Adamastoraltica humicola, Biondi & Iannella & D’Alessandro, 2020

Biondi, Maurizio, Iannella, Mattia & D’Alessandro, Paola, 2020, Adamastoraltica humicola, new genus and new species: the first example of possible moss-inhabiting flea beetle genus from sub-Saharan Africa (Coleoptera Chrysomelidae, Galerucinae), Zootaxa 4763 (1), pp. 99-108 : 105

Adamastoraltica humicola sp. nov.

Diagnosis. Adamastoraltica humicola sp. nov. is the only known species of the new genus here described, thus, it is clearly distinguishable from other flea beetle species by the genus characters. Similarities with moss-inhabitant flea beetle genera are likely due to adaptive convergence (see “Taxonomic notes” in the description of the new genus). The lack of scutellum is the most evident diagnostic trait. Although it is shared with species of the genus Stegnaspea , A. humicola sp. nov. is easily distinguishable from each Stegnaspea species by several features on head, pronotum, elytra, ventral parts, legs, aedeagus and spermatheca (see “Taxonomic notes” in the description of the new genus).

Type material. Holotype ♂. [ Republic of South Africa] Z A.40 / Table Mount. [Table Mountain] / Wynberg- Cave / Ravine C.P. [Newlands Ravine, 33°58’S 18°44’E] // xi-xii.1960 / Humus // N. Leleup leg. ( MNHN). Para- types. Same data as the holotype, 2 ♂♂ and 3 ♀♀ ( MNHN); Republic of South Africa: Z. A.43 / Table Mountain / Doline. Bats Cave [~ 33°58’S 18°57’E] // Humus / xii.1960 // N. Leleup leg. ( MNHN).

Description of the holotype (♂). Body ovate in dorsal view, very strongly and evenly convex in lateral view ( Figs 1–3 ); total length of body (LB) = 1.33 mm; maximum pronotal width at base (WP = 0.59 mm); maximum width of elytra at middle (WE = 0.89 mm). Dorsal surface glabrous, metallic black, without evident punctures ( Figs 1, 3–4 ); antennae and legs brown. Head ( Figs 5–6 ) with impunctate surface; supraorbital and suprafrontal grooves joined and distinctly impressed; inter-antennal space slightly wider than length of the first antennomere; frons length (from upper orbital line to clypeus) about three times the inter-antennal space; frontal ridge wide, slightly raised, apically rounded; eyes sub-elliptical, small; interocular width about four times the transverse width of each eye; labrum apically deeply incised ( Fig. 7 ); antennae about as long as half body length (LAN = 0.71 mm; LAN/LB = 0.54); last antennomeres distinctly wider than middle ones ( Fig. 1 ); LA: 100:82:68:54:64:54:64:64:68:77:136. Pronotum ( Figs 3–5 ) very convex, in dorsal view transverse, distinctly longer medially than laterally (LP = 0.38 mm; WP/LP = 1.54), with slightly rounded sides converging anteriorly; surface apparently smooth, but with very sparse and very shallow punctation; anterior, lateral, and basal margins very finely bordered ( Fig. 5 ); anterior and posterior angles not prominent. Scutellum absent. Metathoracic wings absent. Elytra ( Figs 1–3 ) moderately elongate (LE = 1.16 mm; WE/LE = 0.77; LE/LP = 3.04), strongly convex, with clearly rounded sides, apically jointly acute; lateral margin thin, not visible in dorsal view; surface smooth, with very sparse and very shallow punctation. Humeral calli absent. First pro- and mesotarsomeres weakly enlarged ( Figs 1 , 8a ). Ventral parts brown; last abdominal ventrite without preapical sculptures or impressions. Median lobe of aedeagus ( Fig. 10 ) (LAED = 0.56 mm; LE/ LAED = 2.09) with smooth surface; slightly tapered and weakly sinuate laterally in ventral view, apically rounded, with a median tooth; basal opening large; median lobe distinctly and evenly curved in lateral view, gradually thinner towards apical part, with dorsally oriented apex; dorsal ligula wide, laterally parallel, extending from half-length of aedeagus to subapical part.

