Tuesday, December 15, 2020

[Entomology • 2020] Ancyronyx lianlabangorum • A New Spider Riffle Beetle (Coleoptera, Elmidae) from Sarawak

Ancyronyx lianlabangorum 
Kodada, Jäch, Freitag, Čiamporová-Zaťovičová, Goffová, Selnekovič & Čiampor, 2020

Ancyronyx lianlabangorum sp. nov. (Coleoptera, Elmidae), a new spider riffle beetle from the Kelabit Highlands (Sarawak, northern Borneo), is described. Illustrations of the habitus and diagnostic characters of the new species and the similar, polymorphic A. pulcherrimus Kodada et al. are presented. Differences to closely related species, based on COI nucleotide sequences and morphological characters, are discussed. Ancyronyx pulcherrimus is here recorded from Sarawak for the first time, based on DNA barcoding.

Keywords: Ancyronyx, Coleoptera, Elmidae, taxonomy, variability

Figure 3. Ancyronyx lianlabangorum sp. nov. 
A holotype, dorsal view, body length 2.97 mm B female paratype, dorsal view, body length 2.97 mm 
C holotype, dorsal view of body D holotype, ventral view of body E brachypterous paratype with removed elytron, dorsal view, body length 2.98 mm. 

Figure 4. Ancyronyx lianlabangorum 
A male from Gunung Mulu NP, body length 1.82 mm B brachypterous male from Gunung Mulu NP, dorsal view (left elytron and apical segments of abdomen removed), body length 1.92 mm 
C male from Bayur River, dorsal view, body length 1.70 mm D male [JK106] from Bayur River, dorsal view, body length 1.70 mm.

Ancyronyx lianlabangorum sp. nov.
Diagnosis: Ancyronyx lianlabangorum sp. nov. represents one of the largest species characterized by: (1) large size: body length ca 2.5–3.0 mm and elytral width ca 1.3–1.4 mm; (2) comparatively short obovate body form; (3) shiny black head and unicolored yellow pronotum; (4) black-yellowish color pattern of elytra with moderately prevailing black; (5) femora yellowish around middle, lacking dark spot; (6) aedeagus large, with subparallel-sided, apically abruptly narrowed penis; parameres robust, shorter and reaching only up to apical third of penis length, apices wide and emarginate near middle; (7) ovipositor robust, with numerous conspicuous peg-like sensilla; stylus moderately long: ca 0.43× as long as distal portion of coxite; distal part of coxite short and wide: 1.16× as long as wide at middle; longitudinal baculum of paraprocts about twice as long as coxite.

Figure 5. Habitats of Ancyronyx lianlabangorum sp. nov. (A–C) and A. pulcherrimus (D)
 A type locality, Pa’ Ramudu River B Pa’ Masia River C Pa’ Kasi River D shaded shallow creek in primary forest, Gunung Mulu NP.
Distribution: This species is known from a few small, slowly flowing tributaries of Pa’ Kelapang River near Kampung Ramudu, Kelabit Highlands, Sarawak.

Etymology: We named the species in honor of David Lian Labang (“Uncle David”) and his son David Lian Labang Jr from Bareo (Kelabit Highlands, Sarawak). They run Labang Longhouse Lodge in Bareo. Ján Kodada and David Selnekovič have always been happy to take advantage of this fabulous accommodation during several field trips. Uncle David is a retired, well-known employee of the Forest Department Sarawak, who contributed to the knowledge and conservation of Sarawak’s nature. We are most grateful to both for many stories and shared information about the terrain, nature, culture, as well as for their endless repertoire of jokes!

Ján Kodada, Manfred A. Jäch, Hendrik Freitag, Zuzana Čiamporová-Zaťovičová, Katarína Goffová, Dávid Selnekovič and Fedor Čiampor Jr. 2020. Ancyronyx lianlabangorum sp. nov., A New Spider Riffle Beetle from Sarawak, and New Distribution Records for A. pulcherrimus Kodada, Jäch & Čiampor based on DNA Barcodes (Coleoptera, Elmidae). ZooKeys. 1003: 31-55. DOI: 10.3897/zookeys.1003.55541