Georissus (Neogeorissus) takahashii, Yasuda & Yoshitomi, 2022

Yasuda, Kohei & Yoshitomi, Hiroyuki, 2022, Revision of the genus Georissus (Coleoptera, Hydrophiloidea, Georissidae) of Japan, European Journal of Taxonomy 817 (1), pp. 111-142 : 131-133

Georissus (Neogeorissus) takahashii sp. nov.

urn:lsid:zoobank.org:act:373E0934-2F9D-49BA-96E5-BEBE3023B988

[Japanese name: Takahashi-marudoromushi]

Figs 2F , 5G–H , 6G–H , 7G–H , 8G–H , 9F–G , 10E , 11C, G ; Table 2

Diagnosis

This species is easily distinguished from other Japanese species of Georissus by the elevated intervals 2, 4, 6.

Etymology

This species name is dedicated to Dr Keiichi Takahashi, the collector of the type series.

Material examined

Holotype JAPAN – Okinawa: Iriomote-jima • ♂; Nishifunatsuki-gawa ; 23 Oct. 1995; K. Takahashi leg.; EUMJ.

Paratypes JAPAN – Shikoku : Kochi Pref. • 2 ex.; Shimanto-shi, Shimoda-Tadenogawa ; 27 Jul. 2009; T. and T. Miyata leg.; EUMJ • 24 ex.; Shimanto-shi, Shimanto-gawa ; 23 Jul. 2011; T. and T. Miyata leg.; EUMJ. – Okinawa : Okinawa-jima • 1ex., Isagawa, Nago-shi ; 1 Sep. 2021; M. Nagatsuka leg.; light trap; HOWP • 1 ex.; Nago-dake, Nago-shi ; 22 Jun. 2006; T. Kato leg.; EUMJ. – Okinawa : Ishigaki-jima • 1 ex.; Takeda-rindo ; 24°24′11.557″ N, 124°10′01.638″ E; 150 m alt., 25 Jun. 2010; T. Shimada leg.; EUMJ • 11 ex.; Takeda-rindo ; 24°24′13.597″ N, 124°10′49.973″ E; 140 m alt.; 25 Jun. 2010; T. Shimada leg.; EUMJ • 1 ex.; Omoto-rindo ; 23 Mar. 1995; M. Kimura leg.; EUMJ • 3 ex.; Omoto-rindo ; 26 Mar. 1996; K. Takahashi leg.; EUMJ • 2 ex.; 23 Oct. 1995; K. Takahashi leg.; EUMJ. – Okinawa : Iriomotejima • 4 ex.; Nishifunatsuki-gawa ; 24 Mar. 1995; M. Kimura leg.; EUMJ • 2 ex.; Takeda ; 26 Oct. 1998; K. Takahashi leg.; EUMJ • 3 ex.; Taisho-ike ; 25 Aug. 1994; M. Satô leg.; EUMJ • 2 ex.; Taisho-ike ; 26 Aug. 1994; M. Satô leg.; EUMJ • 1 ex.; Airagawa-rindo ; 2 Mar. 1998; I. Matoba leg.; EUMJ • 1 ex.; Ohtomi ; 20 Nov. 2003; Y. Hirano leg.; EUMJ .

Description

COLORATION ( Fig. 2F ). Light reddish brown, matt. Body surface often covered with greyish to white substance.

HEAD ( Fig. 6G–H ). Clypeus uneven, bearing a few large granules sparsely on median portion; slr consisted of granules, anterior granules distinct, but posterior ones indistinct; reaching to posterior third of frons, posteriorly connected to smb by an arc of sparsely arranged granules and formed a pair of rounded foveae; smb consisted of tubercles and granules; lsa with small indistinct granules sparsely.

PRONOTUM ( Fig. 7G–H ). Relatively small, widest in the anterior third. Anterior portion provided with granules and pits sparsely; anterior margin slightly crenellated; smlg relatively narrow, provided with longitudinal row of small pits. Posterior portion strongly convex than anterior portion; cd rhomboid and large, with granules on only lateral portion; sdp oblong oval, larger than cd, with a few granules; slb poorly developed, with indistinct granules; pg wide and triangular, not reaching median portion of sdp; sdn well developed, having a few teeth.

ELYTRA. Humeral bulges distinct, bearing granules. Intervals 2, 4, 6 highly elevated, with distinct granules. Elytral punctures regular square, seriate and distinct. Lateral ridges on each elytron highly elevate, bearing distinct granules. Hind wings fully developed.

ABDOMEN ( Fig. 8G–H ). Lateral margin of ventrites uniformly narrowing posterior. Ventrite 1 with small and sparse granules. Granulation of ventrites 2‒5 indistinct.

MALE GENITALIA ( Fig. 9F–G ). Aedeagus 0.32 mm long. Parameres shorter than phallobase, their basal portions combined as wide as anterior portion of phallobase; lateral margins bulbous at basal portion. Median lobe longer than parameres, widening basally, obtuse at apex; basal struts long. Phallobase about 2.2 times as long as wide, subparallel-sided; posterior portion with large basal foramen.