Variation. Males (n = 4; range): 1.16 ≤ LE ≤ 1.24 mm; 0.89 ≤ WE ≤ 0.90 mm; 0.38 ≤ LP ≤ 0.40 mm; 0.59 ≤ WP ≤ 0.60 mm; 0.68 ≤ LAN ≤ 0.73 mm; 0.56 ≤ LAED ≤ 0.57 mm; 1.33 ≤ LB ≤ 1.41 mm; 3.04 ≤ LE/LP ≤ 3.13; 1.47 ≤ WE/WP ≤ 1.51; 1.52 ≤ WP/LP ≤ 1.54; 0.72 ≤ WE/LE ≤ 0.77; 0.51 ≤ LAN/LB ≤ 0.54; 2.09 ≤ LE/LAED ≤ 2.14. Fe- males (n = 3; range): 1.22 ≤ LE ≤ 1.38 mm; 0.89 ≤ WE ≤ 1.08 mm; 0.37 ≤ LP ≤ 0.44 mm; 0.60 ≤ WP ≤ 0.65 mm; 0.69 ≤ LAN ≤ 0.75 mm; 0.17 ≤ LSPC ≤ 0.19 mm; 1.40 ≤ LB ≤ 1.67 mm; 2.93 ≤ LE/LP ≤ 3.11; 1.44 ≤ WE/WP ≤ 1.66; 1.44 ≤ WP/LP ≤ 1.62; 0.71 ≤ WE/LE ≤ 0.78; 0.45 ≤ LAN/LB ≤ 0.50; 7.00 ≤ LE/LSPC ≤ 7.25. Paratypes very similar in shape, sculpture and color to the holotype. Females distinguishable by the less enlarged first pro- and mesotarsomeres. Spermatheca ( Fig. 11a ) with elongate, subcylindrical basal part gradually narrower from half-length towards the distal part; distal part about as long as 1/3 of the basal part, lacking distinct collum and appendix; ductus short, uncoiled, U-shaped, apically inserted. Tignum ( Fig. 11b ) elongate and narrow, in lateral view basally and apically clearly curved; vaginal palpi ( Fig. 11c ) thin, basally not connected, moderately sclerotized along their entire length, apically with three setae.

Etymology. The specific epithet is after the word “humus”, the type of habitat where the specimens of the new species were collected.

Distribution. Republic of South Africa, Western Cape Province ( Table 1; Fig. 12 ). Possible Southern-Western Afrotropical chorotype (SWA).

Ecological notes. All the specimens were collected in humus, in a site without trees or shrub vegetation. Considering the species morphology (see “Diagnosis” in the description of the new species) and the absence of leaf litter in the collection site, Adamastoraltica humicola sp. nov. is likely to be a moss inhabitant.

Figures

FIGURE 12. Geographical distribution of the moss-inhabiting flea beetle genera, excluding subtribe Monoplatina.

FIGURES 1–3. Adamastoraltica humicola sp. nov. habitus, ♂ holotype: 1, dorsal view; 2, ventral view; 3, lateral view. 1st av = first abdominal ventrite; ep = elytral epipleurae; ms = mesosternum; mt = metasternum; ps = prosternum.

FIGURES 4–11. Adamastoraltica humicola sp. nov. from Wynberg Cave Ravine: 4, pronotum and basal part of elytra in dorsal view; 5, head and pronotum in dorsolateral view; 6, head in dorsal view; 7, mouthparts; 8, male, front tibia and tarsus (a), hind tibia (b), hind tarsus (c); 9, metafemoral extensor tendon, from top to bottom in inner and outer view; 10, aedeagus from left to right in ventral, dorsal, and lateral view; 11, spermatheca (a), tignum (b), vaginal palpi (c). 1st = first tarsomere, 3rd = third tarsomere, aa = anterior angle, as = apical spur; bav = basal angle of the ventral lobe; be = tendon basal edge; cf = tendon central furrow; dba = dorsal-basal angle; dev = dorsal edge of ventral lobe; dl = dorsal lobe; ea = extended arm; lb = labrum; lp = labial palpus; mp = maxillary palpus; pa = posterior angle, rf = recurved flange; sg = supraorbital groove, tc = tarsal claws, vl = ventral lobe.