Revision of the assassin bug genus Neopirates (Heteroptera: Reduviidae: Peiratinae), with descriptions of two new species from Namibia

The African assassin bug genus Neopirates Miller, 1952, is revised. The type species, N. nyassae Miller, 1952, is redescribed and illustrated; two new species from Namibia, N. bicolor Liu & Cai sp. n. and N. xanthothorax Liu & Cai sp. n. are described and a key is provided to separate the three species of this genus. Sphodrembas fumipennis Swanson, 2019, the type species of Sphodrembas Swanson, 2019, is placed as a junior synonym of N. nyassae, resulting in Sphodrembas becoming a junior synonym of Neopirates. Morphological differences between Neopirates and similar genera and the distribution of Neopirates are briefl y discussed. ZooBank Article Registration: http://zoobank.org/urn:lsid:zoobank.org:pub:10E250F1-27F7-4F11-95AD-BCACE78AE33E * Corresponding author; e-mail: caiwz@cau.edu.cn INTRODUCTION As one of the largest assassin bug subfamilies, Peiratinae (Reduviidae) is a diverse taxon comprising 34 genera and over 300 species distributed worldwide (MaldonadoCapriles, 1990; Chłond, 2007; Zhang & Weirauch, 2011; Melo, 2012; Weirauch et al., 2014; Swanson, 2019). The following combination of characters makes Peiratinae a unique group within Reduviidae: anterior pronotal lobe longer than posterior lobe, elongate forecoxa, prominent fossula spongiosa on the fore and mid tibiae, and asymmetrical male genitalia (Weirauch et al., 2014). Up to now, there have been 18 peiratine genera recorded in the Afrotropical Region but only a few of them have been well reviewed (Coscarón, 1995, 1997, 1999, 2002; Coscarón & Morrone, 1995; Zhang & Weirauch, 2011; Chłond, 2018). Moreover, many Afrotropical peiratine genera are monotypic, not only refl ecting the morphological diversity of this group but also indicating that the true species diversity will be revealed through more detailed studies. Neopirates was established by Miller (1952) based on a single species, Neopirates nyassae Miller, 1952, from Eur. J. Entomol. 117: 343–351, 2020 doi: 10.14411/eje.2020.039

Pronotum with collar process developed; anterior lobe of pronotum longer and narrower than posterior lobe; anterior lobe of pronotum subquadrate with a median, lon gitudinal, shallow sulcus on posterior portion, sculpture not clear;

