Anacaena kumejimana, Minoshima & Kamite & Fikáček, 2023

Minoshima, Yusuke N., Kamite, Yuuki & Fikacek, Martin, 2023, The genus Anacaena Thomson from the Ryukyu Archipelago of Japan (Coleoptera, Hydrophilidae), Deutsche Entomologische Zeitschrift 70 (1), pp. 143-157 : 143

publication ID	https://dx.doi.org/10.3897/dez.70.96994
publication LSID	lsid:zoobank.org:pub:12B52C90-3F09-4093-9DDF-2A89DB92255C
persistent identifier	https://treatment.plazi.org/id/F4E63981-8151-4E0B-8951-4552EC89AD32
taxon LSID	lsid:zoobank.org:act:F4E63981-8151-4E0B-8951-4552EC89AD32
treatment provided by	Deutsche Entomologische Zeitschrift by Pensoft
scientific name	Anacaena kumejimana
status	sp. nov.

Treatment

Anacaena kumejimana sp. nov.

Figs 1A-C View Figure 1 , 3A, F, J View Figure 3 , 4A View Figure 4 , 5H, I View Figure 5 , 6A, B View Figure 6

Type locality.

Japan, Okinawa-ken (Prefecture), Kumejima I., Suhara.

Type series.

Holotype: Japan • male; "KUMEJIMA JPN" / “Suhara” / “Kumejima-chô” // "19. V. 2007" / "Y. Kamite leg." // “spec.#” / “20-138” // “HOLOTYPE” / “ANACAENA” / “kumejimana” / "des. YN Minoshima 2021"; KMNH. Paratypes: Japan - Okinawa Pref., Kumejima I. • 1 male, 2 females, 2 exs; same collection data as holotype; KMNH, YKC • 1 ex.; Daruma-yama; 21 May 2007; Y. Kamite leg.; YKC • 1 ex.; Nakandakari; 20 May 2007; Y. Kamite leg.; YKC • 1 ex.; Shirase-gawa-jôryû (upstream of Shirase-gawa R.); 19 May 2007; Y. Kamite leg.; YKC.

Diagnosis.

Pronotum dark brown to black, with broad yellowish lateral margin. Antenna with eight antennomeres; antennomere 3 narrow. Maxillary palpus yellowish with very slightly infuscate apex. Pronotum with very fine and sparsely distributed ground punctation consisting of uniformly-sized punctures. Elytra with yellowish spot around scutellar shield. Metafemoral pubescence with horizontal hairline. Median lobe wide, elongate triangular with narrow basal apophyses. Gonopore large, situated at apex. Parameres widest in basal half, then slightly attenuated apically, rounded apically with weak inner angle. Lateral margin of paramere weakly sinuate in dorsal view. Phallobase as long as or slightly shorter than paramere, nearly parallel-sided in basal half, then narrowing to somewhat narrow and short manubrium.

Differential diagnosis.

This species is similar to A. okinawana and A. torikaii in size and external features. Based on the observation of specimens available in this study, dorsal colouration of pronotum and elytra (Fig. 1C View Figure 1 ) and aedeagus morphology (Fig. 4A View Figure 4 ) separate these species.

Anacaena kumejimana has a light yellow spot on the proximal medial portion of each elytron (Fig. 1C View Figure 1 ), whereas A. okinawana does not have such distinct spot (the proximal areas may be only indistinctly paler) and A. kumejimana has a broader yellowish margin of the pronotum than A. okinawana (Fig. 1A, C View Figure 1 ). Lateral face of parameres is convex in the basal third in A. kumejimana (Fig. 4A View Figure 4 ), whereas convexity is restricted to the more basal portion in A. okinawana (Fig. 4C-F View Figure 4 ). This results in a different lateral margin of the lateral face of the paramere in dorsal view. Wide median lobe separate A. kumejimana (Fig. 4A View Figure 4 ) and A. okinawana (Fig. 4C-F View Figure 4 ) from A. torikaii (Fig. 4B View Figure 4 ). The median lobe is nearly as long as parameres in A. kumejimana (Fig. 4A View Figure 4 ), whereas slightly longer than the parameres in A. okinawana (Fig. 4C-F View Figure 4 ); the apex of the median lobe is reaching close to the parameral apices in A. okinawana .

