The Pardisomus species from Costa Rica, with descriptions of four new species and one larva

Summary The neotropical weevil genus Pardisomus PASCOE is redefined based on morphological character states of Agalmatus KUSCHEL and association of six species with Pentagonia BENTHAM (Rubiaceae). Procbolus DESBROCHERS, Anambates CASEY, Piagambates VOSS and Agalmatus are new synonyms of Pardisomus. New combinations with Pardisomus are 1) from Agalmatus-. P. brasiliensis (KUSCHEL), P. geniculatus (HUSTACHE), P. nigritarsis (KUSCHEL), P. panamensis (KUSCHEL); 2) from Embates P. cleroides (CHAMPION); 3) from Lydamis: P. squamipes (KlRSCH); 4) from Peridinetus. P. rufescens (HUSTACHE); 5) from Piagambates-. P. piaguroides (VOSS); and 6) from Procholus P. biplagiatus (DESBROCHERS). Four new species of Pardisomus are described from Costa Rica: P. albescens, P. amotus, P. byrrus and P. suffuscus. The larva of putative P. biplagiatus is described for the first time. P. brasiliensis (K uschel ), P. geniculatus (H ustache ), P. nigritarsis (KUSCHEL), P. panamensis (KUSCHEL); 2) aus Embates-. P. cleroides (CHAMPION); 3) aus lydamis. P. squamipes (KIRSCH); 4) aus Peridinetus-. P. rufescens (HUSTACHE); 5) aus Piagambates-. P. piaguroides (VOSS); und 6) aus Procholus P. biplagiatus (DESBROCHERS). Aus Costa Rica werden vier neue Pardisomus-Kttesi beschrieben: P. albescens, P. amotus, P. byrrus und P. suffuscus. Die Larve von mutmaßlichen P. biplagiatus wird erstmalig beschrieben.


Introduction
The neotropical region is inhabited by numerous species of baridine weevils with more or less developed vestiture of minute scales, dentate femora and concealed pygidium. The current system for their classification is based largely on trivial character states, and PREÑA, J.: P a rd isom u s species from Costa Rica little is known about theit phylogenetic relationships. Recent field work carried out in Costa Rica provided now new information toward a better understanding of one group of those weevils. While the majority of species referred to above is associated with plants in Annonaceae and Piperaceae, a number of medium-sized species with triangularly shaped body were found to be associated with plants in Pentagonia (Rubiaceae). This group includes several weevils of equivocal systematic assignment, which have been placed in three different tribes. The general geographic distribution of the weevils matches with that of Pentagonia, and the plant associations observed in Costa Rica and Panama (for P. geniculatus, C.W. O 'BRIEN in litt.) may hold true elsewhere. Surveying the host plant genus should allow entomologists to collect specimens in other regions, from where material is scarce at present. The current paucity in collections of specimens, despite their relatively large size and often showy appearance, may result from the circumstance, that the weevils are caught rarely by standard methods such as beating, sweeping and passive trapping. In this paper, the genus Pardisomus is redefined and the Costa Rican species are revised.
Thanks are due to ROBERT J. MARQUIS and ISIDRO A. CHACON, w ho 's keen field observations directed m y attention to Pentagonia as a possible host plant o f these w eevils. Field studies at Braulio Carrillo N ational Park and La Selva w ere carried out w ith financial support from the US N ational Science Foundation w ithin the framework o f ALAS IV. Logistic support was provided by the Instituto N acional de Biodiversidad, the M inisterio del Am biente y Energia and the O rganization for Tropical Studies. I w ould like to thank all participants o f the ALAS project, in particular JA CK LONGINO for inviting me, and the ALAS staff for doing such splendid w ork at "m il setenta". C om m ents and suggestions by G u i l l e r m o K u s c h e l , C h a r l e s W O 'B r i e n and R o b e r t A n d e r s o n helped to im prove the text.

