Loganius Chapuis, 1869

Smith, Sarah M. & Cognato, Anthony I., 2013, A New Species of Scolytus Geoffroy, 1762 and Taxonomic Changes Regarding Neotropical Scolytini (Coleoptera: Curculionidae: Scolytinae), The Coleopterists Bulletin 67 (4), pp. 547-556 : 551-552

Loganius Chapuis, 1869 new status ( Figs. 4–7 , 10–11 )

Chapuis 1869: 52. Type species, Loganius flavicornis Chapuis, 1869 , by monotypy.

Diagnosis. Loganius can be distinguished from other Scolytini genera by the presence of three concentric procurved sutures on the antennal club ( Figs. 5, 7 ), funicular segments 2–7 which are ventrally produced and wider than long ( Figs. 5, 7 ), and the presence of 1–2 supplemental denticles on the apical margin of the meso- and metathoracic tibiae ( Fig. 6 ).

Redescription. Head visible from above, occasionally sexually dimorphic. Frons usually concave from epistoma to inner apices of eyes, moderately to densely covered with long, erect setae. Female frons may be identical to that of male, less strongly concave and covered in fewer setae or flattened and glabrous. Epistoma entire, unarmed. Eye elongate, ovoid, entire to weakly emarginated and finely faceted. Antennal scape short and narrowly rounded distally, funicle 1.5 times longer than scape. Funicular segment 1 ovoid and laterally compressed. Funicular segments 2–7 ventrally produced and 1.5–4.0 times wider than long. Segments 2–3 sigmoid in some species. Each funicular segment with long tufts of setae on ventral margin, tufts 1.5–2.0 times longer than funicle. Funicular segment 7 with short tuft of setae on dorsal margin that is 1.5 times longer than segment 7. Antennal club flattened, ovoid, with 3 concentric, weakly to strongy procurved sutures marked by rows of setae; club base corneous.

Pronotum large, lateral margins marked by fine, raised line. Pronotal disc finely punctate, punctures larger, coarser toward margins, surface typically appearing smooth but faintly strigate in a few species; median line impunctate. Pronotal base weakly recurved. Meso- and metathoracic tibia armed by 1–2 supplemental denticles on apical margin.

Scutellum small, about as long as wide, smooth, flush with level of elytra. Elytra without scutellar notch; striate. Discal surface rugose, striae weakly to moderately impressed. Declivital striae moderately to strongly impressed and rugose, interstriae often carinate, rugose and granulate. Elytral apex entire, slightly acuminate and weakly serrate. Interstrial setae consisting of uniseriate semi-recumbent scales. Abdominal profile gradually ascending to meet elytra. Profile of elytra sloping ventrally from base to apex.

Distribution. Most Loganius species occur in Mexico and Central America and one species occurs in South America.

Biology. All species occur on Euphorbiaceae .

Comments. Chapuis’ description for Loganius clearly defines the genus: “Antennarum maris articuli 2-7-appendiculati, clava suturis concentricis ornata. Tarsorum articuli 1 et 2 aequales, 3 subdilatatus” which translates as “antennal segments 2–7 articulate, the club decorated with concentric sutures. Tarsal segments 1 and 2 equal length, 3 subdilated” (S. M. Smith translated). The included species are the only species in the tribe that contain more than one suture on the antennal club (3) and which form concentric rings.

Loganius exhibits very little sexual dimorphism in external characters. Determination of the sex of specimens requires examination of the shape of abdominal tergites 7 and 8 or dissection.

Figures

Figs. 1–7. Diagnostic characters of Ceratolepis and Loganius species. 1) C. jucunda, antennal club; 2) C. jucunda, frons; 3) C. jucunda, meso- and metathoracic tibia; 4) L. flavicornis, antennal club; 5) L. flavicornis, frons; 6) L. flavicornis, meso- and metathoracic tibia; 7) L. flavicornis, antennal funicle and club (from Hagedorn 1910).

Figs. 8–11. Ceratolepis and Loganius, habitus. 8) C. jucunda, lateral view; 9) C. jucunda, dorsal view;