Anacaena yunnanensis Orchymont, 1942 (the A. yunnanensis -group sensu Komarek 2012) known from China and A. zamboangana Komarek & Freitag, 2014 from Mindanao I., the Philippines, seem to be similar to A. kumejimana ( Komarek 2012; Komarek and Freitag 2014), but the extent of the metafemoral pubescence separate the Ryukyu species: it has a horizontal borderline (Fig. 3J View Figure 3 ), compared to rounded borderline in the Chinese and Philippine species (e.g., fig. 99 in Komarek 2012, 72 in Komarek and Freitag 2014).

Description.

Body 2.1-2.3 mm in length, oval, slightly attenuated posteriad (Fig. 1C View Figure 1 ). Colour (Fig. 1A-C View Figure 1 ). Head black, lateral part of clypeus yellowish. Pronotum and elytra dark brown; margins of pronotum broadly yellowish; elytra with yellowish patch at anteromesal part around scutellar shield. Ventral face dark brown, legs slightly paler. Maxillary palpus yellowish with very slightly infuscate apex.

Head. Labrum with a fringe of long erect setae. Ground puncture of clypeus and frons fine, densely arranged; interspace between punctures ca. 2-4 times the width of a puncture. Presence of fine setae on clypeus ambiguous (possibly already broken when collected or during preparation). Frontoclypeal sulcus indistinct. Systematic punctures on clypeus and frons slightly larger than ground punctures, each bearing a fine seta. Systematic punctures of clypeus sparsely distributed. Systematic punctures of frons on anterolateral and posterolateral parts close to compound eye and frontoclypeal sulcus.

Antenna with eight antennomeres. Scape stout, moderately long. Antennomere 2 stout, somewhat conical, ca. as long as antennomeres 3 and 4 combined; antennomere 3 narrow; antennomere 4 wider than 3; antennal club longer than antennomeres 2-5 combined. Maxillary palpus short (Fig. 3A View Figure 3 ); palpomere 2 stout, longer than palpomere 3; palpomere 3 short, about half as long as palpomere 4; palpomere 4 longest, shorter than palpomeres 2 and 3 combined. Labial palpus short, shorter than width of mentum. Mentum ca. 1.7 times wider than long, subtrapezoidal, rounded anteriorly with median depression; lateral margin with lateral angle but generally indistinct (this character was observed without dissection of head appendages, thus not very accurate) (Fig. 3F View Figure 3 ). Ground punctation on mentum fine, rather sparsely distributed. Lateral margin of mentum with fringe of fine setae.

Thorax. Pronotum with very fine and sparsely distributed ground punctation consisting of uniformly sized punctures. Systematic punctures on pronotum arranged as irregular transverse row along anterolateral and posterolateral areas. Prosternum weakly and evenly convex.

Ground punctation on elytra coarser than that of head and pronotum; punctures rather densely distributed; interspaces between punctures ca. 1-3 times the width of a puncture. Mesoventrite with median process pointed apically; process as subtrigonal pyramid with posterior transverse and anterior median longitudinal carinas. Metaventrite with inverted triangular elevated portion medially, with small, oval, postero-medial glabrous area.

Metafemora pubescent in anterior half of basal portion (Fig. 3J View Figure 3 ), excluding apical area; hairline indistinct along basal part.

Abdomen. Aedeagus (Fig. 4A View Figure 4 ; see also Fig. 5H, I View Figure 5 ): Median lobe wide, elongate triangular with narrow basal apophyses, ca. 2.2 times longer than its greatest width, dully pointed apically, as long as parameres. Basal apophysis weakly incurved apically. Gonopore large, situated at apex of median lobe. Parameres widest in basal half, then slightly attenuated apically, rounded apically with weak inner angle; apical third of dorsal parameres membranous. In dorsal view, lateral margin of paramere weakly sinuated. Lateral face of paramere convex at basal third. Dorsal inner margin of parameres sinuated. Phallobase as long as or slightly shorter than paramere, nearly parallel-sided in basal half, then narrowing to somewhat narrow and short manubrium; borderline between membrane and sclerite (unpigmented and pigmented area) of ventral face of phallobase very indistinct.

Distribution.

Kumejima I.

Habitat.

Aquatic species. Examined specimens were collected in a shallow small pool at the side of a stream (Fig. 6A View Figure 6 ). The specimen from Nakandakari was collected from a pond (Fig. 6B View Figure 6 ).

Etymology.

Named after the type locality: Kumejima I., Japan.