FEMALE GENITALIA. Latero-tergites 8 ( Fig. 10E ) forming obtuse angle; apex strongly incurved. Setae of gonostylus short. Spermatheca ( Fig. 11G ) curved oval, relatively narrowing at apical portion. Bursal sclerite ( Fig. 11C ) large and almost symmetrical, slightly sclerotized.

Biological notes

This species was collected under rocks near a river (Y. Hisasue pers. com.). Specimens from Kochi Prefecture were collected using a car net trap.

Distribution

Japan: Shikoku ( Kochi Pref.), Okinawa (Okinawa-jima, Ishigaki-jima, Iriomote-jima) ( Fig. 13 ).

Figures

Fig. 2. Dorsal view of Georissus spp. A. G. (G.) canalifer Sharp, 1888. B. G. (G.) babai Satô, 1970. C. G. (Ni.) granulosus Satô, 1972. D. G. (Ne.) japonicus Satô, 1972. E. G. (Ne.) kurosawai Nakane, 1963. F. G. (Ne.) takahashii sp. nov., holotype, ♂ (EUMJ). G. G. (Ne.) satoi sp. nov., holotype (EUMJ). Scale bars = 0.5 mm.

Fig. 5. Dorsal habitus of Georissus spp. A. G. (G.) canalifer Sharp, 1888. B. G. (G.) babai Satô, 1970. C. G. (Ni.) granulosus Satô, 1972. D. G. (Ne.) japonicus Satô, 1972. E–F. G. (Ne.) kurosawai Nakane, 1963 from Hokkaido (E) and Nagano (F). G–H. G. (Ne.) takahashii sp. nov. from Kochi (G) and Okinawa (H). I. G. (Ne.) satoi sp. nov.

Fig. 6. Head of Georissus spp. A. G. (G.) canalifer Sharp, 1888. B. G. (G.) babai Satô, 1970. C. G. (Ni.) granulosus Satô, 1972. D. G. (Ne.) japonicus Satô, 1972. E–F. G. (Ne.) kurosawai Nakane, 1963 from Hokkaido (E) and Nagano (F). G–H. G. (Ne.) takahashii sp. nov. from Kochi (G) and Okinawa (H). I. G. (Ne.) satoi sp. nov.

Fig. 7. Pronotum of Georissus spp. A. G. (G.) canalifer Sharp, 1888. B. G. (G.) babai Satô, 1970. C. G. (Ni.) granulosus Satô, 1972. D. G. (Ne.) japonicus Satô, 1972. E–F. G. (Ne.) kurosawai Nakane, 1963 from Hokkaido (E) and Nagano (F). G–H. G. (Ne.) takahashii sp. nov. from Kochi (G) and Okinawa (H). I. G. (Ne.) satoi sp. nov.

Fig. 8. Ventrites of Georissus spp. A. G. (G.) canalifer Sharp, 1888. B. G. (G.) babai Satô, 1970. C. G. (Ni.) granulosus Satô, 1972. D. G. (Ne.) japonicus Satô, 1972. E–F. G. (Ne.) kurosawai Nakane, 1963 from Hokkaido (E) and Nagano (F). G–H. G. (Ne.) takahashii sp. nov. from Kochi (G) and Okinawa (F). I. G. (Ne.) satoi sp. nov. Abbreviation: vt = ventral teeth. Scale bars = 100 μm.

Fig. 9. Male aedeagus of Georissus spp. A. G. (G.) canalifer Sharp, 1888. B. G. (G.) babai Satô, 1970. C. G. (Ni.) granulosus Satô, 1972. D. G. (Ne.) japonicus Satô, 1972. E. G. (Ne.) kurosawai Nakane, 1963. F–G. G. (Ne.) takahashii sp. nov. from Kochi (F) and Okinawa (G). H. G. (Ne.) satoi sp. nov. Scale bar = 0.1 mm.

Fig. 10. Female ovipositor of Georissus spp. A. G. (G.) canalifer Sharp, 1888. B. G. (G.) babai Satô, 1970. C. G. (Ne.) japonicus Satô, 1972. D. G. (Ne.) kurosawai Nakane, 1963. E. G. (Ne.) takahashii sp. nov. F. G. (Ne.) satoi sp. nov. Abbreviations: gsty = gonostylus; ltg8 = latero-tergite 8. Scale bar = 0.1 mm.

Fig. 11. Female genital organs of subgenus Neogeorissus spp. A–D. Bursal sclerite. E–H. Spermatheca. A, E. G. (Ne.) japonicus Satô, 1972. B, F. G. (Ne.) kurosawai Nakane, 1963. C, G. G. (Ne.) takahashii sp. nov. D, H. G. (Ne.) satoi sp. nov. Scale bar = 0.1 mm.

Fig. 13. Distribution map of Georissus spp. Russian localities for Georissus (G.) canalifer Sharp, 1888 and G. (Ne.) japonicus Satô, 1972 are omitted.