Acicnemis shigematsui Morimoto & Miyakawa, 1995

Lewis, Jake H., Kojima, Hiroaki & Campbell, Erin O., 2025, A Japan-focused review of East Asian Acicnemis Fairmaire, 1849 (Coleoptera, Curculionidae) reveals cryptic diversity in a well-studied region, ZooKeys 1259, pp. 103-167 : 103-167

Acicnemis shigematsui Morimoto & Miyakawa, 1995

Figs 3 F , 6 Q 1–6 , 2 , 28

Type material examined

( Japan: 9). Holotype. Japan: Okinawa Prefecture: • Ishigaki Island, Omoto-dake , 1. VIII. 1989, K. Shigematsu, bears red label reading “ (HOLOTYPE) Acicnemis shigematsui Morimoto et. Miyakawa, 1994 ”, JHL_ACITAI_052 , ELKU, ELKU 2960 . Paratypes. Okinawa Prefecture: • Iriomote Island, Shirahama , 31. VIII – 5. IX. 1969, H. Makihara (2, KUM), JHL_ACITAI_005 (dissected male), JHL_ACITAI_047 ; • Iriomote Island, Mt. Ushiku , 4. XI. 1963, G. A. Samuelson (1, KUM), JHL_ACITAI_053 ; • Iriomote Island, Upper Nakara River , 12. III. 1964, Y. Miyatake (1, KUM), JHL_ACITAI_045 .

Non-type material.

Japan: Okinawa Prefecture: • Ishigaki Island, Yarabu-dake , 3. V. 1998, K. Takahashi (1, KUM), JHL_ACITAI_054 ; • Omoto-dake , 1–4. VII. 2009, R. Ito (1, KUM), JHL_AREV_481 ; • Omoto-dake , 29. III. 2022, T. Nozaki (1, KUM), JHL_AREV_482 ; • Okinawa Island, Naha, Shuri, “ Sumiyoshi Park ” (probably referring to Sueyoshi Park) , 23. XI. 1990, K. Morimoto (1, KUM), JHL_ACITAI_044 .

Diagnosis.

Body length 5.1–7.0 mm. Covered in pale brown, dark gray, and black scales, with a tan-colored, V-shaped, transverse band across middle of elytra. Pronotum lacking distinct longitudinal, impunctate midline (present in A. koguma ). Scutellum covered in pale scales (Fig. 3 F ). Elytra with erect scales only on odd intervals. Sclerolepidia distinct and protruding. Third tarsomeres distinctly emarginate. Pedon with lateral edges approx. parallel in dorsal view, but weakly sinuating into a blunt, subtriangular point. Internal sac not visible inside aedeagus, but with a protruding basal structure extending to the end of the temo and tuberculate (roughened) musculature anteriorly at the apex (Fig. 6 Q 1 – 2 ).

Distribution.

This species is endemic to Okinawa Prefecture, Japan, and is currently only known from Ishigaki, Iriomote, and apparently also Okinawa Island.

Remarks.

This species is quite similar in size and color to A. palliata ; however, it was differentiated by Morimoto and Miyakawa (1995) on the basis of elytral color differences alone. To verify the validity of this species the type series of A. shigematsui and A. palliata were compared, and several significant differences in external and genital morphology were discovered which are all newly reported in the dichotomous key below. Furthermore, although A. shigematsui was previously only known from Ishigaki and Iriomote Islands, a specimen deposited in the KUM was collected on Okinawa Island ( 400 km away from the type localities). No specimens of A. shigematsui have since been collected on the island. Further field studies are required to ascertain whether this rarely collected species is truly established on the island.

Figures

Figure 2. Diagnostic morphological characters in Acicnemis. A. A. azumai Morimoto & Miyakawa, 1995 (JHL _ ACITAI _ 081) showing lack of prominent posterior prosternal projections; B. A. laeta Hubenthal, 1919 (JHL _ AREV _ 533) showing prominent prosternal projections; C. A. kiotoensis Nakane, 1963 (JHL _ AREV _ 982) showing antenna with the second funicular antennomere longer than antennomeres 3 + 4; D. A. koguma Lewis & Kojima, sp. nov. (JHL _ SYN _ 141) showing antenna with the second funicular antennomere shorter than antennomeres 3 + 4; E. A. luteomaculata Morimoto & Miyakawa, 1995 (JHL _ AREV _ 189) showing truncate third tarsomere; F. A. ryukyuana Lewis, 2023 (JHL _ ACI _ 011) showing weakly emarginate third tarsomere; G. A. maculaalba Roelofs, 1875 (JHL _ AREV _ 577) showing strongly emarginate third tarsomere.

Figure 3. Scutella and pronota of various Acicnemis species. A. A. azumai Morimoto & Miyakawa, 1995 (JHL _ ACITAI _ 081) showing two bare (unscaled) tubercles baso-medially on the pronotum; B. A. kiotoensis Nakane, 1963 (JHL _ AREV _ 982) showing a broad, unscaled scutellum; C. A. koguma Lewis & Kojima, sp. nov. (JHL _ SYN _ 141) showing a bare, but more slender scutellum than A. kiotoensis; D. A. maculaalba Roelofs, 1875 (JHL _ AREV _ 577) showing a small scutellum covered in scales; E. A. palliata Pascoe, 1872 (JHL _ AREV _ 779) showing a larger scutellum that is shiny and bare dorsally, and surrounded along the perimeter by yellow scales; F. A. shigematsui Morimoto & Miyakawa, 1995 (JHL _ ACITAI _ 052) showing a smaller scutellum covered in scales.

Figure 6. Aedeagi of Acicnemis. A 1–2. A. albofasciata (Ter-Minasian 1953); B 1–2. A. azumai Morimoto & Miyakawa, 1995; C 1–2), A. cryptica Lewis & Kojima, sp. nov.; D 1–2. A. dividicincta Morimoto & Miyakawa, 1995; E 1–2. A. exilis Morimoto & Miyakawa, 1995; F 1–2. A. kiotoensis Nakane, 1963; G 1–2. A. laeta Hubenthal, 1919; H 1–2. A. luteomaculata Morimoto & Miyakawa, 1995; I 1–2. A. maculaalba Roelofs, 1875; J 1–2. A. nobilis Hubenthal, 1919; K 1–2. A. nohirai Morimoto & Miyakawa, 1995; L 1–2. A. palliata Pascoe, 1872; M 1–2. A. postica Hubenthal, 1919; N 1–2. A. ryukyuana Lewis, 2023; O 1–2. A. sauteri Hubenthal, 1919; P 1–2. A. shibatai Voss, 1971; Q 1–2. A. shigematsui Morimoto & Miyakawa, 1995; R 1–2. Acicnemis sp. 1; S 1–2. A. squamata Lewis & Kojima, sp. nov.; T 1–2. A. suturalis Roelofs, 1875.

Figure 28. Acicnemis shigematsui Morimoto & Miyakawa, 1995 (JHL _ ACITAI _ 052). A. Lateral; B. Dorsal. Scale bar: 1 mm.