A review of the Himalayan genus Trypheridium Brancucci (Coleoptera: Cantharidae: Chauliognathinae) with description of a new species

The genus Trypheridium Brancucci, 1985 is endemic to the Hindu Kush Himalayan Region, and is currently known from a single species, T. nuristanicum (Wittmer, 1956). Here, the genus is reviewed, T. nuristanicum nom. emend. is re-described and T. kashmiricum sp. nov. is described from Kashmir Himalayan Region of India. Descriptions, diagnoses, high quality images, distribution maps and identifi cation keys are presented. The morphology and distribution of Trypheridium are discussed and compared with those of the closely related genus Trypherus LeConte, 1851.


Introduction
The genus Trypheridium Brancucci, 1985 was originally described from the Hindu Kush Himalayan Region, for a single species Trypherus nuristanicus Wittmer, 1956 based on distinct morphological characters and disjunct distribution. Superfi cially, Trypheridium resembles Trypherus LeConte, 1851 but can be distinguished from the latter by 'aberrant' sexual characters and unmodifi ed mid legs (Brancucci 1985a).

R e s e a r c h a r t i c l e
urn:lsid:zoobank.org:pub:5A7D12E9-39DE-4A91-8811-FB1B8B11D190 Trypheridium seems to be restricted to the Hindu Kush Himalayan Region whereas Trypherus is widespread across the eastern Palaearctic and the Nearctic, with a greater diversity in Taiwan (Brancucci 1985b;Pelletier & Hébert 2014;Satô et al. 2014). The Hindu Kush is an 800 km long mountain range that stretches through Afghanistan, from its centre to Northern Pakistan and into Tajikistan, and is home to four global biodiversity hotspots, and hundreds of mountain peaks over 6000 m (Chettri et al. 2008;Searle 2013). The range forms the western section of the Hindu Kush Himalayan Region and is the westernmost extension of the Pamir Mountains, the Karakoram and the Himalayas.
In this study we revise the taxonomy of the genus Trypheridium and describe a new species T. kashmiricum sp. nov. from the Kashmir Himalayan Region of India and re-describe T. nuristanicum nom. emend. All descriptions include diagnoses, taxonomic discussions, and high quality stacked images. In addition, we provide an illustrated identifi cation key to species, as well as maps showing the known distribution ranges.

Material and methods
Specimens of T. kashmiricum sp. nov. were collected at Waripora, Tangmarg area (34º05′30″ N, 74°33′31″ E, 1639 m a.s.l.) of Baramulla District, in Kashmir Valley, the Palaearctic portion of India, located in the northwestern part of the Indian subcontinent between 33°22′ and 34°50′ N latitudes and 73°55′ and 73°33′ E longitudes Wachkoo et al. 2018). The specimens were hand collected from the leaves of walnut trees (Juglans regia L.), which were heavily infested with aphids ( Fig. 1). The alcohol (70% ethanol) preserved specimens were air dried and card mounted for taxonomic studies.
The map of the sampling site was created by using the administrative-boundary vector map of India at district level (Survey of India) at a scale of 1:1 000 000. Geographical coordinates of the sampling site were imported to mapping software and the sampling site was plotted. The ArcMap module of the ArcGIS package ver. 10.1 (www.esri.com) was used to prepare the map of Kashmir Valley showing the sampling site. The species distribution map was prepared using Google maps.
The specimens were obser ved under a Magnus MS 24 stereoscopic binocular microscope. Card point mounted specimens were placed inside a light-box using cool daylight LED lamps (3W) and images were captured using a DSLR camera (Nikon D5300) with a macro lens (Tokina 100 mm f 2.8). Multiple images were generated using an auto stacking-rail (Stackrail rs90) and merged using Combine ZP software. The fi nal images were cleaned with Adobe Photoshop CS4. The abdomens of specimens were detached with forceps and treated with 20-30% KOH for about 48 hours. After appropriate transparency was achieved, abdomens were cleaned in 75% ethanol and placed on cavity slides with glycerin. Abdominal sternites and genitalia were dissected and mounted for microphotography. For brightfi eld microscopy, prepared slides were placed on a stage prepared from cardboard and provided with an LED lamp (3W) to produce the transmission light beam. For darkfi eld microscopy a darkfi eld illumination fi lter was used to illuminate unstained specimens. Microphotographs were captured with a digital mirrorless camera (Nikon Z50) attached with infi nity-corrected microscope objectives (Lomo 3.7 × and Nikon CFI Plan Achromat 10X).
The terminology used in the descriptions follows that of Brancucci (1980Brancucci ( , 1985b, except for the tergite IX and X that replaces the terms paraproct and proctiger respectively, and a new orientation of the aedeagus. The correct orientation of the aedeagus of the Chauliognathinae is still contentious, as two opposite terminologies are used for each of the lineages (cf. Biffi 2020). Brancucci (1985b) attempted to correct the general hypothesis of homology for the aedeagus of the Chauliognathinae proposed by Magis & Wittmer (1974). However, the terminology used by Brancucci (1985aBrancucci ( , 1985b is actually based on an aedeagus disposed in a dorsal position, rather than ventral as he stated. We therefore consider the aedeagus of species of Trypheridium as having two elongate outgrowths: right paramere (rather than "left paramere" sensu Brancucci), and a prolongation of the tegmen to the left (rather than "right prolongation of tegmen" sensu Brancucci). The left paramere ("right paramere" sensu Brancucci) is here considered to be missing. The descriptions and diagnoses below were adapted to accordingly follow this present orientation of the aedeagus.

