Olibroporus Casey, 1890

Gimmel, Matthew L., 2017, Taxonomic Notes onOlibroporusCasey andPycinusGuillebeau (Coleoptera: Phalacridae), with Diagnosis and Distribution of the Widespread SpeciesOlibroporus punctatusCasey, The Coleopterists Bulletin 71 (1), pp. 61-73 : 62-63

Olibroporus Casey, 1890 , sensu novo

Olibroporus Casey 1890: 111 . Type species: Olibroporus punctatus Casey, 1890 , fixed by monotypy.

Pycinus Guillebeau 1893: 289 . Type species: Pycinus politus Guillebeau, 1893 , fixed by subsequent designation. New synonymy.

Ochrodemus Guillebeau 1893: 293 . Type species: Ochrodemus brevitarsis Guillebeau, 1893 , fixed by monotypy. Synonymized with Pycinus by Gimmel (2013: 68).

Radinus Guillebeau 1893: 295 . Type species: Radinus latus Guillebeau, 1893 , fixed by monotypy. Synonymized with Pycinus by Gimmel (2013: 68).

Parasemus Guillebeau 1894: 281 . Type species: Parasemus grouvellei Guillebeau, 1894 , fixed by original designation. Synonymized with Olibroporus by Gimmel (2013: 61).

Euphalacrus Champion 1925: 608 . Type species: Euphalacrus crassipes Champion, 1925 , fixed by original designation. Synonymized with Pycinus by Gimmel (2013: 68).

Notes. In light of examination of additional members of Olibroporus and Pycinus from the Neotropics, I have concluded that the diagnoses of these two genera outlined in Gimmel (2013) are untenable since some specimens possess a mix of characters. Previously, I distinguished Pycinus by the presence of a ventral ridge on the mandible, lack of abdominal calli (in species so far examined), absence of strong microsculpture and presence of spectral iridescence on the elytra, extremely densely setose prosternum medially, and the more robust antennal club. Additionally, males of many species of Pycinus have an enlarged second protarsomere. However, I examined intermediate specimens ( Brazil: Nova Teutonia, 27°11′S, 52°23′W, 300–500 m, Fritz Plaumann, December 1972 [AMNH]) with strong microsculpture (and no spectral iridescence), an extremely densely setose prosternum, and a robust antennal club with an emarginate terminal antennomere. A dissected male specimen from Brazil formed the original basis for my assertion that a second species of the restricted concept of Olibroporus occurred in the New World ( Gimmel 2013: 63). The only totally consistent character observed that separates the two previous concepts of Olibroporus and Pycinus is the reduced amount of setae on the prosternum in the former. Therefore, I consider these two generic concepts to grade into one another and see no reason to arbitrarily maintain a generic distinction for O. punctatus alone. Additionally, the species in question share some highly specific character states, which are illustrated here for the first time using scanning electron microscopy. These are the presence of comb-like grooves on the elytra ( Fig. 13 ; also shared with three other genera, see Discussion below) and a unique shape of the mesoventral plate ( Fig. 15 ). An additional unique putative synapomorphy is the bidentate condition of the mandibles with a row of short blunt teeth on the dorsal cutting edge, further reinforcing the status of Olibroporus + Pycinus as a cohesive group. In the morphological phylogenetic analysis of Gimmel (2013), O. punctatus and two representatives of Pycinus were placed in a polytomy along with other members of the “ Olibroporus -group”. A molecular phylogenetic study will be necessary to accurately assess relationships within this genus.

Olibroporus sensu novo now possesses 13 valid species, all distributed in the Neotropical region, with only O. punctatus extending into the Nearctic region. A few synonyms probably exist among these names, and new species have been seen. In particular, I have examined a form that seems to belong to this genus but possesses an antennal club of five antennomeres ( Brazil; BMNH), and at least one other with a flattened body and testaceous coloration (widely distributed in the Neotropics).

