Mystacides azureus
Creators: name: Kuhara, Naotoshi
name: Nozaki, Takao
name: Zhang, Ao
name: Zhou, Xin
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Trichoptera
Leptoceridae
Mystacides
Mystacides azureus

description: Mystacides azureus (Linnaeus 1761)
Figs. 1, 5A–5M, 6A1–6E6
Phryganea azurea Linnaeus 1761: 380.
This species was originally described from Sweden and has been recorded in a broad geographical range from Western and Northern Europe to the Far East, including Japan. Although several authors described or illustrated the male and female of this species (e.g., Mosely 1939; Vshivkova et al. 1997), we provide illustrations of male and female genitalia of individuals from Japan for comparison (Figs 5A–5M, 6A1–6E6). We detected intraspecific variation in the shape of the male genitalia among Japanese individuals, although conspicuous morphological variation was not observed in the female.
Remarks. The males exhibit great variation in the shape of tergum X even among individuals collected at the same time and place. The tergum X is produced into two asymmetrical spines posteriorly: In most populations, one spine is shorter and sinuous in the distal half and the other spine is curved and longer but variable in shape and length. The latter spine is slightly longer than the former and curved mesad in its apical half or bent mesad at midlength in more than half of the examined specimens (short type; Figs 6A 1, 6A 2, 6B1–6B4, 6C1, 6C 2, 6E 1–6E3), which type well agrees with European individuals (Kumanski 1988; Mosely 1939). However, in some specimens, the latter is far longer than the former and curved sigmoidally in dorsal aspect (long twist type; Figs 6A 5, 6C 5, 6C 6, 6E 5, 6E 6). In addition, a few specimens have the longer spine slightly curved outward subapically, representing an intermediate between the two types (Fig. 6A 3, 6A 4, 6C 3, 6C 4, 6E 4). In most specimens, the longer spine is crossing beneath the shorter.
Frequencies of the long twist type vary geographically. Only a few or no long-twist type individuals were found in specimens collected in Hokkaidô and Kyûshû, but over 20% of individuals exhibit this type in specimens collected in Honshû and Shikoku (Table 1).
The population in lakes in Ômachi, Nagano, and Honshû, however, exhibit a different type of shape of tergum X from the other populations (Figs 5F–5J): The usually short sinuate spine is usually longer than the curved one (reversal type; Figs 6D 1, 6D 2), although some specimens have the curved spine extending beyond the sinuate spine (Figs 6D 3, 6D 4), resembling the intermediate type. Specimens having more extended spines (Fig. 6D 5) almost agree with those of the long twist type.
The degree of the posteroventral excisions of the inferior appendages in lateral aspect is also variable (Figs 5A, 5F, 6). The excision of specimens collected in Honshû (Figs 6C–6E) tends to be deeper than that in Hokkaidô (Figs 6A, 6B), but variation of this character within each population is rather small.
The reversal type specimens of the Ômachi population closely resemble illustrations of Mystacides elongatus from China by Yang & Morse (2000). In addition, our female specimens of this species show no evident variation in genital morphology and are very similar to illustrations those of M. elongatus by them. These facts suggest that M. elongatus may be included in the variation of M. azureus. Morphological and molecular studies of M. elongatus specimens from China would be needed to clarify the relation of M. elongatus and M. azureus.
