Chelonocoris bakonyii, Serrano-Herrera & Espinosa-Sanchez, 2023

Serrano-Herrera, Adela & Espinosa-Sanchez, Juan Manuel, 2023, Two New Chelonocoris Species From Borneo And Sumatra (Hemiptera, Heteroptera, Aradidae), Acta Zoologica Academiae Scientiarum Hungaricae 69 (4), pp. 413-421 : 415-418

Chelonocoris bakonyii sp. n.

http://zoobank.org/ B6AFE5AC-E5C7-4D95-942C-FC90EABE5FF4 ( Figs 2 , 9–12 , 18 )

Type material: Holotype ( HNHM), male: “MY, Borneo , Sarawak / state, Muara Tebas

/ Peninsula // 1° 42ʹ56ʺ N, 110° 26ʹ48ʺ E / 3. I. 2016. / leg M. Lukátsi”.

Description: Male. Apterous, large, body elongate subtriangular, with tomentum and wax-like dirt. Pubescence formed by tufts and evenly distributed hairs. Edge of body and femora with erect hairs, also present on antennal joints II–III.

Colouration: Body black with rusty brown tomentum, wax-like dirt yellowishbrown. Pubescence rusty brown or black.

Head longer than wide across eyes, genae surpassing clypeus, diverging, forming a V, reaching 1/5 of antennal joint I. Antenniferous tubercle on left side stout, laterally convex, pointed, as characteristic for the genus; on right side tubercle missing beyond base of antenna. This may be consequence of an injury. Vertex with M-shaped median tomentose area, laterad to this naked up to eyes. Hairs and wax-like dirt forming an edge on hind margin of head.

Antenna ( Figs 9 , 18 ) relatively slender, subcylindrical joint I densely (especially basomedially), joint II–III sporadically with long erect hairs. Relative length of antennal joints I to IV as 72:20:40:14.

Pronotum wider than long, anterior margin sinuate in almost whole width, lateral borders convex, posterior border shallowly V-shaped. Laterad to median longitudinal sul- cus a pair of subcontiguous ridges, converging and fused anteriorly, laterad to these a crescent-shaped narrow ridge and a blunt tubercle.

Mesonotum with scutellum-like elevation, medially fused with median longitudinal inflation. Laterad to this a pair of converging, wide, flat, arched tubercles. Metanotum with crescent-shaped bare area. Orificium oriented dorsolaterally.

Abdomen with median ridge evenly elevated until rhomboid depression, elevation lower than the thickness of abdomen (as seen in lateral view). Lateral border slightly convex, PE angles of dltgs not protruding, dltg VI with small projection before posterior corner. Median glabrous areas clearly visible, borders covered by dense pubescence. Inner margin of dltgs clearly visible. Tergite VII medially elevated, with two flat tubercles, terminal lobes ( Figs 9, 11 ) triangular, long, outer margin slightly convex, inner border straight. Mesad to the lobe a rounded, prominent tubercle. Paratergites of segment VIII not reaching tip of pygophore, spiracle latero-terminal.

7–8 and 11–12 are out of scale

Measurements: Holotype, male: length of head 2.24 mm, width of head 1.68 mm, length of pronotum 1.84 mm, width of pronotum 2.96 mm, combined length of meso- and metanotum 2.40 mm, maximum width of abdomen 4.96 mm across segment V, width at tip of PE angles VII 4.96, total length of body in median line 13.28 mm, total length of body including terminal lobes 13.84 mm.

Etymology: It is a great pleasure to dedicate this species to the eminent Hungarian zoologist Prof. Dr. Gábor Bakonyi, a fellow hemipterist and co-author in Nepomorpha, contributing also to various fields of ecology, later eco-toxicology, and a lifetime best friend of author. He also served as selfless Editor-in-Chief of Acta Zoologica Academiae Scientiarum Hungaricae from 2006 to 2022.

Notes on habitat and ecology: The collecting locality is in Bako National Park, in primary rain forest, with bulk supply of dead wood and a dense leaf litter layer. The collecting happened in the night, from logs but not from below bark (Márk Lukátsi pers. comm.). This is in accordance with earlier published data in the literature (e.g. KORMILEV & FROESCHNER 1987), concerning usual habitat of apterous Aradidae .