Material and Methods
A pproxim ately 235 specimens belonging to 20 species o f Pardisom us, and m ore than 3000 specimens belonging to related genera were studied. Specimens were obtained on loan from the follow ing collections: M easurem ents o f length were made w ith an ocular microm eter in a dissecting m icroscope as follows: total length, from anterior margin o f eye to elytral apex in dorsal view; pronotal length, longest dorsal extension in lateral view; elytral length, longest dorsal extension, i.e. between hum eri and elytral tip along suture; length o f rostrum , straight distance from apex (without mandibles) to anterior m argin o f eye at middle of rostrum in lateral view; apical portion o f rostrum , straight distance from apex (without mandibles) to point o f antennal insertion in lateral view.
Larvae were prepared for drawing as described in MAY (1994), and her larval term inology is used. The identification o f the larvae is based on their association w ith adult specimens at two different sites in La Selva, their size (synchoreously occurring P. cleroides should be smaller) and com parison w ith three species

P seudam bates
Pia^ambates VOSS, 1954: 304. Type species P iagam batespiaguroides VOSS (by indication). N e w s y n o n y m y . A galm atus KUSCHEL, 1958: 751. Type species A galm atuspanam ensis KUSCHEL (by original designation). N e w s y n o n y m y .
Recognition. Pardisomus includes triangularly shaped species (figs. 2, 4-6) of 5-11 mm length with dentate femora, concealed pygidium and short antennal club. The pronotum undergoes sexual dimorphism in the majority of species (i.e., larger in males). The procoxae may be contiguous, slightly (though appreciably) separated from each other, or either depending on sex. Adults and larvae are associated with plants in Pentagonia BENTHAM (Rubiaceae). D efinition. Body moderately large to large (for Baridinae), total length 5-11 mm, elytra subtriangular, humeri prominent, pygidium covered by elytral apices, all femora equally dentate ventrally, procoxae contiguous or slightly separated, prosternal canal obsolete, antennal club compact, short, all segments pubescent ( fig. 3), elytral interstriae finely costate or convex apically, tarsal claws flat and subconnate at base, tibiae nearly straight and parallel-sided, body of aedeagus short, approximately 2x longer than wide, apex blunt, membranous laterodistally, apical portion more or less rectangular to long axis in lateral view, basal portion sigmoid ( fig. 9), apodemes 2.5-2.7x longer than body of aedeagus, gonopore distal, ejaculatory duct inside internal sac (aedeagal flagellum) sclerotized, filiform, approximately as long as apodemes, basal sclerite short, attached to internal sac from outside, lateral arms of male sternite 9 asymmetric ( fig. 11), spermathecal duct approximately as long as bursa and vagina combined, inserted in distal forth of bursa, stylus with 6 setae. D iscussion. A useful morphological concept for the genus was suggested by KUSCHEL (1958). However, he was not aware of several senior names, which is not surprising considering the sparse material present in the collections and the spectrum of opinions brought forward concerning their systematic position. Our hostplant data not only support KUSCHEL's concept but provide a completely new criterion for the classification of these weevils. My decision to adopt a relatively broad approach and to include Embates cleroides in Pardisomus needs to be explained. That species and the closely related P. amotus may appear at a first glance somewhat isolated in the Middle American fauna through their gibbous pronotum. However, various degrees of gibbosity occur generally in male Pardisomus, and the shape of the pronotum is intermediate in the Brazilian Ambates nobilis FAUST in litt. (not FAUST 1892;in DEIC, SMTD, ZMHB). All these species agree well in structural details of the male genitalia. The only exception occurs in P. amotus, where the base of the aedeagal flagellum is organized differently ( fig. 18), but all other character states concur with the concept of the genus. It can be said generally, that the basal sclerite is relatively distinctive for the various species of Pardisomus, while the shape of the aedeagus exhibits remarkable uniformity. For this reason, genital structures are illustrated only for one species, i.e. P. amotus, while the basal sclerite is illustrated for all species treated in the text.  (1906-09, plate 9), total length 7.5-10.1 mm (mean=8.9, n=33). Head: black, nude, finely punctate, frontal fovea shallow and elongate, transition between head and rostrum very slightly depressed; rostrum black, subcylindrical, slightly curved, finely punctate (apically very subtle in females), nude, dorsomedian carina present (males) or not (females), rostral length males 1.06-1.14x (mean=1.10, n=18), females 1.15-1.31x (mean=1.24, n=13) pronotal length, portion distal to antennal insertion males 0.36-0.40x (mean=0.38, n=18), females 0.35-0.42x (mean=0.40, n= 13) total rostral length; antenna piceous to black, funicular segment 2 longer than 1, antennal scrobe gradually descending, reaching ventral margin of rostrum before eye. Pronotum: black, nude, yellow scales at flank; pronotal length males 0.79-0.84x (mean=0.81, n=18), females 0.76-0.81x (mean=0.79, n=14) maximum width; pronotal width males 0.77-0.80x (mean=0.78, n=18), females 0.72-0.77x (mean=0.74, n=14) greatest elytral width; sides rounded in basal third, then gradually converging and tubulate in front, disk convex, finely punctate, intervals glabrous, dorsomedian carina absent. Elytra: black, scales yellow in curved post-humeral and straight subapical fasciae; elytral length 1.22-1.29x (mean=1.26, n=32) width at humeri, sides gradually converging behind humeri, preapical callus moderately developed, striae distinct, interstriae broad, increasingly convex apically but not clearly costate. Legs: black, femora moderately expanded dorsoventrally, femoral tooth distinct, tibial margin ventrodistally with cluster of cupreous hairs. Venter: black, yellow scales on portions of prosternum, metepisternum, metasternum, sternite 4 (second visible sternite); procoxae contiguous in both sexes. Male genitalia: anterior portion of aedeagus moderately curved ventrad, apodemes ca. 2.5x longer than body of aedeagus, aedeagal flagellum slightly shorter than apodemes, transition to basal portion abrupt, basal sclerite curved irregularly ( fig. 15).  . 28), and may be expected in Nicaragua. Collections from premontane habitats, such as San Carlos and Tres Rios, have not been made since the early 1900s. Discussion. Dr. PERRIN was very helpful in the recognition of the type series housed in the Museum Paris. D ESBROCHERS must have seen at least two specimens, because he gave a size range for the species. Many of D ESBRO CH ERS' exotic specimens went in the C LERC collection, from where H USTACH E obtained some specimens on exchange. In these two collections (now in MNHN) are nine specimens of P. biplagiatus, three with the collecting site San Carlos and reference to the DESBRO CH ERS collection. One of those three specimens has a handwritten label ,,n. sp.", and is designated here as lectotype. The other two specimens are designated here as paralectotypes. The color pattern of P. biplagiatus has deluded more than one entomologist, who felt it was related to certain species of Embates and Peridinetus. CHAMPION (1907) gave a good generic diagnosis based on this species, with criteria similar to those used by K U SC H E L (1958), but failed to relate the species to the differently colored, but morphologically similar P. guttatus (PASCO E). No attempt is made here to interpret any larval character states, because the sparse data available is insufficient for generalization. The conspicuous modification of the caudal segments occurs in several species of Bagous and Neohydronomus (M A Y , 1994), but has not been reported for species in Baridinae. However, it is present in at least three species of Embates (where the apical portion is strongly sclerotized) and in at least one species of Peridinetus (personal unpublished data). I suspect that the caudal "shovel" is employed for cleaning the larval tunnel of debris.
Single observations were made also on Piper arieianum (M A R Q U IS) and Solatium sp.
(H ESPEN H EID E), but these associations are probably accidental. Distribution. Pardisomus amotus occurs in Atlantic Costa Rica ( fig. 28), with most records from elevations below 600 m. The species is likely to be found in the neighboring regions of Nicaragua and Panama. Specific epithet. The name amotus is a Latin participle meaning away from a place or area. It refers to the geographic separation of the species from P. cleroides. D iscussion. Pardisomus amotus is the Atlantic sibling species of the Pacific P. cleroides. Reasons for giving it full specific rank are 1) statistically significant difference in body proportion, 2) different color pattern, 3) different degree of sexual dimorphism, 4) different host plants and 5) allopatry. The showy color pattern derives from two black elytral maculae and a light colored circumferential line. Each of those elements merge transversely across the elytral suture. Male specimens of P. amotus and P. cleroides can be recognized by the presence of white scales apicad of the antennal insertion.