The genus Scutellathous Kishii, 1955 (Coleoptera, Elateridae, Dendrometrinae) in China, with description of three new species

Abstract Five species of Scutellathous Kishii, 1955 are recognized from China, of which three are new. Scutellathoushabenularissp. nov., S.nanlingensissp. nov., and S.quadratasp. nov. are described and illustrated. A key to species from China, a checklist, and a distribution map are provided. The relationships and comparisons among genera Athous Eschscholtz, 1829, Ohirathous Han & Park, 2012, Parathous Fleutiaux, 1918, and Scutellathous Kishii, 1955 are discussed.


Introduction
The genus Scutellathous (Coleoptera, Elateridae), as currently defined, is distributed only in East Asia: China (Taiwan), Japan, and Korea. It was erected by Kishii (1955) based on the type species, Athous comes Lewis, 1894 from Japan. Kishii (1955) also transferred S. porrecticollis (Lewis, 1894) to this genus and described S. horior. The latter has been moved to the genus Stenagostus Thomson, 1959(Kishii 2001. Later, Measurements: body length was measured along the midline from the anterior edge of the head capsule to the apex of the elytra; the body width was measured across the broadest part (usually across the elytra). The pronotal length was measured along the midline; the pronotal width was measured at the broadest part (usually at the hind angles). The ocular index is obtained by dividing the minimum distance between the eyes by the maximum distance across both eyes and multiplying the quotient by 100 (Becker 1979).
The specimens were mounted on paper points. The genitalia were removed, cleaned and fixed under the body of the specimen in glycerol mounts as described by Prosvirov and Savitsky (2011).
The studied specimens were all collected by hand netting.
Remarks. Based on a study of the descriptions and photos of Athous (Elateridae, Dendrometrinae) species from North America, we found the Athous cucullatus (Say, 1825) species-group shares many characters with Scutellathous (Becker, 1979). These include head flattened with triangular depression; frontal carina prominent, well elevated above labrum; eyes large; punctures on pronotum umbillicate; tarsomeres 2and 3-lobed; and male genitalia with parameres lacking subapical lateral tooth and dorsal carina. However, lobes on tarsomeres 2 and 3 are smaller in Scutellathous, the carinae on the pronotal hind angles are present and sharp in all Scutellathous (absent or present in A. cucullatus group), and base of pronotum with sublateral incisions near hind angles in all Scutellathous (some without incisions in A. cucullatus group). Further comparison of members of the North American Athous cucullatus species group to Ohirathous is needed. Aedeagus with penis reaching beyond parameres ( Fig. 8a-d); scutellar shield 1.5 times longer than wide (Fig. 7f )  More pubescent, dorsal pubescence partially hiding integument (Fig. 9a); body brown-black; pronotal hind angles convergent posterad (Fig. 10c)  Diagnosis. Body bright red-brown, shiny; anterior edge of head truncate in dorsal view; antennae reaching apices of pronotal hind angles, nearly cylindrical from antennomere 6 onward, attached apico-dorsally, antennomere 3 1.8 times as long as 2 and nearly as long as 4; pronotum with hind angles divergent posterad, disc flat medially with only trace of a glabrous non-furrowed longitudinal line, shiny with umbillicate punctures; scutellar shield 1.1 times longer than wide; aedeagus with penis reaching to apex of parameres, penis gradually narrowed to pointed apex.

Key to the male species of Scutellathous Kishii from China
Scutellathous habenularis is similar to S. yamashitai Arimoto 1992, but is distinguished by the glabrous non-furrowed longitudinal line throughout the length of the pronotum (with shallow median impression only on basal half of the pronotum in S. yamashitai), the obtuse anterior angles of the pronotum (acute in S. yamashitai), and the penis reaching beyond parameres (penis shorter than parameres in S. yamashitai).
Female. Like male (Fig 5a), except larger (length: 15.9 mm, width: 3.9 mm), antennae shorter (short of pronotal hind angle apices by half length of last antennomere) and pronotum strongly arched laterally and narrowed anteriorly in dorsal view. Bursa copulatrix (Fig. 5b) weakly sclerotized (it dissolved after being macerated in 10% NaOH for 10 hours) with a circular thorny line and without thorny plates. Ovipositor (Fig. 5c) 2.3 times longer than wide, with short styli.
Larva. Unknown. Etymology. The name of the new species is derived from the Latin "habenularis" (Latin for "strip") referring to its hind coxae abruptly and strongly narrowed into a strip at lateral one-fourth part.
Biology. Collected around the elevation of 2000 m in subtropical evergreen forest. Remarks. Its bursa copulatrix resembles Ohirathous in sharing a circular thorny line, but differs in lacking thorny plates. Other characters (carina on hind angles extending only basal 1/5 of pronotal length; antennomere 3 2.1 times as long as 2; shape of male genitalia; shape of female pronotum; only tarsomeres 2 and 3 lobed beneath) are consistent with the diagnosis of genus Scutellathous. Structures of the bursa copulatrix are diverse within Scutellathous species -from five thorny plates (S. comes, S. porrecticollis, S. sasajii, S. shikokuanus) or four (S. seinoi) thorny plates and without thorny line to no thorny plates but with thorny line in S. habenularis. The bursa copulatrix structure of Ohirathous (a circular thorny line and two thorny plates) falls within the range of variation observed in Scutellathous and does not support distinction of Ohirathous from Scutellathous. Unfortunately, male genitalia of Ohirathous is unknown. Further phylogenetic study is needed to understand the monophyly of Ohirathous and the relationship between these two genera.  Diagnosis. Antennae barely reaching apices of pronotal hind angles, antennomere 3 2.2 times longer than 2 and 1.1 times longer than 4; pronotum with narrow median furrow throughout length, shiny with fine, weakly umbillicate punctures; scutellar shield 1.5 times longer than wide; punctures on elytra becoming absent near apex; aedeagus with penis reaching beyond parameres, gradually narrowing to obtuse apex.