HOKKAIDO: Kushiro: 57³ 2³(L) 3³ (I) 13♀, Kushiro-shi, Akan-chô, Akan-ko, 14.ix.1999, TI & N. Minakawa; 6³ 10♀, same location, 7.viii.2007, TI; 6³ 5♀, Kushiro-shi, Akan-chô, Ibeshibetsu-gawa R., 19.ix.1989, NK; 1³ 1³(L) 4♀, Kushiro-shi, Akan-chô, Panketô, 21.ix.1996, TI; 1³, same location, 14.ix.1999, N. Minakawa; 6³ 2♀, same location, 3–4.x.2006, TI; 1³ 2♀, same location, 8.viii.2007, TI; 7♀, Shibecha-chô, L. Shirarutoro-ko, 9.viii.2005, TI; 1³, same location, 16.viii.2007, TI; 1³, same location, 25.vii.2008, TI. Sôya: 16³ 8♀, Sarufutsumura, Asajino, 31.vii.2007, NK. Kamikawa: 1♀, Tôma-chô, Nakadai, 15.vii.2007, NK. Sorachi: 1♀, Yuni-chô, Kawabata, small stream, 15–30.viii.2007, NK. Ishikari: 1♀, Chitose-shi, Bibi, Bibi-gawa R., 29.viii.1991, TI; 1♀, same location, 5–26.ix.1993, TI; 4♀, Chitose-shi, Neshikoshi, Chitose-gawa R., 4.ix.1997, NK; 1³, Chitose-shi, Izumisawa, Mamachi-gawa R., 6.viii.2003, NK; 1♀, Chitose-shi, Okotan, Okotanpe-gawa R., 26.ix.1998, NK; 4³ 1♀, Chitose-shi, L. Shirarutoro-ko, 29.ix.1996, TI & A. Ohkawa; 3♀, same location, 29.ix.1996, A. Ohkawa; 1³ 5♀, same location, 28.viii.1997, TI & A. Ohkawa; 5³ 1♀, same location, 25.ix.1997, NK; 3³ 13♀, same location, 5.viii-7.x.2005, NK; 6³ 5♀, same location, 4–10.viii.2006, NK; 2³ 1♀, Chitose-shi, small stream beside L. Shikotsu-ko, 1.x.1993, NK; 4♀, same location, 21.VII-6.x.1996, Y. Nagayasu; 1♀, Sapporo-shi, Misumai, Toyohiragawa R., 27.vii.1992, NK. Iburi: 1♀, Atsuma-chô, Naganuma, Koi-numa, 13.vii.2006, NK; 1♀, Tomakomai-shi, Misawa, Bibi-gawa R., 18.vi.1990, NK; 2³, same location, 2.viii.1998, NK; 6♀, same location, 5.vii.2009, NK; 2³ 3♀, Tomakomai-shi, L. Utonai-ko, 1–6.vii.1998, NK; 1³ 1♀, same location, 21.vi.2003, NK; 9³, same location, 22.vii.2004, TI. Oshima: 4³ 6♀, Nanae-chô, Konuma, 23.vi.2003, NK; 10³ 12♀, Nanae-chô, Ônuma, 23.vi.2003, NK. HONSHU: Aomori: 1³(I), Fujisaki-machi, Shirako, Iwaki-gawa R., 2.viii.1996, Suzuki; 1³ 1³(L) 2♀, Hirosaki-shi, Akudo, Iwaki-gawa R., 20.viii.1996, Suzuki. Akita: 5³, Kosaka-machi, Towadako-namariyama, L. Towada-ko, 8.viii.1999, H. Kato. Fukushima: 1³ 1³(L) 3♀, Shôwa-mura, Yanohara-kôgen, 19.viii.2008, N. Katsuma. Ibaraki: 4³ 2³(L) 3♀, Kasama-shi, Minamikoizumi, 24.vi.2007, N. Katsuma. Gumma: 1³(L) 1³(I) 2♀, Fujioka-shi, Samba-gawa R., 29.v.1991, S. Ishiwata. Tôkyô: 1³(L), Fussa-shi, Nagatabashi, 9.vi.1985, S. Sasaki. Kanagawa: 1³, Hadano-shi, L. Shinsei-ko, 16.xii.1979, TN; 2³(I) 15♀, Sagamihara-shi, Fujino-chô, Magino, 9.vi.1988, TN; 2³ 1³(L) 5♀, Yamakita-machi, Shiraishi-zawa, 5–6.vii.1984, TN; 1³(L), same location, 19.vii.1982, TN; 10³ 4³(L) 7♀, Zushi-shi, Sakurayama, Morito-gawa R., 20.vii.2009, TN. Fukui: 1³, Tsuruga-shi, Ikenokôchi-shitsugen, 21.vii.2015, TI; 1³ 1³(L) 13♀, same location, 11.vi.2016. Nagano: 1³ 1♀, Koumi-chô, Matsubara, L. Chô-ko, 30.v.1997, TI; 3♀, Maruko-machi, Uchimura-kawa, 21.vi.1997, K. Tojo; 1³(R), Ômachi-shi, L. Aoki-ko, 28.viii.2008, N. Katsuma; 1³(L) 2³(R), same location, 23.ix.2009, NK; 1³(L) 2³(I) 9³(R) 