Urumaelmis flammea, Nakajima & Kamite, 2020

Nakajima, Jun & Kamite, Yuuki, 2020, A new species of the genus Urumaelmis Satô (Coleoptera, Elmidae, Macronychini) from Kyushu Island, Japan, Zootaxa 4853 (3), pp. 421-428 : 422-426

Urumaelmis flammea sp. nov.

( Figs 1–3 , 4A, B & 6A )

Holotype. EUMJ, male, Japan: Jyouhara, Yamato-cho, Kumamoto Pref., Kyushu , 32.6817N, 131.0000E, 9. IX. 2008, J. Nakajima leg.

Paratypes. EUMJ, 1 male, same data as the holotype ; EUMJ, KMNH, 1 male & 1 female, same locality as the holotype, 24. XII. 2008, J. Nakajima leg. ; CKN, 1 ex., same locality as the holotype, 7. I. 2008, J. Nakajima leg. ; JNC, 1 male, Japan: Aitouji, Yamato-cho , Kumamoto Pref., 25. XII. 2008, J. Nakajima leg. ; KMNH, 1 male, Japan: Minamimata, Aya-cho , Miyazaki Pref., 20. III. 2007, Y. Hayashi leg. ; JNC, 1 male, Japan: Kitamata, Aya-cho , Miyazaki Pref., 19. XI. 2007, Y. Hayashi leg.

Diagnosis. The new species differs from other Macronychini species in combination of the following characters (see also Table 1 in Yoshitomi & Hayashi 2020): pronotum smooth and glabrous, anterior angles strongly produced; 8-segmented antennae; elytral punctures small and shallow; elytral carinae on intervals VII incomplete; profemur clavate; aedeagus straight and elongate, and parameres almost completely fused to penis, without apical setae. It is similar to Urumaelmis uenoi ( Figs 4C, D , 5 & 6B ), but differs from it by the following characters: 1) body larger, TL 2.3–2.5 mm (vs. smaller, TL 1.7–2.2 mm); 2) body red or reddish (vs. brownish); 3) median groove of pronotum extending from the base (vs. not extending from the base); 4) the presence of elytral carinae on intervals VI from base to apex (vs. only anterior and apical part); 5) elytral punctures small and shallow (vs. very small and unclear); 6) apical part of penis long, slightly sinuated at apical 1/ 2 in lateral view (vs. apical part of penis short, beak-shaped in lateral view).

Description. Male ( Fig. 1 ). Body oblong and elongate, moderately convex dorsally. Coloration of body red or reddish brown, but head dark brown.

Head ( Fig. 2A, B ) rounded, almost flat dorsally, evenly covered with setae, and densely covered with minute golden setae except in the middle of the head. Eyes moderately small; the distance between eyes is about 2.5 times as long as the maximum diameter of an eye. Antennae ( Fig. 3A ) short, 8-segmented; parts of the margins of antennomere VIII densely covered with setae; approximate ratio of each antennal segment is 2.3: 5.3: 3.0: 1.3: 1.1: 1.3: 1.0: 5.6. Mandibles ( Fig. 3B ) with three apical teeth. Fronto-clypeal suture almost straight. Clypeus transverse, covered with hair, about 3.70 times as wide as its maximum length. Labrum transverse, about 1.90 times as wide as long.

Pronotum ( Fig. 2A ) sparsely and finely punctate, shiny and smooth, sparsely covered with minute setae; lateral side rimmed, sinuate, broadest at basal 1/2; apical margin rounded; basal margin trisinuate; antero-lateral angles strongly produced; postero-lateral angles almost rectangular; sublateral carinae extending from the base to basal 1/3; longitudinal groove extending from the base to basal 3/4; PW/PL 1.15–1.31 (1.22, n=5). Scutellum subtriangular.

Elytra ( Fig. 2C ) elongate parallel-sided; moderately convex; broadest at middle; each elytron with 7 rows of punctures, without distinct striae, punctures small and shallow, diminishing toward apex. Elytral carinae consisting of granules present on intervals IV–VII; interval IV carinate only on apical part; intervals V and VI carinate from base to apex; interval VII carinate from base to basal 1/5. Lateral margins of elytra serrate; intervals V–VIII densely covered with minute golden setae except for carinae; EL/EW 1.59–1.73 (1.66, n=5); EL/PL 2.48–2.59 (2.52, n=5); EW/PW 1.21–1.32 (1.25, n=5); TL/EW 2.32–2.52 (2.41, n=5). Epipleura densely covered with minute setae.

Prosternum ( Fig. 2B ) densely covered with minute setae on lateral sides; prosternal process tappering posteriorly. Legs moderately long; femora swollen, densely covered with minute setae, profemora enlarged, clavate; tibiae longest, with cleaning fringes on inner side; tarsi 5-segmented, last segment slightly shorter than rest combined; tarsal claws simple. Metaventrite and abdomen ( Fig. 2D ) densely covered with minute setae on sides; discrimen thin and short, reaching to basal 1/3. Intercoxal process of sternite III wide, subtriangular. Sternite VII subtriangular. Tergite VIII ( Fig. 3C ) semicircular, covered with minute setae, apically setose. Sternite VIII ( Fig. 3D ) semicircular, with a long median strut, covered with minute setae only in the apical half, sparsely bearing setae apically. Sternite IX ( Fig. 3E ) oblong, with a pair of lateral sclerites and median strut; sparsely bearing setae apically.

