Lycocerus todai Nakamura, 2024

Nakamura, Ryo, 2024, Unexpected discovery of a new Lycocerus (Coleoptera, Cantharidae) from Okinawa Island, Ryukyu Islands, southwest Japan, Zootaxa 5507 (3), pp. 489-497 : 490-493

Lycocerus todai Nakamura sp. nov.

Japanese name: Kisaragi-jôkai

( Figs. 1, 4–7 , 10–11 )

Type materials. Holotype, male, “[ṗäŝ 乙ṟē] 国DZō÷ṣ仁ťīĸ 26. 670470, 127. 969643, 15. II. 2019, leg. DƂ 尚* / JAPAN: Okinawa-jima Is., Nakijin-son , Tamashiro, 26. 670470N, 127. 969643E, 15. II. 2019, Naoki Toda leg.” ( KURA) . Paratypes (3 males): 2 males, same data as the holotype ( KURA) ; 1 male, “ JAPAN: Okinawa-jima Is., Nakijin-son , Jana, Mt. Oppadake, alt. 260 m, 26.6701N, 127.9622E, 15.II.2024, Ryo Nakamura leg., ṗäŝ÷ṣ仁ťā名 乙ṟē ” ( FZUT) .

Description. Male. BL 9.14–10.1 mm (10.1 mm in the holotype = HT). Body almost entirely black but claws reddish brown and abdomen yellowish orange with a pair of small dark brown maculae on basal five segments. Body closely covered with yellowish white pubescence.

Head shorter than width, dorsum slightly depressed between antennal sockets, HW 1.60–1.80 mm (1.80 mm in HT); eyes large, globular and prominent, interocular distance 2.69 times as wide as the diameter of an eye; mandible arcuate and pointed at apex; apical segments of labial and maxillary palpomere knife-shaped; antennae filiform, without any grooves, reaching 3/5 of elytra, comparative lengths of antennomeres of the holotype as follows: 2.08: 1: 2.06: 2.54: 2.67: 2.69: 2.73: 2.67: 2.63: 2.31: 2.75.

Pronotum rectangular, widest at posterior angles, anterior margin arcuate, posterior margin feebly arcuate, lateral margins almost parallel but slightly emarginated in the middle, anterior angles obtuse and rounded, posterior angles nearly right-angled and slightly protruding laterally; PL 1.31–1.54 mm (1.54 mm in HT), PW 1.20–1.41 mm (1.41 mm in HT), HW/PW 1.28–1.34 (1.28 in HT), PL/PW 1.07–1.09 (1.09 in HT); disc with a medio-longitudinal furrow not reaching the anterior and posterior margins, moderately convex and gradually flattened in lateral halves. Scutellum triangular with acute and round apex. Elytra long, parallel in lateral sides, apex normally rounded, EL 6.78–7.27 mm (7.27 mm in HT), EW 1.88–2.17 mm (2.17 mm in HT), EW/PW 1.52–1.57 (1.54 in HT), EL/EW 3.35–3.61 (3.35 in HT). Legs slender, each femur mostly straight, each tibia feebly arcuate, all claws simple.

Male sternite IX (fig. 7D) cymbiform, as long as tergite IX, 3.43 times longer than wide, pubescence in apical 1/3, lateral margins parallel in the middle, feebly narrowing in apical 1/4 to form a round and slightly bifid tip.

Aedeagus (figs. 7A–C) without hairs; ventral process of each paramere slender, feebly bent inwards and slightly expanded at apex in ventral view, almost straight and gradually expanded toward apex in lateral view; dorsal plates of parameres broad with apical margins arcuate, lateral margins approaching and inner margins almost parallel each other in dorsal view, as long as ventral process in lateral view; laterophyse almost straight and thin in ventral view, slightly not reaching the same level as the tip of ventral process and dorsal plates, bent dorsally toward apex of dorsal plates in lateral view.

Female. Unknown.

Distribution. Japan (Ryukyu: Okinawa Island) (fig. 11).

Biology. One male paratype from Jana, Oppadake was collected by sweeping green leaves in the evergreen broad-leaved forest at noon (fig. 10). Adults are collected only in mid-February.

Etymology. The specific name is dedicated to Mr. Naoki Toda, a Japanese colleopterist who collected the type specimens.

Differential diagnosis. This new species closely resembles to Lycocerus okinawanus (Ishida, 1985) and L. yonaensis ( Satô et Okushima, 1992) from the same island but differs in the following characters (see also Okushima (2005)). Body size: larger in L. todai sp. nov. and L. yonaensis (more than 9.1 mm) vs. smaller in L. okinawanus (less than 8.6 mm); color of elytra: dull black in L. todai sp. nov. and L. yonaensis vs. glossy black with blueish lustre in L. okinawanus ; color of abdomen: almost entirely yellowish orange in L. todai sp. nov. vs. black but marginally yellowish-brown in L. okinawanus vs. entirely black in L. yonaensis ; sternite IX: narrow in L. todai sp. nov. (more than 3.4 times longer than wide) vs. wide in L. okinawanus and L. yonaensis (less than 2.8 times longer than wide); ventral process of aedeagus: stick-like in L. todai sp. nov. and L. okinawanus vs. broad and angular on dorsal side in L. yonaensis ; laterophyse of aedeagus: thin in ventral view in L. todai sp. nov. and L. yonaensis vs. stout and widend toward apex in ventral view in L. okinawanus .

Figures

FIGURE 10. Collecting site of Lycocerus todai sp. nov. (Nakijin-son, Jana, Oppadake), taken by the author when a paratype was collected.

FIGURE 11. Distribution map of three black-colored Lycocerus species in the Ryukyu Islands, created based on the distributional information presented in this paper.

FIGURES 1–6. Habitus of Lycocerus spp., male. 1 & 4–6, L. todai sp. nov., 1: holotype, dorsal; 4: paratype from Jana, Oppadale, ventral; 5: ditto, alive, dorsal; 6: ditto, alive, lateral; 2, L. okinawanus, dorsal; 3, L. yonaensis, dorsal. Scale bars: 3.0 mm.

FIGURES 7–9.Aedeagus, male tergite IX and male sternite IX of Lycocerus spp. 7, L. todai sp. nov., paratype; 8, L. okinawanus; 9, L. yonaensis. A: aedeagus, ventral; B: ditto, lateral; C: ditto, dorsal; D: tergite IX and sternite IX, ventral. Scale bars: 0.5 mm.