Scolytodes stramineus Jordal and Smith, 2020

Jordal, Bjarte H. & Smith, Sarah M., 2020, Scolytodes Ferrari (Coleoptera, Scolytinae) from Ecuador: 40 new species, and a molecular phylogenetic guide to infer species differences, Zootaxa 4813 (1), pp. 1-67 : 29-30

Scolytodes stramineus Jordal and Smith , sp. nov.

urn:lsid:zoobank.org:act:2DDC9E53-3433-4A88-AB6B-ACE998D3DD66

( Figs 39, 42, 45 )

Type material. Holotype, female: Ecuador: Napo prov., Tiputini biodiversity station, 220–250 m, October 1998, 00° 37’55’’S, 76° 08’39’’W, T.L. Erwin et al collectors . Allotype, male: same data as HT. Paratypes: same data as HT (3). Holotype and allotype temporarily held in trust at USNM for MECN, and one paratype each in QCAZ, ZMBN and MSUC .

Diagnosis. Interstriae 10 sharply elevated to near apex. Protibiae without additional mesal tooth. Related to a group of species which were previously believed to be unrelated, all with lightly asperate pronotum having small punctures reaching anterior margin, the elytra smooth with confused interstrial punctures, protibiae with tooth 1 and 2 equal with three additional small spines towards the tibial base, meso- and metatibiae with 6–7 socketed, lateral denticles on more than distal half, and a concave female frons with long setae from well above upper level of eyes and along lateral margins. Females of the new species are distinguished from all related species by having fine interstrial setae, and 10–16 long erect setae along the anterior margin of the pronotum. Further from S. pseudoacuminatus (Schedl, 1935) and S. nitellus (Schedl, 1954) the new species differs by the lack of an additional mesal tooth on the posterior face of protibiae; from S. gracilis Schedl, 1976 and S. frontoglabratus (Schedl, 1935) by the lack of a smooth, impunctate (and laterally carinate) lower central area of the female frons, and from S. amoenus Wood, 1967 by the less impressed striae and longer setae in the female frons that also lack any glossy impunctate area.

Description female. Length 2.7–3.0 mm, 2.3–2.4 × as long as wide; colour light brown, with fields of darker brown. Head. Eyes lightly emarginated, separated above by 3.0–3.2 × their width. Frons concavely impressed between eyes from vertex to epistoma, obscurely carinate near lateral margins on lower third; vestiture consisting of long, golden setae arising from vertex and most of the impressed area, slightly curved towards the centre, shorter and more sparse vestiture towards centre. Antennal club pilose, no sutures. Funiculus 6-segmented. Pronotum reticulated, subshining, with small punctures spaced by their diameter, reaching anterior margin; fine asperities present on anterior third. Largely glabrous but with a row of long, erect setae along the anterior margin and four additional setae in middle and posterior lateral areas (16-2-2). Elytra smooth and shiny, striae not impressed, obscure, punc- tures small, shallow, spaced in a row by 2 × their diameter; interstriae 4–6 × wider than striae, punctures slightly smaller, entirely confused. Vestiture consisting of about 50 very fine, erect setae, on interstriae 1 and 3–9, mainly on posterior half. Legs. Procoxae separated by 0.2–0.4 × the width of one procoxa. Mesocoxae separated by 0.6–0.7 × the width of a procoxa. Protibiae narrow, distal teeth 1 and 2 of equal length, three additional small teeth along edge towards tibial base; protibial mucro straight. Meso- and metatibiae with 7 lateral, socketed teeth on distal two-thirds and half, respectively. Ventral vestiture. Setae on mesanepisternum trifid, on metanepisternum and metasternum simple.

Male. Similar to females except frons convex, largely glabrous, finely punctured, reticulated and dull. Elytra nearly glabrous, with only a few erect setae present on posterior part of interstriae 9. The pronotum has fewer erect setae (2-2-2), entirely lacking erect setae on median anterior margin. Despite the peculiar dimorphism we believe these males are conspecific because they have the same size, colour and shine, similar reticulation, size of asperities and punctures on the pronotum and elytra, and identical shapes of the legs.

Key ( Wood 2007). Keys to couplet 41, with no further match. Allowing for some minor mismatches one may reach couplet 49, S. amoenus , but differs as noted in the diagnosis.

Etymology. The Latin name stramineus is a masculine nominative adjective (attributive noun), meaning straw, referring to the row of long erect setae along the anterior margin of the female pronotum.

Biology and distribution. Only known from two lowland Ecuadorian Amazon localities. Specimens were collected by fogging several different trees. In two cases, males and females were found in the same sample.

Figures

FIGURES 37–45. Dorsal, lateral and frontal views of a female specimen of Scolytodes unipunctatus (37, 40, 43), the female holotype of Scolytodes abbreviatus (38, 41, 44), and Scolytodes stramineus (39, 42, 45).