Nesticella terrestris (Yaginuma, 1970)

Ballarin, Francesco & Eguchi, Katsuyuki, 2023, Integrative taxonomic revision of the genera Nesticella and Howaia in Japan with the description of five new species (Araneae, Nesticidae, Nesticellini), ZooKeys 1174, pp. 219-272 : 219

Nesticella terrestris (Yaginuma, 1970)

Figs 6A-J , 7E-H , 15B , 16A (Japanese name: azuma-ko-horahimegumo アズマコホラヒメグモ)

Nesticus terrestris Yaginuma 1970: 390, figs 3-6, 8 (♀) (described ♂ refers to H. mogera ).

N. brevipes Yaginuma 1970: fig. 9 (♂, misidentification); Yamaguchi and Yaginuma 1971: 172, figs 1, 2 (♀, misidentification); Yaginuma 1972: 619, figs 3(?), 4 (♂♀, synonymized); Yaginuma 1977: 315, pl. 2, fig. 18 (♂); Yaginuma 1979: 275, pl. 6, figs 9, 10 (♂♀); Yaginuma 1986: 55, fig. 29.7 (♂♀); Namkung 2002: 80, fig. 12.4a, b (♂♀) (?); Kamura and Irie 2009: 353, figs 103-105, 107 (♂♀); Marusik and Kovblyuk 2011: 199, fig. 25.1, 2, 4, 5 (♂♀); Kim and Lee 2018: 26, fig. 11A-C (♂♀) (?).

Howaia brevipes Marusik and Crawford 2006: 187, figs 20, 32-33 (♂♀).

Type locality.

Japan, Tokyo Pref., Mt. Kagenobuyama.

Material examined.

