Premnobius ambitiosus

Premnobius ambitiosus (Schaufuss)

Fig. 5 C,D

Xyleborus ambitiosus Schaufuss, 1897: 109.

Premnobius ambitiosus (Schaufuss): Eggers 1922: 173.

Premnobius cavipennis spinosus Hagedorn, 1908: 376. Synonymy: Eggers 1922: 173.

Premnobius brasiliensis Nunberg, 1960: 490. Synonymy: Schedl 1960: 107.

Similar species. This is the largest and most robust species found in the Neotropical region. It most closely resembles P. cavipennis, but is much larger.

Diagnosis. Length 3.0– 3.3 mm, 3.0 × as long as wide (Wood 2007: 368). Color dark reddish brown, body covered with fine, short pubescence. Frons granulate-punctate, with a faint longitudinal carina extending to the epistoma. Anterior margin of pronotum rounded, without marginal teeth. Pronotal summit slightly before middle, anterior asperities small and irregular. Elytral disc with interstriae 4 × as wide as striae, striae not impressed. Vestiture of recumbent strial setae, with mostly uniseriate strial setae, these becoming longer and stouter posteriorly. Declivity occupying about 40% of elytral length, the basal portion of first interstriae depressed; raised posterolateral crest beginning on interstria 2 and continuing to apex. Declivital face weakly concave, with large confused strial and interstrial punctures, pubescence absent. Crest with irregular denticles throughout. Longest near middle, toothlike, slightly incurved; a much smaller tooth at base of declivity on interstria 3. Marginal teeth and denticles on crest shorter than surrounding pubescence.

Distribution: Introduced from the Afrotropical region. The earliest collection records in Colombia and Brazil are from 1958. Widely distributed in South America and Panama to south-central Brazil (Fig. 12 B). This is a large and distinctive species and it is surprising that there are so few records.