Arractocetus Kurosawa 1985
Creators: name: Lawrence, John F.
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Lymexylidae
Arractocetus

description: Arractocetus sp.
Description of female specimens from northern QLD and Papua New Guinea. Body about 8 times as long as wide; colour primarily dark reddish-brown to black, with exposed hind wings pigmented, often with metallic blue or violet reflection; elytra variable in colour, dark-brown or almost black with varying amounts of yellow; undersurface of head and some mouthparts yellow, mandibles reddish-brown, coxae, femora, and portions of abdominal ventrites yellow or yellowish-brown; palp-organ black; tibiae and tarsi dark brown. Head 1.25 times as long as wide, somewhat declined, gradually narrowed behind eyes, without temples or neck; base weakly biemarginate dorsally, surface flattened anteriorly, declined posteriorly but without transverse ridge. Eye about 0.71 times as long as head width and 1.43 times as long as wide, distinctly emarginate anteroventrally, weakly protruding and very finely facetted, with flattened facets and fine interfacetal hairs; distance across eyes dorsally 3.00 times and ventrally 1.29 times distance between them. Antennal insertions concealed by frontal ridges which extend slightly into eye emargination. Labrum reduced, apically acute and fused to clypeus. Antennae 11-segmented, about 1.3 times as long as head width, ratio of antennomere lengths 2.50: 1.50: 2.50: 2.00: 2.00: 1.75: 1.75: 1.50: 1.25: 1.00: 2.00 and antennomere length/width ratios 1.25, 1.00, 1.43, 1.00, 1.00, 0.87, 0.87, 1.00, 0.83, 0.67, 1.60; terminal antennomere abruptly narrowed subapically and acute at apex. Mandible about 1.25 times as long as wide; outer edge densely clothed with long, fine setae; apex unidentate; mola and prostheca absent. Maxilla with galea 2.9 times as long as wide, widest at base, distinctly curved mesally with mesal surface concave, apex narrowly rounded and lateral edge densely setose; lacinia shorter than galea, 3.1 times as long as wide with narrowly rounded apex and more sparsely setose; palpomere 3 globose, capsule-like, 4 slender with narrowly rounded apex and palp organ complex, with 14 major branches and numerous secondary ones. Mentum about twice as long as wide; ligula 2.67 times as long as wide with narrowly rounded apex. labial palps separated by slightly more than the basal width of one; ratio of palpomere lengths 1.67: 1.00: 3.83, apical palpomere narrowly rounded at apex. Submentum relatively short, not separated from gula, which is transversely quadrate between parallel gular sutures. Ventral surface of head slightly biconcave, with short subantennal grooves. Cervical sclerites about 6.2 times as long as wide, irregularly undulate, undivided. Pronotum 0.77–0.91 (0.83) times as long as wide, widest anteriorly with sides slightly sinuate, converging posteriorly, without lateral carinae; anterior edge truncate; anterior angles not produced forward, broadly rounded; posterior angles more or less right but with rounded tips; posterior edge strongly biemarginate laterally, with broadly rounded mesal lobe; disc more or less flattened, with deep groove and endocarina extending from posterior edge almost to anterior edge; punctation fine and sparse, vestiture of inclined or suberect fine hairs. Prosternum about 0.57 times as long as mid length of a procoxal cavity, anteriorly biemarginate forming median angulate lobe; surface relatively flat; posterior edge triemarginate with an internal marginal ridge; notosternal sutures very short, straight and complete. Prosternal process absent. Procoxal cavities large and broadly open externally and internally, without notch at base of notosternal suture; postcoxal (hypomeral) process absent; protrochantin well-developed, externally visible, transverse, mesally slender and laterally subtriangular. Scutellar virtually absent, consisting of a short strip of cuticle weakly bilobed at apex, not separated from scutum, which has a complete median endocarina and is concave laterally to house sub-basal portions of elytra. Elytra 1.39–1.81 (1.58) times as long as greatest combined basal width and 1.60–1.96 (1.69) times as long as pronotum; separated for most of their lengths, but meeting at anterior fourth just behind scutellar shield; each elytron 2.96 times as long as wide, widest at anterior fifth with outer edge weakly curved and inner edge more or less sinuate and apex very broadly rounded; outer elytral angles more or less rounded; disc inflated between anterior fifth and sixth, forming an ovate boss covered with darkly pigmented, spiculate punctures, remaining punctation fine, confused and bearing short, inclined hairs. Mesoventrite 0.38 times as long as wide, widest at middle; anterior edge broadly, deeply emarginate, without coxal rests; sides slightly sinuate and incompletely separated from the almost vertical mesanepisterna; surface smooth and apunctate; posterior edge weakly emarginate on either