Scolytus stepheni sp. n. - a new species of bark-beetle (Coleoptera, Curculionidae, Scolytinae) from Northern India with a key to Indian Scolytus Geoffroy, 1762 species

Abstract A new species of bark-beetle from Kashmir, Scolytus stepheni sp. n., dedicated to the late Professor Emeritus Stephen Lane Wood, is described and figured. Key to Indian Scolytus Geoffroy, 1762 species is provided.


Introduction
In the recently published monograph by Maiti and Saha (2009) only three species from the genus Scolytus, namely S. major Stebbing, 1903, S. kashmirensis Schedl, 1957and S. chelogaster Schedl, 1957 are mentioned as occurring in India. Schedl's paper about Indian bark and timber beetles (1957) also lists S. nitidus Schedl, 1936, S. scolytus (Fabricius, 1775 from India and S. rugulosus (Müller, 1818) var. baluchistani, n.var. andS. amygdali Guérin, 1847 as Scolytines native to the Indian subcontinent. As we have demonstrated, S. scolytus was wrongly recorded from India and in fact the records of this species refer to the newly described species S. stepheni sp. n. Although S. rugulosus and S. amygdali were recorded from Pakistan, we found it desirable to include these species into the key to the Indian Scolytus species provided below.
Th e two specimens considered in the current paper were labeled by K. Schedl and cited by him (Schedl 1957) as Scolytus scolytus (Fabricius, 1775), despite clearly diff erent frontal vestiture, and abdominal armature in the male. Th e species was mentioned by Beeson (1941) as Scolytus himal-ulmi but without any description (Schedl 1957 Description. Holotype. Male. Body length 4.6 mm, 2.1 times as long as wide Head black, faintly shining. Frons fl at, longitudinally aciculate, its surface with fi ne pale hair-like setae; lateral parts of frons near eyes covered by denser and longer hair-like setae. Vertex deeply punctured. Antennae brown, antennal club nearly elliptical, its surface with short golden hair-like setae.
Pronotum reddish-brown, nearly as long as wide, wider than its length. Sides of pronotum parallel for most of their length; gently rounded towards pronotal apex; constriction in apical portion of pronotum only weakly developed. Surface punctured, with punctures larger in frontal portion than in center of pronotal disk. Anterolateral angles of pronotum bear sparse long light hair-like setae.
Elytra reddish-brown, faintly shining, as wide as pronotal base and 1.5 times as long as pronotum. Elytral base slightly elevated; scutellum triangular; impression near scutellum only poorly developed. Striae slightly impressed, strial punctures circular, closely placed; interstriae fl at with smaller punctures than in striae and less closely placed. Subapical elytral constriction distinct. Prior to apex (in subapical constricted part) elytra with faint impression with irregularly set punctures. Pale sparse erect hairlike setae only visible near elytral apex.
Abdomen reddish-brown, dull. First and second sternites darker than third, fourth and fi fth sternites . All sternites with densely set round punctures. Posterior margins of third and fourth sternites with minute median tubercles. Lateral sides of fi fth sternite clearly thickened on posterior margin and with carinate apex. Two strong tubercles developed on fi fth sternite, their apices with brushes of densely set golden hair-like setae, the brushes not confl uent at glabrous apical margin of abdomen.
Legs reddish-brown, covered by golden hair-like setae.
Female. Similar to male but can be distinguished by the larger size (4.9 mm), more convex frons and by less strongly developed "callous-like elevations" at 5-th sternite without hair-like brushes of setae.
Diagnosis. Th e new species is more closely related to S. dahuricus (Fig. 2) than to any other Indian Scolytus species. From S. dahuricus it is distinguished by the broader  body, by the fl at elytral interstriae without any transverse rugosities or furrows. In the new species, the hair-like setae at the lateral parts of the frons are shorter and sparser. Th e clearest diff erence from S. dahuricus is seen in the form of the tubercles on the fi fth abdominal segment and in their vestiture. In S. dahuricus long hair-like setae, forming tufts attain the apical margin of the fi fth sternite where the two tufts are confl uent, and intergrade. Th e tubercles of the fi fth sternite in S. dahuricus are spatuliform, blade-like whereas in S. stepheni these tubercles have the form of truncated cones. Th e tubercles in S. stepheni are set closer to the median line of the fi fth sternite, whereas in S. dahuricus the tubercles occupy the whole space from center to lateral sides of sternite. Th e distance from the tubercle apices to the posterior margin of the fi fth sternite is significantly greater in S. stepheni compared to the relevant distance in S. dahuricus.
Etymology. Professor Stephen Lane Wood worked extensively on collections of Scolytinae preserved in Indian museums, and described a number of new Scolytinae species from India. In this paper we describe one more new bark-beetle species from India kept in the Natural History Museum in Vienna (NHMW) and dedicate this species to the late Professor Stephen Lane Wood.

Discussion
Th e new species is closely related to Scolytus dahuricus Chapuis, 1869, but diff ers in many details. Body length 4.6 mm, 2.1 times as long as wide (in S. dahuricus body is 2.3-2.6 as long as wide). Other features to distinguish new species from S. dahuricus are given in the section Description and Diagnosis. To help researchers to deal with Indian Scolytus species we add below the key to species that is absent in Maiti and Saha (2009) monograph. Tubercle of the second abdominal sternite is small, conical and sharp; this tubercle is set nearby the posterior margin of the second sternite, but not at the posterior margin itself. Th is tubercle is slightly larger in male than in female. Second abdominal sternite strongly ascending. Pronotum with small and widely separated punctures essentially as in European S. mali. Scutellum and scutellar impression are covered by white elongate hair-like setae in inabraded specimens. Punctures of elytral striae are large, round and shallow, only slightly larger compared to interstrial punctures which are also round and shallow. Frons in male is fl attened, aciculated, each side of the frons has a row of long golden hair-like setae sloping from vertex to epistoma, each seta exceeding half of the frontal width. In females frons is in rather dense long hair-like setae throughout the whole surface, the individual hair-like setae are less than 1/3 of the frontal width. Posterior margin of the 2nd abdominal sternite is modifi ed. In females it is carrying two sharp denticles set one fi fth of sternite width apart from sternite lateral margin and in males there are two strong conical denticles set at the posterior sternite margin at one fouth of sternite width apart from it lateral margin. Central portion of second sternite posterior suture is thickened in females and in males this portion of sternite forms a triangular elevation projecting backwards and overhanging the third sternite. Besides, in males there is a button-like tubercle in the middle of the anterior third of second sternite; in females this tubercle is larger and is laterally compressed. Puncturation of the central part of the pronotum is minute, essentially as in S. mali. Anterior 2/3 of pronotum is black, posterior part of the pronotum and elytra completely are light brown in colour. Scutellum set deeply in scutellar impression and is covered with elongated scale-like white setae. Elytral strial and interstrial punctures are large, round and shallow, nearly equal in size. Posterior portion of elytra, base of the second abdominal sternite, fi fth abdominal sternite and hind legs are covered by the very long hair-like setae not forming tufts anywhere. Male frons at sides with two parallel rows of long setae, individual setae equal to one half of the frontal width; there are no bundles of long setae at interior margin of the eyes. In female frons is covered by sparse erect hair-like setae throughout all frontal surface. Body length 3.6 in the male and 4.1 mm in the female ........... S. kashmirensis Schedl, 1957