Hydroptila ogasawaraensis, Ito, 2011

Ito, Tomiko, Sasaki, Tetsuro, Takahashi, Chicaco, Sugawara, Hirotaka & Hayashi, Fumio, 2023, The family Hydroptilidae Curtis (Trichoptera) in the Ogasawara Islands, northwestern Pacific, with particular reference to adaptive radiation in the oceanic islands, Zootaxa 5231 (2), pp. 141-164 : 160-161

Hydroptila ogasawaraensis Species Group Ito

Diagnosis. Males of this species-group are somewhat similar to those of the H. pulchricornis Species Group of Marshall (1979), a small Palearctic group, in having a short, subacute apicoventral process on abdominal sternite VII, relatively short and annular segment IX with a narrow (longitudinally short) dorsal bridge, and an almost straight and fine phallic apparatus, but they can be discriminated from the later by the length of the inferior appendages: The relative length of the appendages to segment IX is more than 1.0 in the H. pulchricornis Species Group ( Marshall 1979; Ito et al. 2011), but 0.5–0.8 in this new H. ogasawaraensis Species Group. Final instar larvae of the H. ogasawaraensis Species Group are also similar to those of the H. pulchricornis Species Group, but differ from the later by the presence of dorsal chloride epithelia on abdominal segments I–VI or a depressed oblong head capsule; in contrast, the described larvae of the H. pulchricornis Species Group species have the chloride epithelia on segments II–VI and a roundish head capsule and include H. phenianica Botosaneanu 1970 , H. dampfi Ulmer 1929 , and H. oguranis Kobayashi 1974 ( Ito 2021) .

Male: Pair of anterolateral processes of sternite V each with two setae, one long and one short; sternite VII with short, subacute, ventral process; segment IX short, annular with narrowly transverse dorsal bridge; phallic apparatus almost straight; and inferior appendages moderately short.

Final instar larva: Small dorsal sclerites or small dorsal chloride epithelia on abdominal segments I–VI or with depressed, oblong head capsule.

Species belonging to the Group: Hydroptila ogasawaraensis , H. demersa sp. nov., H. ishiura sp. nov., H. tokoyo sp. nov., H. hahajima sp. nov., and H. nagahama sp. nov. All species are endemic to the Ogasawara Islands.

Remarks: Larval morphology differs greatly between H. demersa and the other five species, but the molecular phylogeny suggests that they all belong to the same species group ( Fig. 2 ).

Japanese name: Ogasawara-himetobikera-shugun.

Figures

FIGURE 2. Phylogenetic trees of six species of Hydroptila endemic to the Ogasawara Islands (H. demersa sp. nov., H. ishiura sp. nov., H. tokoyo sp. nov., H. hahajima sp. nov., H. nagahama sp. nov., and H. ogasawaraensis Ito 2011, in Ito et al. 2011) and the outgroup H. pulchricornis Species Group from mainland Japan (H. phenianica Botosaneanu 1970, H. chinensis Xue & Yang 1990, H. oguranis Kobayashi 1974 and/or H. dampfi Ulmer 1929), based on (2A) 429-bp mitochondrial COI and (2B) 306-bp nuclear 28S sequences. See Table 1 and Fig. 1 for locality of each specimen. The topology is the same between the trees drawn by the neighbor-joining method (NJ) and the maximum likelihood (ML). The numerals at nodes show % bootstrap probabilities in ML (NJ).