Bryothinusa okinawana, Liu & Ono & Maruyama, 2021

Liu, Tian-tian, Ono, Hiroki & Maruyama, Munetoshi, 2021, Revision of the intertidal rove beetle genus Bryothinusa from Japan (Coleoptera: Staphylinidae: Aleocharinae), Acta Entomologica Musei Nationalis Pragae (Acta. Ent. Mus. Natl. Pragae) 61 (1), pp. 163-201 : 187-192

publication ID	https://doi.org/ 10.37520/aemnp.2021.009
publication LSID	lsid:zoobank.org:pub:27EA8466-6B29-40F4-8236-DD49061C523B
persistent identifier	https://treatment.plazi.org/id/03CB023B-AC12-FF9F-4E51-FC0615F8F7D8
treatment provided by	Carolina
scientific name	Bryothinusa okinawana
status	sp. nov.

Treatment

Bryothinusa okinawana View in CoL sp. nov.

( Figs 1M View Fig ; 2M View Fig ; 15 View Fig ; 22 View Fig )

(Japanese name: Okinawa-nagisa-hanekakushi)

Type material. Hඈඅඈඍඒඉൾ:J, JAPAN: Nൺඇඌൾං-ඌΗඈඍත: Gesashi,Higashison, Okinawa-jima, Okinawa-ken, 15.viii.2004, M. Moriguchi ( KUM). Pൺ*©ൺඍඒඉൾඌ: 1♀, Mage-shima (near Tanega-shima), Kagoshima-ken, 14.x.2000, M. Maruyama (under stone on sandy beach, in a port) ( KUM); 3 ♀♀, 3 unsexed spec., same data as holotype. ( KUM).

Description. Body ( Fig. 1M View Fig ) small, about 2.1–2.2 mm in length, covered with minute setae. Basically, yellowish brown. head and pronotum similarly coloured, elytra lightly paler than body colour, abdomen darkest; antenna, mouthparts and legs similarly coloured, lightly paler than head colour and paler toward apex.

Head oval, wider than long, shorter than pronotum and elytra; eyes ( Fig. 2M View Fig ) small, reniform, longer than 1/2 of head length, with 29–31 facets; antennal length shorter than distance from anterior margin of head to posterior margin of elytra; segment I as long as II, almost 2 times longer than III, and as long as XI; antennal segments I–IV and XI longer than wide; antennal segments V–X almost as long as wide.

Mouthparts ( Figs 15A–E View Fig ) with distribution of labral setae as in Figure 15A View Fig ; mandibles ( Fig. 15B View Fig ) elongate triangle, asymmetrical, right mandible with median tooth; median tooth shorter than 1/4 of mandibles; left mandible without tooth, blunt at apex; maxilla with apical margin of lacinia ( Fig. 15C View Fig ) at right angle and second spines not very small, at tip with two spines not closely interdigitating; 4 setae on inner margin of lacinia; labial palpus ( Fig. 15D View Fig ) with most setae located basally; mentum ( Fig. 15E View Fig ) with antero-lateral angles prolonged into spinose processes; anterior margin deeply truncate; small “v seta” of mentum lower than level of anterior margin.

Pronotum shorter than elytra, wider than head.

Elytra subquadrate, wider than pronotum; hind wings fully developed.

Male abdominal sternite VIII ( Fig. 15F View Fig ) with posterior margin obviously serrate. Median lobe of aedeagus ( Fig. 15H View Fig ) and dorsal view in Figure 15I View Fig ; paramere ( Fig. 15J View Fig ) elongate.

Female abdominal sternite VIII ( Fig. 15G View Fig ) with posterior margin slightly serrate but obviously smoother than in male. Spermatheca ( Fig. 15K View Fig ) simplified in shape, about half times coiled near base.

Measurements. BL 2.10–2.20, FBL 1.00–1.10, HL 0.33– 0.38, HW 0.40–0.43, PL 0.38–0.40, PW 0.43–0.45, EL 0.48–0.50, EW 0.50–0.51, HTL 0.33–0.36, AL 0.78–0.85, AS-I 0.10–0.13, AS-II 0.09–0.11, AS-III 0.05–0.06.

Differential diagnosis. In general appearance the species in is closely allied to B. moriguchii sp. nov., but easily distinguished from it by the shape of the spermatheca, and lack of large, thick spiniform seta at the antero-lateral part of the labrum, and the posterior margin of the tergite X being rounded medially.

