Acalles vorsti , Schütte, André & Stüben, Peter E., 2015

Schütte, André & Stüben, Peter E., 2015, Molecular systematics and morphological identification of the cryptic species of the genus Acalles Schoenherr, 1825, with descriptions of new species (Coleoptera: Curculionidae: Cryptorhynchin, Zootaxa 3915 (1), pp. 1-51: 25-26

publication ID

publication LSID

persistent identifier

treatment provided by


scientific name

Acalles vorsti

sp. nov.

Acalles vorsti  sp. nov.

1. Elytra short and oval; widest at or directly in front of the middle (fig. 8, 9). 2. Pronotum widest at the end of the first third in front of the elytral base. 3. Apex of the aedeagus (ventral view) spoon-like, laterally subapically more curved (fig. 10). Acalles breiti 

1 *. Elytra obovate; widest directly behind the base (digit 27).

2. Pronotum widest in the middle or immediately behind the middle; stronger rounded laterally towards the foremargin than to the elytral base.

3 *. Apex of the aedeagus (ventral view) tapered; laterally subapically rectilinear (digit 27).

The internal sac structures of the aedeagus of the new species is very similar to the aedeagus of the closely related species Acalles breiti  (fig 10 vs. digit 27), but based on our knowledge of more than 1000 sequences of flightless Cryptorhynchinae  the CO 1 p-distance (uncorrected) of 8.4 to 8.6 % between A. vorsti  and A. breiti  lies above the barcoding gap.

Description. Length. 2.1–2.9 mm (without rostrum).

Head & Rostrum. Eyes small, slightly oval. Rostrum of males deeply punctate, red brown; length-width ratio of 3.5 between insertion of antennae; closely covered with beige scales in front of base, finely punctate at middle, wider, deeply punctate on sides; rostrum of females longer; length-width ratio of 3.8 between insertion of antennae and more shiny (digit 29). Last three antennal segments as long as broad, last segment spherical, other segments trapezoidal, clearly separated from very large, wide club; first two segments elongate.

Pronotum. Slightly broader than long; widest at end of first third in front of elytral base; regularly rounded laterally towards fore-margin and towards base; with depression at sides directly behind fore-margin. In lateral view contour-line of pronotum and of elytra clearly separated: pronotum in front of fore-margin flattened, more curved towards base. In dorsal view without keels or humps on flat disc of the pronotum. Integument beige, circular non-overlapping scales, cuticle visible between scales. Small pits of pronotum fine and closely separated. Pronotum with some short, bright, slanted bristles.

Elytra. Length-width ratio of 1.20 (holotype); oval, broadest at or directly in front of middle. In lateral view contour-line of elytra flat behind base of declivity forming arc towards apex. Integument of elytra not rich in contrast and consists, like scales of pronotum, of brown and beige circular scales. Striae narrower than intervals, with elongate, shallow, closely packed punctures. Clubbed bristles on sutural stripe and intervals at most 1.5 times as long as wide, their separation ranging from two to five times length of a bristle.

Legs. Long; margin of front femur reaching fore-margin of eyes, hind femur ending just in front of elytral apex. Covered with predominantly beige, non-overlapping and very long, close-lying bristles.

Venter. Abdomen with 2 nd sternite clearly shorter than 1 st sternite, slightly longer than sternites 3 and 4 together. Covered with some very long, separate standing bristles.

Female genital. Ovipositor, spiculum ventrale, fig. 11

Aedeagus. Apex of the aedeagus (ventral view) spoon-like, laterally subapically more curved, fig. 10

Etymology. I dedicate the new species to my colleague Oscar Vorst ( The Netherlands: Utrecht).

Ecology. The specimens of the type series were sieved under Quercus  .

Distribution. So far this species is only known from the type locality near Sóller (Son Coll) on the northwest side of the Balearic island of Mallorca: fig. 12.