Mecinus pascuorum group

Gosik, Rafal, Skuhrovec, Jiri, Caldara, Roberto & Tosevski, Ivo, 2020, Immature stages of Palearctic Mecinus species (Coleoptera, Curculionidae, Curculioninae): morphological characters diagnostic at genus and species levels, ZooKeys 939, pp. 87-165 : 87

Mecinus pascuorum group

Differential diagnosis.

Larva. (1) cuticle of the body tuberculate; (2) pedal lobes prominent, clearly distinct; (3) abdominal segment X reduced to three anal lobes; (4) thoracic spiracle unicameral; (5) abdominal setae various in length, progressively longer from abdominal segment I to VIII; (6) abdominal segments I-VIII with four pds and two ss; (7) head white, rounded; (8) frontal suture weakly visible; (9) endocarina 4/5 length of frons; (10) des4 short; (11) presence of fs1; (12) absence of fs2; (13) fs3 very short; (14) head with one stemma; (15) absence of cls1; (16) labial palpi one-segmented; (17) premental sclerite cup-like, posterior extension with short, dull apex; (18) surface of postlabium smooth.

Pupa. (1) body stout, rather short; (2) urogomphi short; (3) rostrum moderately slender; (4) setae various in length; (5) head with one os; (6) rostrum with one or two rs; (7) pronotum with two as, without or with one ds, two ls, three pls; (8) meso- and metanotum with two setae; (9) abdominal segments I-VII with two or three setae dorsally and three minute setae ventrally.

Remarks and comparative notes.

The adults of this assemblage of several taxa are mostly very similar to each other, but, lacking synapomorphies, they were treated by Caldara et al. (2013) as a “complex” of species. Overall, they are characterised by small size (length shorter than 2.5 mm), usually with short, oval elytra, and with integument, at least in part, reddish. The larvae also have a combination of characters that distinguish them from those of the other groups, although with no clear autapomorphies. In contrast, the pupae are unique in having abdominal segments I-VII with 2-3 setae dorsally and three minute setae ventrally. Therefore, we can consider these species as an informal group like the other species groups.