Re-description (Figs 6-7)
Coloration General coloration pale to sulphur yellow with dark brown to black patches; head yellow anteriorly at frons and clypeus and infuscate at vertex and occipital region; antennae dark brown to black, the three or four basal antennomeres yellow; pronotum with a transversal black band at posterior half; elytra with dark brown to black triangular patches, from the base of elytra (not reaching the humeri) and extending posteriorly; wings dark brown; legs dark brown or black, usually fore and mid legs light brown with dark spots; abdominal tergites and ventrites black in the centre and yellow at the margins. Coloration in females usually darker.
HEAD. Head (including the eyes) wider than pronotum; vertex fl at, frons concave between the eyes, occipital region convex, sides rounded and regularly narrowing behind the eyes. Eyes large, oblong, bulging, longer than wide, broadly separated. Fronto-clypeal suture distinct laterally, indistinct in the middle; anterior margin of clypeus slightly sinuous, nearly straight; labrum membranous. Mandibles arcuate, apex acute, blunt, retinaculum in the same plan as incisor, apex rounded, with a small supplementary tooth at the base of retinaculum. Maxillary palp with fourth palpomere elongate, narrowing apicad. Antennae not juxtaposed, separated by at least the width of antennal sockets; with 11 antennomeres, fi liform, without modifi cations; antennomere I slender, without swellings. PRONOTUM. Transverse, wider than long, convex; anterior margin broadly arched, lateral margins nearly straight, slightly narrowing posteriorly; posterior margin projected posteriorly; anterior and posterior angles rounded, barely distinct. Elytra short, 1.2-1.4 times longer than combined width, slightly narrowed laterally, suture dehiscent posteriorly, apex rounded.
WINGS. With reduced venation, radial cell 2R 1 closed; vein r-m barely visible, vein Cu straight, vein Mr fading; transversal vein cu-a absent; Rr extends beyond the joining of vein r; vein A x2 well visible, not joining Ax 1+2 and ending near the joining of vein A and Ax 1+2 .
LEGS. Slender, without swellings, teeth or remarkable modifi cations; apex of fore tibia with a pair of tiny spurs; all tarsal claws with broad internal teeth.
AEDEAGUS. Elongated and weakly sclerotised; left paramere absent, right paramere and the prolongation of tegmen elongate and directed posteriorly; left prolongation of tegmen broad and lamellar, margins sinuous. Median lobe membranous, short, not twisted, with its broad opening located apically.

