 5 View FIGURES 4–8 , 16 View FIGURES 15–19 ) with dense brownish appressed setae, inner margins of eyes with conspicuous yellow longitudinal stripes expanding backwards, narrower stripe also on underside of eyes. Labrum yellowish with a few longer light setae. Antennae ( Figs 7 View FIGURES 4–8 , 18 View FIGURES 15–19 ) with indistinct light pubescence, only with very short, soft, sparse setae. Disc of pronotum ( Figs 6 View FIGURES 4–8 , 17 View FIGURES 15–19 ) with fine sculpture, covered with indistinct brown dense setae. In central part of pronotum longitudinal yellow stripe continuing to pronotal declivity, stripe can be narrowed or completely interrupted in its central part. Pronotal declivity also with two yellow spots on lateral sides. Elytra ( Figs 4 View FIGURES 4–8 , 15 View FIGURES 15–19 ) with short dense delicate brownish and blackish setae. Each elytron (before sub-basal tubercle) with one yellow spot in humeral part extended from third to fifth elytral interstria, with large transverse yellow spot behind sub-basal tubercle, reaching from interstria 1 to 9, and with four small yellow spots on interstriae 2 and 8 on median and preapical part. The second interstria (including sub-basal tubercles) significantly darker along entire length than other interstriae. Scutellum yellow. Pygidium with longitudinal yellow stripe or spot in proximal part. All spots or bands on upper side of body clearly bordered, covered with dense bright yellow setae. Femora ( Figs 4 View FIGURES 4–8 , 15 View FIGURES 15–19 ) covered with dense delicate brownish to yellowish setae, tibiae covered with dense brown setae appressed in proximal part and subdecumbent in distal part. All tibiae with yellowish stripe in proximal third interrupted in ventral part. Tarsomeres with brownish setae. Venter of thorax and abdominal sternites with dense pubescence of short dense delicate setae. Pygidium covered with short dense brown appressed setae, central yellowish stripe or spot only in proximal part of pygidium.

Structure. Head ( Figs 5 View FIGURES 4–8 , 16 View FIGURES 15–19 ) rather long, rostrum slightly wider than long, ratio of rostrum length to maximum width ca. 0.85 in both sexes. Rostrum straight in lateral view. Lateral sides of rostrum weakly extended apically. Dorsal part of rostrum with two longitudinal carinae, not extending to distal part of rostrum, but reaching anterior margin of eyes, and one short central longitudinal carina only reaching middle of rostrum. Area between lateral carinae depressed. Upper side of rostrum with moderately coarse sculpture, area between eyes and frons rather longitudinally wrinkled. Eyes elliptical, not emarginate, dorsal ocular index ca. 1.46 in male, 1.57 in female. Antennae ( Figs 7 View FIGURES 4–8 , 18 View FIGURES 15–19 ) short in both sexes, reaching only to ca. half of length of pronotum. Antennal club slender and cylindrical. Scape only slightly swollen, indistinctly wider than pedicel, antennomeres 3–6 slender than pedicel, 7 equally wide, 8 wider, 9–11 forming distinct longitudinal club: 9 and 11 longer than wide, 10 slightly wider than long.

Pronotum ( Figs 6 View FIGURES 4–8 , 17 View FIGURES 15–19 ) slightly transverse, ratio of its length to width at carina 0.85 in male, 0.79 in female, the widest in dorsal transverse carina, then narrowed to distal part. Disc of pronotum flat, without any imprint. Dorsal transverse carina of pronotum form wide arch or only slightly bisinuate laterally, in same specimens shortly and indistinctly interrupted in middle. Lateral carina of pronotum well-developed but short, scarcely reaching to half of pronotum, widely rounded at contact with dorsal transverse carina.

Elytra ( Figs 4, 8 View FIGURES 4–8 , 15, 19 View FIGURES 15–19 ) longitudinal, with distinct sub-basal tubercles, disc of elytra without imprint. Ratio of the maximum length to maximum width of elytra ca. 1.67 in male, 1.62 in female. Elytral interstriae completely flat, dorsal punctures very small and inconspicuous, their diameter much smaller than distance of individual punctures.

Claws without teeth. Pygidium transverse, ratio of the maximum length to maximum width 0.89 in male, 0.85 in female.