Etymology. Toponym. Named after Okinawa, the type locality of this new species; adjective.

Distribution. Japan (Nansei-shotô: Kagoshima-ken: Tanega-shima; Okinawa-ken: Okinawa-jima).

Remarks. This species probably occurs in other areas, especially the coastline of southwest Japan. A distribution map of examined specimens of this species in Japan is illustrated in Figure 22 View Fig .

Bryothinusa nigra sp. nov.

( Figs 1N View Fig ; 16 View Fig ; 21B, D View Fig ; 22 View Fig )

(Japanese name: Kuro-nagisa-hanekakushi)

“ Bryothinusa nakanei ”: Sൺඐൺൽൺ (1971): 88 (misidentification); A*üඇ &

Jൾඈඇ (2004): 34 (misidentification; illustration of spermatheca);A*üඇ

et al. (2017): 307 (misidentification; in checklist of Staphylinidae

in Korea). Type material. Hඈඅඈඍඒඉൾ:J, JAPAN: HඈඇඌΗǕ: Mouth of Obitsu-gawa,

Kuroto, Kisarazu-shi, Chiba-ken, 24.i.2011, H. Ono (KUM).Pൺ*©ൺඍඒඉൾඌ: HඈඇඌΗǕ: 1 unsexed spec., same locality as holotype, 19.ii.2007, H.

Ono (KUM); 2 JJ 4 ♀♀, 15 unsexed spec., same locality as holotype, 12.iii.2009, H. Ono (KUM, NMPC, BMNH); 1 J 1 ♀, 5 unsexed spec., same locality as holotype, 16.iii.2009, H. Ono (KUM); 1 J 5 unsexed spec., same locality as holotype, 4.i.2010, H. Ono (KUM); 2 unsexed spec., same locality as holotype, 14.i.2011, H. Ono (KUM); 3 JJ 2 ♀♀, 17 unsexed spec., same data as holotype (KUM); 1 ♀, 3 unsexed spec., Edo-gawa, Gyôtoku, Ichikawa-shi, Chiba-ken, 18.vi.2012, H. Ono (KUM); 1 unsexed spec., Kushida-gawa, Matsunase-chô, Matsuzaka-shi, Mie-ken, 2.iv.2002, T. Wada (KUM). SΗංκඈκඎ: 1 ♀, 7 unsexed spec., Nio, Nio-chô, Kagawa-ken, 20.iv.2008, H. Fujimoto (KUM); 2 JJ 1 ♀, Kaigan-ji, Nishishirakata, Tadotsu-chô, Kagawa-ken, 31.iii.2008, H.

Fujimoto (KUM). KඒǕඌΗǕ: 2 JJ 1 ♀, 7 unsexed spec., Aiboshi-gawa, Aiboshi, Minamisatsuma-shi, Kagoshima-ken, 20.iv.2008, M. Maruyama (KUM). Nൺඇඌൾං-ඌΗඈඍත: 1 J 6 ♀♀, 19 unsexed spec., Uken-son, Edateku-jima (near Amami-Ôshima), Kagoshima-ken, 5.vi.2008, M.

Maruyama (KUM).

Description. Body ( Fig. 1N View Fig ) small about 2.0– 2.5 mm in length, covered with minute setae. Body almost black; elytra lighter than other parts; antenna and legs brown.

Head evenly rounded, more or less produced anteriorly, wider than long, almost as long as pronotum, shorter than elytra; eyes ( Fig. 2N View Fig ) large, setae present between about

32–33 facets, longer than 2/3 head length; antenna almost as long as distance from anterior margin of head to posterior margin of pronotum; segment I 1.3 times longer than II, almost 2.7 times longer than III, and longer than XI; antennal segments V–X almost as long as wide.

Mouthparts ( Figs 16A–E View Fig ) with distribution of labral setae as in Figure 16A View Fig , with large and thick spiniform seta at antero-laterally; mandibles ( Fig. 16B View Fig ) elongate triangle, asymmetrical, right mandible with median tooth; median tooth almost as long as 1/4 of mandibles; left without tooth, blunt at apex; maxilla with apical margin of lacinia ( Fig. 16C View Fig ) at tip with two spines very small and not closely interdigitating; 4 setae on inner margin of lacinia; labial palpus ( Fig. 16D View Fig ) with most setae located basally; mentum ( Fig. 16E View Fig ) with antero-lateral angles prolonged into spinose processes; anterior margin deeply truncate; small “v seta” far away from apical setae.

