Scolytodes Ferrari

Jordal, Bjarte H., 2013, New species and records of Scolytodes (Coleoptera, Curculionidae: Scolytinae) from South America, Zootaxa 3721 (6), pp. 529-551 : 530

Scolytodes Ferrari

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Scolytodes is generally recognized by the sharply carinate lateral edges of the pronotum, separated procoxae, with protibiae having two large lateral teeth near its distal end that appear unsocketed (socketed teeth embedded in cuticle, see fig. 8 in Jordal, 1998b), the eyes are entire, and the antennal funicle is 5- or 6-segmented (including the pedicel, see Wood, 1982).

Variation in characters important for distinguishing groups of species in the genus has been addressed elsewhere (Jordal, 1998b). The most important characters for navigating the first couplets in Wood's (2007) identification key include protibial features, pronotal surface and the shape and length of interstriae 10. The protibiae in the atratus group are very broad, with cuticle extending between the lateral teeth and with a strong laterally bent mucro. In most other lineages the protibiae are narrow, with a short straight mucro. Some species with narrow protibiae also have a distinct socketed tooth mesal to the base of the two lateral main teeth (Jordal, 1998b: fig. 8). Species in the atratus group have a very broad prosternal process which separates the procoxae by more than the width of one coxa. The width of the prosternal process is little used as a taxonomic character in bark beetles, but has yielded valuable information in this genus (Jordal, 1998b: fig. 9).

The pronotum may be entirely smooth, or strongly asperate on the anterior part, the asperities entirely or partly replacing pronotal punctures. This feature may be sexually dimorphic, particularly within the atratus group where males are generally more asperate than females. One unique feature for Scolytodes is the distinct pattern of erect pronotal setae along the anterior margin and each hind corner, and sometimes also just mesal to its lateral margin (e.g. Jordal, 1998b: fig 5d). Descriptions here use e.g. the notation '(4–2–2)' to illustrate the number and placement of these setae (anterior margin–lateral margin–hind corners). Elytral interstria 10 is a characteristic feature of Scolytodes by its sharply elevated shape; it reaches at least the level of metacoxae, but is often much longer (see Jordal 1998b: fig 5a vs. b).

Some little-used characters may prove informative in a phylogenetic context and are included in the descriptions. Setae found on the ventral sclerites can vary from long and simple to short and scale-like; many are bi- or trifid, or even plumose. In the head region, a new feature is discovered for some Scolytodes , an obliquely impressed submentum area. Unless specified in the description, the normal condition is a flat submentum at the same level as the gena. In some species in the atratus group, the submentum is tilted and impressed in a fashion similar to xyleborines, although to a much lesser degree.

In the description of new species, there is a guide to the identification key to South American Scolytodes (Wood, 2007) . In many cases that key is of little help because the character states referred to are not unique–or worse, are not correct–for some of the species. This means that the correct path through the key may include one or several contradictions. Hence, all descriptions of potential close relatives in Wood’s monograph must be read in their entirety to enable identification or affiliation with close relatives.