Discussion: The species level identification of the examined male specimen was first based on a survey of differences and similarities of male and female specimens of described species using published descriptions and illustrations ( MILLER 1938: Ch. malayensis Miller, 1938 and Ch. dyak Miller, 1938; USINGER 1954: Ch. kormilevi Usinger, 1954, Ch. mancinii Usinger, 1954 and Ch. bloetei). In species of Chelonocoris females are generally larger, their abdomen is more rounded, abdominal inflation is higher, the abdominal sculpture in dorsal view is different to various degree from that of males, dltgs are provided with definite longitudinal carinae, and PE lobes of tergite VII (terminal lobes) tend to bend inwards in contrast with the condition found in males. Insignificant sexual dimorphism was found in the antenna, pronotum, mesometanotum, the development of the scutellar area (except in Ch. mancinii), the outline of the body from lateral view, and the shape and size of the terminal lobe (although the latter is usually somewhat longer in males). The sexual dimorphism is apparently more expressed in Ch. dyak and especially Ch. peregrinus Miller, 1938, than in other species of the genus.

Diagnosis: The male holotype of the new species matches into the Malay- an and Borneo group of species of Chelonocoris (USINGER 1953) . It is definitely not conspecific with Ch. dyak, and using the key of USINGER and MATSUDA (1959) runs to Ch. bufo, but it is different from the latter species in the following diagnostic characters (provided in key format):

A(B) (Female) Head strongly narrowing posteriorly, with straight hind bor- der. Antennal joint I thickening in apical part. In lateral view pronotum unevenly bulging, abdominal inflation strongly elevated on segments III–IV. Terminal lobe narrowing posteriorly, but sides subparallel behind segment VIII. Malay Peninsula. Ch. bufo

B(A) (Male) Head strongly narrowing behind eyes, then sinuate, with medially convex hind border. Antennal joint I thickest in its basal third. In lateral view pronotum flat; abdominal inflation unevenly convex, but no portion more strongly elevated. Terminal lobe continuously narrowing. Borneo. Ch. bakonyii sp. n.

Body length of the female Ch. bufo, as given by MILLER (1938), is 1.27 times that of this male of Ch. bakonyii sp. n., which may also result from individual variation. This ratio is between 0.98–1.10 in those species where both sexes are described, and, as given by MILLER (1938), could be calculated 1.15 in Ch. peregrinus which later proved to represent two species. These data also support the species separation.

The male holotype of Ch. bakonyii sp. n. is also similar to the female holotype of Ch. usingeri . Their differences are listed below. For each character, first the female Ch. usingeri , then the male Ch. bakonyii sp. n. is referred

Body less covered by pubescence, e.g. dorsal median ridge is naked, vs more covered, the ridge bearing hairs. Slit between genae is of a narrow V shape vs of wider V shape. Vertex slightly convex towards genae, vs vertex frontally bent downwards. Antennal joint I is thickest at basal third, vs subcylindrical. Median longitudinal, inflated carina or ridge is flattened and widened anteriorly vs evenly emerged and narrow in whole length. Lobe on PE angles VII first narrowing, then evenly wide, tip more rounded vs continuously narrowing, with sharper tip. Edge of body, including the terminal lobes naked, with very few, scattered hairs only, vs densely haired. Femora with few, scattered erect hairs (0–10 in dorsal view) vs femora with more, 20–30 erect hairs, especially on hind femur. On the basis of hairs on the femora the female holotype of Ch. usingeri runs in the key of USINGER and MATSUDA (1959) to Ch. dyak, the male holotype of Ch. bakonyii sp. n. to Ch. bufo. This feature is not satisfyingly depicted in the referred work, but the text seems to be unambiguous. Hairs on femora alone is considered as of specific importance by USINGER (1954).

Figures

Figs 1–3. 1 = Chelonocoris usingeri Kormilev, 1957, female holotype; 2 = Ch. bakonyii sp. n., male holotype; 3 = Ch. heissi sp. n., male holotype

Figs 4–12. Chelonocoris usingeri Kormilev, 1957 female holotype (4–8) and Ch. bakonyii sp. n. male holotype (7–12): 4, 9 = body in dorsal view, only visible parts depicted; 5, 10 = lateral view of body; 6 = tip of abdomen, ventral view; 7, 11 = terminal lobes; 8, 12 = genae. Figs

Figs 13–19. Chelonocoris heissi sp. n. male holotype (13-17), Ch. bakonyii sp. n. male holotype (18) and Ch. usingeri Kormilev, 1957 female holotype (19): 13 = dorsal habitus; 14 = body in lateral view; 15 = tip of abdomen, ventral view; 16–19 antennae, dorsal view. The 5 mm