Araneus matsumotoi, Suzuki & Tanikawa, 2021

Suzuki, Yuya & Tanikawa, Akio, 2021, A new species of the genus Araneus (Araneae: Araneidae) from Japan, Zootaxa 5052 (4), pp. 591-596 : 592-595

Araneus matsumotoi new species

Figs. 2–15

Type series. Holotype: male (NSMT-Ar 20952), Takahata-cho, Nara-shi , Nara Pref., collected as a juvenile on 29-V-2019 and matured on 25-IX-2019 under rearing, R. Matsumoto leg. Paratypes: 1 female (NSMT-Ar 20953), Lake Tazawa, Senboku-shi , Akita Pref., 18-VIII-1990, S. Tazoe leg. ; 2 females and 3 males, same locality as the holotype [1 male (NSMT-Ar 20954), collected as a subadult on 2-V-2020 and matured on 25-V-2020 under rearing; 1 female (NSMT-Ar 20955), collected as a juvenile on 20-VI-2020 and matured on 24-VI-2020 under rearing, scape of epigynum incompletely formed; 2 males (NSMT-Ar 20956-20957), collected as juveniles on 29-V-2019 and matured on 3-VI-2020 and 17- VI-2020 under rearing; 1 female (NSMT-Ar 20958), 15-VII-2020], R. Matsumoto leg. ; 1 female (NSMT-Ar 20959), Amedaki, Tottori-shi , Tottori Pref., collected as a juvenile on 14-VII-2019, and matured on 17-VI-2020 under rearing, Y. Obae leg. ; 1 male (NSMT-Ar 20960; COI haplotype: AMT01), Kitazato, Izuhara-machi, Tsushima-shi , Nagasaki Pref., collected as a juvenile on 25-VIII-2018 and matured on 31-I-2019 under rearing, K. Terada leg.

Additional specimens examined. 1 female, Sagayama, Ôtoyo-cho, Nagaoka-gun , Kochi Pref., collected as a juvenile on 3-V-2021 and matured on 23-V-2021 under rearing, R. Serita leg. 1 male (both palps were incompletely formed), Ogawa, Sekimoto-cho , Kita-ibaraki-shi, Ibaraki Pref., collected as juvenile on 19-VII-2020 and matured on 4-V-2021 under rearing, K. Nishiura leg. 1 male, Amedaki, Tottori-shi , Tottori Pref., collected as a juvenile on 4-XI-2020, and matured on 16-IV-2021 under rearing, Y. Suzuki leg.

Etymology. The specific name is dedicated to Rikio Matsumoto, who provided us with many invaluable specimens of the new species.

Diagnosis. The new species resembles A. seminiger (L. Koch 1878) in appearance (also see Ono 2002 & Tanikawa 2001), but can clearly be distinguished by the combination of the following body color and marking characters: the carapace of the new species is uniformly covered with gray hairs when living, whereas it is reddish brown in A. seminiger ; legs and abdomen of the fresh specimens are dark green, similar to green moss (Bryophyta), whereas those of A. seminiger are whitish green, resembling Parmotrema lichen ( Parmeliaceae ); a light green chevron marking edged with black is present between the shoulder humps, whereas it is absent in A. seminiger ( Figs. 2, 3 ). The new species can also be differentiated from A. seminiger based on the following characters: a wide unsclerotized area on the tip of subterminal apophysis (unsclerotized area is very narrow in A. seminiger ); a thin sclerotized appendix on the posterior side of subterminal apophysis ( Figs. 4, 5 ; 11, 12 , arrows; the appendix is absent in A. seminiger ); a longer slender epigynal scape, with outwardly directed copulatory openings ( Figs. 6–8 , 13, 14 ; epigynal scape of A. seminiger is shorter and wider than that of the new species, and copulatory openings of A. seminiger is directed ventrally). In terms of general appearance (i.e., body coloration and markings), the new species can be distinguished from the morphologically related species A. ventricosus (L. Koch 1878) , A. macacus ( Uyemura 1961) , A. uyemurai Yaginuma 1960 , and A. reizan Tanikawa 2020 . Although the epigynum of the new species is similar to that of A. reizan , it differs with respect to a deeper invagination on the posterior side of median plate ( Figs. 8 , 13, 14 ; A. reizan has a very shallow invagination).

Description. Based on the holotype male (NSMT-Ar 20952) and paratype 1 female (NSMT-Ar 20958) from Nara Pref.

