Helophorus (Ropalohelophorus) simiensis, Bilton, 2023

Bilton, David T., 2023, Out of the Palaearctic: the Helophorus water beetles of the Afrotropical Region (Coleoptera: Helophoridae), Acta Entomologica Musei Nationalis Pragae (Acta. Ent. Mus. Natl. Pragae) 63 (2), pp. 249-264 : 261-262

Helophorus (Ropalohelophorus) simiensis sp. nov.

( Figs 1G , 2L , 3F , 5 )

Type locality. Ethiopia, Gondar province, Simien Mountains, Inatye (Enatye) plateau, approximately 13°15′N 39°09′E, 4,000 m.

Type material. HOLOTYPE: J, labelled: “ ÄTHIOPIEN: Prov. Gondar // Simien : Inatye 4000m // 17.4.1976 // leg. Löffler ” “1997 // H. aethiopicus Rég. // R.B.Angus det.” [97, name and describer Hw.], with red holotype label ( NMW) . PARATYPES: 1 J 4 ♀♀, same data as holotype, with red paratype labels ( NMW).

Description. Male ( Fig. 1G ). Head dark brown to black, with strong green to gold aeneous reflection; strongly shining. Granules strong, sometimes coalescent, particularly on lateral margins of Y-groove stem; individual granules most strongly developed inside compound eyes and laterally on clypeus. Y-groove deep; floor of stem with dense, coarse, rugose punctures, extending into base of lateral branches, shining as rest of head; stem strongly diverging anteriorly; lateral branches very narrow, particularly over apical 0.5, broadly arcuate laterally in front of eyes. Clypeus strongly elevated in centre; anterior margin almost straight. Labrum with shining, impunctate, basal portion with anterior margin acuminate at centre; anterior portion with coarse, rugose punctures, each puncture bearing a short, stout, whitish semi-erect seta; anterior margin arcuate with small anteromedian emargination. Antennae 9-segmented, yellowish brown, with cupule and club segments darker. Maxillary palpi yellow, apex of terminal segment infuscated; moderately elongate, terminal segment longest, curved and clearly asymmetrical.

Pronotum ( Fig. 3F ) reddish brown, with strong green to golden aeneous reflections, particularly on internal and middle intervals; anterior border narrowly and lateral borders more widely paler, yellowish brown; shining over entire dorsal surface. Broadest between middle and anterior margins; weakly arched in frontal and dorsal views and somewhat flattened over internal intervals, particularly anteriorly. Anterior margin slightly concave over central 0.3, then sinuate to broadly rounded front angles; posterior margin broadly bisinuate around centre. Sides straight over posterior 0.4, then weakly arcuate around broadest point to anterior angles. Lateral margins setose and weakly crenulated to serrate. Internal intervals distinctly arched, middle intervals relatively flat, strongly shining; granules distinct, but often partly coalescent with adjacent ones. External interval, with distinct granules, surface strongly shining. Grooves smooth and shining, with coarse, shallow punctures, giving a somewhat rugose appearance in places. Median groove narrowed anteriorly and posteriorly, open at both ends more widely so posteriorly. Submedian and submarginal grooves broadly open anteriorly and posteriorly. Submedian grooves relatively narrow and arcuate. Submarginal grooves weakly arcuate, broader than submedian. Marginal grooves curved parallel to the side of pronotum, width uniform. All grooves relatively shallow, with intervals curving down towards their margins, which are well-defined but somewhat sloping rather than vertical.

Elytra ( Fig. 1G ) brown, with diffuse paler markings, particularly posteriorly. Shape elongate oval, sides rounded to bluntly rounded apex. In lateral profile flat over anterior 0.5, then gradually descending to apex. Puncture rows moderately striate, particularly laterally; intervals relatively broad and weakly arched, particularly so laterally.

Legs yellowish-brown, apex of last tarsal segment and claws infuscated. Swimming hairs distinct and clearly visible.