Pronotum shorter than elytra, wider than head.

Elytra subquadrate but wider than long, wider than pronotum; hind wings fully developed.

Male abdominal sternite VIII ( Fig. 16F View Fig ) with posterior margin slightly serrate. Median lobe of aedeagus ( Fig. 16H View Fig ) and dorsal view as in Figure 16I View Fig ; paramere ( Fig. 16J View Fig ) elongate.

Female abdominal sternite VIII ( Fig. 16G View Fig ) with posterior margin slightly serrate alike male. Spermatheca ( Fig. 16K View Fig ) very small, shorter than 0.25 mm.

Measurements. BL 2.00–2.50, FBL 1.00–1.30, HL 0.35– 0.40, HW 0.41–0.44, PL 0.31–0.42, PW 0.40–0.54, EL 0.41–0.46, EW 0.50–0.56, HTL 0.37–0.39, AL 0.65–0.70, AS-I 0.11–0.14, AS-II 0.08–0.10, AS-III 0.04–0.05. Differential diagnosis. In general appearance, the species is closely similar to B. nakanei and B. gangjinensis , but it is easily distinguished from them by a different shape and size of spermatheca. It differs from B. nakanei also by the shape of the posterior margin of tergite X (rounded medially in the new species).

Etymology. The species epithet, the Latin adjective niger (- a, - um), refers to the blackish colour of the body.

Distribution. Japan (Honshû: Chiba-ken, Kanagawa-ken, Mie-ken; Shikoku: Kagawa-ken; Kyûshû: Kagoshima-ken; Nansei-shotô: Kagoshima-ken: Edateku-jima); Korea.

Remarks. Sൺඐൺൽൺ (1971) illustrated the mouthparts and sexual organs of “ B. nakanei ” but the large, thick spiniform seta at the antero-lateral part of the labrum and the shape of aedeagus is very similar to those of B. nigra sp. nov. Therefore, we consider that the Figure 3 View Fig (Sൺඐൺൽൺ 1971) is of B. nigra sp. nov.

A*üඇ & Jൾඈඇ (2004) illustrated the spermatheca of “ B. nakanei ” based on the Korean specimens but its shape agrees well with that of B. nigra sp. nov.. Therefore, we consider that their figure (A*üඇ & Jൾඈඇ 2004: Fig. 18 View Fig ) represents the spermatheca of B. nigra sp. nov. The misidentification by A*üඇ & Jൾඈඇ (2004) was probably caused by the redescription of Sൺඐൺൽൺ (1971). See also the Remarks of B. nakanei below.

This species is found mainly west of Kantô District. A distribution map of examined specimens of this species in Japan is illustrated in Figure 22 View Fig .

Bryothinusa nakanei ( Sawada, 1955)

( Figs 1O View Fig ; 2O View Fig ; 17 View Fig ; 21B View Fig , D-F; 22)

(Japanese name: Nakane-nagisa-hanekakushi)

Halesthenus nakanei Sawada, 1955: 85 View in CoL (original description; type locality: Japan, Nansei-shotô, Tokara-rettô, Takara-jima).

Bryothinusa nakanei View in CoL : Sൺඐൺൽൺ (1971):87 (transferred from Halesthenus View in CoL ; redescription); Sൺඐൺൽൺ (1972): unnumbered table at end of article (characters); Mඈඈ*©ൾ et al. (1973): 74 (in key to species of Bryothinusa View in CoL ), 77 (nomenclatorial history; diagnosis); Mඈඈ*©ൾ & Lൾ*ûඇൾ*© (1975): 109–110 (in key to species of Bryothinusa View in CoL ), 111 (in tabular

key to known species of Bryothinusa ); Aඌ*üൾ (2004): 592 (in annotated catalogue of world species); Sආൾඍൺඇൺ (2004): 464 (in catalogue of Palearctic species); F*©ൺඇκ & A*üඇ (2011): 27 (in checklist); Sർ*ü*“අκൾ

& Sආൾඍൺඇൺ (2015):676 (in catalogue of Palearctic species); Lංඎ et al. (2020): 589 (in key to Japanese species), 592 (in checklist).

