Colenisia chungi Schilthuizen, Seip & Otani

Schilthuizen, Menno, Seip, Lilian A, Otani, Sean, Suhaimi, Jadda & Njunjic, Iva, 2017, Three new minute leaf litter beetles discovered by citizen scientists in Maliau Basin, Malaysian Borneo (Coleoptera: Leiodidae, Chrysomelidae), Biodiversity Data Journal 5, pp. 21947-21947 : 21947

Colenisia chungi Schilthuizen, Seip & Otani sp. n.

Materials

Type status: Holotype. Occurrence: catalogNumber: BOR/COL/14090 ; recordedBy: I. Njunjić; M. Schilthuizen; Taxon Expeditions; individualCount: 1; sex: male; lifeStage: adult; preparations: card-mounted; disposition: in collection; Taxon: scientificName: Colenisiachungi; order: Coleoptera; family: Leiodidae; genus: Colenisia; specificEpithet: chungi; taxonRank: species; scientificNameAuthorship: Schilthuizen, Seip & Otani; Location: continent: Asia; island: Borneo; country: Malaysia; stateProvince: Sabah; municipality: Tongod; verbatimLocality: Maliau Basin, near Studies Centre, along Seraya Trail, where stream enters the river; verbatimElevation: 260 m; verbatimCoordinateSystem: decimal degrees; decimalLatitude: 4.7389; decimalLongitude: 116.9696; Event: samplingProtocol: Winkler, litter from basis of trees; samplingEffort: 15 l of leaf litter; eventDate: 2017-09-27; habitat: lowland dipterocarp forest; fieldNumber: TxEx-MBSC1wb; Record Level: institutionID: Universiti Malaysia Sabah; collectionID: Institute for Tropical Biology and Conservation, BORNEENSIS; institutionCode: UMS; collectionCode: BORN; basisOfRecord: PreservedSpecimen Type status: Paratype. Occurrence: catalogNumber: BOR/COL/14091 ; recordedBy: I. Njunjić; M. Schilthuizen; Taxon Expeditions; individualCount: 1; sex: female; lifeStage: adult; preparations: card-mounted; disposition: in collection; Taxon: scientificName: Colenisiachungi; order: Coleoptera; family: Leiodidae; genus: Colenisia; specificEpithet: chungi; taxonRank: species; scientificNameAuthorship: Schilthuizen, Seip & Otani; Location: continent: Asia; island: Borneo; country: Malaysia; stateProvince: Sabah; municipality: Tongod; verbatimLocality: Maliau Basin, near Studies Centre, along Seraya Trail, where stream enters the river; verbatimElevation: 260 m; verbatimCoordinateSystem: decimal degrees; decimalLatitude: 4.7389; decimalLongitude: 116.9696; Event: samplingProtocol: Winkler, litter from basis of trees; samplingEffort: 15 l of leaf litter; eventDate: 2017-09-27; habitat: lowland dipterocarp forest; fieldNumber: TxEx-MBSC1wb; Record Level: institutionID: Universiti Malaysia Sabah; collectionID: Institute for Tropical Biology and Conservation, BORNEENSIS; institutionCode: UMS; collectionCode: BORN; basisOfRecord: PreservedSpecimen Type status: Paratype. Occurrence: recordedBy: A.Y.C. Chung; Momin Binto; J.L. Yukang; individualCount: 1; sex: male; lifeStage: adult; preparations: card-mounted; dissected; coated for SEM; disposition: in collection; Taxon: scientificName: Colenisiachungi; order: Coleoptera; family: Leiodidae; genus: Colenisia; specificEpithet: chungi; taxonRank: species; scientificNameAuthorship: Schilthuizen, Seip & Otani; Location: continent: Asia; island: Borneo; country: Malaysia; stateProvince: Sabah; municipality: Tongod; verbatimLocality: Maliau Basin, along the Seraya Trail and Agathis Trail near the Ginseng Camp; verbatimElevation: 670 m; verbatimCoordinateSystem: decimal degrees; Event: samplingProtocol: Winkler extraction of leaf litter; samplingEffort: 20 1-square-m units of leaf litter and soil; eventDate: 2005-03-06 /12; fieldNumber: A1 (3); Record Level: institutionID: Forest Research Centre; institutionCode: FRCS; basisOfRecord: PreservedSpecimen