Japan: Honshu Is.: Iwate Pref.: 1♀, Iwate-gun, Kuzumaki-machi , 4.Aug.1995, H. Okawa leg. (NSMT-Ar.11299, identified as N. brevipes ) ; Miyagi Pref.: 1♂, 1♀, Minamisanriku-cho, Mt. Tatsugane , 21. July. 2013, A. Tanikawa leg. (MNHAH) ; Akita Pref.: 1♀, Akita-shi, Shimokitateyanagitate, Akahira , 18.Jul.2005, A. Fukushima leg. (NSMT-Ar.17417, identified as N. brevipes ); Yamagata Pref. : 3♀, Oguni-machi, Tamagawanakazato , 18. July. 2010, A. Tanikawa leg. (MNHAH) ; 2♀, Nukumidaira , 18. July. 2010, A. Tanikawa leg. ; 1♀, Kotamagawa, 19. July. 2010, A. Tanikawa leg. (MNHAH) ; 1♀, Sakata-shi, Tamasudarenotaki Waterfall , 38.99706°N, 140.05332°E, 27.Aug.2019, Y. Suzuki leg. (YSPC) ; Ibaraki Pref.: 1♀, Tsukuba-shi, Oda, Mt. Hokyo-san , 36.15260°N, 140.11853°E, 22.Aug.2017, Y. Suzuki leg. (YSPC) ; 1♂, 1♀, Tsukuba-shi, Mt. Tsukuba , 36.22662°N, 140.09885°E, 29.Jun.2019, Y. Suzuki leg. (YSPC) ; Tochigi Pref.: 1♀, Imaichi-shi, Iwasaki , 12.Aug.1990, A. Tanikawa leg. (MNHAH) ; 1♀, Nikko-shi , 7.Jul.1996, Y. Suganami leg. (NSMT-Ar.17205, identified as N. brevipes ) ; Saitama Pref.: 1♂, 2♀; Iruma-gun, Motoyama, near Kamakita cave , Aza-ana cave , 11.Aug.1974, leg. Unknown (FBPC) ; 3♂, Hiki-gun, Ogawa-machi, Kami-furutera , Furutera-do cave , 6.Jul.2019, T. Hiramatsu leg. (FBPC) ; 1♂, 6♀, Chichibu-shi, Kuroya, Iwane-do cave , 36.055145°N, 139.114867°E, 06.Nov.2022, T. Nagai leg. (TNPC) ; Chiba Pref: 1♂, Kamogawa-shi, Kiyosumi , 35.13982°N, 140.17725°E, 20.Feb.2020, Y. Suzuki leg. (YSPC) ; Tokyo Pref.: 1♀ (holotype), Mt. Kagenobuyama , 20.Dec.1968, E. Shinkai leg. (epigyne dissected and not present in the vial) (NMST-Ar.72) ; 1♂, 4♀ (topotypes, ~ 3 km Est of the type locality area of the species), Hachioji-shi, Hachioji, trail near the Hachioji castle ruins, 339 m, scree in a narrow valley near a temporary creek, 35.64654°N, 139.25175°E, 31.May.2021, F. Ballarin leg. (FBPC) ; 1♂, 1♀, Hachioji-shi, Mt. Jinba , 27.May.1984, H. Ono leg. (NSMT-Ar.13401, identified as N. brevipes ) ; 1♀, Okutama-machi, Kaniwasawa , 35.83906°N, 139.07345°E, 27.Jun.2020, Y. Suzuki leg. (YSPC) ; 1♀, Nishitama-gun, Nippara, near Ichiishiyama Shrine , 1015 m, leaf litter in a beech forest, 35.85506°N, 139.03513°E, 5.May.2022, F. Ballarin leg. (FBPC) ; Kanagawa Pref.: 1♂, Kawasaki-shi, Tama-ku, Ikuta Ryokuchi , 29.Jun.1991, M. Ban leg. (NSMT-Ar.10062, identified as N. brevipes ) ; 1♀, Atsugi-shi, Nanasawa , 17.Apr.1997, M. Ban leg. (NSMT-Ar.10814, identified as N. brevipes ) ; Fukui Pref.: 1♀, Onyu-gun, Natashou, Nagatani , 30.Jul.2002, K. Kumada leg. (NSMT-Ar.15214, identified as N. brevipes ) ; Shizuoka Pref.: 1♂, 8♀, Tagata-gun, Amagiyugashima-cho, Mt. Ichiyama , 14.Feb.1983, K. Kumada leg. (NSMT-Ar.17762, identified as N. brevipes ) ; 2♀, Kamo-gun, Higashiizu, Mt. Amagi , 18.Oct.1986, A. Tanikawa leg. (MNHAH) ; 2♀, Fujinomiya-shi, Myojoyama Park , 17.Nov.2014, A. Tanikawa leg. (MNHAH) ; 1♀, Fujinomiya-shi, Hitoana, Shin-ana Cave (新穴), long and humid lava cave (temp: 11.7 °C, hum: 95.3%), 35.36406°N, 138.59478°E, 725 m, 3.Dec.2022, F. Ballarin leg. (FBPC) ; 2♀, Hamamatsu-shi, Tenryu-ku, Ryokukeidai , 34.86801°N, 137.79494°E, 2-3.Jan.2018, Y. Suzuki leg. (YSPC) ; 1♀, Susono-shi, Iwanami, Iwanami Fuketsu Wind Cave (岩波風穴), warm and humid lava cave (temp: 18.9 °C, hum: 99.9%), 35.21835°N, 138.92003°E, 255 m, 2.Dec.2022, F. Ballarin leg. (FBPC) ; Aichi Pref.: 1♀, Toyohashi-shi, Suse-cho, near the entrance of Susenoja-ana cave (嵩山蛇穴), 34.79678°N, 137.48575°E, litter of a mixed forest, 29.IX.2019, F. Ballarin leg. (FBPC) ; Mie Pref.: 2♀, Ise-shi, Ujitachi-cho, Naigu , Ise Jingu shrine, 8.Nov.2003, K. Kumada leg. (NSMT-Ar.14059) ; 1♂, 1♀, Kiya, Koumori-ana (こうもり穴), 27.Sep.-10.Oct.1980, Y. Terumi leg. (OMNH) ; Russia: Sakhalin Oblast: Moneron Is.: 1♂, 1♀, 23.Aug.2001, Y.M. Marusik leg. (YMPC, identified as N. brevipes ).

Diagnosis.

This species is closely related to N. brevipes and N. silvicola . But generally larger in size than the latter two species (females 2.31-3.30 vs 1.76-2.50 in N. brevipes and 1.84-1.94 in N. silvicola , see also Fig. 17A, B ). Male of N. terrestris can be distinguished from male of N. brevipes by the presence of a single, sharper distal process of paracymbium (Di), a stockier radical apophysis ending with a rounded tip (Ra), and a thicker median process of the conductor (Cm) (vs two Di, a sharper Ra ending with a pointy tip, and a thinner Cm in N. brevipes ). (Figs 6A-D , 7E-G cf. Figs 5A-D , 7A-C ). It can be separated from male of N. silvicola by the sharper distal process of paracymbium (Di), the stockier and rounder radical apophysis (Ra), and by the thinner ventral process II of paracymbium (Ve-II), (vs stockier Di, sharper Ra, and wider Ve-II in N. silvicola ). (Figs 6A-D , 7E-G cf. Figs 8A-D , 10A-C ). In addition, the origin of the embolus I from the radix is located in a different position than in the other two species (6:00 o’clock in N. terrestris vs 4:30 o’clock in N. brevipes and N. silvicola ) (Figs 6A , 7E cf. Figs 5A , 7A , 8A , 10A ).