Female
Similar to males, except for eyes slightly smaller and more separated; sternite VII long and broad, mostly concealing sternite VIII, distal margin with elongate lobes projecting posteriorly. Sternite VIII membranous, broadly rounded, distal margin with a broad rounded lobe projecting posteriorly; coxites small, not fused medially, anterior arms very long and slender, apparently fused with valvifers, styles elongate, digitiform. Genitalia membranous, consisting of a long and broad vagina; oviduct anteriorly in the vagina; bursa copulatrix elongate, wrinkled, spiralling; spermatheca formed by two tubular projections; accessory gland large, connected by a long winding duct to the postero-dorsal part of bursa copulatrix.

Diagnosis
This species resembles T. nuristanicum in general morphology and coloration, but differs in the structure of male and female terminal abdominal segments. In males, the right blade of tergite IX bifurcates terminally into two unequal lobes and tergite X divides into two very long asymmetrical projections. Sternite VII in females projects beyond the tip of abdomen, mostly concealing sternite VIII, and forms three projections apically.

Etymology
The species epithet is in reference to the type locality.

Description Coloration
Head black in vertex and occipital region, yellow in frons and clypeus. Antennae dark brown, except the three and part of fourth basal antennomeres and sometimes underside of latter, yellow; sometimes antennomeres II and III infuscate. Mandibles yellowish with dark-brown apex. Palpi light brown, infuscate at distal palpomeres. Pronotum partly translucent, yellow with transversal black band at posterior half, not reaching lateral and posterior pronotal margins. Elytra sulphur yellow with triangular dark brown patch from base of elytra extending posteriorly along suture up to about posterior third of elytra; integument shinning, covered with fi ne yellow pubescence. Wings, meso-and metaventrite dark brown to black. Legs: fore and mid coxae yellow, hind coxa partly yellow and partly brown; fore and mid femora yellowish (black in females) except having black patch towards dorsal apex; fore tibia and tarsus yellow; mid tibia testaceous brown and tarsus dark brown; hind legs completely dark brown except yellowish brown basal margin; darker specimens have legs more broadly infuscate. Abdominal ventrites and tergites dark brown to black at the centre and yellow at margins; last ventrites and tergites light to dark brown (especially in females).
HEAD. Head (including eyes) wider than pronotum (Fig. 2D-E), 1.3 times as wide as long (across middle of eyes); vertex fl at, frons slightly concave between eyes, with pair of longitudinal furrows running between antennae sockets; area around antennal sockets depressed and with carinated margin, forming ridge between antennae that reaches up to vertex; integument smooth and lustrous, with very small punctures and densely covered with short and fi ne setae. Fronto-clypeal suture defi ned laterally, indistinct medially. Eyes large, bulging, longer than wide, glabrous; interocular space 1.6 times wider than widest width of eye. Antennae fi liform (Fig. 2F), slender, 0.56 times body length, covered with short and fi ne setae; antennomere I 1.68 times length of II, 0.88 times length of antennomere III, 0.84 times length of antennomere IV, antennomeres IV-VI longest, subequal, latter decreasing apicad, XI pointed at apex.
PRONOTUM. Transverse (Fig. 2G) 1.3 times as wide as long, sides narrowed posteriorly, rounded, anterior margin arcuate, anterior angles rounded, not defi ned, posterior margin projected posteriorly, sinuous; disc slightly arched, integument partly translucent, smooth and lustrous, coarsely punctured and densely covered with fi ne pubescence. Scutellum with sides parallel, apex truncate. Scutellum trapezoidal, with pair of shallow and broad concavities anteriorly, posterior margin with rounded notch.
ELYTRA. Short, 0.28 times as long as body length, about 1.89 times length of pronotum, 1.2 times longer than width of both elytra; sides slightly narrowed at posterior third, sutures parallel anteriorly and dehiscent from posterior half, apex of each elytron rounded and fl attened; integument slightly rugose, almost smooth, with fi ne punctures and densely covered with short and fi ne setae.
WINGS. With reduced venation (Fig. 2H), radial cell 2R 1 closed; vein r-m barely visible, vein Cu straight; transversal vein cu-a absent; Rr extends beyond the joining of vein r; vein A x2 well visible, not joining Ax 1+2 and ending near the joining of vein A and Ax 1+2 .
LEGS. Slender, increasing in length from fore to hind, without strong modifi cations. Apex of fore tibia with a pair of very tiny spurs (Fig. 2I).