Type material examined. Hඈඅඈඍඒඉൾ:unsexed specimen (not dissected), JAPAN: Nൺඇඌൾං-ඌΗඈඍත: “ Halesthenus / nakanei / Sawada.// TAKARA- JIMA / ( TOKARA Is.) / 29.v.1953 / coll. S. Uéno / Holotype / 49-16”. Deposited in the Hokkaido University Museum.

Additional material examined. JAPAN: Nൺඇඌൾං-ඌΗඈඍත: 1 J, Mage -shima (near Tanega-shima), Kagoshima-ken, 14.x.2000, M. Maruyama (under stone on sandy beach, in a port); 8 JJ 6 ♀♀, 57 unsexed spec., Ôgomori, Takara-jima, Tokara-rettô, Kagoshima-ken, 3.vii.2019, T. Liu, N. Tsuji & H. Ono; 1 unsexed spec., same locality, 6.vii.2019, T. Liu, N. Tsuji & H. Ono; 2 ♀♀, 9 unsexed spec., Tean, Setouchi-chô, Amami -Ôshima, Kagoshima-ken, 19.vii.2007, M. Moriguchi; 2 JJ 2 unsexed spec., Chatan-chô, Okinawa-jima,Nansei-shôtô, Okinawa-ken, 26.v.2002, M. Moriguchi; 3 ♀♀, 9 unsexed spec., Senaha, Yomitani-son, Okinawajima, Okinawa-ken, 21.v.2004, M. Moriguchi; 1 J 1♀, 2 unsexed spec., Fuchaku, Onna-son, Okinawa-ken, 8.iv.2000, T. Watanabe; 2 JJ 3 ♀♀, 31 unsexed spec., Todoroki-gawa, Shiraho, Ishigaki-shi, Okinawa-ken, 29.iii.2010, T.Hayama; 2 ♀♀, 10 unsexed spec., Hira-kawa,Ishigaki-shi, Ishigaki-jima, Okinawa-ken, 29.iii.2010, T. Hayama; 2 ♀♀, 5 unsexed spec., Kabira-wan, Ôtake, Ishigaki-jima, Okinawa-ken, 3-11.vi.2000, S. Hori; 2 ♀♀, 11 unsexed spec., same locality, 1.vi.2003, M. Moriguchi; 2 JJ 1 ♀, 9 unsexed spec., same locality, 26.iii.2015, Y. Hisasue; 1 ♀, 2 unsexed spec., same locality, 11.iii.2000, T. Kurihara; 2 JJ 1 ♀, 50 unsexed spec., Nagura, Ishigaki-jima, Okinawa-ken, 21.iv.2009, M. Maruyama; 3 ♀♀, 5 unsexed spec., Nagura-anparu, Nagura, Ishigaki-shi, Ishigaki-jima, Okinawa-ken, 4.ii.2009, H. Ono; 1 J 1 unsexed spec., Nakasuji, Ishigaki-shi, Ishigaki-jima, Okinawa-ken, 12.iii.2000, T. Kurihara; 4 ♀♀, 8 unsexed spec., Nakama-gawa, Ôtomi, Iriomote-jima, Okinawa-ken, 19–20.iv.2009, M. Maruyama; 1 ♀, Mouth of Honeragawa, Takana, Taketomi-chô, Iriomote-jima, Okinawa-ken, 24.vi.2019, T.Liu & N. Tsuji; 2 unsexed spec., Mouth of Maira-gawa, Taketomi-chô, Iriomote-jima, Okinawa-ken, 21.iii.2000, T. Kurihara; 2 ♀♀, 53 unsexed spec., Haemida,Taketomi-chô, Iriomote-jima, Okinawa-ken, 19.iii.2000, T. Kurihara. Deposited at KUM but some will be distributed to NMPC and BMNH.

Redescription. Body ( Fig. 1O View Fig ) small, about 2.0– 2.2 mm in length, covered with minute setae. Abdomen almost black and darker than head and pronotum; elytra lighter than pronotum, clearly bicolour, base darker than apex; legs yellowish brown.

