Sphrigodellus marshalli Yunakov, 2022

Yunakov, Nikolai, 2022, Afrotropical weevils of the Cadoderus Marshall generic complex (Coleoptera: Curculionidae: Entiminae: Embrithini). Part 2. Two new species of the genus Sphrigodellus Marshall, 1942 from Udzungwa Mountains, Tanzania, Zootaxa 5200 (2), pp. 479-488 : 484-487

Sphrigodellus marshalli Yunakov , sp. n.

( Figs 1C–D , 4 , 5 , 6 )

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Diagnosis. This species partly resembles minute species of the genus Dicasticus Pascoe, 1886 due to the well-developed granules on the disc of the pronotum, but significantly differs by gracile antennae; structure of abdominal sternite 8 of female; knife-shaped setae-less lamella, robust apodeme and well-developed caput; acute posterior margin of tergite 8 of female. It differs from all known species of the genus Sphrigodellus by black, glabrous, setiferous, flat granules on disc of the prothorax. It differs from S. lineatus Yunakov, 2012 by the presence of green scales covering intervals 1–2, posterior declivital portion of interval 3, and intervals 8–11. From S. nguruensis Yunakov, 2012 , it also differs by the strongly developed transverse sulcus of rostrum, distinct median fovea, evenly convex eyes, and green 2nd interval of elytra.

Description.

Measurements. BL f: 4.65 mm, BW f: 2.3, BH f: 2, RL/RWA f: 1.17, VW/ELD f: 1.43, PL/PW f: 0.92, EL/BH f: 0.70, EL/EW f: 1.41.

Vestiture: Body densely covered with overlapping rounded scales, setose. Setae of head spatulate, forming rows along lateral surfaces of epifrons (recumbent or subrecumbent) and medial to eyes (erect). Subocular row consisting of five setae. Pronotum uniformly covered with subrecumbent setae. Elytral intervals 1–7 each with distinct row of setae. Elytra in basal half with short subrecumbent setae (as long as 0.3x width of interval), posterior declivity with long, erect weakly spatulate, truncate setae (as long as width of interval). Ventral side rather sparsely squamose. Abdominal sternites with dense rounded scales, metapleura densely squamose but scales not overlapping; basisternum and mesobasisternum bare. Antennal scape densely squamulate and setose, scales lanceolate, not overlapping; setae acute, subrecumbent. External surface of femora and tibiae covered with overlapping scales and subrecumbent setae; internal surface with sparse piliform scales and hairs; outer surface of distal portion of tibiae without scales; setae on femora slender, acute, setae of tibiae broad, truncate. Medial surface of male hind tibiae with vestigial grooming brush; hairs very short. Tarsi setose аnd scarcely squamose. Funicle setose; setae suberect 1.5x longer than antennomere 8. Club densely tomentose.

Coloration: Integument of body, legs and antennae dark-brown. Background scaling roseous-light-brown, with pearly shine; striped longitudinal pattern formed by light green scales. Head posteriad of eyes with green scales; subgenae partly covered with green scales. Pronotum with narrow greyish-roseous median and two sublateral longitudinal stripes; sides green. Elytra with alternate brown, roseous, and green longitudinal stripes. Intervals 1–2, posterior declivital portion of interval 3, and intervals 8–11 green; intervals 3, 5, and basal portion of 7, grey; interval 4 and basal portion of 6 roseous. Ventral side with sparse green scales. Main surface of femora with maculate pattern of brown and grey scales, proximal portion with green scales. External surface of tibiae with grey scales.

Head: Rostrum parallel-sided. Pterygia not extended beyond rostrum.Antennal sockets dorsal. Antennifer partly-visible. Epifrons narrow, narrowed from base to posterior margin of antennifer, then abruptly widened apically; at the level of antennal articulation 0.62x as wide as width of vertex, weakly convex longitudinally and transversally, with very narrow median carina almost completely concealed by scales. Transverse sulcus deep, partly concealed by dense scaling. Frons vertical, glabrous, bare, with six frontal setae. Epistome vestigial, surrounded by narrow carina, bearing two epistomal setae. Prementum with two setae. Eyes: sublateral, moderately convex, highest at mid-length [VW/ELD=1.43]. Vertex: longitudinally and transversally convex. Median fovea strongly elongate. Antennae: Scape reaching middle of pronotum, weakly, evenly curved and widened, swollen in distal portion. Funicular antennomeres oblong; 1st 0.85x as long as 2nd; 2nd 3.50x longer than wide; 3rd 2.25x longer than wide; 4–7th 2x longer than wide. Club spindle-shaped, 2.57x longer than wide.