Genitalia and associated structures. Male terminalia ( Figs 9–14 View FIGURES 9–14 ). Sternite 8 ( Fig. 14 View FIGURES 9–14 ) slightly bilobed, its halves close to each other, but with clear central line. Tergite 8 ( Fig. 14 View FIGURES 9–14 ) overlapping sternite 8 anteriorly, widely rounded at apex. Sternite 9 (= spiculum gastrale) as in Fig. 14 View FIGURES 9–14 . Aedeagus ( Figs 9–11 View FIGURES 9–14 ) relatively wide. Tectum ( Fig. 11 View FIGURES 9–14 ) overlapping pedon, arrow-shaped, apex of tectum protruding into a small ball; pedon significantly wider compared to tectum, rectangular, apex of pedon straight. Apodemes of aedeagus ( Figs 9–10 View FIGURES 9–14 ) parallel. Tegmen ( Figs 12–13 View FIGURES 9–14 ) subtle, tegminal plate slender, equally wide along its entire length, apex of plate rounded, with group of short dense setae. Apodeme of tegmen rather shorter.

Female terminalia ( Figs 20–24 View FIGURES 20–24 ). Ovipositor short and wide, lateral rods diverging. Hemisternites ( Figs 21–22 View FIGURES 20–24 ) armed, with distinct toothed plates, each plate with three distinct teeth outwardly oriented. Tergite 8 ( Fig. 23 View FIGURES 20–24 , left) longer than wider, its anterior margin distinctly trilobed, each lobe with long setae apically. Sternite 8 ( Fig. 23 View FIGURES 20–24 , right) transverse, with anterior margin slightly convex in middle, and with sclerotized apodeme, anterior margin with shorter numerous setae along entire length. Shape of spermatheca as in Fig. 24 View FIGURES 20–24 .

Sexual dimorphism. Body comparatively more slender in males than in females, eyes of male slightly longer, male abdominal ventrites flat in middle.

Variability. Indistinct. Size of body ca. 7–11 mm. Specimens may slightly vary in shape of dorsal transverse carina of pronotum which is sometimes interrupted in middle. Location and shape of pronotal and elytral spots is mostly constant with only minimal variability.

Differential diagnosis. Diastatotropis elegans belongs to the group of species with the antennal club slender and cylindrical, the terminal segment is elongate-oval, always distinctly longer than wide, and antennomere 10 more or less as long as wide (not distinctly wider than long). Only Diastatotropis tessellata Fairmaire, 1897 from this group also has sub-basal tubercles on the elytra; however, these tubercles are poorly developed, blunt, rounded on apex in D. tessellata , while in D. elegans they are well developed, prominent and pointed apically. Diastatotropis tessellata also has a completely different colour pattern, elytra are spotted and tessellated: even-numbered interstriae with alternating areas of blackish, brownish and yellowish, while odd-numbered interstriae have monochromatic brownish colour.

Distribution. Diastatotropis elegans is so far known only from northern Madagascar, from Montagne d’Ambre National Park. All historical specimens labelled with exact locality data come only from this area. The specimens labelled as ‘Diego Suarez’ in BMNH undoubtedly come from Montagne d’Ambre, since this city, known today as Antsiranana, is located in its immediate vicinity. Also, the senior author (MT) found this species exclusively in Montagne d’Ambre National Park during his 11 expeditions focused on collecting Malagasy anthribids. Thus, we cautiously consider D. elegans to be endemic to the Montagne d’Ambre area.

Biology and collecting circumstances. The first author had the opportunity to observe and collect D. elegans in Montagne d’Ambre National Park ( Figs 25–26 View FIGURES 25–26 ), northern Madagascar (IUCN category: II, national park). The park extends from elevations of 750–1474 m a.s.l., with the margins of the park descending to 250 m a.s.l. Antsiranana (formerly Diego Suarez), the capital of the Diana region, is only 20 km distant from the national park. The protected area is dominated by a sub-humid climate, with an annual average rainfall of around 1400–3000 mm (depends on elevation). The area receives much more precipitation than neighbouring regions, 92% of which falls between November and April ( Goodman et al. 2018). The presence of numerous craters points to the massif’s volcanic nature. Most of the area is covered by intact medium elevation moist evergreen forest, generally of high stature, with a canopy up to 25 m high. The frequent impact of cyclones is apparent by the presence of felled trees, open sunny forest glades, and also overgrown dense stands. For more details of the area see Goodman et al. (2018).

All specimens were collected at elevations of 1061–1086 m a.s.l. above Ambohitra (Joffreville) village. The adults were found on dead wood within an intact forest, but surprisingly always on thin twigs up to 4 cm in diameter. The species was found repeatedly in 2015, 2016 and 2019, but only a few specimens were found each time. This species must be considered as rare, which also corresponds to its poor representation in collections.