Ten species from the genus Tricorynus (Coleoptera: Ptinidae: Mesocoelopodinae) are described from Paraguay. All type-species are deposited in the Museo Civico di Genova, Italy (MCG).
T. boggianii is mainly brown, head and pronotum reddish, tarsi ends yellow. Pubescence grey, appressed. Body 1.8 times as long as wide. Frons nearly flat; surface with fine punctation, where punctures separated by 1 puncture diameter. Eyes a little irregularly shaped, nearly oval, separated by two longitudinal diameters of an eye. Pronotum 1.57 times as wide as long. Punctation dual on disc, large punctures separated by 2–4 diameters of a puncture; anterior angles without large punctures. Elytra 1.47 times as long as wide and 2.3 times as long as pronotum. Each elytron with two lateral striae; lower stria reaches the elytron middle, upper stria is shorter. Both striae run forwards to basal margin of elytron as rows of large punctures. Punctation dual on elytral disc, large punctures arranged in narrow bands. Mesosternum without hook. Metasternum with thin carina; surface with small punctures separated by 2–4 diameters of a puncture in the middle of metasternum, and punctures are sparser to sides. Fore tibia with complete lower groove, and short upper one; middle tibia with a complete groove. On the third abdominal sternite punctures are small and separated by 3–4 diameters of a puncture. Length 2.6 mm. T. boggianii belongs to the group of Tricorynus without hook on mesosternum, with carina on metasternum, and with small eyes (i.e. separated not less than two diameters of an eye: T. minutipunctatus Toskina, 2000, T. parvirugusus Toskina, 2017, T. rugosus Toskina, 2000, T. subvittatus Toskina, 2000). T. boggianii differs from these species by the following basic morphological characters: both lateral striae are short, metasternal surface is smooth without hollow and large coarse wrinkles, there are puncture bands on elytral disc and peculiarities of punctation on the pronotum.
T. densipunctatus is wholly black-brown. Pubescence dark grey, a little suberect, rather dense, arranged in broad longitudinal bands. Frons longitudinally convex; surface with large dual punctation. Eyes irregularly shaped, separated by 1.6 vertical diameter of an eye. Pronotum 1.8 times as wide as long; surface with dual punctation, large punctures separated by 2–4 diameters of a puncture on pronotal disc, and they are dense on pronotal sides where punctures are separated by less than one diameter of a puncture. Elytra 1.5 times as long as wide and 1.27 times as long as pronotum, with two lateral striae. Lower stria reaches the basal margin of elytron; upper stria shortened. Elytral surface with dual dense punctation; large punctures separated by one puncture diameter on elytral disc. Mesosternum without hook. Metasternum without carina and hollow. Surface covered with large punctures, punctation is dense in the middle of metasternum and sparser to the sides. Transverse folds run from the centre along distal margin in both parts. Fore tibiae with two grooves: lower groove is complete, upper groove is short; middle tibiae with a complete groove. Length 2.45 mm. This species differs from the other species without mesosternal hook and metasternal carina by long body, short pronotum, large punctures on metasternum, by long lateral striae (see Figures).
T. flavicornis is dark brown, antennal club dark yellow. Pubescence a little suberect, fine, grey. Body 1.85 times as long as wide. Frons nearly flat; surface with dual punctation, large punctures separated by 1 diameter of a puncture. Eyes a little oval, separated by 2.5 longitudinal diameters of an eye. Pronotum 1.5 times as wide as long; surface with small dual punctation, large punctures are separated by 2–3 diameters of a puncture on the disc, but they disappear on anterior acute angles. Elytra 1.3 times as long as wide and two times as long as pronotum; with two lateral striae. They reach the level of metasternum and run forward to basal margin as puncture rows. Punctation dual and rather small on disc; large punctures and pubescence arranged in bands on disc. Mesosternum without hook. Metasternum without carina. Surface of metasternum with uniform punctation, which is denser in the middle and sparser to the sides. Fore tibiae with two grooves; the lower groove is complete, the upper one reaches the half of tibia. Middle tibiae with a complete groove. The middle of basal half of the 5th abdominal sternite is impressed. Length 2.2 mm. T. flavicornis differs from the other species of Tricorynus by punctation on elytral disc arranged in bands, broadly separated eyes (2.5 longitudinal diameters of an eye), by punctation without large punctures on anterior angles of pronotum.