Scutellathous nanlingensis
Scutellathous nanlingensis is similar to S. sasajii Kishii, 2001, but can be separated from the latter by the short antennae of male (hardly or just reaching apices of pronotal hind angles; longer in S. sasajii, with apical three antennomeres exceeding apices of the hind angles), with narrow median furrow through the length of the pronotum (in S. sasajii the pronotum lacks longitudinal furrow), and the longer male penis.
Description. Male (holotype). Body (Fig. 6a-c) length 11.7 mm, body width 3.0 mm; red-brown, head, pronotum, base of elytra, ventral parts of the body and antennae darker, apex of mandible, inner margin of hypomeron, fore and middle coxae, apical parts of legs and elytra paler, more yellowish or reddish; dorsal pubescence yellow, semi-recumbent, longer, sparse and pointed anterad on pronotum and head, pointed posterad on elytra, ventral pubescence more recumbent, thinner and denser, especially on abdomen.

Larva. Unknown.
Etymology. The new species named after Nanling Mts in Guangdong prov., referring to its only known locality.

Biology. Unknown.
Remarks. Genitalia of this specimen is shrunken, membranous parameres apices are folded in (Fig. 8c). Diagnosis. Body brown-black, dorsal pubescence partially hiding integument; anterior edge of head arched anterior-laterally in dorsal view; antennae reaching apices of pronotal hind angles, antennomere attached apico-dorsally near base, more centrally near apex, antennomere 3 2.2 times longer than 2 and 1.1 times longer than 4; pronotum with hind angles convergent posterad, disc with median non-furrowed glabrous line, with simple punctures; scutellar shield as wide as long, anterior edge straight, widest and rounded posteriorly, concave at sides.

Scutellathous quadrata
Scutellathous quadrata is similar to S. spinosus Platia & Schimmel, 2007(see Schimmel 2007 in body shape and size, but can be separated from the latter by the squareshaped scutellar shield (in S. spinosus it is 1.2 times longer than wide, measured from original figure), base without spine near humeral angles of the elytra (with spine in S. spinosus), the wholly brown-black body (in S. spinosus the body is entirely ferruginous), and the shape of parameres.
Female. Unknown. Variability. Body length 14.7-15.7 mm; body width 3.7-4.3 mm. Larva. Unknown. Etymology. The name of the new species refers to its quadrate scutellar shield. Distribution. China: Zhejiang (Tianmu Mts) (Fig. 12). Biology. Unknown. Remarks. Unfortunately, aedeagi of both specimens were damaged by poor preservation after prior dissection.  Diagnosis. Following Platia and Schimmel (2007): length 13-16 mm, width 3.2-4 mm; red-brown with vague brown-black areas on head and pronotum; frons deeply impressed medio-anteriorly; antennae falling short of pronotal hind angles by about one antennomere, feebly serrate from antennomere 3, antennomere 2 more than twice longer than wide, antennomere 3 subtriangular, 2.5 times longer than 2, and longer than following; pronotum slightly longer than broad, widest at hind angles, disc strongly convex, abruptly sloping posterad, where with a trace of short median furrow, hind angles truncate, not divergent, with a short carina following edge, punctation coarse and variable; scutellar shield 1.2 times longer than wide, gently convex, sparsely punctate; elytra as broad pronotal posterior, 2.5-2.6 times longer than pronotum, base near humeral angles with a short spine.

Scutellathous spinosus Platia & Schimmel, 2007
Distinguished from other Scutellathous in China by elytral spine and red-brown colour. Distinguished from S. yamashitai by the shorter antennae not reaching the apices of the hind angles of the pronotum and rounded pronotal anterior angles.
Remarks. No additions to the male genitalia except the length (1.75 mm) in original description. But we can see from the original image that the penis is reaching a little beyond the apex of the parameres, gradually narrowed to a pointed apex and the parameres are thick, strongly sinuate laterally at midlength, weakly tapered to a blunt apex.
Distribution. China (Taiwan) (Fig. 12). Fig. 12 Scutellathous yamashitai Arimoto, 1992: 73. Diagnosis (after Arimoto 1992). Length 12.6 mm, width 2.8 mm; body almost parallel-sided, flattened and shining dorsally, dark brown; antennae extending beyond apices of hind angles of pronotum by at least apical two antennomeres, antennomere 2 obconic, slightly longer than wide, antennomere 3 elongate triangular, about twice as long as 2 and longer than 4; pronotum as wide as long, with a shallow median impression in basal half, surface smooth and shining, sparsely and evenly punctate, hind angles short, divergent posterad, with carina; scutellar shield subvertical, with the sides somewhat constricted at posterior fourth; elytra about 2.9 times as long as humeral width, striae with coarse, uneven and elongate punctures, interstriae slightly elevated, irregularly punctate and transversely rugose; aedeagus with penis not reaching apex of parameres, apex of parameres depressed and furnished with some short setae. Scutellathous yamashitai is similar to S. comes from Japan, but distinguished from by its darker color, smaller pronotal punctures, and divergent pronotal hind angles (Arimoto 1992).