Taxonomic review of the Themus (Telephorops) nepalensis species-group (Coleoptera, Cantharidae)

Abstract The diagnosis of the Themus (Telephorops) nepalensis species-group is summarized. A catalogue, a key and a distribution map of all world species are provided. Two synonymies are proposed: Themus (Telephorops) subcaeruleiformis Wittmer, 1983, syn. nov. = T. (Telephorops) crassimargo Champion, 1926; T. (Telephorops) separandus Wittmer, 1975, syn. nov. = T. (Telephorops) laboissierei (Pic, 1929). The female internal genitalia are photographed and described in this species-group for the first time, the aedeagi of T. (Telephorops) crassipes Pic, 1929 and T. (Telephorops) impressipennis (Fairmaire, 1886) are illustrated and described for the first time, and some additional distribution information is provided for the species. Themus (Telephorops) cavipennis (Fairmaire, 1897) is a new record for the Chinese fauna.


Introduction
Themus Motschulsky, 1858 is one of the largest cantharid genera and comprises about 250 species in total (Yang et al. 2014;Kopetz 2016). It consists of four subgenera (Wittmer 1973(Wittmer , 1997, which were redefined by Švihla (2008) on the basis of the shapes and color of the pronotum and elytra.
The subgenus Telephorops Fairmaire, 1886 for T. impressipennis (by original and monotypic designation) was subdivided into two species groups, which however were Habitus photos were taken using a Leica M205 A stereomicroscope, multiple image layers were stacked using Combine ZM (Helicon Focus 5.3). Line drawings were made using a camera lucida attached to a Nikon SMZ1500 stereomicroscope, then edited in CorelDRAW 12 and Adobe Photoshop 8.0.1. Body length was measured from the anterior edge of the clypeus to the elytral apex and body width across the humeri of elytra. Morphological terminology of female genitalia followed Brancucci (1980). The key to the species was prepared mainly based on the characters of the aedeagus. If the aedeagi of different species were too similar to be described, the female abdominal sternite VIII and internal genitalia were compared; body size and coloration was also referred to when necessary.
In the checklist, valid scientific names and original sources, synonyms and publications for the taxonomical changes, type localities and depositories, additional material information and all distributions were included, as well as additional description or remarks were added if necessary. Complete label data were cited for type specimens, using square brackets "[ ]" for our remarks and comments, [p] indicating that the following data were machine printed and [h] that they were handwritten, quotation marks to separate data from different labels. A distribution map was prepared using the geographic information system software ArcGIS (ver. 10.2), based literature records and the author's databases of specimens examined for this study.
The specimens were identified based on examination of types if available and original literature. In practice, species were determined mainly by the aedeagus of male, and the females were associated with males based on evidence that they were collected at the same locality and date. Also, the female could be identified by the structure of abdominal sternite VIII, which was useful in species' recognition and illustrated in the literature by cantharid specialists. For each species, compared with males, the females have smaller eyes, shorter and narrower antennae, simple middle antennomeres, without smooth narrow impressions along the outer edges, wider pronotum and elytra, and only seven abdominal ventrites.

Themus (Telephorops) nepalensis species-group
Diagnosis. Elytra enlarged posteriorly and widest near apical third. Aedeagus: conjoint dorsal plate of parameres narrowed apically in dorsal view, emarginate at middle of apical edge; laterophyses flattened dorsoventrally, reduced and not reaching apices of conjoint dorsal plate except in a few species. Female internal genitalia: diverticulum situated at end of vagina, presenting with a sclerotized ring around at base, confluent in middle and extending to median oviduct; spermatheca arising from middle of the sclerotized ring.
Distribution. Most species are restricted in their distribution (Figs 1, 2), except T. impressipennis (Fairmaire, 1886) and T. coelestis (Gorham, 1889), which are widely distributed in China. Remarks. The diagnosis is developed from the definition of the species-group by Švihla (2008). Characters of the elytra and aedeagus, the female internal genitalia are supplemented in the present study. This differs from the davidis species-group in the female genitalia having a sclerotized ring around the base of the diverticulum, delimit- ing it from the vagina; and spermatheca opening on the opposite side to the median oviduct. While in the davidis species-group, there are only a pair of short conjoint sclerotized ridges below the diverticulum, hardly delimitated from the vagina; and spermatheca opening on the same side as the median oviduct (Yang et al. 2019).

