Limnocentropus haeuseri MEY & lEGER, sp. nov., 2024

Mey, Wolfram, Léger, Theo & Lien, Vu Van, 2024, Limnocentropus haeuseri sp. noV. – a neW endemic caddisfly from the Central Highlands of Vietnam (Trichoptera: Limnocentropodidae), Entomologische Zeitschrift. Schwanfeld. 134 (4), pp. 209-213 : 209-212

publication ID	https://doi.org/10.5281/zenodo.15078109
DOI	https://doi.org/10.5281/zenodo.15078111
persistent identifier	https://treatment.plazi.org/id/3B7687BE-FFD5-FF9E-FBEA-17CCBD66B94A
treatment provided by	Valdenar
scientific name	Limnocentropus haeuseri MEY & lEGER, sp. nov.
status	sp. nov.

Treatment

Limnocentropus haeuseri MEY & lEGER, sp. nov. ( Figs 5–14 View Fig View Figs 6–9 View Figs 10–13 View Fig )

Holotype. ♂, Vietnam, Lamdong Province , Bidoup-Nuiba National Park , Thien Thai waterfall , N 12°08.710' E 108°31.723', 1473 m, 8.III.2024, light trap, leg. W. MEY, [pinned].

Paratypes. 2 ♀, same data as holotype [pinned]; 1 ♂, 2 ♀, same locality, 30.IV. 2022, leg. W. Mey [pinned]; 1♀, Vietnam, Lamdong Province , Bidoup-Nuiba National Park , Du An Cu Lan Forest , north of Dalat, TSD km 660, “plateau”, 12°05'32''N 108°22'37''E, 1792 m, 8.III.2024, leg. A. ZWICK [in alcohol]. GoogleMaps

Etymology. The species is named in honour of CHRISTOPH HÄUSER (MfN, Berlin), expert on Rhopalocera and organiser of the VIETBIO project.

Description. Adult ( Fig. 5 View Fig ). Length of body 10 (♂) to 15 (♀) mm, length of forewing 13 (♂) to 20 (♀) mm. Head pale brown, setal warts with yellow-brown setae, ocelli present, eyes black, with fine, short hairs. Clypeolabrum short, remnants of mandibles absent; maxilla with voluminous setose, galea and five-segmented maxillary palpus (♂, ♀), first segment shortest, brown, subsequent segments black; haustellum small, hidden under galeae; labial palpi three segmented, black. Antenna about two thirds of wing length, scape pale brown, pedicel shorter than subsequent black flagellomeres, each with an apical ring of white hairs. Thorax pale-brown, pro- and metanotum with two pairs of setal warts, coxae and femora yellow-brown, tibiae and tarsi black, hindtibia only black at tip, spur formula 2.4.4., spurs covered by small hairs, tibial segments with black spines on ventral side, praetarsus with short ungues and cup-like arolium. Forewing uniformly yellow-brown, hairs on membrane short and dense, longer setae on veins; wing venation in Fig. 14 View Fig , distal end of thyridial cell with a naked spot; hindwing pale brown, some short bristles on base of costa. Abdomen grey-brown, with antecostal lines on sterna and terga, segment V with lateral sternal glands ( Figs 10, 13 View Figs 10–13 ) present, its orifice without appendage.

Male genitalia ( Figs 6–9 View Figs 6–9 ). Segment IX broad, with anterior margin strongly convex, in dorsal view with deep, U-shaped incision anteriomesally. Preanal appendages absent. Dorsal part of segment IX fused with tergum X, complex of apical tergum X elongate, split apically into pair of slender processes, directed caudad and with acute apices, tergum X in lateral view tapering along its length, not divided into upper and lower parts. Inferior appendages slightly shorter than tergum X in lateral view, with a bundle of strong, curved bristles on dorsal margin; in dorsal and ventral view inferior appendages bent evenly mesad forming a semi-circle. Phallus cylindrical, slightly down-curved, long phallotremal sclerites present, curved ventrad.

