Meligethinus hamerlae, Sabatelli & Liu & Cline & Lasoń & Macuvele & Muambalo & Chuquela & Audisio, 2020

Sabatelli, Simone, Liu, Meike, Cline, Andrew Richard, Lasoń, Andrzej, Macuvele, Suzana, Muambalo, Kisimenda, Chuquela, Lucilia & Audisio, Paolo, 2020, Palms and pollen beetles: two new anthophilous beetle species of Meligethinus from Mozambique (Coleoptera: Nitidulidae: Meligethinae), Zootaxa 4802 (1) : -

Meligethinus hamerlae sp. nov.

( Figs 1 e–f, i, p)

Diagnosis. Narrowly elongate, moderately transversely convex, uniformly testaceous-orange. Similar in external shape and color to M. mondlanei sp. nov. described above and similar to the sympatric M. suffusus , but easily differentiated from the former by the markedly distinct shape of metatibiae in males, and the different shape of male and female genitalia, as well as the presence of a small dorsal, medial, pre-distal projection on the female pygidium. The new species is easily differentiated from the latter by the presence of the medial projection on the female pygidium, by the markedly distinct shape of male genitalia, and the usually paler body color. This new species is likely closely related to the central African M. muehlei Jelínek, 1992 , which is on average larger and darker, characterized by completely different male metatibiae, a markedly larger and longer pygidial female projection, and distinctively shaped male and female genitalia.

Description. (male holotype). Size: body length 2.4 mm, width 1.10 mm. Body narrowly elongate, scarcely transversely convex, uniformly testaceous-orange. Dorsal surface rather densely, finely and shallowly punctate (spaces between pronotal and elytral punctures ~1.5–2× diameter), with dull and shagreened interspaces; elytra without traces of transverse strigose sculpturing. Pronotum trapezoidal in shape, with widely arcuate lateral sides, maximum width near posterior five sixths. Pubescence on pronotum and elytra sparse, golden-whitish, moderately long and distinct, each seta markedly shorter than antennomere 6, slightly longer along posterior base. Body uniformly orange-yellowish, without pale areas, including peripheral margins (pronotal carina) of pronotum; legs and antennae uniformly yellowish-orange, testaceous, with antennal club distinctly darker, pale brown. Antennal club elongate, symmetrical, without differences between sexes. Proximal base of pygidium with normal, “V” shaped medial impression, directed posteriad. Prosternal process broadly rounded distad, maximum width near distal 2/5. Metaventrite almost flat, only slightly depressed in posterior half, with a scarcely distinct longitudinal impression. Last abdominal ventrite bearing two rather small proximal semicircular impressions, diameter nearly 1.2× the diameter of an eye.

Legs: protibia ( Fig. 1k) wide, triangular, as in M. suffusus Kirejtshuk, 1980 , protarsus nearly as wide as length of antennomere 3 (ratio WFTA/LFTA ≈ 0.25). Mesotibia wide, trapezoid shaped. Metatibia ( Fig. 1m) scarcely wide, along inner side almost simple and regular in posterior half, not denticulate, almost identical to that of M. suffusus Kirejtshuk, 1980 , exhibiting no marked sexual dimorphism.

Male genitalia: distinctively shaped, with elongate and subparallel-sided tegmen ( Fig. 1e), aedeagal median lobe rather small, maximum width at proximal fifth, ratio LEAE/WIAE = 2.15–2.20 ( Fig. 1f); aedeagal apex narrowly truncate with a distinct and narrowly chisel-shaped distal apex, ~1/5 as wide (0.20×) as maximum basal aedeagal width ( Fig. 2f). Ratio DTIN/LETE ≈ 0.44–0.48, median excision of tegmen narrow along first four-fifths of its length; ratio LETE/WITE = 1.40–1.42.

Female: Protibia rather wide, triangular, slightly narrower than males, protarsus slightly narrower than males (ratio WFTA/LFTA ≈ 0.22). Mesotibia wide, trapezoid as in males. Metatibia simple and uniformly slightly nar- rower than males, along inner side almost rectilinear and not denticulate. Pygidium with a small but distinct median obliquely positioned conical protuberance directed posteriad, similar to females of Meligethinus muehlei from Rwanda ( Jelínek 1992; Fig. 1n), but smaller ( Fig. 1p). Ovipositor rather small and moderately sclerotized, not darkened toward the moderately blunt distal apex, exhibiting short styli, similar to that exhibited by M. suffusus ( Kirejtshuk 1980; Fig. 1h), although exhibiting a slightly narrower distal gonocoxal apex ( Fig. 1i). Ratio STLE/DSIA ≈ 0.40; ratio STLE/CGOW ≈ 0.17; ratio GONL/CGOW ≈ 3. Ratio OVPL/GONL ≈ 2.15.