T. gibbus is rufousish-brown. Pubescence fine, yellowish, appressed. Body twice as long as wide. Frons slightly convex, surface with dual dense punctation. Eyes separated by 1.5 longitudinal diameters of an eye. Pronotum 1.5 times as wide as long; anterior angles rectangular, posterior ones obtuse, rounded, and a little flattened. Surface with dual punctation; large punctures separated by 1–2 diameters of a puncture. Surface with only large dense punctures on anterior angles. Elytra 1.6 times as long as wide and 2.5 times as long as pronotum, with two lateral striae. These striae reach basal margin as rows of punctures. Puncture row is present above upper stria. Elytral surface with dual punctation; large punctures arranged in longitudinal rows, in which the punctures are separated by one diameter of a puncture. Mesosternum without hook. Metasternum without carina; surface with rather large and uniform punctures arranged more densely in the middle of metasternum. Fore tibiae with two complete grooves, middle tibiae with a complete groove. Length 2.0 mm. T. gibbus differs from the other species: by long body (from T. brevis Toskina, 2000), by long pronotum (from T. densipunctatus sp.n.), by short lateral striae (from T. longistriatus Toskina, 2017), by smooth metasternum (from T. rufulus sp.n.), by peculiarities of punctation (from T. bonacei Toskina, 2017, T. multipunctatus, Toskina, 1993, T. tenebricus Toskina, 2017), by absence of fossa, hook, and carina on metasternum (from various species).
T. latescapulis is dark brown, antennal club yellow. Pubescence grey, fine, appressed. Frons nearly flat; surface with dual punctation, large punctures separated by 1.5–2.0 diameters of a puncture. Eyes are shortly oval, separated by 1.6 longitudinal diameters of an eye. Pronotum 1.5 times as wide as long; anterior angles rectangular, posterior angles obtuse, slightly flattened. Surface with dual punctation; large punctures separated by 0.5 puncture diameter near basal margin of pronotum, and they are a little sparser on sides. Elytra 1.4 times as long as wide and 2.2 times as long as pronotum, with two lateral striae. Lower stria reaches the level of metasternum, the upper one is shorter. Both striae run forward to basal margin as puncture rows. There is a short puncture row above upper stria. Elytral surface with rather dense dual punctation in which large punctures are arranged in longitudinal rows, and separated by 1–2 puncture diameters in them. Mesosternum without hook. Metasternum with short carina. Punctation denser in the center of metasternum. Several rather small oblique folds move away from the center. Fore tibiae with complete lower groove and short upper one. Middle tibiae with a complete groove. Abdominal surface with small and dense punctation, punctures separated by one puncture diameter on the second sternite. Length 2.7 mm. T. latescapulis belongs to the group of Tricorynus without mesosternal hook and with metasternal carina and large eyes (i.e. eyes separated by less than two diameters of an eye). T. latescapulis differs by round apices of elytra (from T. caudatus (Pic, 1928)), by smooth metasternum (from T. ingens Toskina, 2017, T. minutipunctatus Toskina, 2000), by short lateral striae (from T. parvirugosus Toskina, 2017), by regular punctation on elytra (from T. rugosus Toskina, 2000, T. subvittatus Toskina, 2000), by small simple carina (from T. ruidus Toskina, 2000).
