Hypotelus chusqueaticus McClarin and Caron 2025, new species
Creators: name: Caron, Edilson
name: Mcclarin, Jim
name: Buss, Bruna Caroline
name: Foti, Leonardo
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Staphylinidae
Hypotelus
Hypotelus chusqueaticus

description: Hypotelus chusqueaticus McClarin and Caron, new species
(Figs. 1–22)
Material examined. Holotype, male (dissected, segments VIII–X), deposited in QCAZ, labels: (1) “ Ecuador, Napo, Cosanga\ 2117m, 29.I.2019 \ Jim McClarin, col.” [white label, printed in black]; (2) “Collected from the sub-stipule\ space of Chusquea scandens bamboo” [white label, printed in black]; (3) “Holotype\ Hypotelus chusqueaticus McClarin and Caron \desig. Caron, 2024” [red label, printed in black]. Paratypes (6): two paratypes, 1 male (dissected, segments VIII–X), deposited in FMNH, and 1 female, deposited in QCAZ, with the same first two labels as holotype; (3) “Holotype\ Hypotelus chusqueaticus McClarin and Caron \desig. Caron, 2024” [yellow label, printed in black]. And four paratypes, females (dissected, segments VIII–X), deposited in QCAZ (1), FMNH (1), CESP (2), labels: (1) “ Ecuador, Napo, Cosanga\ 2117m, 8.VII.2018 \ Jim McClarin, col.” [white label, printed in black]; (2) “Collected from the sub-stipule\space of Chusquea scandens bamboo” [white label, printed in black]; (3) “Holotype\ Hypotelus chusqueaticus McClarin and Caron \desig. Caron, 2024” [yellow label, printed in black].
Diagnosis. Hypotelus chusqueaticus differs from H. testaceus by having unicolored elytra (Fig. 1); male sternite 8 with posterior margin somewhat pointed (Fig. 16); female sternite 8 with posterior margin pointed at the middle-third (Fig. 17); median lobe of aedeagus with apex truncate and with one prominent process on median region at posterior margin in ventral view (Fig. 21).
Description. Male. Maximum body length 4.00 mm, maximum elytral width 0.70 mm. Body elongate and parallel-sided (Fig. 1); dark brown to black, with posterior margin of abdominal segments III–VII and appendages rusty brown. Dorsal integument of front of head with granulate microsculpture; vertex and tempora of head and pronotum with dispersed fine punctures and undulate microstriae; elytra with dispersed fine punctures and only one longitudinal, finely punctate stria close to elytral suture; abdominal tergites overall dull with granulate microsculpture on lateral areas (Fig. 13). Head wider than long; pentagonal in shape, front deflected, supra-antennal area slightly prominent. Eyes prominent, each eye with one macroseta on posterior half of dorsal margin. Neck absent. Antenna long, reaching apex of elytra; antennomeres 1–4 only with some long setae on apex of each antennomere (Fig. 2); antennomeres 5–11 entirely covered with microsetae and some long setae on apex of each antennomere; antennomeres 5–11 with long setae on inner face slightly longer than that on outer face; scape longest; antennomeres 3 slightly longer than pedicel; antennomere 4 shortest; antennomeres 5–11 longer than wide, gradually increasing in length towards apex. Labrum with anterior margin deeply emarginate on median third (Fig. 3), three pairs of long setae medially; lateral thirds with two pairs of long setae. Epipharynx dorsally short with long fringes on anterior margin. Mandibles symmetrical; internal margin smooth (Fig. 6); prostheca developed and with transversal lines of microsetae; external margin somewhat granulate. Maxillary cardo as wide as long, somewhat subquadrate and base club-shaped (Fig. 7); stipes triangular; galea extending slightly beyond apex of lacinia; lacinia with dense short setae on apex; galea wider than lacinia, dense short setae on apex and some long setae on external margin near apex; maxillary palpus with palpomere 1 shortest; palpomere 2 twice longer than 3; palpomere 4 longest, with same length as 1–3 combined; external margin of palpomere 4 with some longitudinal grooves. Labial palpomere 1 longer than 2; palpomere 3 longest, with same length of 1–2 combined (Fig. 4). Gular sutures joined on apical two-thirds (Fig. 5). Pronotum slightly wider than long, anterior angles rounded; apical half with curved sides and basal half gradually narrowing toward base; pronotal disc with longitudinal median sulcus, not reaching anterior and posterior margin of pronotum; one pair of conspicuous setae on anterior margin of pronotum. Prosternum with anterior margin truncate; integument with central area glossy, lateral areas with granulate microsculpture; prosternal process long and curved toward apex, posteriorly projecting and partially covered by procoxae and apex easily visible behind the procoxae (Fig. 8); protrochantin visible externally; postcoxal hypomeral projection acute and long. Scutellum visible; triangular; integument with apical third smooth, rest with granulate microsculpture, thinner on lateral areas (Fig. 9). Elytra longer than wide, almost 1.5 longer than pronotum, covering abdominal tergite 3 on basal third; one long seta on humeral angle (Fig. 11); longitudinal sutural stria punctate, not reaching apical margin; apex slightly emarginate at