Chikunia subrapulum ( Zhu, 1998 ), 2023

Brindha, T R, Prabhu, K, Jones, Sumathi, Janaki, C S, Sheriff, Dhastangir, Kumar, Hayagreva Muttevi, Kalaivani, S & Lakshmi, Deepa, 2023, New Records of Chikunia subrapulum (Zhu, 1998), n. comb., (Araneae: Theridiidae) from Japan, with Taxonomical and Nomenclatural Notes, Bulletin of the National Museum of Nature and Science. Series A, Zoology 49 (4), pp. 123-127 : 124-126

Chikunia subrapulum ( Zhu, 1998) , n. comb.

[Japanese name: Kabura-himegumo]

( Figs. 1–9 )

Chrysso subrapulum Zhu, 1998, p. 47 , 65, 361, 390, fig. 37 A–C,

♂ holotype from Hefeng County (29.48N, 110.00E), Hubei Province, China, 1–VI–1989, M.-S. Zhu leg., preserved in the Chinese Academy of Sciences , not examined. — Song, Zhu & Chen, 1999, p. 107, fig. 50 M–N; Zhu et al. 2005, p. 496 .

Chrysso subrapula Zhu and Zhang, 2011, p. 88 , fig. 49 A–C; WSC, ver. 24, 2023, the list for Theridiidae . — Incorrect emendation of the species name. New synonymy.

Theridiidae sp.: Bando, 2021, p. 3, fig. 14,

1 ♀, Nakao, Funatsu, 30–VII–2020, 1 ♀, Kamikaitsu, Aikawa, 3– VIII–2020, both from Kaiyo-cho, Kaifu-gun, Tokushima Prefecture, Shikoku, Japan, H. Bando leg., preserved in the Tokushima Prefectural Museum ( TKPM), not examined.

Etymology. The modification of the ending of the species name made by Zhu and Zhang (2011) was grammatically incorrect and was regarded as the suggestion of a new name by an incorrect emendation. The present authors have changed the species name back to the original spelling in accordance with the terms (article 11.9, 33.2 and others) of the International Code of Zoological Nomenclature ( ICZN). In detail, Zhu (1998) named it sub- + rapulum because of its resemblance to Theridion rapulum Yaginuma, 1960 , originally described from Japan. However, the Japanese spider has a different name (a senior synonym), Chikunia albipes ( Saito, 1935) , at the present, and its distributional range extends to Korea, China and the Russian Far East as well as Japan. Theridion rapulum was transferred from its original genus Theridion Walckenaer, 1805 to Chrysso O. Pickard-Cambridge, 1882 by Yoshida (1993) and synonymized with Theridula albipes Saito, 1935 by Yoshida (2001), and finally, further transferred to the genus Chikunia established with this species as the type species by Yoshida (2009 a). Although the motive for naming of Theridion rapulum was not stated in the original description, Yaginuma explained its etymology on another occasion. In Yaginuma, Hirashima and Okuma (1990), p. 142, they stated that rapulum is a Latin word (a neuter noun) meaning a little turnip (rapum with diminutive) because the shape of the abdomen of the spider resembled the shape of the vegetable. Therefore, the species name made by a noun in apposition does not change its ending when the gender of the genus changes. The problem would not have arisen if the genitive case of the noun, rapuli, or the adjective rapinus, -a, -um or rapiformis, -is, -e had been used, but the word used in reality is clearly the nominative of a noun. Moreover, because Latin grammar indicates that the prefix sub- changes to sur- when attached to a word beginning with r, the species name made by sub - + rapulum should be expressed as surrapulum in the nominative case, and surrapuli in the genitive case. Unfortunately, this grammatically correct change is not permissible under the agreement of ICZN, thus the original spelling subrapulum has to be maintained.

Specimens examined. 1 ♀, 10–IX–2015, 1 ♀1 ♂, 11– VIII –2016, 2 ♂, 12– VI –2017, 3 ♀, 24– VIII –2017, 1 ♀, 7–IX–2018, 1 ♂, 3– VI –2020, Ikenotaira , Tatsue , Iida-shi , Nagano Pref., Honshu, Japan (35.4502N, 137.8422E); 1 ♂, 17– VI –2021, Shimo-hisakata-kakinosawa, Iida-shi , Nagano Pref., Honshu, Japan (35.4607N, 137.8499E); 1 ♀, 21– VIII –1990, Sagasawa , Kadonohara , Amagi-yugashima-cho, Tagata-gun, Shizuoka Pref., Honshu, Japan (34.9007N, 138.9239E); 7 ♀, 7–IX–2013, Takitaniike , Makiyama , Iga-shi, Mie Pref., Honshu, Japan (34.8840N, 136.1117E); 7♀juv. 2♂juv., 12–IV–2008, 1 ♀, 27–IV–2008, 1 ♀1 ♂, 9– V – 2008, 6 ♀1 ♂, 23– V –2008, 1 ♀, 12– VI –2009, 8 ♀, 13– VI –2009, 9 ♀1 ♂, 9– VII –2010, Higashi-iketani , Hojo-cho-higashitakamuro, Kasai-shi, Hyogo Pref., Honshu, Japan (34.9159N, 134.8485E); 1 ♀1 ♂, 13– VIII –2011, Tsurarakannon , Wajikigo , Naka-cho , Naka-gun, Tokushima Pref., Shikoku, Japan (33.8672N, 134.4962E); 3 ♀, 19–IX–2011, Oto , Kitagawauchi , Minami-cho , Kaifu-gun, Tokushima Pref., Shikoku, Japan (33.7669N, 134.5400E); 1 ♀, 30–IX–2013, Ikenouchi , Awai-cho , Kanonji-shi, Kagawa Pref., Shikoku, Japan (34.0711N, 133.7136E), all the above specimens were collected by K. Kumada; 1 ♀, 21– VIII –1989, Imuta-ike , Imuta , Kedoin-cho , Satsuma-gun , Kagoshima Pref., Kyushu , Japan (31.8144N, 130.4659E), S. Inaba leg. Of these, voucher specimens are deposited in the arachnid collection of the Department of Zoology , National Museum of Nature and Science, Tsukuba, Japan.