Female of N. terrestris can be separated from female of N. brevipes by the thicker and more squared scapus ~ 1.5-2 × longer than wide and having a flat posterior margin (vs a slimmer scapus approximately as long as wide, with a rounded posterior margin in N. brevipes ) (Figs 6E, F , 7H cf. Figs 5E, F , 7D ). In addition, N. terrestris shows spermathecae (S) which diameter is approximately as wide as the copulatory ducts (vs S wider than copulatory ducts in N. brevipes ) and straight internal ducts with a regular trend and few visible coils (vs ducts with a more irregular trend and more visible coils in N. brevipes ). (Fig. 6E-G cf. Fig. 5E-G ). Female of N. terrestris can be separated from female of N. silvicola by the more lobated scapus (Sc) with rounder lateral margins and straight internal ducts (vs more squared lateral margins and strongly bent internal ducts in N. silvicola ) (Figs 6E-G , 7H cf. Figs 8E-G , 10D ).

Description of male

(one of the topotypes). Habitus as in Fig. 6H . Total length 2.54. Prosoma 1.22 long, 1.18 wide. Carapace rounded, uniformly yellowish with borders and central area slightly darker. Cervical groove and fovea distinct. Eyes well developed. Eyes measurements: AME = 0.06, ALE = 0.09, PME = 0.09, PLE = 0.09, AME-ALE = 0.06, ALE-PLE = 0.01. Chelicerae, labium, maxillae, and sternum of the same color as carapace. Legs yellowish with darker annulation on femur, patella, and tibia. Legs measurements as follows: I 7.07 (2.03, 0.47, 1.99, 1.77, 0.81), II 5.56 (1.64, 0.47, 1.41, 1.31, 0.73), III 4.55 (1.39, 0.41, 1.09, 1.07, 0.59), IV 6.12 (1.89, 0.47, 1.61, 1.48, 0.67). Opisthosoma greyish with large black marks on dorsal and lateral sides.

Male palp as in Figs 6A-D , 7E-G . Cymbium relatively short, covered with sparse setae, several thicker setae on distal-prolateral margin (Fig. 6D ). Paracymbium with a single distal process (Di), two ventral processes (Ve-I-II), and a dorsal apophysis (Do): distal process (Di) thick, hook-like when observed laterally, with a sharp tip headed ventrally and retrolaterally; ventral process I (Ve-I) stocky and blunt, headed internally; ventral process II (Ve-II) long, headed internally; dorsal apophysis (Do) lobated, wide and flat (Figs 6A-D , 7E-G ). Embolus (E) long and filiform, origin of embolus positioned ~ 6:00 o’clock on radix (Rx). Radical apophysis (Ra) strongly sclerotized, triangular, ending with a rounded tip. Conductor with 3 distinct processes (Cp, Cr, Cm) and a half-transparent distal lobe (Cl). Prolateral process of the conductor (Cp) flat, ribbon-like and headed counterclockwise, wrapped around embolus. Retrolateral process of conductor (Cr) wide and thick, curved inside. Median process of conductor (Cm) thick and strongly sclerotized, spine-like, ending sharp, with a ribbon-like lobe wrapped around its prolateral side. (Figs 6A-C , 7E, F ).

Redescription of female

(one of the topotypes). Habitus as in Fig. 6I , 15B . Total length 2.95. Prosoma 1.55 long, 1.16 wide. Cephalic area as in Fig. 6J . Carapace piriform. Eyes measurements: AME = 0.06, ALE = 0.09, PME = 0.09, PLE = 0.09, AME-ALE = 0.07, ALE-PLE = 0.00. Coloration and other details as in male. Legs measurements as follows: I 7.85 (2.32, 0.61, 2.13, 1.91, 0.88), II 6.01 (1.79, 0.53, 1.52, 1.41, 0.76), III 4.72 (1.46, 0.44, 1.04, 1.11, 0.67), IV 6.65 (2.19, 0.53, 1.72, 1.47, 0.74). Epigyne and vulva as in Figs 6E-G , 7H . Scapus (Sc) short and stumpy, rectangular, laterally elongated, ~ 1.5-2.0 × wider than long, ending with a flat or slightly curved posterior margin (Figs 6E, F , 7H ). Copulatory opening (Co) at the inner-lateral sides of scapus. Internal ducts slightly visible through the transparent tegument, V shaped. Copulatory ducts (Cd) short, straight, and thick, strongly diverging from each other. Insemination ducts thin, coiled around the Cd. Spermathecae (S) small and rounded, separated from each other by ~ 2-2.5 × their diameter (Fig. 6G ).