middle; two long setae and series of short setae on posterior margin. Hind wings fully developed. Integument of mesoventrite with granulate microsculpture; integument of metaventrite with undulate microstriae on central area and granulate microsculpture on lateral areas; intercoxal process of mesoventrite about half length of mesocoxae, mesocoxae narrowly separated (Fig. 12); intercoxal process of metaventrite wider and slightly shorter than process of mesoventrite. Tibiae with apex wider than base, more conspicuous on pro- and mesotibiae; longitudinal row of robust spines. Tarsomeres 1–4 subequal in length; tarsomere 5 longest, same length as 1–4 tarsomeres combined. Abdominal tergite 2 short fused to tergite 3 (Fig. 13); segments III–VI with two pairs of paratergites and segment VII with only one pair; abdominal segment VII longest; tergites 4–6 on each side with some pairs of setae; tergite 8 longer than wide, with posterior margin curved and with laterotergites (Fig. 14); sternite 8 with posterior margin with somewhat pointed tip (Fig. 16); each tergite 9 with short ventral struts, separated by tergite 10; sternite 9 almost three times longer than wide, posterior margin truncate and with two pairs of long setae (Fig. 19); tergite 10 at posterior margin rounded, with short fringes and some setae (Fig. 18); median lobe of aedeagus curved in lateral view, with slightly bulbous base in ventral view, truncate at apex and with one prominent process on median region at posterior margin in ventral view, two internal areas darker than rest; parameres thin, parallel-sided, reaching apex of median lobe (Figs. 21–22). Female. Similar to male, except antenna shorter, reaching base of elytra; antennomeres 5–11 subquadrate to slightly longer than wide, gradually increasing in length toward apex; tergite 8 as long as wide, with posterior margin curved and with laterotergites (Fig. 15); sternite 8 with posterior margin with pointed tip at middle-third and with short setae (Fig. 17); sternite 9 consisting of a pair of hemisternites and a pair of more apical coxites, and with many long setae on apex (Fig. 20); bursa copulatrix with anterior margin rounded, spermathecal duct short, inserted laterally; spermatheca weakly sclerotized.
Distribution. South America: Ecuador. The species is known only from the type locality, Cosanga (Napo), on the eastern slope of the Andes at 2117 meters of elevation.
Etymology. The specific name is treated as an adjective, agrees with the gender of generic name and derived from the generic name of the bamboo from which the new species was collected, Chusquea scandens Kunth, 1822. The term “chusquea” receives the ending “-ticus” meaning belonging to Chusquea.
Biological Notes. The specimens of Hypotelus chusqueaticus sp. nov. were collected on two occasions from the sub-stipule space of Chusquea scandens bamboo, a host species to a great many arthropods. Chusquea scandens has a weak thin-walled stalk and pithy core that is often penetrated by fly larvae and assorted beetles. It has a protective stipule that covers emerging bundles of blades but loosens and splits under pressure from the growing blade bundle and hangs in place rather than falling to the ground (Figs. 23–25). The resulting sub-stipule space provides a moist microhabitat for fungi, assorted Diptera larvae, Hemiptera, and Coleoptera of the families Nitidulidae (18 morphotypes), Silvanidae (1), Laemophloeidae (1), Monotomidae (2), Ptiliidae (1), Carabidae (1), prostomiine Salpingidae (1), hapalipine Erotylidae (1), and Staphylinidae (2). Of the Staphylinidae, one species is Hypotelus chusqueaticus sp. nov., and another is a species of Philonthina (Staphylininae) that has not yet been described (Fig. 26) (Chani-Posse, Instituto Argentino de Investigaciones de las Zonas Aridas, Mendoza, Argentina, personal communication).
Occasional spiders, centipedes, other beetle families, and pseudoscorpions are also found in the sub-stipule space. More families of beetles and other arthropods are found in great number on the foliage of this bamboo species, which makes for very productive beating sessions. Dynastine Scarabaeidae and aphids (Hemiptera) have been found feeding on the tender shoots (Figs. 27–28).
In general, the other species of Hypotelus have been captured using flight intercept and Malaise traps, Berlese and Winkler leaf litter extraction, and pitfall traps only occasionally (Bortoluzzi et al. 2017).
Taxonomic notes. Hypotelus chusqueaticus shares almost all the diagnostic characteristics of the genus according to Bortoluzzi et al. (2017), except maxilla with galea wider than lacinia (fig. 7). Bortoluzzi et al. (2017) mentioned and illustrated (fig. 33, in that article) galea narrower than lacinia.
description: Published as part of Caron, Edilson, Mcclarin, Jim, Buss, Bruna Caroline & Foti, Leonardo, 2025, Combining molecular and morphological data to test the monophyly of Hypotelus Erichson and description of new species from Ecuador (Coleoptera, Staphylinidae, Piestinae), pp. 548-560 in Zootaxa 5631 (3) on pages 551-556, DOI: 10.11646/zootaxa.5631.3.8, http://zenodo.org/record/15371255