Three new species of the myrmecophilous genus Doryloxenus from China (Coleoptera, Staphylinidae, Aleocharinae)

Abstract Three new species of the pygostenine genus Doryloxenus Wasmann, viz., Doryloxenus aenictophilus sp. n. (from Zhejiang), Doryloxenus tangliangi sp. n. (from Zhejiang), and Doryloxenus songzhigaoi sp. n. (from Yunnan), are described, illustrated and distinguished from the Asian congeners. An identification key to the Chinese species is given.

In 2013, the senior author and his colleagues surveyed the myrmecophilous and termitophilous staphylinidae at Longwangshan Natural Reserve, Zhejiang (Fig. 4A) and Zizhi Village, Yunnan (Fig. 4C), and collected a series of aleocharine beetles from the colonies of army ant Aenictus sp. and Dorylus orientalis. A closer examination of this material revealed three new species of the genus Doryloxenus, which are described herein.

Material and methods
Holotypes and most of the paratypes are deposited in the Insect Collection of the Shanghai Normal University, Shanghai, China (SNUC), and some of paratypes are deposited in the Kyushu University Museum, Fukuoka, Japan (KUM).
Specimens were killed with ethyl acetate and preserved in 75% ethanol before dissection; photos of habitus were taken by a Canon EOS 7D with an MP-E 65mm macro photo lens; photos of characteristic pattern were taken by a Canon G9 Camera mounted on an Olympus CX31 microscope.
The following abbreviations are applied in the text: BL -body length, from the anterior margin of the head to the posterior margin of the abdominal tergite VIII; FBL -forebody length, from the clypeal anterior margin to the posterior margin of elytra; HL -head length, from the clypeal anterior margin to the occipital constriction; PL -length of the pronotum along the midline; HW -width of the head across the eyes; PW -maximum width of the pronotum.
Remarks. The genus is most similar to Odontoxenus Kistner in general appearance. It can be easily separated from Odontoxenus by the eyes having no part of their surface on the anterior margin of the head, the quadrate mesocoxal cavity, and the shorter mesosternum (Jacobson and Kistner 1975). Doryloxenus is also similar to Pygoplanus Kistner by the limuloid shape, but can be distinguished from it by the different shapes of the mandibles and labrum, the maxillary palpus distinctly longer than the setulate galea (Kistner et al. 2003 Comparative notes. Doryloxenus aenictophilus is most similar to D. tangliangi described below by the forebody sparsely covered with yellow setae and the macrochaetotaxy of tergites II-V: 6, 4, 4, 4, 4. It differs from D. tangliangi by the smaller eyes, the shorter elytra and the reduced hind wings. The new species is also similar to the unique blind and wingless species D. coecus Kistner by the light color and the short elytra, but can be easily distinguished from it by the presence of small eyes, the different macrochaetotaxy of abdominal tergites II-VIII. Description. Body ( Fig. 1A) smooth, glossy. Coloration: Light reddish-brown overall.
Head shaped as in Fig. 1B, sparsely covered with yellow setae; eyes small. Pronotum ( Fig. 1A) wider than long, about 1.44 times as wide as long; disc sparsely covered with yellow setae. Elytra (Fig. 1A, C) short, wider than long, about 3.72 times as wide as long; disc sparsely covered with yellow setae, with a row of setae on lateral margins. Hind wings reduced. Abdomen wedge-shaped; posterior margins of tergite II-VI with a row of very long yellowish setae; abdominal tergite VII (Fig. 1D) truncate at apex, with 2 pairs of macrochaetae at the anterior 1/3; tergite VIII ( Fig. 1E) slightly truncate at apex, with 1 pair of lateral macrochaetae; sternite VIII shaped as in Fig. 1F. Macrochaetotaxy of abdominal tergites II-VIII: 6, 4, 4, 4, 4, 4, 2.
Male. Median lobe of aedeagus shaped as in Fig. 1G (Fig. 5A-B). According to the key provided by Jaitrong and Yamane (2011), the host ant should belong to the A. ceylonicus group. This is the first record of a Doryloxenus associated with Aenictus ant together with the next new species.
Biological notes. Eleven Doryloxenus aenictophilus were sifted together with a large series of D. tangliangi from the colony of Aenictus sp. nesting under a rock. One individual was observed riding on the head of a worker ant.
Etymology. The specific name is a combination of 'Aenictus', generic name of the ant host, and the Greek stem 'philos', meaning 'to be fond of'. Comparative notes. Doryloxenus tangliangi is most similar to D. aenictophilus described above by the forebody sparsely covered with yellow setae and the macrochaetotaxy of tergites II-V: 6, 4, 4, 4, 4. It differs from D. aenictophilus by the larger eyes, the relatively long elytra, as well as the different shapes of the aedeagus and spermatheca.
Male. Median lobe of aedeagus shaped as in Fig. 2G (Fig. 5A-B). Biological notes. Most of the specimens were sifted from a colony of Aenictus ant, at least four individuals were observed riding on the abdomen of worker ants (Fig. 4B).
Etymology. Dedicated to Dr. Liang Tang, who found the colony of the host ants. Comparative notes. Doryloxenus songzhigaoi is most similar to D. nepalensis Naomi in general appearance, but can be easily separated from it by the different macrochaetotaxy of abdominal tergites II-VIII. The new species can be distinguished from the other congener known from the Gaoligong Shan, D. yunnanus, by the slender tergite VIII, rounded apex of sternite VIII, and different shape of the aedeagal median lobe.