Tyrannasorus Ratcliffe and Ocampo

Ratcliffe, Brett C. & Ocampo, Federico C., 2001, Tyrannasorus rex Ratcliffe And Ocampo, A New Genus And Species Of Miocene Hybosorid In Amber From The Dominican Republic (Coleoptera: Scarabaeoidea: Hybosoridae), The Coleopterists Bulletin 55 (3), pp. 351-355 : 351-352

Tyrannasorus Ratcliffe and Ocampo , new genus

Type Species. Tyrannasorus rex Ratcliffe and Ocampo.

Description. Body form ( Fig. 1 ) convex, subglobose. Color reddish brown. Head: Frons irregularly punctate, lateral margins narrowly reflexed. Clypeus with anterior margin truncate. Labrum protruding beyond clypeus, weakly trapezoidal, wider at apex, with series of setae either side of middle. Antennae ( Figs. 3 , 6 ) with 9 segments; basal segment apically expanded, with long erect setae on anterior side, second segment broader than long, third segment about twice as long as wide, fourth as long as wide, fifth and sixth wider than long, fifth with 2 setae; club 3­segmented with basal segment weakly hollowed to receive second and some of third segment; all segments tomentose. Pronotum: Surface weakly convex. Anterior margin sinuate; anterior angles strongly produced, subacutely rounded ( Fig. 3 ); lateral margins rounded, widest just behind middle; posterior angles broadly rounded; posterior margin sinuate, produced backward at middle; anterior and lateral margins with marginal bead. Scutellum: Surface smooth. Elytra: Shape convex, subglobose. Lateral margins rounded, widest at middle, and with marginal bead. Legs: Claws on all legs simple. Meso­ and metatibiae ( Figs. 8–9 ) with transverse ridge near middle of external surface, ridge with erect setae on margin; apex with 2 spurs, external spur much longer than first segment of respective tarsus, median spur shorter than first tarsal segment; apex of tibiae truncate, dilated, with large, rounded, flattened lobe on external edge, lobe with crown of setae.

Remarks. The genus Tyrannasorus is unique among other hybosorids from the West Indies because its has 9­segmented antennae whereas all the other genera have 10­segmented antennae. The genus Tyrannasorus is similar to the genera Coilodes and Apalonychus in the following characters: body form convex, subglobose; color reddish brown; apex of tibiae truncate, dilated, and with a large, rounded, flattened lobe on its external edge, lobe with terminal crown of setae. Coilodes species are different from Tyrannasorus species because they have a cup­shaped antennal club (only weakly concave in Tyrannasorus ), a labrum wider at its base, and the anterior margin of pronotum not sinuate. Apalonychus species are different from Tyrannasorus species because they have the club of the antenna much more elongated, a labrum wider at its base, the anterior margin of pronotum not sinuate, and eyes subglobose and clearly visible in dorsal view (eyes not clearly visible in dorsal view for Tyrannasorus ).

Etymology. The loosely formed stem of this name, tyranna, is from the Latin tyrannus, indicating ‘‘master’’ or ‘‘tyrannical.’’ The suffix sorus is Latin meaning ‘‘hump’’ or ‘‘pile’’, and it is also the suffix for the family name of Hybosoridae and its type genus, Hybosorus . Hence, we have the tyrannical hump, suggesting the possible state of ‘‘mind’’ (ganglion?) of this small, humped beetle getting hopelessly stuck in a blob of sticky Hymenaea sap. The genus is masculine in gender.

Figures

Figs. 1–4. Holotype of T. rex embedded in amber. 1) Dorsal view; 2) oblique ventral view; 3) dorsal view of head and pronotum; note especially antenna, clypeus, and mandibles; eyes are not dorsally visible; 4) anterior view of head and proleg.

Figs. 5–9. Line drawings of T. rex. 5) Dorsal view of head and pronotum; 6) dorsal view of left antenna; 7) dorsal view of left proleg; 8) ventral view of left middle leg; 9) ventral view of left posterior leg.