Size variation.

Male (based on 5 specimens): total length: 2.01-2.54, prosoma length: 1.05-1.25, prosoma width: 0.95-1.18. Female (based on 15 specimens): total length: 2.31-3.30, prosoma length: 1.03-1.45, prosoma width: 0.94-1.21.

Distribution.

Japan (Hokkaido, central-eastern Honshu, western Honshu?), Russian Far East (Sakhalin and Kuril Is.), Korea? (Fig. 16A ). The presence of this species in western Honshu and Korea needs confirmation. See also "remarks on misidentification" for additional notes on the distribution of N. terrestris .

Habitat and ecology.

Nesticella terrestris is found in humid and shadowed habitats, including forest leaf litter, under rotten logs and stones, vegetated cliffs, screes, and caves, both limestone and lava caves. This species builds simple scaffold webs in empty spaces among leaf litter and in rock recesses.

Remarks on intraspecific variation.

This species shows some degree of variation in size and in the shape of the epigyne, different individuals having a slightly wider or slightly narrower scapus. The posterior margin is usually straight but it might be also slightly concave or slightly convex depending by the individuals. Specimens from the Kansai area seem to have a general smaller size and a scapus proportionally narrower than those of other populations.

Remarks on misidentifications.

Nesticella terrestris was originally described by Yaginuma (1970: p. 387, 390, 391, figs 3-5) on the basis of a female collected from the Tokyo area. The author misidentified the male describing a male of H. mogera as a paratype of N. terrestris ( Yaginuma 1970: p. 387, 391, fig. 8). An additional male from Gifu was also wrongly identified as N. brevipes and illustrated but not described ( Yaginuma 1970: p. 387, fig. 9). The other records reported in the same work are probably a mix of the three species ( Yaginuma 1970: p. 392). Nesticella terrestris was subsequently synonymized with N. brevipes by Yaginuma himself (1972: p. 619-621) believing that the differences in the shape of male palp and epigyne were part of the intraspecific variability of the species. Both the morphological and molecular results illustrated in our study clearly show that N. terrestris and N. brevipes are in fact two distinct species. Based on these conclusions the resurrection of N. terrestris as a valid species is herein proposed. Accordingly, we describe and illustrate for the first time the male of N. terrestris based on specimens collected from the type locality of the species. Due to the synonymization of N. terrestris with N. brevipes the published records of these two species are currently mixed. In this study we considered only the records that we could directly confirm on the basis of published drawings or checked samples. Based on our material all records from central and eastern Honshu up to Hokkaido refer to N. terrestris , while N. brevipes can be found in the islands of Honshu, Kyushu, and part of the Kansai area. (Fig. 16A ). Due to the lack of specimens from western Kansai and Chugoku areas we cannot confirm the presence of N. terrestris in western Honshu although it seems plausible. Specimens of N. brevipes from Kuril Is. ( Marusik and Crawford 2006) were checked by us and confirmed as N. terrestris . The illustrated specimens of N. brevipes from Korea (e.g., Kim and Lee 2018, fig. 11a-c) show close similarities with the palp and epigyne of N. terrestris rather than N. brevipes and possibly refer to the this or another closely related species (cf. Figs 5A-G , 7A-D vs Figs 6A-G , 7E-H vs Kim and Lee 2018: fig. 11A-C). The presence of N. terrestris in Korea needs to be properly verified directly examining the specimens.

Figures

Figure 5. Nesticella brevipes A male palp (paratype), ventral view B same, retrolateral view C same, ventro-prolateral view D same, dorsal view E female epigyne (holotype), ventral view F same, female from Kyushu G vulva, dorsal view H habitus of male (old specimen from Kyushu); I habitus of female (specimen from Shikoku); J cephalic area of female, frontal view. Abbreviations: Cd - copulatory duct; Co - copulatory opening; Id - insemination duct; S - spermatheca; Sc - scapus. Scale bars: 0.2 mm (A-G, J); 1.0 mm (H, I).

