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The new species Parachorius semsanganus sp. n. is described from Laos. This enigmatic Oriental deltochiline represents a “morphological link” between Parachorius and Cassolus by sharing characters of the two genera. The fact that Parachorius semsanganus cannot be unequivocally placed in either of these two genera stresses some more general problems of the current classification of Parachorius and Cassolus. Such problems can be solved only in the course of phylogenetic analysis, the need of which is briefly outlined.
Deltochilini, Parachorius , Cassolus , new species, Laos, “morphological link”
The dung beetle tribe Deltochilini Lacordaire, 1856 (= Canthonini Lansberge, 1874, synonymy according to
The Oriental genus Parachorius Harold, 1873 comprises six species and, according to the last monographic study (
Whilst surveying recent scarab collections from Laos
deposited at the Naturhistorisches Museum in Basel, Switzerland (NHMB),
we discovered a very interesting deltochiline species displaying a
mixed character set between Parachorius and Cassolus. This species cannot be unequivocally placed in either genus using current taxonomic concepts of these taxa (
Discovery of this species supports the above mentioned evidence for the close relationship between Cassolus and Parachorius as well as our provisory placement of Parachorius within the Deltochilini. Its description, provided here, enables its incorporation in the upcoming phylogenetic analysis of the entire generic complex.
Material and methodsAll photos were taken with a digital camera attached to a dissecting microscope (Leica MZ16A). Male aedeagi in Figs 1–3 were photographed in glycerin. First, the dissected aedeagus was macerated in 10% solution of KOH for several hours and then rinsed with distilled water. Finally, the aedeagus was placed in glycerin for taking pictures and subsequent storage.
All the material used in this study is housed in the NHMB.
Species descriptionurn:lsid:zoobank.org:act:E79FA444-725E-40E6-986A-9FB48B7D232A
http://species-id.net/wiki/Parachorius_semsanganus
Figs 1–5Laos, Xieng Khouang prov., Phou Sane Mt.
Holotype (NHMB), male bearing the following labels:
LAOS-NE, Xieng Khouang prov., 19°38.20'N, 103°20.20'E, Phonsavan (30 km NE): PHOU SANE Mt., 1420 m, 10.-30.v.2009, D. Hauck leg.
NHMB Basel, NMPC Prague Laos 2009 Expedition: M. Brancucci, M. Geiser, Z. Kraus, D. Hauck, V. Kubáň
HOLOTYPE Parachorius semsanganus S. Tarasov & D. Keith det. 2011
Paratypes. 9♀, same data as holotype; 2♂, same data as holotype but Z. Kraus leg.; 4♂, 3♀, LAOS-NE, Xieng Khouang prov., 19°37'N, 103°20'E; 19°38'N, 103°20'E, 30 km NE Phonsavan: Ban Na, Lam Phou Sane Mt., 1300–1500 m, 10.-30.v.2009, M. Brancucci leg.
Oval, convex, black, entirely shiny; mouthparts, antennae and legs red-brown. Dorsal body side covered with two types of punctures: larger (normal) punctures and very tiny punctures (which can be observed only under higher magnification of 40x or more) Dorsal and ventral body sides glabrous. Length 8.2–10.6
Male (Fig. 4). Head flat, punctation fine; anterior margin notched medially; notch delimited by 2 prominent triangular obtuse teeth; clypeus laterad of each tooth very slightly notched; eyes completely divided by canthus into lower and upper lobes; lower lobes significantly larger than upper ones; genae and clypeus not distinctly separated from frons; genae rounded and protruding; antennae with 9 segments, antennal club with 3 segments.
Pronotum broadly trapezoidal, punctation fine, separated by 1–2 puncture diameters on disc, becoming slightly denser laterally. Lateral margins of pronotum flattened, arcuate, widest near base; lateral and anterior side marginate, posterior side not marginate; anterior angles obtuse; posterior angles rounded. Prothoracic fovea excavated, delimited by ridge reaching propleural lateral margin.
Elytra with eight striae, sublateral carina forming pseudepipleuron beyond eighth stria; epipleura narrow; interstriae flat with sparse, fine punctation.
Protibiae with three outer teeth; 1st tooth slightly thicker than two others; inner margin with two vertical teeth underneath, located approximately opposite to 2nd and 3rd outer teeth; protibial apical spur acute, long, reaching middle or apical portion of 3rd tarsal segment; sometimes protibial teeth and apical spur abraded.
Metafemoral posterior margin with keel bearing indistinct and slight serration on top (Fig. 5). Metatibiae slightly curved, conspicuously denticulate on inner margin (Fig. 5, indicated with arrow); teeth are abraded in some specimens.
Pygidium with rather coarse, uniform, dense punctation.
Aedeagus (Figs 1–3) with converging, spatulate apices of parameres.
Female. Similar to male but with the 1st protibial outer tooth slightly thinner than in males; metafemoral posterior margin not serrate; metatibial inner margin not denticulate.
Variation. All specimens of the type series look very similar to each other. Some variation may be observed in the shape of teeth on the metatibial inner margin, which are less expressed in some males due to abrasion.
Holotype (Fig. 4). The holotype specimen lacks the tarsus of the right middle leg.
The new species is quite distinct among all other known species of Parachorius and Cassolus. It can be easily separated from them by the following unique set of character states: clypeus near outer side of each clypeal tooth very slightly notched, metatibial inner margin with large teeth (Fig. 5, arrowed), and aedeagus with spatulate apices which are largely bent inward (Figs 1–3).
The species is known from only 16 specimens of the type series collected across a range of altitudes between 1300–1500 m on Phou Sane Mt. of Xieng Khouang province in Laos.
The name of the new species is derived from the Latinized Lao words “syam” – link and “sanga” – spectacular. Its meaning “spectacular link” refers to the fact that this species represents a “morphological link” between the genera Parachorius and Cassolus.
Based on taxonomic concepts of the most recent monographic study dealing with Parachorius and Cassolus (
Morphological features of Parachorius semsanganus sp. n.: 1–3 paratype, aedeagus 1 aedeagus lateral view 2 aedeagus apical view 3 aedeagus dorsal view 4 male holotype, habitus 5 male paratype, hind leg, arrow indicates teeth on inner tibial margin.
We are very thankful to Alexey Solodovnikov (Natural History Museum of Denmark, Copenhagen) for his suggestions, advice and first review of the manuscript. Adrian Davis (University of Pretoria, Republic of South Africa), Jan Krikken (Nationaal Natuurhistorisch Museum, Leiden, the Netherlands), Andrey Frolov (Zoological Institute, St. Petersburg, Russia) and Daniel Whitmore (Corpo Forestale dello Stato - Centro Nazionale Biodiversità Forestale “Bosco Fontana”, Verona, Italy) are sincerely acknowledged for their suggestions and corrections that significantly helped to improve this paper. Our thanks are due to Michel Brancucci and Isabelle Zürcher (NHMB) for making material under their care available for this study. We are also grateful to Pierre Tauzin (Vanves, France) for his help in obtaining needed literature, and to Tristao Branco (Porto, Portugal) for his advice and help. This paper is completed during the stay of one of us (S.T.) as a visiting student at the Department of Entomology of the Natural History Museum of Denmark, under financial support from the grants of that department. S.T. is sincerely thankful to friendly team of the Department for their help and support.