Endaeus xylopiae Haran & Zelvelder sp. nov.

urn:lsid:zoobank.org:act: AFABF503-2DC4-4361-B80B-11E9ECB43133

Figs 7–8

Differential diagnosis

Endaeus xylopiae Haran & Zelvelder sp. nov. is morphologically very close to E. baikieae Marshall, 1933, E. jaculifer Haran & Zelvelder sp. nov. and E. convexiculus Haran & Zelvelder sp. nov. It differs by having a shorter and very moderately downcurved rostrum. Males of the three species differ greatly in the shape of their penis, that of E. xylopiae being the only one bearing strong hook-like setae at apex and hook-like processes laterally in dorsal view. Among the species of Endaeus for which a barcode sequence is available, this species is closest to E. jaculifer, also found on Xylopia aethiopica (COI p -distance of 16.0%).

Etymology

This species is named in reference to its association with flowers of Xylopia aethiopica (Annonaceae).

Type material

Holotype GABON • ♂; “GABON, Parc de la Lékédi / 26.x.2023 / J. Haran & R. Allio coll. / JHAR06086-04; -1.778 13.000 [1°46′40.8″ S, 13°00′00.0″ E], 25m, 20h45 / Xylopia aethiopi.[ca] / Collection-Cirad / Holotype / Endaeus xylopiae Haran & Zelvelder 2026 ”; CBGP, JHAR06086-04.

Paratypes GABON • 1 ♂; Parc de la Lékédi; 1°46′40.8″ S, 13°00′00.0″ E; 26 Oct. 2023; J. Haran and R. Allio leg.; on flower of Xylopia aethiopica (Annonaceae); CBGP, JHAR06086-01 • 1 ♀; same data as for preceding; CBGP, JHAR06086-03 • 1 ♂; same data as for preceding; HNG, JHAR06086-05 • 1 ♀; Parc de la Lékédi; 1°46′40.8″ S, 13°00′00.0″ E; 26 Oct. 2023; J. Haran leg.; beating understory vegetation, 4:00 pm; CBGP, JHAR06081-01.

Description

Male

BODY LENGTH. 2.2–2.45 mm.

COLOUR. Body integument uniformly pale brown; vestiture of head, prothorax and elytra made of pale yellow to light orange setae, not concealing the integument; vestiture of prothorax and elytra made of combination of short, subrecumbent setae, ½ to ¾ as wide as width of interstriae, forming 3–4 ill-defined longitudinal rows on each interstria and long suberect setae, forming a row on each interstria, on average 3 × as long as subrecumbent setae, about as long as width of interstriae.

HEAD. Head capsule with short, pale, subrecumbent setae and longer, pale suberect setae forming two ill-defined rows on forehead; rostrum slightly shorter than prothorax (0.9 ×) in lateral view, 2.2 × as long as width of eye, moderately downcurved; antennae inserted near apical ⅓ of length of rostrum; eyes convex, strongly exceeding lateral curve of head capsule in dorsal view and dorsal curve of head capsule in lateral view; space between eyes about half as wide as base of rostrum; antennal scape slightly longer than segments 1–5 of funicle, widening at apical ⅓ of length; funicle with segment 1 globular; 2 twice as long as wide, 3–6 isodiametric; club slightly longer than wide (W:L ratio 0.55–0.6).

PROTHORAX. Wider than long (W:L ratio 1.3), widest near middle of length, sides rounded, apical margin about 0.75 × wider than basal margin; dorsum flat in lateral view; integument shiny, micropunctuate, with uniformly distributed, medium-sized, roughly circular punctures; space between punctures as wide as diameter of punctures or larger; sides and apical margin of prothorax with erect setae pointing upwards and forwards, respectively; subrecumbent setae pointing towards median line of prothorax on dorsum.