Diagnosis
Trypheridium nuristanicum differs from T. kashmiricum sp. nov. in the structure of the male and female terminal abdominal segments. In males, the right blade of tergite IX is undivided terminally and tergite X is divided into two short asymmetrical lobes. Sternite VII in females is short, partly exposing sternite VIII, with 2 projections at the distal margin.

Coloration
Head black in the vertex and occipital region, yellow in the frons and clypeus. Antennae dark brown, except the three or four fi rst antennomeres and sometimes the underside of the later, yellow. Palpi light brown, infuscate at distal palpomeres. Pronotum yellow with a transversal black band at posterior half, nearly reaching the lateral and posterior pronotal margins. Elytra sulphur yellow, sometimes lighter at the apex; a triangular dark brown patch from the base of elytra extending posteriorly along the suture up to about posterior third of elytra. Wings, meso-and metaventrite dark brown to black. Legs usually black; fore tibia and base of femur sometimes testaceous to light brown, fore femur rarely completely testaceous; bases of mid femur and tibia sometimes lighter. Abdominal ventrites and tergites dark brown to black at the centre and yellow at the margins; last ventrites and tergites mostly to completely yellow. Coloration in females, especially of the legs, usually a little darker.
HEAD. Head (including the eyes) wider than pronotum; vertex fl at, frons slightly concave between eyes, with fi ne longitudinal furrow in middle, which ends in semicircular impression between antennae sockets; integument smooth and lustrous, with very small punctures and densely covered with short and fi ne setae. Eyes large, bulging; interocular space slightly wider than widest width of eye. Antennae fi liform, slender, reaching apex of elytra posteriorly, covered with short and fi ne setae; antennomere I slender, II more than a third shorter than III, antennomeres IV and V subequal and following decreasing in length. PRONOTUM. Transverse (Fig. 6B) 1.1 times as wide as long, sides narrowed posteriorly, anterior margin regularly arched, anterior angles barely defi ned, posterior margin projected posteriorly, truncate at middle and concave laterally; disc slightly arched, integument smooth and lustrous, coarsely punctured and densely covered with fi ne pubescence. Scutellum with sides parallel, apex truncate.  Magis & Wittmer (1974). 764: 18-36 (2021) ELYTRA. Short, 1.4 times longer than width of both elytra; sides slightly narrowed at posterior third, sutures parallel anteriorly and dehiscent from posterior third, apex of each elytron rounded and fl attened; integument slightly rugose, almost smooth, with fi ne punctures and densely covered with short and fi ne setae.

European Journal of Taxonomy
LEGS. Slender, increasing in length from fore to hind, without strong modifi cations. Apex of fore tibia with pair of tiny spurs (Fig. 6C).
Female (Fig. 7) Similar to males, except for eyes smaller, less protruding, interocular space 1.4 times larger than widest diameter of eye; antennae shorter, not reaching apex of elytra posteriorly. Sternite VII strongly and variably modifi ed, elongate, projected distally into pair of forked lamellar projections, parallel to slightly divergent, apices rounded, sides of projections angulate at base or near mid length (Fig. 7B); sternite VIII subquadrate, broad and long, partly concealed by sternite VII, lateral margins arched, distal margin with rounded projecting lobe in middle tergite VIII convex, lateral margins slightly arched, distal margin broadly arched, concave, distal angles projected posteriorly, with glandular openings; tergite IX short and broad, distal margins slightly arched, concave (Fig. 7C). Genitalia membranous (Fig. 7D); vagina long and broad; bursa copulatrix elongate, wrinkled, spiralling; spermatheca formed by two tubular projections; accessory gland large, connected by long winding duct to the postero-dorsal part of bursa copulatrix. Brancucci (1985a) proposed Trypheridium nuristanicus (sic) as a new combination in his description of the neuter genus Trypheridium, of which it is the type species. He omitted to adjust the gender of the species name to agree with Trypheridium. The gender of nuristanicus (an adjective formed from the name of the type locality Nuristan in Afghanistan) is emended to nuristanicum to agree with the neuter Latin suffi x -idium of Trypheridium (ICZN 1999, Art. 34.2). When proposing the genus, LeConte (1851) did not give an etymology for Trypherus, but Gemminger & Harold (1869) defi ned the name as meaning "debilis" (week, feeble, fragile, etc). "Trypheridium" is a diminutive, a 'little Trypherus'.