Key to species (adults) of Themus (Telephorops) nepalensis species-group
(characters based on illustrations in the present study or those from Wittmer (1983aWittmer ( , b, 1997). Supplementary description. Female. Like male, but antennomeres V-X without impressions along outer edges (while present with smooth narrow longitudinal or oblong impressions in male), terminal abdominal ventrite wide (while narrow and triangular in male) ( Fig. 9A) with posterior edge narrowly and triangularly emarginate medially and paired rounded middle protuberances, which are wider than the distance between protuberance and apicolateral angle and exceeding apex of the latter. Internal genitalia (Fig. 6A): diverticulum hardly narrowed apically and rounded at apex, about 2.5 times as long as its maximal width; spermatheca expanded apically.
Distribution. Taiwan.   Supplementary description. Male (Fig. 3A). Female. Like male, but antennomeres IV-X without impressions along outer edges (while present with smooth narrow longitudinal or oblong impressions in male), terminal abdominal ventrite wide (while narrow and triangular in male) ( Fig. 9B) with posterior edge narrowly and triangularly emarginate medially between paired rounded middle protuberances, each protuberance narrower than the distance between it and apicolateral angle and exceeding apex of apicolateral angle. Internal genitalia (Fig. 6B): diverticulum narrowed apically and nearly pointed at apex, about twice as long as its maximal width; spermatheca abruptly expanded apically.
Themus (Telephorops) subcaeruleiformis Wittmer, 1983b: 199, fig. 3 (Fig. 3B). Like male, but antennomeres V-XI without impressions along outer edges (while present with smooth narrow longitudinal or oblong impressions in male), terminal abdominal ventrite wide (while narrow and triangular in male) (Fig. 9D) with posterior edge triangularly protuberant on each side, space between lateral protuberances about twice as wide as each width.
Remarks. Themus (T.) subcaeruleiformis Wittmer, 1983 was originally described based on a single male type, from China, Szechwan, Kuanshien Umg. (now in Sichuan, Dujiangyan). Here a female (Fig. 3B) collected from Qingcheng, which is near the type locality, is discovered for the first time. The structure of its abdominal sternite VIII (Fig. 9D) is like that of T. crassimargo Champion, 1926, illustrated by Okushima (1999 fig. 35). Furthermore, T. subcaeruleiformis was only compared with T. subcaeruleus located in Yunnan, China in the original publication (Wittmer 1983b), but not with species from the Himalayas (Wittmer 1975).Moreover, the types of T. subcaeruleiformis and T. crassimargo were compared, but no differences between them were found in external morphology (Fig. 4A, B) and aedeagi illustrated by Wittmer (1975: fig. 2; 1983b: fig. 3, 3a).Therefore, T. subcaeruleiformis is proposed here to be junior synonym of T. crassimargo, according to the Principle of Priority (ICZN 1999, Article 23.1).
Distribution. China (Guangxi, Yunnan); Vietnam.   Female. Like male, but antennomeres V-X without impressions along outer edges(while present with smooth narrow longitudinal or oblong impressions in male), terminal abdominal ventrite wide (while narrow and triangular in male) (Fig. 9F) with posterior edge narrowly and triangularly emarginate medially and paired rounded protuberances, each nearly as wide as the distance between it and apicolateral angle and not reaching apex of the latter. Internal genitalia (Fig. 7A): diverticulum little thinned apically and rounded at apex, about 2.5 times as long as its maximal width; spermatheca expanded apically.
Remarks. Themus (Tryblius) separandus was described based on a single male type and its aedeagus was illustrated by Wittmer (1975). Except the original publication, no additional information was available. The type locality is "Gopaldhara, Darjeeling" (N. India), not Bhutan as that listed by Kazantsev and Brancucci (2007). Wittmer (1975) noted that the single specimen designated as holotype of T. separandus was separated from the collection of T. crassimargo in BMNH. Wittmer differentiated T. separandus from T. crassimargo by the structure of aedeagus, also from T. cavipennis and T. nepalensis in the body coloration and aedeagus. He made no comparison with other species.
In the present study, the habitus ( Fig. 4C-D) and aedeagi of T. separandus and T. laboissierei were compared (Wittmer 1975: fig. 2;Wittmer 1983b: 4), but no differences found. Thus we recommend T. separandus Wittmer, 1975 9H) with posterior edge narrowly and triangularly emarginate medially between paired rounded protuberances, each protuberance nearly as wide as the distance between it and apicolateral angle and exceeding apex of the latter. Internal genitalia (Fig. 7C): diverticulum expanded apically and rounded at apex, about twice as long as its maximal width; spermatheca expanded apically.

Themus (Telephorops) minor Wittmer, 1997
Themus (Telephorops) minor Wittmer, 1997: 272, fig. 104  Supplementary description. Female. Like male, but antennomeres VI-X without impressions along outer edges (while present with smooth narrow longitudinal or oblong impressions in male), terminal abdominal ventrite wide (while narrow and triangular in male) (Fig. 9I) with posterior edge triangularly emarginate medially and largely and triangularly emarginate on both sides, lateral emargination about 3 times as deep as middle one, the protuberances between middle and lateral emarginations acute, exceeding the acute apices of apicolateral angles. Internal genitalia (Fig. 8A): diverticulum hardly narrowed apically and rounded at apex, about twice as long as its maximal width; spermatheca expanded apically.