Female genitalia ( Figs 10–13 View Figs 10–13 ). Segment IX and X fused to a globular structure that bears only less conspicuous margins of genital parts. Segment IX is discernible by its more melanised anterior part and a pair of dark-shaped sclerites on ventral side; segment X with lateral flat lobes with small setae, ventral side separated into two triangular, membranous plates. Spermathecal sclerite a flat plate with caudal margin straight and folded ventrad.

Diagnosis. Concerning the male genitalia the new species resembles L. auratus MALICKY & CHANTAMARONKOL, 1989 ,

described from northern Thailand. The main distinguishing characters are the much larger size of the phallotremal sclerites of the phallic apparatus and a different form of the fused tergal IX+X complex.

Biology. The immatures and biology of only a few species of Limnocentropus ULMER, 1907 have been described up to now. The larvae live in turbulent streams. Cases are constructed of small sand grains and are attached to boulders by a silken stalk. The larvae use their legs armed with stout setae, extending them into the current to capture drifting organisms and detritus ( WIGGINS 2004). The Thien Thai waterfall ( Fig. 3 View Figs 1–3 ), where the new species was collected, is formed by several cascades and flat, inclined bed-rocks in shaded areas which appear to be a suitable habitat for the larvae of L. haeuseri sp. nov.

Distribution. LAUDEE & MALICKY, 2016 have communicated a single record of L. auratus from the Kon Tum Province in Vietnam. This record is based on an erroneous identification (H. MALICKY, personal communication).

Concluding remarks. Limnocentropus was first reviewed by YANG & MORSE (2005) and later again by LAUDEE & MALICKY, (2016), who listed 17 species occurring in mountainous regions of Asia. The range of the genus is depicted in Fig. 15 View Fig . Recently, MEY & MALICKY (2021) described L. rossicorum from northern Myanmar and, with the addition of the herein described L. haeuseri sp. nov., the genus currently contains 19 species.

Limnocentropodidae TSUDA, 1942 is one of the two endemic families of Trichoptera in Asia. In contrast to Phryganopsychidae Wiggins, 1959 , the other endemic family, Limnocentropodidae has a related group with only a few species occurring in Australia and South America: Tasimiidae RIEK 1968 . The monobasic Charadropsyche FLINT, 1969 and Trichovespula SCHMID, 1955 were described from Chile. The ranges of the Australian Tasimia MOSELY, 1936 and Tasiagma NEBOISS, 1977 are encompassing Tasmania and southeast Australia. The disjunct distribution of both families as shown in Fig. 16 View Fig may be explained by vicariance events, which correspond to/ are consistent with the gradual break-up of the Gondwana continent during the Cretaceous. Indochina is geologically a composite area which was formed by the fusion of microcontinents and terranes which became detached from the western and northern margins of Gondwana and rafted northwards to dock with Eurasia (METCALF 2001, 2017). If not submerged during their passage, they may have carried species of the old Gondwanan fauna.

Examples or evidence of successful shifting of taxa of Gondwanan origin into Asia via these microcontinents are provided by insect inclusion in Burmese amber. The amber Lagerstätte itself is located on the West Burma block, one of those microcontinents, and was deposited about 100 Ma ago. Fossil species of the primitive lepidopteran groups Agathiphagidae , Lophocoronidae and Heterobathmiidae , whose extant species are restricted today to the southern Hemisphere, were discovered as amber inclusions ( MEY et al. 2021, MEY 2024). The model of shifting terranes or microcontinents was proposed as a possible explanation for the formation of these disjunct ranges. If applied to the family pair Limnocentropodidae – Tasimiidae its disjunct range pattern fits to the model even better, because shifting and arrival times of the West Burma Block agrees with the divergence time of the families estimated as being between 84 and 155 Ma ( THOMAS et al. 2020). The ancestors of Limnocentropodidae obviously managed to survive the passage with the terrane and the arrival in Eurasia, dispersed into the continent and became an integral and characteristic part of the Asian Trichoptera fauna.