Pseudostenophylax tochigiensis Schmid 1991

Nozaki, Takao, 2013, The genus Pseudostenophylax Martynov (Trichoptera, Limnephilidae) in Japan, Zootaxa 3666 (4), pp. 559-578 : 560-563

Pseudostenophylax tochigiensis Schmid 1991

( Figs. 1 , 2 , 10 )

Pseudostenophylax tochigiensis Schmid 1991 , 24, pl. 2, male.

Pseudostenophylax ondakensis (Iwata 1928) : Tanida 1985, 197, larva, case, misidentification.

Adult. Body, antennae dark brown. Head shorter than wide; with large ocelli, about 1/4 of eyes in length; with pair of anteromesal and anterior setal warts, oval, anterior warts smaller than ocelli; pair of posterior setal warts oval, slightly larger than ocelli. Pronotum with pair of setal warts dorsally, large oval; laterally with pair of small setal warts, occasionally divided into 2 warts. Mesoscutal setal warts elongate oval; mesoscutellar setal warts long, usually fused posteriorly. Forewings dark brown with numerous pale spots, reticulated; each 16–22 mm long in male, 17–19 mm in female. Hind wings pale brown, wider than forewings, with brush of white hair-like bristles on jugal region in male, hair-like setae short and sparse in female. Venation as in Figures 1 B, 1C. Tibial spurs 1-3-4.

Male genitalia. Tergum VIII higher than long in lateral aspect; posterodorsal sclerotized area densely covered by short spine-like setae, crescent-shaped in dorsal aspect, slightly concave posteriorly. Segment IX in lateral aspect short dorsally, swelling posterolaterally at midway. Superior appendages ear-like in lateral aspect, slightly concave mesally. Intermediate appendages large, long semicircular; upper side deeply concave, covered with minute denticles except for basolateral part. Lateral sclerites of segment X largely fused into intermediate appendages. Inferior appendages one segmented, triangular in lateral aspect, round or square or trapezoidal in ventral aspect, often slightly protruding midway in ventral aspect. Aedeagus (= Phallicata auct.) sclerotized, slender, bottle-shaped with long neck in dorsal aspect; basal part strongly sclerotized, black basally. Parameres large, membranous basally, sclererotized apically; sclerotized part hook-shaped, denticulate apically, mesal apex with several long spines, often variable in shape even in same locality.

Female genitalia. Tergum IX triangular in lateral aspect. Sternum IX long rectangular in lateral aspect, slightly protruding posterolaterally, concave ventrally. Segment X developed into two large lobes, each long bell-shaped in dorsal aspect, mesal line angled near apex; with slender finger-like process apically, slightly curved mesoventrad, unpigmented; 1.2–1.6 times as long as basal width in dorsal aspect. Supragenital plate vestigial, weakly sclerotized. Vulval scale consisting of small median lobe and pair of large lateral lobes; median lobe slender, directed posteroventrad; lateral lobes strongly sclerotized, projecting posterad, ear-like in ventral aspect, with subapicomesal part concave; semicircular in lateral aspect. Vaginal sclerite simple, situated posteriorly, reverse Lshaped in lateral aspect, bathtub-like in dorsal aspect.

Final instar larva. Length up to 20 mm. Head round in dorsal aspect; mostly reddish or dark brown, but posterior corner of frontoclypeal apotome pale brown; primary setae 5 each about 1–1.5 times as long as distance between bases of setae 5; setae 6 transparent, short, each 1/4–1/2 length of seta 5; setae 14 longest; ventral setae 18 minute. Ventral apotome vase-shaped, elongated caudally. Labrum yellowish brown; with primary setae 2–6 on dorsum; anteroventral setae 1 shortest. Mandibles black, but often paler apically; right and left ones almost symmetrical, triangular in dorsal aspect; four apical teeth present, although often shortened or made indistinct by abrasion. Prosternal horn long. Pronotal sclerites dark brown, but slightly paler in posterior half; with many pigmented or transparent setae; anterior edge with transparent hair-like setae. Mesonotal sclerites mostly dark brown. Metanotal sclerites dark brown, with transverse band of setae between sa 2 sclerites. Hind femora each bearing 5–7 setae along ventral edge, with 10–16 setae laterally. Abdominal segment I with more than 100 setae dorsally and ventrally. Abdominal gills single, present on following segments: dorsal gills on abdominal segments II to V (anterior and posterior), on VI (anterior and often posterior) and usually on VII (anterior); lateral gills on II to IV (anterior and posterior), on V (anterior and often posterior) and often on VI (posterior); ventral gills on II to VII (anterior and posterior) and often on VIII (anterior). Lateral fringe and forked lamellae present on abdominal segments III to VIII. Ventral chloride epithelia present on abdominal segments II to VIII. Anal claws each with one accessory hook.