MATERIAL AND METHODS
This study is based on specimens deposited in the Natural History Museum, London, UK (NHMUK) and the Natural History Museum of Los Angeles County, California, USA (LACM). Label data are copied verbatim in quotation marks (" ") with different labels separated by a double slash (//). Male genitalia were soaked in hot 20% lactic acid solution for approximately ten minutes to remove soft tissue, rinsed in distilled water and dissected under a dissecting microscope. Dissected genitalia were placed in vials with glycerin and pinned under the corresponding specimens after examination. Images were taken using a Canon 7D Mark II digital camera with Canon EF 100 mm micro lens or 65 mm micro lens and an Olympus E-M1 II digital camera with Olympus M. ZUIKO digital ED 60 mm micro lens. Helicon Focus version 5.3 was used for image stacking. Measurements were obtained using a calibrated micrometer. Body length represents the distance between the apex of the head and the tip of the abdomen in resting condition. The distribution map was built using the online version of SimpleMapper (Shorthouse, 2010). The distribution data are based on our examination of museum specimens, supplemented by data from Miller (1952) and Swanson (2019 Diagnosis. Male macropterous (Figs 1-3, 21-23, 41-43), female unknown; head moderately elongate with postocular part somewhat abruptly narrowed (Figs 4,24,44); transverse width of eye in dorsal view subequal to width of interocular space (Figs 4,24,44); anterior lobe of pronotum subquadrate; pronotal transverse sulcus obsolete (Figs 24,44) or slight (Fig. 4); metapleural sulcus curved and unicarinate (Figs 5,25,45); fore tibia with fossul a spongiosa occupying about 1/3 (Figs 27, 47) or 1/4 ( Fig. 7) of tibial length, mid tibia with fossula spongiosa occupying only apex of ventral surface (Figs 8,28,48); hind coxae separated from each other by width of one coxa (Figs 6,26,46); hemelytron and hind wing both extending beyond tip of abdomen (Figs 10,30,50); male genitalia with median pygophore process nearly straight, oblique to right side in caudal view, ventral surface of median pygophore process with a longitudinal ridge (Figs 13,14,33,34,53,54); base of left lateral phallothecal sclerite with a slender, strongly sclerotized sclerite, extending to venter of phallosoma, venter of phallosoma with another slender sclerite, shorter than lateral one and nearly connected to it (Figs 18,19,38,39,58,59).
Abdomen oval; connexivum slightly dilated laterally; venter of abdomen slightly carinate in middle (Figs 30,50) or with a median ridge running from anterior of second abdominal sternite to posterior of seventh abdominal sternite and slightly curved to right side of body (Fig. 10); left side of seventh abdominal sternite sometimes with an extragenital process (Figs 10, 50).
Description. Male macropterous (Figs 1-3), female unknown. Coloration. Yellow. First antennal segment yellow, second segment yellow with apical portion brownish, third segment brown with apex yellow, fourth segment unknown; head dark yellow to yellowish brown with irregular blackish mark around ocelli (Fig. 4) and sometimes with blackish spot in front of eye on lateral surface of head (Fig. 5); anterior lobe of pronotum yellow, posterior lobe brown with basal margin yellow (Fig. 4); scutellum brown ( Fig. 4); pleura brown with margin diffused yellow (Fig.  5); basal half of hemelytron yellow, apical half of hemelytron brown with lateral margin darker, membrane with a whitish stripe along inner side of R (Fig. 9); abdomen yellow, sometimes with some diffuse brown markings laterally (Fig. 10).
Structure: Small sized. Head length 1.13-1.21 times as long as its width; width of interocellar space subequal to width of ocellus (Fig. 4); second antennal segment about three times as long as fi rst segment. Pronotum with apex of collar process rounded; anterior lobe of pronotum 1.27-1.30 times longer than posterior lobe; posterior lobe of pronotum about 1.65-1.71 times wider than anterior lobe; pronotal transverse sulcus slight (Fig. 4). Scutellum with Y-shaped ridges slender, apex of scutellum prolonged as a small process (Fig. 4). Stridulitrum fairly long with total-striate type of sculpture (Fig. 6). Fore tibia with fossula spongiosa occupying about 1/4 of tibial length (Fig.  7). Venter of abdomen with a medi an ridge running from anterior of second abdominal sternite to posterior of seventh abdominal sternite, slightly curved to right side of body and with a triangular extragenital process on left side of seventh abdominal sternite (Fig. 10).
Etymology. The specifi c epithet is derived from Latin bicolor (meaning "of two colors"), referring to the conspicuously bicolored hemelytron of this new species.

Distribution. Namibia.
Remarks. Of the three specimens of this new species found in NHMUK one is missing the abdomen, so we exclude it from the type series. The intraspecifi c color variation of this new species is mainly in the head and abdomen: the head of the holotype is dark yellow (Figs 1-3) but the head of the paratype is yellowish brown with a blackish spot in front of the eye on the lateral surface (Figs 4-6) and the abdomen of the paratype (Fig. 10) with more diffuse brownish markings laterally than that of the holotype (Fig. 2).
This new species can be easily distinguished from its congeners due to its bicolored hemelytron, the pronotal transverse sulcus slight and the apex of the scutellum prolonged as a small process instead of rounded. Besides these features, the most special character is the distinct triangular extragenital process on the left side of the seventh abdominal sternite. This kind of extragenital process was fi rst studied by Ghauri (1964) who found that they always occur on the left-hand side of the body and their function could be related to mating behavior. Such extragenital process cannot be included in the generic diagnosis because this structure may only be present in some species of the same genus, such as species in Peirates Serville, 1831, and Pha lantus Stål, 1863. In N eopirates, the extragenital process is only present in this new species and N. xanthothorax sp. n. and their shapes are totally different (smaller and  Diagnosis. Body length 10.11-14.5 mm; anterior lobe of pronotum dark yellow, posterior lobe brown; hemelytron brown; anterior lobe of pronotum about 1.30-1.50 times longer than posterior lobe, pronotal transverse sulcus obsolete; scutellum with Y-shaped ridges thi ck, apex of scutellum rounded; fore tibia with fossula spongiosa occupying slightly longer than 1/3 of tibial length; venter of abdomen only slightly carinate in middle, without extragenital process; parameres subtriangular; apex of median pygophore process sharp in lateral view; basal portion of dorsal phallothecal sclerite distinctly upturned; basal margin of right lateral phallothecal sclerite serrate. Redescription. Male macropterous (Figs 21-23), female unknown. Coloration. Yellow, color of head, pleura, sterna and abdomen varies from yellow to brown among conspecifi c individuals. Antenna dark yellow; head yellow ( Fig. 21) to brown (Fig. 24) with irregular blackish mark around ocelli (Figs 2 1, 24); anterior lobe of pronotum dark yellow, posterior lobe brown (Fig. 24); pleura, sterna and abdomen yellow (Figs 22,23) to yellowish brown (Figs 25,26,30), sometimes with diffuse brown markings (Figs 25,26,30); hemelytron brown with a whitish thin stripe along R on membra ne (Fig. 29).
Structure. Medium sized. Head length 1.30 times as long as width; width of interocellar space slightly longer than width of ocellus (Fig. 24); second antennal segment about twice as long as fi rst segment. Pronotum with apex of collar process rounded; anterior lobe of pronotum about 1.30-1.50 times longer than posterior lobe; posterior lobe of pronotum 1.65 times wider than anterior lobe; pronotal transverse sulcus obsolete (Fig. 24). Scutellum with Y-shaped ridges thick, apex of scutellum rounded (Fig. 24); Stridulitrum long with total-striate type of sculpture (Fig.  26). Fore tibia with fossula spongiosa occupying slightly longer than 1/3 of tibial length (Fig. 27). Venter of abdomen only slightly carinate in middle, without extragenital process (Fig. 30).

