Litostilbus Guillebeau, 1894

Gimmel, Matthew L., 2023, Distribution and Synonymy in New World Litostilbus Guillebeau (Coleoptera: Cucujoidea: Phalacridae), The Coleopterists Bulletin 77 (2), pp. 189-193 : 189-190

Litostilbus Guillebeau, 1894

Litostilbus Guillebeau 1894: 283 . Type species: Sphaeridium testaceum Fabricius, 1792 , by original designation.

Pseudolitochrus Liubarsky 1993: 16 . Type species: Phalacrus festivus Motschulsky, 1858 , by original designation. Synonymy by Gimmel (2013: 46).

Diagnosis. Adults of the genus Litostilbus are readily recognized among all other Phalacridae by the combination of a large scutellar shield (width at base greater than greatest diameter of eye in dorsal view), presence of a long ctenidium on the outer edge of the protibia ( Fig. 4 , arrow), and metatarsomere 1 longer than metatarsomere 2. Additionally, the dorsal surface has sparse, very short, recumbent microsetae, the elytra have irregular transverse strigae and a distinct diffraction grating, and each elytron has one to three engraved striae (i.e., striae that reflect light in a thin line at a steep angle, as opposed to a shallow groove), including the sutural stria.

Remarks. Gimmel (2013: 47) reported the existence of “at least one undescribed species from Central and South America”; however, this comment was based on observation of the extensive variation in coloration and elytral striation described below for L. testaceus and with further study has proved incorrect.

Figures

Figs. 1–5. Litostilbus testaceus, specimen from Pinellas Co., Florida, USA (FSCA).1) Dorsal habitus; 2) Lateral habitus; 3) Ventral habitus; 4) Closeup of protibia, arrow indicates protibial ctenidium; 5) Frontal. Images by Lucie Gimmel.