Thorax: Prothorax transverse, evenly and slightly convex at sides, not constricted, widest at middle, bearing paired bilateral shallow depressions aside of disc. Disc with black, glabrous, scale-less, setiferous, flat granules. Size of granules decreases with distance from center of the disc. Posterior edge of pronotum truncate. Posterior setal fringe of spatulate setae, partly hidden by posterior edge of pronotum. Tergosternal and metepisternal sutures complete. Elytra: ovate, basal declivity vertical, slightly convex longitudinally and transversally. Femora: edentate, swollen in middle part. Tibiae: Protibiae weakly curved, not widened at the apex; medial margin weakly C-shaped, serrate in distal portion; denticles accompanied with narrow, dark-brown spine ( Fig. 2G ). Size of the denticles decreases from mid-length of the tibia to apex. Meso- and metatibiae with medial margin dentate in distal portion. Mucro well developed, thorn-shaped, acute. Grooming brush moderately developed. Setal comb of protibia of 7 sparse black setae not extending beyond other margin of tibiae. Bevel of metatibia narrowly enclosed, setose, its surface covered with yellowish setae. Tarsi: Tarsomere 2 as long as width; tarsomere 3 with two wide lobes; tarsomere 5 of metatarsus extending beyond apical lobes of 3rd by length of the lobes. Claws connate in basal half.

Abdomen: 1st and 2nd ventrites fused, with distinct immovable suture. Posterior margin of 1st ventrite straight, 5th ventrite flat, posterior margin rounded.

Female genitalia: Coxites weakly sclerotized, dorsal baculi strongly sclerotized, sensilla absent. Styli well developed, rod-shaped, each bearing 1 seta. Spermatheca moderately sclerotized, with swollen ramus, collum slender, 2x as long as ramus; corpus slightly swollen; cornus slender, extended beyond corpus. Tergite 8 attenuate, posterior margin without setae. Sternite 8 thick; lamella strongly sclerotized, knife-shaped, sharply narrowed, acute, posterior margin without setae; apodeme thick; caput strongly developed, club-shaped ( Fig. 5C ).

Distribution. Tanzania (Udzungwa Mountains: Ukami Forest) ( Fig. 6 ).

Ecology. The single specimen of Sphrigodellus marshalli was found in the early 1910s in Ukami Forest (coordinates of the forest -7.8834, 36.4001; now in Kilombero Nature Reserve, Udzungwa Mountains, Iringa District, Tanzania) .

Material examined. Holotype, female, ( NHMUK) ‘ Ukami / Germ. E. Afr. ’; ‘ Ellimenistes bellus Fst. ’; ‘ Cadoderus sp. n. ’; ‘GAK Marshall / Coll. / B.M. 1950-255’.

Etymology. The name is dedicated to Sir Guy Anstruther Knox Marshall, a British entomologist who significantly contributed to the knowledge of weevils of Tropical Africa and Oriental Region.

Figures

FIGURE 1. Dorsal and lateral habitus of Sphrigodellus species. A, B: Sphrigodellus griseus sp. n., paratype, female, dorsal and lateral view. C, D: Sphrigodellus marshalli sp. n., holotype, female, dorsal and lateral view. Scale bar: 1 mm.

FIGURE 2. Sphrigodellus griseus sp. n., structural details. A: head dorsal and lateral view. B: head capsule, anterior view. C: labium D: antennal scape. E: antennal funicle. F: body shape. G: protibia of male. H: metatibia of male.

FIGURE 4. Sphrigodellus marshalli sp. n. (holotype, female), structural details. A: head dorsal and lateral view. B: head capsule, anterior view. C: labium D: antennal scape. E: antennal funicle. F: body shape. G: protibia of female. H: metatibia of female. I: metatibial apex (bevel setose).

FIGURE 5. Sphrigodellus marshalli sp. n. female genitalia. A: spermatheca. B: ovipositor. C: female sternite 8. D: female tergite 8. Abbreviations: ba—baculi, co—collum, cp—corpus, cr—cornus, cxt—coxite, du—spermathecal duct, gl—spermathecal gland, ra—ramus, sty—stylus, st8—8th sternite, st8ap—apodeme of 8th sternite, st8ca—caput of apodeme of 8th sternite.

FIGURE 6. Occurrence map of Sphrigodellus species in southern part of Eastern Arc Mountains.