Stenomorpha furcata

Smith, Aaron D., Miller, Kelly B. & Wheeler, Quentin D., 2011, A new species of Stenomorpha Solier (Coleoptera: Tenebrionidae: Pimeliinae: Asidini) from Cuatrociénegas, Mexico with a key to the furcata species group, Zootaxa 2909, pp. 27-37 : 29

furcata species group

Diagnosis. The furcata species group is placed within Stenomorpha based on the following shared characters: Ligula large and tumid, width one-fifth or more mentum width, length approximately 3X width, strongly curved and raised above anterior margin of mentum ( Fig.14 ). Scutellum gradually raised above scutum; mesonotum with two deep rounded paramedial depressions. Protibial spurs subequal. Mesotrochantin large and exposed. Apical segment of maxillary palps enlarged, sexually dimorphic, securiform in females, larger and isotriangular or scalene in males ( Fig.14 ).

Members of the furcata species group are distinguished from other Stenomorpha species by a unique combination of the following characters: Mentum transverse, sub-trapezoidal, nearly filling buccal cavity. Submentum distinctly projecting into buccal cavity; width approximately four-fifths that of buccal cavity, laterally exposing a quadrate space before postgena. Pronotum gibbose (viewed laterally); prosternal process declivous behind procoxae. Elytron with marginal costa, bifurcate or not, and one non-bifurcated discal costa. Protibia with outer apical margin unarmed or forming a small indistinct spine with a ring of socketed spiniform setae surrounding the entire margin ( Fig. 9 ).

The furcata group can also be separated from the remainder of the species currently in Asidina Casey by the gibbose pronotum (viewed laterally) and lack of prominent protibial spines. The sub-trapezoidal mentum and wide submentum (exposing only small quadrate pockets between the submentum and postgenal processes) exhibited in the furcata group are also present in Asidina confluens (LeConte) and A. semilaevis (Horn) , as opposed to the more oval mentum and narrower submentum (exposing large rounded spaces between the submentum and postgenal processes) present in Asidina parallela (LeConte) and A. rugicollis Triplehorn and Brown. Stethasida Casey species are separated from the furcata group based on their raised prosternal process (declivous in the furcata group species) and Trichiasida Casey species are separated by their large protibial spines.

Figures

FIGURES 13 – 15. Stenomorpha roosevelti: 13) Recurved setae on elytron; 14) Mentum and apical segment of maxillary palp; 15) Protarsi, venter.

FIGURES 9 – 10. Protibia, outer apical margin: 9) Stenomorpha wickhami; 10) Asidina parallela.