Variation: Overall body sizes range from 1.9–2.6 mm (length) and 0.90–1.20 mm (width).

Examined material. Holotype, male: Mozambique: Maputo Province, Inhaca Island, Farol, 10–15 m a.s.l., 25°58’22”S, 32°59’08”E, 21.ix.2018, P. Audisio & S. Sabatelli lgt, sparsely forested and bushy area, beating male inflorescences of Phoenix reclinata Jacq. (Arecaceae) (MHNMM). Paratypes: 10 males, 13 females; same data as holotype, 2 males, 2 females (MHNMM, CAR-MZUR); same locality, 27.ix.2019, S. Sabatelli lgt, open and sparsely bushy area, beating male inflorescences of Phoenix reclinata Jacq. (Arecaceae) , 6 males, 8 females (MHNMM, CAR-MZUR, CAS, CLA, ACC, NMPC); same locality, road between Farol and the Marine Biological Station, 10–15 m a.s.l., 26°00ʹ26ʹʹS, 32°56ʹ37ʹʹE, 27.ix.2019, S. Sabatelli lgt, open and sparsely bushy area, beating male inflorescences of Phoenix reclinata Jacq. (Arecaceae) , 2 males, 3 females (NMMU, CAR-MZUR).

Distribution. This species is known from Inhaca Island in southern Mozambique ( Fig. 3). The host-plant Phoenix reclinata is widespread in Eastern Africa (see above information on M. mondlanei sp. nov.; Coates Palgrave 2002; see also pza.sanbi.org/phoenix-reclinata). The geographic range could be wider, potentially including at least part of these areas. However, several attempts (2018–2019) aimed to collect M. hamerlae sp. nov. in nearby localities of continental southeastern Mozambique near Maputo failed in producing any additional specimens. The apparently exclusive presence of this new species at Inhaca is odd, considering this small island is separated from coastal areas of southeastern Mozambique by a shallow sea that did not create a barrier with the mainland during the most recent Würm Glaciation.

Host-plants. This species appears to be strictly associated with male inflorescences of Phoenix reclinata Jacq. (Arecaceae) . All specimens of the type series were collected by sweeping flowering males in conjunction with the more abundant Meligethinus dolosus , M. peringueyi , and M. suffusus , as well as a few specimens of the locally less abundant M. mondlanei sp. nov., and M. humeralis .

Habitat. Locality data indicate this species prefers edges of sparsely forested and bushy areas, in sandy habitats close to the sea at very low altitudes.

Phenology. The few available specimens were collected in middle and late September, which likely indicates adult activity from late August to early October.

Etymology. The specific epithet honors Maria Grazia Hamerl, mother of the senior author S. Sabatelli.

Taxonomic remarks. As reported above, this new species is similar in external shape to the sympatric M. mondlanei sp. nov. and especially to the sister species M. suffusus (see below), being otherwise unmistakable due to the peculiar shape of the female pygidium ( Fig. 1p), and the distinctly different shape of the male genitalia ( Figs 1 e–f), in particular the distinctly more narrowly chisel-shaped distal apex of the aedeagus (distinctly wider in M. suffusus : Figs 1 c–d). The shared presence of a pre-distal conical protuberance on the female pygidium also suggests a close taxonomic relationship of the new species to the larger Meligethinus muehlei from Rwanda ( Jelínek 1992), which is easily differentiated from the new species by the different male and female genitalia, a much larger size of the pygidial conical protuberance in females ( Fig. 1n), darker body color with large, dark brown elytral spots, and longer golden hairs on legs in males ( Jelínek 1992). Preliminary molecular analyses of the genus Meligethinus (Sabatelli et al., unpublished data) demonstrates that the sympatric and syntopic M. hamerlae sp. nov. and M. suffusus are sister species, amply separated by an average genetic p -distance (COI gene) of ≈ 0.6, indicating a well-estab- lished specific differentiation, combined with a clear common origin from a shared most recent ancestor.