Case. Case of final instar larva up to 20 mm long; constructed of sand grains, often mostly phlogopite micas; cylindrical; posterior end closed by silk and sand grains with central hole. In pupal case, both ends covered by coarser sand grains than those of larval case, with perforations in gaps of sand.

Specimens examined. Honshu. Miyagi: Yoko-kawa, 850 m a.s.l., near Funagata-yama, Aoba-ku, Sendai-shi, 5.x.2001, T. Nozaki, 20 larvae (TN); ibid., larvae collected on 5.x.2001, adults emerged on 21.iv–26.v.2002 by T. Nozaki, 5 males, 5 female (TN); Tochigi: Nagasawa, Yunishi-gawa, Nikko-shi, 15.iv.1999, T. Kagaya, 1 male (TN); near Furumine-jinja, 700 m a.s.l., Kusagyu, Kanuma-shi, 25.ix.2002, N. Kubota, 6 larvae (2 larvae, NMNH; others, TN); Saitama: Wasabi-zawa, 1,200 m a.s.l., Otaki, Chichibu-shi, larvae collected on 24.ix.1999, adults emerged on 13.iii–1.iv.2000 by T. Nozaki, 4 males, 2 females (1 male: CBM-146877; 1 male, 1 female: NMNH; others: TN); ibid., 24.ix.1999, T. Nozaki, 2 larvae (TN); Kanagawa: headwaters of Haragoya-sawa, 1,280 m a.s.l., Tsukui-cho, Sagamihara-shi, larvae collected on 10.v.1995, adults emerged on 28.vii–21.viii.1995 by T. Nozaki, 2 males, 1 female (TN); ibid., 10.v.1995, T. Nozaki, 2 males, 1 female (TN); Niigata: Otashinden, Tsunan-cho, 16.v.1993, H. Moriya, 1 male (TN); Kiyotsu-kyo, Mitsumata, Yuzawa-machi, 11–14.v.1999, N. Kawase, 2 males (NK); Yamanashi: Sakubadaira, Ichinose, Kamiogiwara, Koshu-shi, 15.vi.1989 (light), T. Nozaki, 2 males (TN); ibid., 1.viii.1989, T. Kagaya & T. Nozaki, 1 male (TN); ibid., 23.v.1990 (light), T. Nozaki, 7 males, (TN); ibid., 13.vi.1990, T. Nozaki & T. Kagaya, 1 male (TN); ibid., 19.vii.1990, T. Nozaki, 1 male, (TN); ibid., 22.v.1999 (light), T. Hattori, 15 males, 1 female (TN); Hi-kawa, 1,450 m a.s.l., Koshu-shi, 26.iv.1986, T. Nozaki, 4 larvae (TN); Fudo-gawa, Koshu-shi, 4.v.1984, S. Ishiwata, 3 males (TN); Nagano: Sanbon-daki, Norikura-kogen, Azumi, Matsumoto-shi, 13.ix.2008, T. Nozaki, 2 larvae (TN); Kiso-gawa, Ina-gawa main, 1,800 m a.s.l., 29.ix.1990, Y. Takemon, 1 male, 4 larvae (KT); Ogi-onsen, 3.v.1990, H. Nishimoto, 1 male, 1 female (TN); Oguro-gawa, 900 m a.s.l., Ina, Ina-shi, 21.vi.1999, T. Tsuruishi, 1 male (TN); ibid., 28.viii.1999, T. Tsuruishi, 1 larva (TN); Oizumigawa, 1,020 m a.s.l., Minami-minowa-mura, 5.v.1998, T. Tsuruishi, 4 males (TN); Minoto, Yanagawa, Chino-shi, 10.iv.2001, T. Tsuruishi, 5 larvae (TN); Nakano-sawa, Sugadaira, Ueda-shi, 25.ix.1983, T. Nozaki, 1 larva (TN); Shibusawa, Sugadaira, Ueda-shi, 26.ix.1983, K. Tanida, 15 larvae (KT); Mt. Ontake, Tsumeta-gawa, Kaidakogennishino, Kiso-machi, 4.v.1986, S. Ishiwata, 2 larvae (TN); Gonbei-toge, Narai, Shiojiri-shi, 3.v.1986, S. Ishiwata, 1 larva (TN); Ibara-zawa, Saku, Koumi-cho, 30.v.1997, T. Hattori et al., 1 larva (TN); Gifu: Kagamidaira, 2,380 m a.s.l., Kamitakara-cho, Takayama-shi, 28.vii.1998, K. Eda, 1 male (TN); Hikagedaira, Takayama-shi, 20.ix.1998, H. Nishimoto, 1 male (TN); Shizuoka: Higashizawa-deai, Abe-kawa, 900 m a.s.l., Umegashima, Aoi-ku, Shizuoka-shi, 2.vi.1995, T. Hattori, 1 male (TN); Abe-toge, a head of Sakasa-gawa, 1,400 m a.s.l, Aoi-ku, Shizuoka-shi, 3.v.1999, T. Hattori & T. Ito, 24 larvae (TN); Nara: Odaigahara, Kami-kitayama-mura, 6.ix.1984, H. Nishimoto, 1 female (TN).