17♀, Ômachi-shi, L. Nakatsuna-ko, 27.ix.1990, NK; 3³(L) 2³(I) 14³(R) 19♀, same location, 23.ix.2009, NK. Gifu: 1³(L), Higashishirakawa-mura, Oppara, 27.v.1988, TN. Shizuoka: 2³ 3³(L) 1³(I) 1♀, Shimoda-shi, Tateno, 12.iv.2009, S. Inaba. Mie: 4³ 2³(L) 2³(I) 2♀, Shima-shi, Isobe-chô, Natsukusa, 5.vii.2008, H. Morita. Hyôgo: 2³ 1³(I), Asago-shi, Wadayama, Kudawa, Ishibe-jinjya, 3.xi.2006, K. Inazu. & TI. Shimane: 1³ 3♀, Gôtsu-shi, Sakuraechô, Kawagoe, 2.v.1999, SN; 2³, Oochi-chô, Shiki, 10.viii.1999, SN; 1³ 1♀, Kawamoto-machi, Inbara, 12.v.1999, SN; 4³ 1♀, Masuda-shi, Mukaiyokotachô, 7-8.v.2000, SN; 1³ 4♀, same location, 29.vii.2000, SN; 3³, Masuda-shi, Yasudomichô, 18.vii.2000, SN; 2³ 8♀, Masuda-shi, Musochô, 6.v.2001, SN; 2³ 1³(L), Masuda-shi, Musochô, Takatsu-gawa R., 27.vii.2000, SN. Hiroshima: 1³(I), Akitakata-shi, Yachiyo-chô, Haji, Haji-dam, 11.vii.2000, SN; 1³ 2♀, Akitakata-shi, Yoshida-chô, Yoshida, 21.iv.1999, SN; 1³(L) 1³(I), Higashihiroshima-shi, Takaya-chô, Nakashima, 13.vii.1999, SN; 1³, Hiroshima-shi, Asakita-ku, Kabechô, Imaida, 24.iv.1999, SN; 3³ 1³(L) 2♀, Kôzan-chô, Uzuto-gawa R., Hattabara-dam, 5.viii.1998, SN; 6³ 1³(L) 1♀, same location, 25.vii.2000, SN; 1³(I), Miyoshi-shi, Minamihatajikimachi, 1.viii.1999, SN; 2³, same location, 6.x.1999, SN; 1³ 2♀, Ôtake-shi, Fukase, Kose-gawa R., 8.v.2001, SN; 1³, same location, 23.vii.2001, SN; 1³(L) 4♀, Ôtake-shi, Bouroku, Kose-gawa R., 7.v.2001, SN; 5³ 4♀, Ôtake-shi, Kuritanicho, Yasaka-dam, 28.vii.2000, SN; 1³, Sera-chô, Io, Hattabara-dam, 26.vii.2000, SN; 2³ 1³(L), Yuki-chô, Shimominauchi, 25.iv.1999, SN; 1³(L), same location, 15.v.2003, TN. Yamaguchi: 1³ 2♀, Iwakuni-shi, Miwachô, One-gawa, Yasaka-dam, 25.ix.2000, SN. SHIKOKU: Tokushima: 1³ 1³(L), Kitô-son, Takanose-kyô, 18.vii.1998, I. Yamashita. Kagawa: 2³ 1³(I) 1♀, Takamatsu-shi, Shionoe, 14.ix.2006, NK. Kôchi: 11³ 2³(L) 6♀, Kami-shi, Monobechô, Befu, 2.viii.2003, I. Yamashita; 2³(L), Muroto-shi, Sakihama, Sakihama-gawa R., 29.iv.2004, M. Takai; 1³(L) 1♀, Nankoku-shi, Nakanogawa-rindô, 29.v.2004, M. Takai; 1³(L), Ochi-chô, Tokoroyama, Ichigaya, 21.vii.2004, K. Nio; 1³(L), Sukumo-shi, Itchûbara, 28.iv.2001, M. Takai; 1³, same location, 30.iv.2004, M. Takai; 1³, Tosashimizu-shi, Mochiishi, Kitayamahigashi, 21.vii.2004, K. Nio. KYÛSHÛ: Fukuoka: 1³ 1♀, Chikushino-shi, Yoshiki, 30.iv.1986, N. Gyotoku; 1³ 1♀, same location, 9.x.1986, N. Gyotoku; 2³, Ukiha-shi, Yoshiimachi, Sakurai, Chikuko-gawa R., 8.iv.1997, TN. Saga: 4³ 9♀, Takeo-shi, 22–23.iv.2009, T. Shimizu; 7³ 1♀, Ureshino-shi, 4.vi.2009, T. Shimizu. TSUSHIMA: 5³ 2³(L) 2♀, Tsushima-shi, Kamiagata-chô, Sago, upper reaches of Sago-gawa R., 22.vii.2009, R.B. Kuranishi.
description: Published as part of Kuhara, Naotoshi, Nozaki, Takao, Zhang, Ao & Zhou, Xin, 2023, DNA barcoding facilitates discovery and description of two new species of the Mystacides azureus Species Group (Trichoptera: Leptoceridae) in Japan, pp. 215-231 in Zootaxa 5306 (2) on page 225, DOI: 10.11646/zootaxa.5306.2.3, http://zenodo.org/record/8058719