Aedeagus ( Fig. 4A, B ) elongate, about 1.00 mm, moderately sclerotized; phallobase parallel-sided; only apical part of parameres visible in basal 1/3 of penis; penis elongate, about 3.3 times as long as phallobase; nearly straight at basal 1/2, than tapering toward rounded apex; penis in lateral view with apex feebly sinuated at apical 1/2, subparallel in basal 1/2.

Female. Externally similar to male, without apparent sexual dimorphism. The sternite VII slightly wider in female. Tergite VIII ( Fig. 3F ) semicircular, bearing setae in caudal part. Sternite VIII ( Fig. 3G ) semicircular, with a long median strut, sparsely bearing setae in caudal margin. PW/PL 1.20–1.30 (1.25, n=2); EL/EW 1.60–1.61 (1.61, n=2); EL/PL 2.46–2.60 (2.53, n=2); EW/PW 1.24–1.27 (1.26, n=2); TL/EW 2.31–2.45 (2.38, n=2). Ovipositor ( Fig. 3H ) relatively short; stylus very short; apical part of coxite projecting laterally.

Male (n=5): TL 2.26–2.51 (2.37) mm; PW 0.75–0.84 (0.79) mm; PL 0.61–0.67 (0.64) mm; EL 1.58–1.71 (1.63) mm; EW 0.93–1.02 (0.98) mm. Female (n=2): TL 2.31–2.45 (2.38) mm; PW 0.77–0.81 (0.79) mm; PL 0.62–0.64 (0.63) mm; EL 1.59–1.60 (1.60) mm; EW 0.99–1.00 (0.99) mm.

Distribution. Japan (Kyushu: Kumamoto and Miyazaki prefectures).

Etymology. The body color of this species is red, like a flame. Also, the type locality, Kumamoto Prefecture, used to be called Hi-no-kuni (= land of fire). Therefore, the Latin adjective flammeus, which means fiery or flaming, was used as the species name.

Japanese name. Kaen-tsuya-doromushi

Biology. Although this species was collected in the riffles ( Fig. 7 ), the number of individuals was low in all localities. Around the type locality is a lot of spring waters, and since this species was found only in winter, it is possible that it lives mainly in ground water.

Key to the species and subspecies of the genus Urumaelmis

1 Body larger, TL 2.3–2.5 mm. Median groove of pronotum reaching base. Elytral carinae on intervals VI from base to apex..................................................................................... .. U. flammea sp. nov.

- Body smaller, TL 1.7–2.2 mm. Median groove of pronotum not reaching base. Elytral carinae on intervals VI only in anterior and apical part........................................................................................ 2

2 Elytra shining, punctures of each stria less feeble. Each side of pronotum slightly sinuate near base. Yaku-shima Is., Amami Isls., Okinawa Isls........................................................................... U. uenoi uenoi

- Elytra subopaque, punctures of each stria very feeble. Lateral sides of pronotum not sinuate near base. Kuchino-shima Island (Tokara Isls.)............................................................................ U. uenoi tokarana

Figures

FIGURE 1. Habitus of Urumaelmis flammea sp. nov. A, Holotype, in dorsal view; B, ditto in lateral view. Scale bar = 0.5 mm.

FIGURE 2. SEM photographs of Urumaelmis flammea sp. nov. A, Head and pronotum; B, ventral surface of the head and prosternum; C, elytra in dorso-lateral view; D, ventral surface of the mesoventrite, metaventrite and abdomen. Scale bar = 0.5 mm.

FIGURE 3. Urumaelmis flammea sp. nov. A–E: Male, paratype, A, Antenna; B, mandible; C, tergite VIII; D, sternite VIII; E, sternite IX; F–H: Female, paratype, F, tergite VIII; G, sternite VIII; H, ovipositor.

FIGURE 4. Aedeagus of Urumaelmis spp. in lateral (A, C) and dorsal (B, D) views: A, B, U. flammea sp. nov.; C, D, U. uenoi uenoi (Nomura, 1961).

FIGURE 5. Urumaelmis uenoi uenoi (Nomura, 1961). A, Head and pronotum; B, ventral surface of the head and prosternum; C, elytra in dorso-lateral view; D, ventral surface of the mesoventrite, metaventrite and abdomen. Scale bar = 0.5 mm.

FIGURE 6. Habitus photographs of living specimens of Urumaelmis. A, U. flammea sp. nov., Yamato-cho, Kumamoto Pref., Kyushu, Japan; B, U. uenoi uenoi (Nomura, 1961), Amami-oshima Is., Kagoshima Pref., Ryukyu, Japan.

FIGURE 7. Type locality of Urumaelmis flammea sp. nov.