Distribution. Malawi, Tanzania, Kenya, Lesotho (new record).
Remarks. The body color varies from yellow to brown among individuals in this species. The color of the head, the thorax (except the pronotum) and the abdomen of the holotype (Figs 21-23) is yellow in large part while it's different shades of brown or with some brownish markings in the other examined specimens. Other structural characters and the colors of the pronotum (the anterior lobe dark yellow while the posterior lobe brown), the legs (entirely yellow) as well as the irregular blackish mark around the ocelli are stable among all the examined specimens. We therefore conclude that the color variation mentioned above is an intraspecifi c difference.
The new junior synonym of this species, Sphodrembas fumipennis, was described based on the holotype male from Tanzania and four paratypes from Tanzania and Kenya (deposited in the American Museum of Natural History and the University of Michigan Museum of Zoology). Based on the original description, the color of these specimens is also variable, and the hemelytra are surrounding fuscous in Kenyan specimens but concolorously fuscous in Tanzanian specimens. See discussion for details on synonymy. Diagnosis. Body length 9.15 mm; pronotum entirely yellow; hemelytron dark brown; anterior lobe of pronotum about 1.10 times longer than posterior lobe, pronotal transverse sulcus obsolete; scutellum with Y-shaped ridges thick, apex of scutellum rounded; fore tibia with fossula spongiosa occupying about 1/3 of tibial length; venter of abdomen only slightly carinate in middle, with a small fusiform extragenital process; left paramere sickle-shaped, right paramere subtriangular; apex of median pygophore process sharp in lateral view; basal portion of dorsal phal-lothecal sclerite slightly upturned; basal margin of right lateral phallothecal sclerite serrate.
Description. Male macropterous (Figs 41-43), female unknown. Coloration. Yellow. First antennal segment yellow, second and third segments brown, fourth segment unknown; head yellow with irregular blackish mark around ocelli (Fig. 44); hemelytron dark brown with forked whitish stripe along outer side of M and inner side of R on membrane (Fig. 49); abdomen yellow with some diffuse brown markings laterally (Figs 43, 50).
Structure. Small sized. Head length 1.16 times as long as width; width of interocellar space about twice width of ocellus (Fig. 44); second antennal segment about twice as long as fi rst segment. Pronotum with apex of collar process prominent; anterior lobe of pronotum about 1.10 times longer than posterior lobe; posterior lobe of pronotum about 1.80 times wider than anterior lobe; pronotal transverse sulcus obsolete (Fig. 44). Scutellum with Y-shaped ridges thick, apex of scutellum rounded (Fig. 44). Stridulitrum long with total-striate type of sculpture (Fig. 46). Fore tibia with fossula spongiosa occupying about 1/3 of tibial length (Fig. 47). Venter of abdomen slightly carinate in middle, left side of seventh abdominal sternite with a small fusiform extragenital process (Fig. 50).