Figure 6. Nesticella terrestris A male palp (one of the topotypes), ventral view B same, retrolateral view C same, ventro-prolateral view D same, dorsal view E female epigyne (topotype), ventral view F same after dissection, shape variation G vulva, dorsal view H habitus of male (topotype) I habitus of female J cephalic area of female, frontal view. Abbreviations: Cd - copulatory duct; Co - copulatory opening; Id - insemination duct; S - spermatheca; Sc - scapus. Scale bars: 0.2 mm (A-G, J); 1.0 mm (H, I).

Figure 7. Genitalia of Nesticella brevipes and N. terrestris A male palp of N. brevipes, ventral view B same, retrolateral view C detail or paracymbium, dorsal view E female epigyne, ventral view E male palp of N. terrestris, ventral view F same, retrolateral view C detail or paracymbium, dorsal view H female epigyne, ventral view. Abbreviations: Cl - lobe of conductor; Cm - median process of conductor; Co - copulatory opening; Cp - prolateral process of conductor; Cr - retrolateral process of conductor; Di I-II - distal process (es) I and II of paracymbium; Do - dorsal process of paracymbium; E - embolus; P - paracymbium; Ra - radical apophysis; Rx - radix; S - spermatheca; Sc - scapus; Sd - sperm duct; St - subtegulum; Te - tegulum; Ve I-II - ventral processes I and II of paracymbium. Scale bars: 0.2 mm.

Figure 8. Nesticella silvicola sp. nov. A male palp (holotype), ventral view B same, retrolateral view C same, ventro-prolateral view D same, dorsal view E female epigyne (one of the paratypes), ventral view F same, from shape variation G vulva, dorsal view H habitus of male I habitus of female J cephalic area of female, frontal view. Abbreviations: Cd - copulatory duct; Co - copulatory opening; Id - insemination duct; S - spermatheca; Sc - scapus. Scale bars: 0.2 mm (A-G, J); 1.0 mm (H, I).

Figure 10. Genitalia of Nesticella silvicola sp. nov. and N. insulana sp. nov. A male palp of N. silvicola sp. nov., ventral view B same, retrolateral view C detail or paracymbium, dorsal view E female epigyne, ventral view E male palp of N. insulana sp. nov., ventral view F same, retrolateral view C detail or paracymbium, dorsal view H female epigyne, ventral view. Abbreviations: Cl - lobe of conductor; Cm - median process of conductor; Co - copulatory opening; Cp - prolateral process of conductor; Cr - retrolateral process of conductor; Di I-II - distal process (es) I and II of paracymbium; Do - dorsal process of paracymbium; E - embolus; P - paracymbium; Ra - radical apophysis; Rx - radix; S - spermatheca; Sc - scapus; Sd - sperm duct; St - subtegulum; Te - tegulum; Ve I-II - ventral processes I and II of paracymbium. Scale bars: 0.2 mm.

Figure 15. Nesticella and Howaia species in life and their natural habitats A female of H. mogera B female of N. terrestris C female of H. alba sp. nov. D female of N. occulta sp. nov. E female of N. okinawaensis F example of the epigean habitat of Nesticella species in the Ryukyus G habitat of H. alba sp nov. (dark zone of Tsuzupisuki-abu cave) H habitat of N. occulta sp. nov. (dark zone of Kabirano-ana cave) (all photos by F. Ballarin).

Figure 16. Distribution of Nesticella and Howaia species in mainland Japan and Ryukyu Archipelago A distribution of N. brevipes and N. terrestris in mainland Japan and neighboring countries B distribution of Nesticella and Howaia species endemic to the Ryukyu Archipelago C distribution of H. mogera in mainland Japan and neighboring countries D distribution of H. mogera in the Ryukyu Archipelago and neighboring countries. Colored squares refer to the type localities of the species, colored dots indicate the locations of specimens whose morphology has been checked during this study, dashed areas refer to the generally known distribution of the species, question marks refer to unclear distributions (see " remarks on misidentifications " of N. brevipes and N. terrestris).

Figure 17. Size comparison between Nesticella brevipes and N. terrestris A visual comparison of adult females of Nesticella brevipes (left) and N. terrestris (right) B Scatterplot of the Tibia I / carapace lengths ratio in females of N. brevipes (blue circle) and N. terrestris (orange circles). Measurements are reported in millimeters. Scale bar: 1 mm (A).