 |
| Apeuthes pollex Pimvichai, Panha & Backeljau, 2022 |
Abstract
Hitherto, the millipede genus Apeuthes (family Pachybolidae, subfamily Trigoniulinae) was only known from three species described in Vietnam based on morphological characters. The present study uses two partial mitochondrial gene fragments (cytochrome c oxidase I (COI) and 16S ribosomal RNA) and morphology to define four new Apeuthes species from Malaysia, Thailand and Vietnam: A. fimbriatus, sp. nov., A. longeligulatus, sp. nov., A. pollex, sp. nov. and ?A. spininavis, sp. nov. The intraspecific COI sequence divergence of two Apeuthes species is 3–7% (mean: 5%) and the interspecific divergence of five species is 11–16% (mean: 13.7%). All members of the genus share unique male characters, viz the posterior gonopod telopodite with several dentate, serrate or tuberculate lamellae in a boat-like cavity or a boat-like cavity covered with spines. The delimitation of the four new species is supported by the congruence between mitochondrial DNA and morphological data. However, while the monophyly of Trigoniulinae is well supported, the relationships within this subfamily, and particularly among Apeuthes species, including the monophyly of Apeuthes, lack strong support. Therefore assignment of the four new species, and particularly of ?A. spininavis sp. nov., to the genus Apeuthes is tentative and awaits a comprehensive revision of the group.
Keywords: DNA barcoding, Malaysia, mitochondrial DNA, monotypic genera, phylogeny, species delineation, Thailand, Trigoniulinae, Vietnam.
Class DIPLOPODA de Blainville in Gervais, 1844
Order SPIROBOLIDA Bollman, 1893
Suborder TRIGONIULIDEA Attems, 1909
Family PACHYBOLIDAE Cook, 1897
Subfamily TRIGONIULINAE Attems, 1909
Genus Apeuthes Hoffman & Keeton, 1960
Apeuthes Attems, 1938; invalidly proposed (as subgenus of Eucarlia Brölemann, 1913)
Type species: Eucarlia (Apeuthes) maculata Attems, 1938
Included species: Apeuthes eydouxii (Gervais, 1847) (formerly Iulus eydouxii Gervais, 1847 and Eucarlia (Apeuthes) charactopyga Attems, 1938), Apeuthes exustus (Attems, 1938) (formerly Eucarlia (Apeuthes) exusta Attems, 1938), Apeuthes maculatus (Attems, 1938) (formerly Eucarlia (Apeuthes) maculata Attems, 1938), Apeuthes fimbriatus, sp. nov., Apeuthes longeligulatus, sp. nov., Apeuthes pollex, sp. nov., ?Apeuthes spininavis, sp. nov.
Diagnosis: A genus of the pachybolid subfamily Trigoniulinae defined by having posterior gonopod telopodite with several dentate, serrate or tuberculate lamellae in a boat-like cavity (Attems 1938) or a boat-like cavity covered with spines (diagnostic extension provisionally added here to better accommodate ?A. spininavis, sp. nov., see Discussion).
Distribution: Malaysia, Thailand and Vietnam.
Apeuthes fimbriatus, sp. nov.
Diagnosis: Differing from all other species in the genus by having a triangular mesal sternal process of anterior gonopod, not reaching so far as the tip of coxae (Fig. 3a, d). Anterior gonopod telopodite far overreaching coxa, distally bifid, forming a butterfly-like structure (Fig. 3b, e). Posterior gonopods apically with rounded and spiny lamellae, one above the other (Fig. 3f–h).
Distribution: Da Nang Province, Vietnam (Fig. 9).
Etymology: The specific name is a Latin adjective, meaning ‘fringed’ and referring to the fringed lamella on the posterior gonopod.
Apeuthes longeligulatus, sp. nov.
Diagnosis Differing from all other species in the genus by having a narrow mesal sternal process of anterior gonopod, protruding slightly higher than coxae (Fig. 4a, d). Anterior gonopod telopodite distally bifid (Fig. 4b, e). Posterior gonopods apically with several flattened lamellae in a boat-like cavity (Fig. 4c, f–i).
Distribution: Sa Kaeo and Trad provinces, Thailand (Fig. 9).