Discussion
The two species are very similar by the general morphology and coloration: both exhibit yellow and black regions on the head, a transversal band on the pronotum and a triangular patch on the elytra. However, the species can easily be distinguished by the external morphology of the last tergites and ventrites of the males and females and by the aedeagus. Males of T. nuristanicum have tergite IX with shorter blades, with the apex of the right blade entire, and tergite X divided into two short lobes, whereas those of T. kashmiricum sp. nov. have the tergite IX with longer and broader blades, with the right blade  (Wittmer, 1956). Abbreviations: VII St = 7 th sternite; IX Tg = 9 th tergite. Scale bars: 0.5 mm.
ZUBAIR R.M. et al., Review of Trypheridium Brancucci (Coleoptera: Cantharidae) divided at the apex, and tergite X divided into two very long and asymmetrical lobes. The aedeagi of the species are rather similar yet distinguished especially by the shape of the prolongation of the tegmen, which is much wider and abruptly narrowed before the apex in T. nuristanicum, and gradually narrowed in T. kashmiricum sp. nov. The females differ especially in the shape and number of the posterior projections of sternite VII: two projections in T. nuristanicum and three in T. kashmiricum sp. nov. The ventrite VII shows slight to strong differences among the specimens examined (Fig. 9). In T. kashmiricum sp. nov., the length and width of the lateral lobes vary and the distal margin of the median lobe may be truncate or notched (Fig. 9A-B). In T. nuristanicum, however, the differences in the shape, length, width and position of the lateral angles of the distal lobes are more remarkable (Fig. 9C-D). Four different shapes of sternite VII were observed in the four examined female paratypes from the same locality. A thorough examination of the ca 207 type specimens of T. nuristanicum might confi rm if that structure is in fact broadly variable or if the type series of T. nuristanicum is composed of more than one species.
The strange morphology of Trypherus nuristanicus had already been pointed out by Magis & Wittmer (1974) and Brancucci (1980), and Brancucci (1985a) justifi ed the elevation of the genus Trypheridium for that species based on morphological characters and on their widely disjunct distribution. Superfi cially, Trypheridium is very similar to Trypherus. Both genera are distinguished from the other Palaearctic and Oriental Ichthyurini genera Ichthyurus Westwood, 1848 and Microichthyurus Pic, 1919 especially in the smaller eyes, the antennal insertions separated (not juxtaposed), the pronotum more transverse, not remarkably convex, the males with sternite VIII not split into long prolongations, and tergite IX with well-developed blades directed ventrally and posteriorly (Brancucci 1983(Brancucci , 1985a. Despite the similarity between Trypherus and Trypheridium, according to Brancucci (1985a) the latter differs by their "aberrant" sexual characters, such as the blades of tergite IX in males, which are very elongate, the aedeagus without left paramere (right, according to Brancucci) and the median lobe membranous with a terminal opening (rather than preapical), and sternite VII of females elongate, mostly concealing the sternite VIII (which is uncommon in Trypherus). In addition, the males of species of Trypherus usually have conspicuous modifi cations on the mid legs, which can be short teeth in the trochanter (one species), the femora slightly to strongly swollen and/or curved (most species) and the tibiae sometimes broader in the apex. The mid legs of both species of Trypheridium are slender, without modifi cations.