Ctonoxylon torquatum, Jordal, 2024

Jordal, Bjarte H., 2024, An integrated taxonomic revision of Ctonoxylon (Coleoptera, Curculionidae, Scolytinae) reveals new Malagasy species originating from multiple recent colonisations of the island, ZooKeys 1203, pp. 95-130 : 95-130

Ctonoxylon torquatum sp. nov.

Figs 41 , 44 , 47

Type material.

Holotype, Madagascar, Toliara, Sept Lacs [GIS: 23.527, 44.155], MGF 076 , 02. 03. 2002, B. Fischer, leg. [ CAS] . Paratypes, same data as holotype [ CAS (2), NHMW (2), MSUC (2), ZMUB (2)] .

Diagnosis.

Protibiae with shallow anterior groove of depth <1 / 3 width of the tibia; anterior margin of prothorax from coxa to top with an indented row of deep circular pits; scutellar shield and elytral suture with soft white setae; elytral apex with pair of tubercles.

Description.

Body length 1.9–2.5 mm, 2.0–2.1 × as long as broad; mature colour dark brown. Frons flattened from just below upper level of eyes to epistoma, surface finely punctured and granulated, central third smooth and impunctate; vestiture of fine short setae, nearly glabrous in middle. Eyes divided, each part separated by 2 / 3 the size of upper half. Antennal funiculus 7 - segmented; club with two asymmetrically and strongly procurved sutures, suture one partly grooved, club segments 1 and 2 each with a dark septum clearly indicated. Pronotum asperate on central half of anterior three quarters, two front teeth separated by little less than width of a tooth, located at the margin, one additional pair of larger teeth a little behind the front teeth. Lateral anterior margin of prothorax with indented row of deep circular pits running from pronotal teeth to coxa; propleural pit longitudinally elongated, located between coxa and lateral costa on pronotum. Scutellar shield slightly detached from elytra, slightly sunken, broader than long, with fine white setae. Elytral striae impressed, punctures round or subquadrate, spaced by less than their diameter; interstriae raised, profile rounded, cuticle rough, vestiture consisting of confused, dense, bristle-like setae, with densely placed soft white setae along a straight elytral suture; apex with a pair of small tubercles. Metanepisternum with short plumose setae; metaventrite with scattered simple setae. Protibiae on anterior face with shallow groove for reception of tarsus, ~ 1 / 3 as deep as width of tibia.

Etymology.

The Latin adjective torquatus in its neuter form, meaning adorned with a collar, referring to the row of deep pits along the front margin of the prothorax.

Distribution and biology.

Only known from a long series of specimens collected at the type locality in the dry forest of south-western Madagascar.

Figures

Figures 39–47. Dorsal, lateral, and front views of 39, 42, 45 Ctonoxylon camerunum female 40, 43, 46 Ctonoxylon cornutum female holotype, and 41, 44, 47 Ctonoxylon torquatum sp. nov. female holotype.