Osmylus (Osmylus) pryeri MacLachlan, 1875

Matsuno, Shigetomi & Yoshitomi, Hiroyuki, 2016, Descriptions of three larvae of Osmylus species from Japan (Neuroptera: Osmylidae), with a proposed naming system for the larval sclerites, Zootaxa 4189 (2), pp. 348-366 : 358-361

Osmylus (Osmylus) pryeri MacLachlan, 1875

( Figs 16 , 20–21 , 25 , 28 , 32–33 , 37 , 41–42 )

Osmylus pryeri McLachlan, 1875 , 180.

Osmylus kisoenis Iwata, 1928 , 16, figs. 1–14. syn. nov. Other synonyms see Sekimoto & Yoshizawa (2011).

Description of 3rd instar larva. BL 14.8–20.5 (16.5, n = 20) mm.

Coloration. Head brown, except for black colored stemmata and its surrounding parts; legs light yellow; dorsal side of thorax and abdomen basically purple to gray, with patchy pattern purplish-yellow; ventral surface of thorax light gray; ventral surface of abdominal segments purple, with patchy pattern purplish-yellow; sclerites blackish brown; 9th and 10th abdominal segments and their sclerites brown, subhyaline.

Head ( Fig. 16 ). Mandiblomaxillary stylets long, about 2.6 times as long as head capsule length; ML/CW 2.7– 3.1 (2.9, n = 20). Frontal edge of cranium with 4 long setae and 2 pores. Antennae 40 or 42 segments (n = 2).

Prothorax ( Fig. 20 ): DPc square, separated with DM, its setae in middle part long, 1st and 3rd setae from within in posterior half margin short. Mesothorax ( Figs 20–21 ): DPm1 absent; four short setae bearing on DPm2; DPm2 somewhat long, its seta on anterior margin short; a seta on DPp1and DPp2 short. Metathorax ( Figs 20–21 ): DAa not expanded; DAm2 and DAm3 connected.

First abdominal segment ( Fig. 25 ): DM1 present; DM2, DPp1, and DPp4 smaller than DPp2; a seta on DM2, DPp1, and DPp4 short; DPa absent; a seta in dorso-anterior part of LP short. Second to 5th abdominal segment ( Fig. 25 ): DM3 present; a seta on LA short. Sixth abdominal segment ( Fig. 25 ): DM2 roughly the size of DPp2; VM3 mostly present. Seventh abdominal segment ( Fig. 28 ): VM3 absent. Eighth abdominal segment ( Fig. 28 ): DPp1+DPp2 with a pore on anterior margin. Ninth abdominal segment ( Figs 32–33 ): Dc bearing 9 pairs of long setae in posterior margin; outer setal row on VPc composed of 3 setae and without a pore in exterior margin.

Variation. VM3 on 6th abdominal segment are mostly present but are absent in 15% of materials (n = 20). In addition, VM2 are present in 15% of materials (n = 20). VM3 on 7th abdominal segment are usually absent but are present in 25% of materials (n = 20).

Material examined. 1 exs. (in Kyoto University Museum, 3IL), Chiisagata-gun , Nagano Pref., vii.1929, Iijima leg. ; 2 exs. (2IL), Sentsû-zan, Okuizumo-chô, Nita-gun , Shimane Pref., 10.iv.2007, M. Hayashi leg. ; 2 exs. (3IL), same locality, 16.v.2007, M. Hayashi leg. ; 1 ex. (2IL), Omogokei, Kumakôgen-chô , Ehime Pref., 19.viii.2010, S. Matsuno leg. ; 1 ex., Ishizuchi skyline, Kumakôgen-chô , Ehime Pref., 9.v.2009 (collected in 3IL), 23.v.2009 (PP), 2.vi.2009 (EM), H. Yoshitomi leg. ; 10 exs. (3 2IL & 7 3IL), Ishizuchi-san, Saijô-shi , Ehime Pref., 5.vi.2010, S. Matsuno leg. ; 3 exs. (3IL), Ishizuchi-san, Saijô-shi , Ehime Pref., 6.vi.2011, S. Matsuno leg. ; 1 ex. (1IL), Saragamine, Tôon-shi , Ehime Pref., 11.x.2010, S. Matsuno leg. ; 5 exs. (3IL), same locality, 6.iii.2011, S. Matsuno leg. ; 1 ex. (3IL), Komeno-machi, Matsuyama-shi , Ehime Pref., 10.v.2010, S. Matsuno leg. ; 4 exs. (3IL), Komeno-machi, Matsuyama-shi , Ehime Pref., 16.v.2010, S. Matsuno leg.