ELYTRA. Sides slightly convex in dorsal view, widest near middle of length (W:L ratio: ~0.70); humeri raised; interstriae 3–4 × as wide as striae; interstriae 10 widening from base to the level of metacoxae, about 1.5 × as wide as interstriae 9 at widest point; in lateral view, dorsum of elytra almost flat on basal ¾ of length, then declivity; scutellar shield shiny, rounded.

ABDOMEN. Underside covered with recumbent whitish setae longer than subrecumbent setae of elytra.

LEGS. Femora subequal in thickness, thickened in middle of length, each armed with flat triangular tooth, profemoral tooth followed by row of 6 erect setae located between base of the triangular tooth and distance from apex of femora equal to length of tarsomere 1; protibiae curved in basal ½, external margin straight in apical ⅔, internal margin bisinuate, carinate, apex with sharp, slightly curved mucro located medially on corbel, similar in size to claw, curvature pointing inwards to almost perpendicular; apex of meso-tibiae with robust, slightly downcurved mucro located on inner part of corbel, erected almost perpendicularly; tarsal claws widely divergent, appendiculate with dull triangular inner tooth.

TERMINALIA. Body of penis elongate (W:L ratio: 0.33), about 1.7 × as long as apodemes, sides bisinuate in dorsal view, strongly narrowed in apical ⅔ to 0.66 × its maximum width and narrowing towards apex from apical ¾; lateral processes of body gradually translucent, oriented backwards, each bearing 6-7 dull, flattened hooks directed towards apex; apex rounded, bearing 5–7 strong anteapical hook-like setae laterally; tip forming button-like shape; inner part of apical ⅔ coated with sclerified papillae pointing forward; in lateral view, widest near middle of length, curvature irregular, stronger near middle of length; internal sclerite not distinct in specimens examined (Fig. 7C).

Sexual dimorphism

Females can be distinguished from males by their rostrum which is narrower and longer in lateral view (2.5 × as long as width of eye). Antennal insertion is located near middle of length of rostrum in ♀♀ (near apical ⅓ in ♂♂). Meso-tibial mucro more broadly downcurved in ♀♀.

Life history

This species was collected on a flower of Xylopia aethiopica in anthesis (Fig. 8A–C). The flower was located at 25 m high in the tree and started producing a strong scent at dusk. Adults were observed reaching this flower and standing on petals around 8 pm (Fig. 8C). Most specimens then moved into the floral chamber. The flower sampled contained four individuals of this species. These biological data echos with the observations made for Xylopia championii Hook.f. & Thomson in Sri Lanka, where an Endaeus was identified pollinating this species via a synchronization of floral phenology and beetle activity (Ratnayake et al. 2007). Despite detailed searches, the immatures of this species could not be found in the petals of the flower sampled, nor in the flowers that had fallen at the base of the tree. Flowers hosting larvae of Endaeus can be rare, see life history section under E. canangae Haran sp. nov. Given the trend in ciophily and in Endaeus - Annonaceae interactions (host specificity, flower structure, etc.), it is very likely that larvae of this species develop in the petals of X. aethiopica. Endaeus xylopiae Haran & Zelvelder sp. nov. was found in sympatry, in the same flower, with E. jaculifer Haran & Zelvelder sp. nov. and E. convexiculus Haran & Zelvelder sp. nov. One specimen of E. xylopiae was also collected by beating understorey vegetation at 4 pm. This species is seemingly not attracted by UV light, since it was not observed at a UV light trap set in an X. aethiopica tree in the vicinity of the flowers in anthesis on which specimens were observed.

A first assessment of floral scent emitted by flowers in anthesis of Xylopia aethiopica revealed a scent composed of several groups of chemicals, mainly terpenoids, and largely dominated by one unique terpene derivative, showing a chemical skeleton similar to Farnesyl although it could not be precisely identified (Unknown terpene derivatives 2, see Appendix 2).

Distribution

This species is currently only known for the type locality in La Lékédi park, in south-east Gabon (Haut-Ogooué Province). Its host is widely distributed in tropical Africa, from Senegal to Ethiopia and from Mozambique to Chad (WFO 2024).