Diagnosis. The species is transferred from its original genus Chrysso O. Pickard Cambridge, 1882 to the genus Chikunia Yoshida, 2009 based on the following characteristics: Legs of the females of this species are short, the total length of the first patella and tibia of the palp is 1.4 times the length of the carapace in dorsal view, whereas that of Chrysso species is more than 1.8 times. The shoulders of each side of the female abdomen are rounded, projected and expanded horizontally, the posterior end (tail) of the abdomen is long, pointed and projecting beyond the spinnerets. The male abdomen is ovoid, unscaled, and the shape of embolic part with the embolus and the conductor is triangular. This species is closest to Chikunia albipes .

Description based on the Japanese specimens (1 ♀1 ♂ from Higashi-iketani, Hojocho-higashitakamuro, Kasai-shi, Hyogo Pref., Honshu, Japan, 9–VII–2010). Female ( Fig. 1 , left): total length 2.78 mm. Carapace 0.84 mm long and 0.76 mm wide. Abdomen 2.10 mm long and 2.24 mm wide. Length of leg segments (in mm): [femur+patella+tibia+metatarsus+tarsus=total]: I, 1.28+0.32+0.84+0.96+0.40=3.80; II, 0.86+ 0.28+0.44+0.58+0.34=2.50; III, 0.56+0.24+ 0.24+0.34+0.28=1.66; IV, 1.10+0.30+0.62+ 0.66+0.40=3.08. Leg formula: 1-4-2-3. Prosoma oval. Eyes almost same in size except PLE smaller than the others. AME=ALE=PME> PLE (5: 5: 5: 4). AME–AME>AME–ALE (3: 1), PME–PME>PME–PLE (4: 5). The anterior eye row recurved and the posterior eye row slightly recurved in dorsal view. Median ocular area: anterior side>posterior=length (6: 5: 5). Clypeus longer than AME–AME (2: 1). Chelicerae not very long and thick (1.90 mm), with two projections (possibly teeth) near the apex. Labium transverse, longer (5: 3), fused with sternum. Sternum inverted triangular, equal in length and width. Shoulders on both sides of abdomen rounded, swollen and expanded laterally; abdomen with long caudal end, projecting beyond the spinnerets and pointed. The length of first patella and tibia 1.4 times the carapace length. Epigynum ( Figs. 5–8 ) expanded and protruding ventrad.

Male ( Fig.1 right): total length 1.81 mm. Carapace 0.80 mm long and 0.66 mm wide. Abdomen 1.00 mm long and 1.02 mm wide. Length of leg segments (in mm): I, 1.50+0.36+0.94+1.18+0.41 =4.39; II, 1.05+0.32+0.59+0.73+0.38=3.07; III, 0.60+0.24+0.33+0.46+0.26=1.89; IV, 1.18+ 0.28+0.75+0.82+0.40=3.43. Leg formula: 1-4- 2-3. Prosoma oval. Eyes almost equal in size except PLE smaller than the others. AME= ALE=PME>PLE (5: 5: 5: 4). AME–AME> AME–ALE (4: 1), PME–PME>PME–PLE (3: 4). The anterior eye row recurved and the posterior eye row slightly recurved in dorsal view. Median ocular area: anterior side> posterior side=length (6: 5: 5). Clypeus longer than AME–AME (2: 1). Chelicerae not very long and thick (1.90 mm), with two projections (possibly teeth) near the apex. Labium transverse, longer (2: 1), fused with sternum. Sternum inverted triangular, equal in length and width. Abdomen spherical. The conductor of palp and embolus forming a triangle ( Figs. 3–4 ).

Distribution. Japan (Honshu, Shikoku and Kyushu), China (Hubei, Henan, Guizhou and Yunnan).

Remark. By the reviewer`s suggestion, the authors confirmed that the unknown theridiid spider recorded by Bando (2021) from Tokushima Prefecture was the same species as the present one. Its collection record has been added to the transition list of scientific names above.

Figures

Figs. 1–9. Chikunia subrapulum (Zhu, 1998). 1–2, female and male, dorsal view; 3–4, male left palp, ventral view; 5–6, epigynum, ventral view; 7–8, epigynum, lateral view; 9, chelicerae, ventral view. Scales: 1–2: 1mm; 3–9: 0.1mm.