Description

Length of body 1.25 mm. Maximum width of elytra 0.86 mm. Head width (including the eyes) 0.46 mm. Greatest width of pronotum 0.8 mm. Winged. Short and oval, shiny and sparsely pubescent, dark chestnut, angles of pronotum, strip along suture, and head dark ochre (Fig. 2). Legs and antennomeres I-VI yellow, antennomeres VII-XI orange. Entire dorsum transversely microsculptured.

Head: Ratio of horizontal width of eye (measured in dorsal view and perpendicular to the longitudinal axis of the head) to distance between eyes: 1:7.4. Transverse microsculpture recognisable but too fine to distinguish individual cells at 50x magnification (distance between individual striae is 3-5 µm; Fig. 3a). At 50x magnification, no punctuation is clearly visible. Length of antennomere III 0.8 times the length of antennomere II. Antennomere XI slightly wider than antennomere X (Fig. 5a). Mandible with 16 parallel rows transversely situated on the dorsal molar surface (Fig. 5b).

Pronotum: Broadest at the base. Base completely straight to posterior angles. Posterior angles form a right angle, while the tip of the angle itself is slightly rounded. From posterior angles to anterior angles, the pronotum is gently curved inwards. The sides and the anterior angle have a fine groove along the entire margin. Transverse microsculpture slightly less distinct than on the head, individual grooves narrowly spaced (3-5 µm apart), but just visible at 50x magnification (Fig. 3b). Punctures (when viewed at 50x magnification) fine and sparse, separated by 5-10 times their own diameter, bearing short, inconspicuous hairs.

Scutellum: Microsculptured as on pronotum.

Elytra: Broadest at basal quarter, roundly curved to apex. Surface with transverse microsculpture. Microsculpture much more pronounced than on the pronotum, already recognisable at 15x magnification. Individual horizontal striae separated from one another by ca. 20 µm (about the width of antennomere III). Punctures separated by around 5-8 times their own diameter, irregularly arranged, each with a hair that can be up to 30 µm long (Fig. 3c). Sutural stria absent.

Legs: Anterior tarsomeres I-IV not markedly widened in the male.

Aedeagus: Median lobe elongated, parallel-sided, at the tip extended into a flat processus reminiscent of a duck-bill. Parameres thin, short, two-thirds of the length of the median lobe, slightly widened at the tip and provided with two long hairs, each about one-third of the length of the paramere itself (Fig. 4a). In lateral view, the median lobe is gently curved and apically flattened into a wedge (Fig. 4b).

Spermatheca: A near-spherical bulb with a tube about twice as long as the diameter of the bulb and about a third of its diameter. Tube from its base narrowing to about half its own diameter towards the terminus.

Diagnosis

The eye size, dorsal microsculpture, shape of aedeagus and antenna, as well as the presence of irregularly arranged punctuation on the elytra, place this species near C. championi (Portevin 1937) from South India, C. pecki Daffner 1988 from Japan and C. castanea Švec 2011 from China. However, C. championi has longer parameres and a less clearly sinuous outline of the aedeagus apex ( Daffner 1991). C. pecki has the 11th antennomere much smaller than in C. chungi . C. castanea has acute posterior angles of the pronotum and a more stocky aedeagus ( Švec 2011).

Etymology

Named in honour of Dr. Arthur Y. C. Chung, who collected the first known specimen in 2005.

Distribution

Known only from two locations in the valley where the Maliau river flows out of Maliau Basin, located at 290 m elevation (Maliau Basin Studies Centre) and 670 m elevation (Ginseng Camp).

Ecology

Only collected from leaf litter on the forest floor in lowland dipterocarp tropical rainforest. The two specimens from the Maliau Basin Studies Centre were both collected from between buttress roots, whereas leaf litter from the forest floor yielded no specimens. Perhaps this is an indication of its preferred microhabitat.