Diagnosis. Adult members of this genus may be recognized by the combination of lack of a ctenidium on the outer edge of the protibia; metaventral process not protruding anterior of the mesocoxae ( Figs. 15 , 24–26 ); metaventral postcoxal lines not separated from coxal cavities ( Fig. 16 ); small scutellar shield (width at base less than diameter of eye); metatarsomere I shorter than II ( Fig. 17 ); mandible with apex bidentate (and with a dorsal row of small, blunt teeth); and elytra with a single sutural stria ( Fig. 11 ) and either strong microsculpture ( Fig. 12 ) or spectral iridescence. Another important character, which is quite difficult to observe in dry specimens with a light microscope, is the disposition of the “mesoventral plate” (central part of the mesoventrite delimited by strong sutures), whose lateral sutures bend abruptly laterad just before reaching the margin of the mesocoxal cavity and trace the anterior border of the meso- coxa, without connecting to the cavity or any suture ( Fig. 15 ; see also line drawings in Gimmel 2013: figs. 17f, 19f). This state is unique to Olibroporus . Other members of the Olibroporus - group ( Austroporus , Platyphalacrus ) also possess incomplete lateral sutures of the mesoventral plate, but these evanesce in the middle of the mesoventrite (see Gimmel 2013: figs. 16f, 18f). One character shared by all members of the genus is the transverse band of grooves near the basal margin of the elytron (see Discussion for elaboration of this structure). A complete redescription of the new concept of Olibroporus will be presented in a future contribution along with a revision of the species.

CHECKLIST OF THE SPECIES OF THE GENUS OLIBROPORUS (original genus in parentheses)

Olibroporus brevitarsis ( Guillebeau, 1893) , new combination ( Ochrodemus ) [ Venezuela]

Olibroporus crassipes ( Champion, 1925) , new combination ( Euphalacrus ) [ Brazil]

Olibroporus guatemalenus (Sharp, 1888) , new combination ( Olibrus ) [ Guatemala, Panama]

Olibroporus hemisphaericus ( Guillebeau, 1893) , new combination ( Pycinus ) [ Venezuela]

Olibroporus latipes (Sharp, 1888) , new combination ( Olibrus ) [ Panama]

Olibroporus latus ( Guillebeau, 1893) , new combination ( Radinus ) [ Venezuela]

Olibroporus microsternus (Sharp, 1888) , new combination ( Olibrus ) [ Panama]

Olibroporus politus ( Guillebeau, 1893) , new combination ( Pycinus ) [ Venezuela]

Olibroporus punctatus Casey, 1890 [ USA to Brazil]

Olibroporus rubiginosus (Sharp, 1888) , new combination ( Olibrus ) [ Guatemala, Mexico]

Olibroporus subrotundatus ( Guillebeau, 1893) , new combination ( Pycinus ) [ Venezuela]

Olibroporus tropicus ( Kirsch, 1873) , new combination ( Phalacrus ) [ Colombia]

Olibroporus vulgaris (Sharp, 1888) , new combination ( Olibrus ) [ Guatemala]

Figures

Figs. 10–17. Scanning electron micrographs of characters in Olibroporus punctatus. 10) Right eye and antenna (scale bar = 100 μm); 11) Right elytron (scale bar = 1 mm); 12) Detail of elytral surface showing punctures and microsculpture (scale bar = 100 μm); 13) Elytral subbasal line showing crenulate cuticular projections (scale bar = 20 μm); 14) Prosternal process (scale bar = 100 μm); 15) Central part of mesoventrite showing “mesoventral plate” and metaventral process (scale bar = 100 μm); 16) Metaventrite showing area around left mesocoxal cavity (scale bar = 100 μm); 17) Metatarsus (scale bar = 100 μm). Specimen from 3.2 km S Sebring, Highlands Co., Florida (FSCA).

Figs. 24–26. Comparison of thoracic ventrites, ventral view. 24) Pycinus politus (lectotype, male); 25) Ochrodemus brevitarsis (holotype, female); 26) Radinus latus (holotype, female). Scale bar = 0.5 mm.