side of a short, broadly rounded lobe. Mesocoxal cavities very weakly impressed, contiguous, without posterior edges. Metaventrite 1.35 times as long at midline and 1.73 times as long laterally as greatest width, strongly convex, without discrimen; posterior edge slightly curved and oblique on either side of subtriangular intercoxal lobe with fine notch at apex; Metanepisternum about 5.45 times as long as wide, widest anteriorly and narrowed to subacute apex. Metendosternite with long, narrow stalk, paired, slender lateral arms forming an angle of about 30° and a long, slender, apically acute anterior process. Hind wing about 3.1 times long as wide; apical field 0.28 times as long as wing length, with radial extensions obliterated basally but extending to apical wing margin; radial cell absent; radial and medial veins joined at apical fourth of wing by transverse connection straight anteriorly curved posteriorly and probably derived from cross-vein r4 and the radiomedial loop; MP 1+2 long, straight and continuing as medial spur to wing edge; medial field with six veins, the last two reaching wing edge. Anal lobe reduced, without embayment, containing AP 3+4. Procoxa 3.00 times as long as wide, widest near base and very slightly narrowed to apex, strongly projecting; Mesocoxa 2.14 times as long as wide, widest near base and slightly narrowed apically, slightly projecting. Metacoxa about 0.27 times as long as wide, strongly oblique, almost contiguous and projecting near midline, without weak coxal cowling on mesal half. Trochanterofemoral joints strongly oblique, but with femur well separated from coxa. Fore legs relatively short: profemur subeqal in length to coxa, 3.0 times as long as wide; protibia 1.2 times as long as femur, 7.2 times as long as wide, parallelsided, not expanded at apex; protarsi combined about equal in length to tibia, with segment length ratio 7.50: 3.00: 2.00: 1.00: 4.00. Mid and hind legs longer and slender. Mesofemur 4.10 times as long as wide, barely wider at middle; mesotibia 1.60 times as long as femur, 14.4 times as long as wide and more or less parallel-sided; combined tarsal length 0.82 times that of tibia, with segment lengths 4.60: 2.40: 1.80: 1.00: 2.00. Metafemur 4.00 times as long as wide, widest at basal third; metatibia 1.60 times as long as femur, 16.0 times as long as wide and more or less parallel-sided; combined tarsal length 0.97 times that of tibia, with segment lengths 4.17: 1.83: 1.33: 1.00: 2.00. All tarsomeres simple, without ventral lobes, but densely lined with fine, erect hairs; pretarsal claws moderately long and slender, empodium with several setae. Abdomen with tergites and sternites more or less equal in length and degree of sclerotisation; first segment (sternite and tergite II) about 0.85 times as long as second, with intercoxal process absent; segments 2–6 subequal in length; ventrite 7 (sternite VIII) shorter than 6, 1.50 times as long as wide, with broadly rounded apex; tergite VIII with strongly rounded apex; segment IX 0.58 times as long as VIII and 1.25 times as long as wide, with both tergite and sternite emarginate; spiculum ventrale extending from about middle of sternite to beyond its base. Ovipositor 3.00 times as long as wide, 1.20 times as long as segment VIII, more or less parallel-sided; paraprocts 0.5 times as long as gonocoxites, which are twice as long as wide; apical coxital lobe about 2.67 times as long as basal lobe, with sides subparallel for basal two-thirds, then converging to form paired acute extensions; gonostyli about 0.33 times as long as apical lobes, 4.0 times as long as wide, parallel-sided and attached laterally at bases of acute extensions; ventral sclerite about as long as apical coxital lobe without extension; proctiger setose and apically truncate, bacula converging anteriorly and almost meeting. Male not examined.
Note. This species is probably one of the “blackish” forms keyed out by Kurasawa (1985), such as A. nipponicus (Nakane), A. morio (Pascoe) or A. monticola Kurasawa, but additional material would be necessary to place the species, assuming it has been described.
Specimens Examined. QLD: Gordon Creek area, Claudie River district, 5.vii.1982, M. A. Schneider, G. Daniels (1♀, QMB); McIlwraith Range, 11 km WbyN of Bald Hill (13°44’S, 143°20’E), search party campsite, 520m,, 27.vi–12.vii.1989, surfaces at night, on ground, T. A. Weir (1♀, ANIC); Mt. Tozer, 9 km NE (12°43’S, 143°17’E), 5–10.vii.1986, Malaise trap /ethanol, J. C. Cardale (1♀, ANIC); Mt. Tozer, 11 km ENE (12°43’S, 143°18’E), 11– 16.vii.1986, J. C. Cardale, Malaise trap /ethanol, J. C. Cardale (1♀, ANIC). Papua New Guinea: Morobe Province: Bulolo, 20.i.1970, on log, L. Radunz (1♀, QMB).
description: Published as part of Lawrence, John F., 2020, The Australian Lymexylidae (Coleoptera: Tenerionoidea) with one new genus and two genera new to Australia, pp. 211-238 in Zootaxa 4895 (2) on pages 223-225, DOI: 10.11646/zootaxa.4895.2.3, http://zenodo.org/record/4322473