Measurements and morphology ( Figs. 2–15 ). ♂ / ♀. Body 12.30/17.95 long. Carapace 6.75/7.77 long; 5.34/6.43 wide. Eye size: AME 0.32/0.33; ALE 0.24/0.23; PME 0.22/0.25; PLE 0.19/0.22. Length of legs = [femur + patella + tibia + metatarsus + tarsus = total]. I, 6.82 + 2.65 + 6.75 + 6.20 + 2.18 = 24.60 / 8.47 + 3.58 + 7.72 + 7.69 + 2.93 = 30.39; II, 6.67 + 2.60 + 5.93 + 5.60 + 2.01 = 22.81 / 7.69 + 3.40 + 6.97 + 6.12 + 2.27 = 26.45; III, 4.80 + 1.73 + 3.08 + 2.92 + 1.47 = 14.00 / 5.64 + 2.37 + 3.74 + 3.14 + 1.56 = 16.45; IV, 6.90 + 2.40 + 5.03 + 4.86 + 1.69 = 20.88 / 7.62 + 3.35 + 5.90 + 5.37 + 1.65 = 23.89. Apophysis with a long pedestal developed on prolateral side of male tibia II ( Fig. 9 ) and sharp projection on ventral side of coxa II ( Fig. 10 ). Abdomen 6.43/10.51 long; 5.77/9.96 wide. A pair of shoulder humps well developed.

Coloration and markings ( Figs. 2, 3 ). Coloration: when living/specimens fixed in ethanol, respectively. Carapace gray/dark yellowish brown with black markings and spots on cervical grooves, redial furrows, and fovea. Sternum pale green/light yellowish brown. Legs pale green with dark green ring bands/light yellowish brown with dark brown ring bands; ventral side of coxae black/dark yellowish brown. Dorsum of abdomen dark green/light green and yellowish brown with black folium; internal area of folium darker; green chevron marking edged with black between humps; two pairs of large sigilla on dorsum; ventral side of abdomen light yellowish brown with pair of light yellowish spots.

Genital organs. Male palp ( Figs. 4, 5 , 11, 12 ): tip of terminal apophysis sclerotized and sharp; conductor strongly sclerotized with bent tip; subterminal apophysis with wide unsclerotized area and sharp thin sclerotized appendix on posterior margin; embolus hidden under subterminal apophysis and conductor; median apophysis transverse with prolateral tip pointed and retrolateral tip truncated; paracymbium hook-like with blunt tip. Female genitalia ( Figs. 6–8 , 13–15 ): scape slender with apical half sclerotized and basal half wrinkled; median plate rounded with deep invagination on posterior edge, looking like inverted heart shaped from ventral view; lateral plates strongly sclerotized; copulatory openings outwardly directed.

Variation (5 males and 3 females). Male body length 11.24–12.30; female body length 14.30–17.95.

Distribution. The Honshu, Shikoku and Tsushima Islands, Japan.

Habitat. The new species inhabits deciduous and evergreen forests, in which specimens are often found in green moss on the bark and trunks of trees during the daytime.

Figures

FIGURES 2–8. Araneus matsumotoi n. sp., male holotype (NSMT-Ar 20952; 2, 4, 5) and one of the female paratypes from Nara Pref. (NSMT-Ar 20958; 3, 6–8); habitus (2, 3), male palp (4, 5) and female genitalia (6–8). 2, Habitus of male, dorsal view. 3, Habitus of female, dorsal view. 4, Male left palp, prolateral view. 5, Same, anterior view. 6, Epigynum, ventral view. 7, Same, lateral view; 8, basal part of epigynum, ventral view. Arrows in Figs. 4 and 5 indicate a sharp appendix on the posterior margin of subterminal apophysis. Scale bars, 4–7, 1.0 mm; 8, 0.5 mm.

FIGURES 9–15. Araneus matsumotoi n. sp., male holotype (NSMT-Ar 20952; 9, 11–12) and one of the female paratypes from Nara Pref. (NSMT-Ar 20958; 10, 13–15). 9, Apophysis on prolateral side of tibia II. 10, Projection on ventral side of coxa II. 11, Male left palp, prolateral view. 12, Same, apical part, anterior view.13, Epigynum, ventral view.14, Same, posterior view.15, Internal genitalia, dorsal view. Arrows in Figs. 11–12 and 13, 14 indicate a sharp appendix on the posterior margin of subterminal apophysis (arrows 1, 3), bent tip of conductor (arrows 2, 4) and copulatory opening (arrows 5, 6), respectively. Abbreviations: c, conductor; fd, fertilization duct; lp, lateral plate; ma, median apophysis; mp, median plate; pc, paracymbium; s, spermatheca; st, subterminal apophysis; ta, terminal apophysis. Scale bars, 8–11, 1.0 mm; 12–14, 0.5 mm.