Distribution. Japan (Honshu).

Biology. Larvae inhabit leaf accumulations of cool mountain streams and spring flows and mainly feed on dead plant material. Adult males are often collected by light traps in high mountain areas from early summer through autumn, but females of this species group fly to lights very rarely, perhaps because their fore- and hind wings are shorter than those of the males.

Japanese name. Tochigi-miyama-tobikera.

Remarks. This species belongs to the P. ondakensis Species Group (Schmid 1991). The male of this species is unique among those of the P. ondakensis Group in having large, egg-shaped intermediate appendages of segment X. In the female, the genitalia of all Japanese species are similar to each other, but the female of this species can be distinguished from those of other species by the large bell-shaped segment X. The larva is also distinguishable from those of other members of the P. ondakensis Group by having both ventral chloride epithelium on abdominal segment VIII and a pale marking on the posterior corner of the frontoclypeal apotome.

Tanida (1985) illustrated a larva as P. ondakensis . His larva has a pale posterior corner of the frontoclypeal apotome; however, larvae of P. ondakensis have an entirely dark head (Iwata 1928, 1930). I examined specimens used by him, and confirmed that these larvae are in accord with those of P. tochigiensis described above.

Figures

FIGURE 1. Adults of Pseudostenophylax tochigiensis. A, head and pro- and mesonota, dorsal. B, male right wings, dorsal. C, female right wings, dorsal. D – J, male genitalia: D, left lateral; E, dorsal; F, ventral; G, caudal; H, phallus, dorsal; I and J, apex of right paramere, variations, dorsal. K – O, female genitalia: K, left lateral; L, dorsal; M, ventral; N, vaginal sclerite, left lateral; O, vaginal sclerite, dorsal. Abbreviations: IX = segment IX; X = segment X; ae = aedeagus; inf = inferior appendage (paired); int = intermediate appendage (paired); mvul = median vulval lobe; pa = paramere (paired); sIX = sternum IX; scl = lateral sclerite of segment X; lvul = right lateral vulval lobe (paired); spr = supragenital plate; sup = superior appendage (paired); tVIII = tergum VIII; tIX = tergum IX.

FIGURE 2. Larva, larval case and pupal case of Pseudostenophylax tochigiensis. A – H, larva: A, right lateral; B, head, pro-, meso- and metanota, dorsal, primary setae 5, 6 and 14 numbered; C, left mandible, dorsal; D, left mandible, mesal; E, head, ventral; F, right foreleg, lateral / caudal; G, right middle leg, lateral / caudal; H, right hind leg, lateral / caudal. I – J, larval case: I, right lateral; J, posterior end, caudal; K – L, anterior closure of pupal case: K, right lateral; L,, anterior. Abbreviations: ce = chloride epithelia; va = ventral apotome.

FIGURE 10. Distributions of Japanese Pseudostenophylax species.