Venter black, with pronotal hypomeron, antennal pocket and pseudepipleura and epipleura brown. Mentum shining, centre without microreticulation, with sparse, medium punctures; lateral marginal areas with weak isodiametric microreticulation centrally; margins with fine yellow setae, denser towards posterolateral angles. Submentum shining, without microreticulation; anterior 0.5 with sparse, shallow, coarse punctures and fine, hair-like vestiture. Gula and genae rugose, with dense hydrofuge vestiture. Gular sutures well marked as pits anteriorly. Vestiture only absent around margin of compound eyes and their posterolateral corners. Prosternum dull, rugose, with dense hydrofuge vestiture and sparse, long, erect setae approximately 2× length of vestiture. Pronotal hypomeron dull, with dense hydrofuge vestiture. Pronotal epipleura shining, glabrous, with sparse shallow punctures. Anterior antennal pocket well developed, with long, dense setae internally and long, curved setae at posterolateral margins. Elytral epipleura dull, glabrous, narrowing posteriorly at level of metaventrite and continuing until posterior margin of ventrite. Elytral flanks not visible from below. Ventral surface of mesothorax, metathorax and abdomen dull, with dense hydrofuge vestiture and longer, erect setae; longer setae concentrated on centre of metaventrite and abdominal ventrites 2–5; setae on ventrites arising from longitudinal tubercles, which sometimes appear as shining patches. Hind margin of abdominal ventrite 5 weakly crenulate.

Aedeagus ( Fig. 2L ) elongate, 0.55 mm in length. Parameres longer than basal piece; outer margins of parameres straight basally, then broadly arcuate to apex; interior margins of parameres sloping strongly at apex, then rather straight, apices bluntly rounded. Median lobe narrow, with weakly pointed apex; sides diverging slightly posteriorly to base of struts, weakly concave; struts distinctly shorter than tube.

Female. Externally as males, but on average slightly larger.

Measurements. Holotype: BL = 3.40 mm; EL = 2.45 mm; EW = 1.45 mm. Paratype male: BL = 3.15 mm; EL = 2.20; EW = 1.40 mm. Paratype females: BL = 3.55–3.85 mm; EL = 2.60–2.75 mm; EW = 1.55–1.70 mm.

Variation. Some variation in the degree of development of pronotal granulation, some specimens having this somewhat stronger than in the holotype. In some specimens the aeneous reflections on the head and pronotum are purplish as well as green/golden.

Differential diagnosis. This new species has 9-segmented antennae and is closest to H. aethiopicus , from which it can be distinguished on the basis of its larger body size and relatively granulate pronotum, with a more weakly angled submedian groove. In addition the aedeagus is larger and the parameres more expanded at their apices. These differences are relatively slight, but are consistent across all specimens of the two species that I have examined, including a relatively large number of H. aethiopicus from three separate localities. Given experience of Helophorus in the Palaearctic, the differences strongly suggest that two species are involved here.

Etymology. Named in reference to the type locality in the Simien Mountains; adjective.

Distribution and ecology. Known only from the type locality at 4,000 m in the Simien Mountains, in northern Ethiopia ( Fig. 5 ).

Figures

Fig. 1. Afrotropical Helophorus, habitus. A – H. aethiopicus Régimbart, 1907, lectotype; B – H. aethiops J. Balfour-Browne, 1954, holotype; C – H. aethiops J. Balfour-Browne, 1954, Kokstad, South Africa; D – H. cooperi Orchymont, 1947, holotype; E – H. brumopluvialis sp. nov., holotype; F – H. nyandaruaensis sp. nov., holotype; G – H. simiensis sp. nov., holotype. Scale bar = 1 mm.

Fig. 2. Afrotropical Helophorus, aedeagi. A – H. aethiopicus Régimbart, 1907, lectotype; B – H. aethiopicus, paralectotype; C – H. aethiops J. Balfour-Browne, 1954, holotype; D–F – H. aethiops J. Balfour-Browne, 1954, Kokstad, South Africa; G – H. cooperi Orchymont, 1947, holotype; H – H. brumopluvialis sp. nov., holotype; I–J – H. brumopluvialis sp. nov., Hopefield, South Africa; K – H. nyandaruaensis sp. nov., holotype; L – H. simiensis sp. nov., holotype. Scale bar = 100 μm.

Fig. 3. Afrotropical Helophorus, pronota.A – H. aethiopicus Régimbart, 1907, lectotype; B – H.aethiops J. Balfour-Browne, 1954, holotype; C – H. cooperi Orchymont, 1947, holotype; D – H. brumopluvialis sp. nov., holotype; E – H. nyandaruaensis sp. nov., holotype; F – H. simiensis sp. nov., holotype.

Fig. 5. Afrotropical Helophorus, known distributions.Map by https:// mapswire.com.