DESCRIPTION OF A NEW BAT-ASSOCIATED BUG SPECIES OF THE CIMEX LECTULARIUS GROUP FROM VIETNAM

Department of Parasitology and Zoology, University of Veterinary Medicine, István u. 2, H-1078 Budapest, Hungary; Plant Protection Institute, Centre for Agricultural Research, Hungarian Academy of Sciences, Budapest, Hungary; Institute of Ecology and Biological Resources, Vietnam Academy of Science and Technology, Hanoi, Vietnam; Graduate University of Science and Technology, Vietnam Academy of Science and Technology, Hanoi, Vietnam

The common bedbug, Cimex lectularius Linnaeus, 1758 is a cosmopolitan blood-sucking ectoparasite, primarily infesting humans, but also frequently found on or near chickens and vespertilionid bats (Usinger, 1966). Bat-associated bugs of the Cimex lectularius group are not only important as pests, but also significant in an evolutionary context (Balvín et al., 2012a). Recently, two highly divergent novel genotypes have been reported in this species complex (Hornok et al., 2017). The purpose of the present study was to morphologically describe and illustrate that novel Cimex genotype which was the most different from other members of the C. lectularius group. In particular, the degree of barcoding sequence similarity between this novel genotype and C. lectularius was lower than between well-established Cimex species (Hornok et al., 2017), justifying the status of this novel genotype as a new species.

Materials and methods
Two bugs were collected from a male and a female Chinese pipistrelle (Hypsugo pulveratus Peters, 1870) at Ngoc Khe, Ngoc Lac, Thanh Hoa in Vietnam, 2011. DNA was extracted and two genetic markers were amplified, sequenced from the whole body of one male and from four legs of a female specimen, as reported (Hornok et al., 2017). Pictures were taken and measurements were performed with a VHX-5000 digital microscope (Keyence Co., Osaka, Japan). Sizes below are provided in mm.
Diagnosis. Small-sized (3.8 mm) bug species with dense, short pubescence. Head and body brown, hemelytral pads golden yellow. Area around the paragenital sinus with bristles. Head broad, 2nd to 4th antennal segments long. Pronotum width to length ratio above 2.5 and hind margins of the hemelytral pads broadly rounded on inner halves (lectularius group). Paragenital sinus broadly rounded. Bristles anteriorly (on the pronotum and hemelytral pads), as well as posteriorly (last abdominal segment) exceed 100 µm.

Acta Veterinaria Hungarica 66, 2018
Gene sequences Mitochondrial cytochrome oxidase subunit I (cox1) gene sequence deposited in the GenBank is MF415647. The internal transcribed spacer 2 (ITS2) sequence is MF161540. The phylogenetic relationships of the new species have been reported (Hornok et al., 2017).

Differential diagnosis
Bristles around the paragenital sinus and width to length ratio of the pronotum distinguish the new species from members of the C. pipistrelli group.
Cimex lectularius group: concerning the morphology of females, C. pulveratus sp. nov. is similar to C. lectularius based on its coxal spur and width to length ratio of pronotum (exceeding 2.5). However, the paragenital sinus of C. pulveratus sp. nov. is different from that in C. lectularius and other Palearctic members of its group, i.e. it is rounded, which is a character of Neotropical species of the genus Cimex, not reported previously from the Old World (Usinger, 1966).
Cimex hemipterus group: C. pulveratus sp. nov. is similar to C. hemipterus Fabricius, 1803 based on its head shape (wider than long). In addition, the 2nd antennal segment is shorter than the interocular space. However, the width to length ratio of the pronotum of C. pulveratus sp. nov. exceeds 2.5, unlike in the case of C. hemipterus. A further member of the C. hemipterus group, i.e. C. insuetus Ueshima, 1968 (indigenous in Thailand and India) can be distinguished from C. pulveratus sp. nov. by its width to length ratio of the pronotum (which is below 2), elongated head and 2nd antennal segment (which is longer than the interocular space) (Ueshima, 1968).
The above differences were confirmed by molecular and phylogenetic analyses (Hornok et al., 2017).

Etymology
The new species was named after its host species, Hypsugo pulveratus.

General
In accordance with section 8.5 of the ICZN's International Code of Zoological Nomenclature, details of the new species have been submitted to ZooBank with the life science identifier (LSID) D64E4517-FF7C-48C4-9AAB-60156E82517E.

Discussion
In the family Cimicidae, the common bedbug (C. lectularius) can be regarded as the species with the highest historical, economical and veterinarymedical importance, also taking into account its worldwide occurrence and preference of human environment and body. Recently, high degrees of genetic differences have been reported between cimicid bugs, both within Europe and between specimens collected in Europe and Asia (Hornok et al., 2017). In particular, the sequence divergence between a newly discovered genotype (described here as C. pulveratus sp. nov.) and C. lectularius greatly exceed the limit of known intraspecific variation (Hornok et al., 2017), i.e. in the cox1 gene this difference was above 17% in comparison with C. lectularius, while this value is 5.8-6.4% between C. lectularius and members of the C. hemipterus or C. pipistrelli species groups. In line with this, the morphological characteristics of C. pulveratus sp. nov. described above justify its distinct species status.
The host species of C. pulveratus sp. nov., i.e. Hypsugo pulveratus, is closely related to the genus Pipistrellus, which contains important hosts of batassociated bugs from both the lectularius and pipistrelli groups (Balvín et al., 2014). Host associations have been considered important drivers in the evolution/speciation of bat-associated bugs, as exemplified by C. lectularius (Balvín et al., 2012b;Booth et al., 2015). In the present case, to the best of our knowledge, no previous records and contemporaneous genetic/morphologic analyses of cimicid bugs from H. pulveratus are available. Thus, it can only be postulated that this host association may have contributed to the genetic and morphologic segregation of C. pulveratus sp. nov. Taking into account the geographic range of H. pulveratus (including China, Laos, Thailand and Vietnam), C. pulveratus sp. nov. most likely has a wide distribution in southeast Asia.