Etymology: The specific name is a Latin adjective, meaning ‘with a long tongue’ and referring to the sternal process of the anterior gonopod.
 |
| Live Apeuthes pollex, sp. nov. from Tham Sue Temple (WTS), male (paratype, CUMZ D00143-2). |
Apeuthes pollex, sp. nov.
Diagnosis: Differing from all other species in the genus by having coxa of anterior gonopod distinctly concave for accommodation of telopodite (Fig. 5b, e). Anterior gonopod telopodite protruding slightly over coxa, apically abruptly narrowed, ending in one slender process (Fig. 5b, e). Posterior gonopods apically with a rounded lobe, with serrated lamellae mesally and with a thumb-like process basally (Fig. 5c, f, g).
Distribution: Krabi and Phang-Nga provinces, Thailand (Fig. 9).
Etymology: The specific epithet is a noun in apposition, meaning ‘thumb’ and referring to the thumb-like basal process on the posterior gonopod.
?Apeuthes spininavis, sp. nov.
Diagnosis: Anterior gonopods with broad, triangular mesal sternal process (Fig. 6a, d). Similar in this respect to A. pollex, sp. nov. Differing from all other Apeuthes species by having posterior gonopods that are apically abruptly narrowed, forming a pointed lobe (Fig. 6c, f–h), and with a mesal margin forming a deep boat-like cavity covered with spines (Fig. 6h, i) and without a conical process at mesal margin of posterior gonopod telopodite.
Distribution: Johor and Perak provinces, Malaysia (Fig. 9).
Etymology: The specific epithet is a noun in apposition, ‘spiny boat’, referring to the shape and texture of the posterior gonopod telopodite.
Note: ?Apeuthes spininavis, sp. nov. shares several characters with other species in the genus Apeuthes. However, it differs from all of other species of Apeuthes by the absence of a conical process covered with spinules midway on the mesal margin of the posterior gonopod telopodite. Hence, for the time being, we only tentatively assign this species to Apeuthes and refer it to as ?Apeuthes spininavis, sp. nov.
Piyatida Pimvichai, Somsak Panha and Thierry Backeljau. 2022. Combining Mitochondrial DNA and Morphological Data to Delineate Four New Millipede Species and Provisional Assignment to the Genus Apeuthes Hoffman & Keeton (Diplopoda: Spirobolida: Pachybolidae: Trigoniulinae). Invertebrate Systematics. 36(2) 91-112. DOI: 10.1071/IS21038
***งานวิจัยใหม่: กิ้งกือกระบอกเล็ก 4 ชนิดใหม่ของโลก
สกุล 𝐴𝑝𝑒𝑢𝑡ℎ𝑒𝑠 จากเอเชียตะวันออกเฉียงใต้***
สกุล 𝐴𝑝𝑒𝑢𝑡ℎ𝑒𝑠 จากเอเชียตะวันออกเฉียงใต้***
1. กิ้งกือกระบอกเล็กดานัง 𝐴𝑝𝑒𝑢𝑡ℎ𝑒𝑠 𝑓𝑖𝑚𝑏𝑟𝑖𝑎𝑡𝑢𝑠 Pimvichai, Backeljau & Panha, 2022 ค้นพบที่ จ. ดานัง ประเทศเวียดนาม
2. กิ้งกือกระบอกเล็กตะวันออก 𝐴𝑝𝑒𝑢𝑡ℎ𝑒𝑠 𝑙𝑜𝑛𝑔𝑒𝑙𝑖𝑔𝑢𝑙𝑎𝑡𝑢𝑠 Pimvichai, Backeljau & Panha, 2022 ค้นพบที่ จ. สระแก้วและตราด
3. กิ้งกือกระบอกเล็กภาคใต้ 𝐴𝑝𝑒𝑢𝑡ℎ𝑒𝑠 𝑝𝑜𝑙𝑙𝑒𝑥 Pimvichai, Backeljau & Panha, 2022 ค้นพบที่ จ.กระบี่และพังงา
4. กิ้งกือกระบอกเล็กมาเลเซีย ?𝐴𝑝𝑒𝑢𝑡ℎ𝑒𝑠 𝑠𝑝𝑖𝑛𝑖𝑛𝑎𝑣𝑖𝑠 Pimvichai, Backeljau & Panha, 2022 ค้นพบที่รัฐยะโฮร์และเประก์ ประเทศมาเลเซีย