Head evenly rounded, more or less produced anteriorly, wider than long, shorter than pronotum and elytra; eyes ( Fig. 2O View Fig ) large, setae present between about 34–36 facets, slightly longer than 2/3 of head length; antenna almost as long as distance from anterior margin of head to posterior margin of pronotum; segment I 1.3 times longer than II, almost 2.8 times longer than III, and longer than XI; antennal segments VII–X slightly wider than long.

Mouthparts ( Figs 17A–E View Fig ) with distribution of labral setae as in Figure 17A View Fig , with large and thick spiniform seta at antero-laterally; mandibles ( Fig. 17B View Fig ) elongate triangle, asymmetrical, right with median tooth; median tooth shorter than 1/4 of mandibles; left mandible without tooth, blunt at apex; maxilla with apical margin of lacinia ( Fig. 17C View Fig ) at right angle; at tip with two spines not closely and second spine very small, not obvious; 6 setae on inner margin of lacinia; labial palpus ( Fig. 17D View Fig ) with most setae located basally; mentum ( Fig. 17E View Fig ) with antero-lateral angles prolonged into spinose processes; anterior margin deeply truncate; small “v seta” far away from apical setae.

Pronotum shorter than elytra, almost as wide as head.

Elytra subquadrate but wider than long, wider than pronotum; hind wings fully developed.

Male abdominal sternite VIII ( Fig. 17F View Fig ) with posterior margin slightly serrate; medial posterior margin of tergite X protruded ( Fig. 17H View Fig ). Median lobe of aedeagus and dorsal view as in Figures 17J, K View Fig ; paramere ( Fig. 17L View Fig ) elongate.

Female abdominal sternite VIII ( Fig. 17G View Fig ) slightly sunken at median posterior margin but wider and smoother than in male; medial posterior margin of tergite X more protruded than in male ( Fig. 17I View Fig ). Spermatheca ( Fig. 17M View Fig ) of complicated shape, about 2.5 times coiled near base.

Measurements. BL 2.00–2.20, FBL 1.10–1.20, HL 0.35– 0.38, HW 0.45–0.50, PL 0.40–0.41, PW 0.45–0.50, EL 0.48–0.50, EW 0.45–0.54, HTL 0.35–0.38, AL 0.75–0.80, AS-I 0.11–0.15, AS-II 0.09–0.11, AS-III 0.04–0.05.

Differential diagnosis. In general appearance the species is very similar to B. nigra sp. nov. and B. gangjinensis . In the shape of the spermatheca, the species is closely similar to B. moriguchii sp. nov. However, the new species is easily distinguished from B. nigra sp. nov. and B. gangjinensis by the medial posterior margin of tergite X being protruded and is different from B. moriguchii sp. nov. in the body colour being darker.

Distribution. Japan (Nansei-shotô: Kagoshima-ken: Tanega-shima, Takara-jima, Amami-Ôshima; Okinawa-ken: Okinawa-jima, Ishigaki-jima, Iriomote-jima).

Remarks. Sൺඐൺൽൺ (1955) originally described B. nakanei based on a single specimen from Takara-jima, Tokara-rettô, Nansei-shotô, without illustrating any sexual characters.

Sൺඐൺൽൺ (1971) redescribed “ B. nakanei ” in detail including the male aedeagus based on the “ holotype.” However, we examined the holotype of B. nakanei deposited in the late Dr. Takehiko Nakane collection of the Hokkaido University Museum and confirmed it was not dissected. Sൺඐൺ- ൽൺ (1971) also examined a male specimen of this species from Aburatsubo of Kanagawa, Honshû. The redescription is probably based on the specimen from Kanagawa. Moreover, the redescription does not coincide with the holotype but actually agrees well with the characteristics of B. nigra sp. nov. Bryothinusa nakanei is very similar to B. nigra sp.

nov. in general appearance and Sൺඐൺൽൺ (1971) probably confused them. As discussed in the Remarks of B. nigra sp. nov., A*üඇ & Jൾඈඇ (2004) described the spermatheca of “ B. nakanei ” from Korea but it was of the same shape as that of B. nigra sp. nov. Bryothinusa nakanei may not occur in Korea because it has not been found in temperate zones in Japan, but in Nansei-shotô, a subtropical zone.

This species likely occurs in other areas, mainly in Nansei-shotô. A distribution map of examined specimens of this species in Japan is illustrated in Figure 22 View Fig .