Remarks. This species is similar to O. (O.) halynatus , but differs from it in the long mandiblomaxillary stylets ( Fig. 37 ).

Osmylus kisoensis Iwata, 1928 was described based on a single larval specimen (collecting data: “Narai river, Sogamura, Nagano-ken, in April 1927 by Mr. K. Kimura” after the original description), and no additional specimen has not been collected. We also could not obtain any additional specimen of this species by our survey in the type locality. The first author went to the Kyoto University Museum where the Iwata specimen collection is deposited to examine the holotype of this species in 2012. There was a specimen identified as O. kisoensis (see the above “material examined”); however, the holotype was not found. In this paper, we treat this species as a junior synonym of O. (O.) pryeri MacLachlan, 1875 based on the comparison of three Osmylus larvae described here and the original description and figures of O. kisoensis ( Iwata 1928, figs 1–14) (see Table 1).

characters species

kisoensis hyalinatus pryeri tessellatus DM1 present absent present absent DM3 present absent present absent comparing DM2 with DPp2 small size same size small size same size comparing DPp1 with DPp2 small size same size small size same size comparing DPp4 with DPp2 small size same size small size same size Biological notes. This species inhabits sympatrically with O. (O.) hyalinatus , but is found only in high altitude areas (ca. 700–1,000 m) ( Figs 41–42 ).

The pupal period is 10 days in a rearing condition under 22? (n = 1).

Distribution. Japan (Hokkaidô, Kunashir, Honshû, Shikoku, Kyûshû).

Figures

FIGURES 15 – 17. Head of Osmylus spp., dorsal view. 15) O. (O.) hyalinatus; 16) O. (O.) pryeri; 17) O. (P.) tessellatus.

FIGURES 18 – 23. Thorax (18, 20, 22) in dorsal view and DPa 2 (19, 21, 23) in lateral view of Osmylus spp. 18 – 19) O. (O.) hyalinatus; 20 – 21) O. (O.) pryeri; 22 – 23) O. (P.) tessellatus.

FIGURES 24 – 26. First to 8 th abdominal segments of Osmylus spp., dorsal view. 24) O. (O.) hyalinatus; 25) O. (O.) pryeri; 26) O. (P.) tessellatus.

FIGURES 27 – 29. Seventh abdominal segments of Osmylus spp., ventral view. 27) O. (O.) hyalinatus; 28) O. (O.) pryeri; 29) O. (P.) tessellatus.

FIGURES 30 – 35. Ninth abdominal segment of Osmylus spp., dorsal (30, 32, 34) and ventral (31, 33, 35) views. 30 – 31) O. (O.) hyalinatus; 32 – 33) O. (O.) pryeri; 34 – 35) O. (P.) tessellatus.

FIGURES 36 – 38. Habitus of the larvae of Osmylus spp. 36) O. (O.) hyalinatus; 37) O. (O.) pryeri; 38) O. (P.) tessellatus. Photo by S. Matsuno.

FIGURES 39 – 44. Habitats of larvae of Osmylus spp. 39) Small stream; 40) O. (O.) hyalinatus in wooden pocket; 41) small stream; 42) O. (O.) pryeri in wooden pocket; 43) canyon stream; 44) O. (P.) tessellatus in moss on rock. Locality: 39) Takaosan, Tokyo; 40) Komeno-machi, Ehime Pref.; 41 – 42) Saragamine, Ehime Pref.; 43 – 44) Omogokei, Ehime Pref. Photo by S. Matsuno.