Distribution. Namibia.
Remarks. This new species is also distributed in Namibia like N. bicolor sp. n., and is more simil ar to N. nyassae at fi rst sight. It can be distinguished from the latter species by following characters: body length less than 10 mm (vs. body length over 10 mm in N. nyassae); antenna with the fi rst segment yellow, the second and the third brown (vs. the antenna unicolored in N. nyassae); pronotum entirely yellow (vs. the anterior lobe of the pronotum dark yellow with the posterior lobe brown in N. nyassae) and the left side of the seventh abdominal sternite with a small fusiform extragenital process (vs. the venter of the abdomen without an extragenital process in N. nyassae). The male genitalia of this new species differ from the male genitalia of N. nyassae in having the left paramere sickle-shaped (vs. the left paramere subtriangular in N. nyassae) and the basal portion of the dorsal phallothecal sclerite slightly upturned (vs. the basal portion of the dorsal phallothecal sclerite distinctly upturned in N. nyassae).

Synonymy
Swanson (2019) established his new genus Sphodrembas with detailed description and illustrations of its type species, S. fumipennis. He recorded the generic diagnosis of Sphodrembas as "Easily separated from all other peiratine genera by the unicarinate metapleuron, apically rounded scutellum, and widely separated metacoxae. The taxon also is distinctive in the thickened pedicel and the testaceous coloration." We examined the holotype of N. nyassae deposited in NHMUK and found that this holotype looks similar to the holotype of S. fumipennis and the shape of the parameres and median pygophore process, fi gured in the original description, also match those of S. fumipennis.
Swanson (2019) noted that in his new genus Sphodrembas, the unicarinate metapleuron is a condition unknown to him in any other peiratine genus, but also, he had not been able to assess this condition in many of the less speciose genera. Probably Swanson did not examine the holotype of N. nyassae, and the special character of the metapleural sulcus, not mentioned by Miller (1952) when he established Neopirates, was probably therefore overlooked. Another unique character that separates Neopirates from other peiratine genera is the indistinct transverse sulcus of the pronotum, recorded by Miller (1952) as "transverse sulcus not entire". Swanson did not include this character in the diagnosis of Sphodrembas but it can be noticed from his close-up view of the pronotum of S. fumipennis.
Swanson (2019) also provided a key to the genera of Peiratinae of the Old World, the characters listed in the key to distinguish Neopirates from some other genera (including Sphodrembas) are "Transverse sulcus of pronotum incomplete medially; scutellum regularly triangular, not produced apically; venation of hemelytral membrane with inner cell narrow, of similar width throughout length (reduviine type); known from Malawi". Most of these characters are also shared with Sphodrembas and the recorded distribution of S. fumipennis (Tanzania and Kenya) and the type locality of N. nyassae (Malawi) are not far from each other.
As discussed above, we concluded that S. fumipennis should be regarded as a junior synonym of N. nyassae and therefore the genus Sphodrembas becomes a junior synonym of Neopirates.

Diagnostic characters and relationships of Neopirates
The revised diagnosis of Neopirates is given above based on the three included species. This set of characters separates this genus from all other genera of Peiratinae, especially the obsolete or slight pronotal transverse sulcus and the unicarinate metapleural sulcus. Typically, in other peiratinae genera, the metapleural sulcus is created by two closely situated ridges and the pronotal transverse sulcus is distinct or indistinct only in the middle portion.
In the Afrotropical Region, Neopirates is most similar to Peirates, Phalantus and Rapites Villiers, 1948, with a similar body shape and coloration. Besides the two unique characters mentioned above, Neopirates can also be distinguished from Peirates by the anterior lobe of the pronotum subquadrate and the hind coxae separated from each other by the width of one coxa in Neopirates (vs. the anterior lobe of the pronotum rounded and the hind coxae separated from each other less than the width of one coxa in Peirates), and from Phalantus by the fore femur slightly thickened with the ventral surface unarmed and the fore tibia clavate with the fossula spongiosa occupying 1/3 or 1/4 of the tibial length in Neopirates (vs. the fore femur strongly compressed with denticles on the ventral surface and the fore tibia curved with the fossula spongiosa occupying only the apex of the tibia in Phalantus). Rapites differs from Neopirates in the smaller body size, deeper median depression on the anterior lobe of the pronotum and the fossula spongiosa reduced to a brush of hairs.

Distribution and habitat
Neopirates is distributed in Eastern and Southern Africa (Fig. 61). Neopirates nyassae occurs along the eastern side of the Great Rift Valley and east of the South African plateau in Lesotho. Neopirates bicolor sp. n. and N. xanthothorax sp. n. are both distributed in Namibia's central plateau. The habitats of this genus are mainly savanna regions where the natural vegetation consists of tall grass and short deciduous trees. Peiratinae species are primarily grounddwelling and nocturnal (Weirauch et al., 2014). It can be speculated that Neopirates species usually hide in some cryptic microhabitats such as in dead wood or in cracks of rocks in the day time to avoid the high temperature and become active at night.