T. nigriculus is dark brown, antennae dark yellow, tarsi ends yellowish. Pubescence small, grey, a little suberect. Pronotum shiny, elytra dull. Body 1.9 times as long as wide. Frons nearly flat; surface with dual punctation, large punctures separated by 1–1.5 puncture diameters. Eyes round, separated by 1.4 longitudinal diameters of an eye. Pronotum 1.6 times as wide as long; anterior angles rectangular, posterior ones obtuse, flattened. Pronotal basal margin two-emarginate. Surface with dual punctation; large punctures separated by 2–4 puncture diameters on disc, and they disappear on anterior angles. Elytra 1.4 times as long as wide and 2.27 times as long as pronotum, with two lateral striae; lower stria reaches basal margin, upper one goes as far as only middle of elytron and runs forward to basal margin as large punctures. Elytral surface with dual dense punctation, large punctures separated by a diameter of a puncture on disc, and they disappear at basal margin of elytra. Mesosternum without hook. Metasternum without carina; surface with very small punctation, punctures are sparser to sides and nearly disappear at upper angles. Fore tibiae with two grooves, upper groove slightly shortened; middle tibiae with a complete groove. Abdominal sternites with rather dense punctation; punctures separated by a puncture diameter on the second sternite. Length 2.8 mm. T. nigriculus belongs to the group of Tricorynus without mesosternal hook, without metasternal carina, and with large eyes. T. nigriculus differs from the other species by basic morphological characters: by long body (from T. brevis Toskina, 2000), by long pronotum (from T. densipunctatus sp. n.), by long lower lateral stria and uniform punctation on anterior angles of pronotum (from T. bonacei Toskina,2017, T. gibbus sp. n., T. multipunctatus Toskina, 1993, T. tenebricus Toskina, 2017), by smooth metasternum (from T. kochalka Toskina, 2000, T. rufulus sp.n.), by short upper lateral striae (from T. longistriatus Toskina, 2017).
T. nigroaquilus is wholly black brown. Pubescence brown, small, appressed. Body 1.8 times as long as wide. Frons slightly convex; surface with dual punctation, large punctures separated by a diameter of a puncture. Eyes separated by 2.3 longitudinal diameters of an eye. Pronotum 1.7 times as wide as long; anterior angles acute, posterior ones obtuse, rounded. Surface with dual punctation, large punctures separated by 1–2 puncture diameters. Punctation dense on anterior angles. Elytra 1.47 times as long as wide and 2.5 times as long as pronotum, with two lateral striae. Both striae reach the last third of way to elytral basal margin as puncture rows. There is also a puncture row above upper stria. Elytral surface with dual punctation, large punctures arranged in longitudinal rows. Small punctures are very dense. Mesosternum without hook. Metasternum without carina and hollow. Surface with dual punctation, large punctures are separated by more than a puncture diameters in the middle of metasternum, and punctures are sparser to sides. Fore tibiae with two grooves, upper groove shortened; middle tibiae with a complete groove. Length 2.0 mm. T. nigroaquilus belongs to the group of Tricorynus without mesosternal hook and without metasternal carina, with small eyes (separated by two and more longitudinal diameters of an eye). The new species differs from the other species by basic morphological characters: by regular arrangement of large punctures on elytral disc (from T. aguilari Toskina, 1993, T. deminutus Toskina, 2017, T. piceus Toskina, 2000); by frons and metasternum with dense punctation (from T. fuligineus Toskina, 2000); by only round punctures (from T. ovatipunctatus Toskina, 2000); by metasternum without tubercle and fossa (from T. virgulatus sp.n., T. piceus Toskina, 2000); by different proportions of pronotum and elytra (from T. flavicornis sp. n., T. sublatus sp. n.).
T. rufulus is wholly rufousish-brown. Pubescence greyish-yellowish, fine, slightly suberect. Body 1.9 times as long as wide. Frons nearly flat. Eyes slightly oval, of irregular form, separated by 1.5 longitudinal diameters of an eye. Pronotum 1.5 times as wide as long; anterior angles acute, posterior ones obtuse, rounded. Surface with dual punctation, large punctures separated by 2–3 puncture diameters on disc, and large punctures disappear on anterior angles. Elytra 1.6 times as long as wide and 2.4 times as long as pronotum, with two lateral striae; upper stria not reaches the basal margin of elytra. Two puncture rows are present above upper stria. Elytral surface with dual punctation; large punctures separated by one puncture diameter on disc. Mesosternum without hook. Metasternum without carina and in the middle with numerous longitudinal wrinkles. Surface with dual, rather dense punctation. Fore tibiae with two grooves; lower groove is complete, upper one is short. Middle tibiae with a complete groove. Surface of 3rd abdominal sternite with dual small punctation. Length 2.1 mm. T. rufulus differs from the other Tricorynus by metasternum with numerous longitudinal wrinkles in the middle.
T sublatus is dark brown, antennal club yellow. Pubescence grey, short, appressed on disc, suberect on sides. Body 1.67 times as long as wide, slightly flattened. Frons convex, surface with dual dense punctation, large punctures separated by 0.5–1 diameter of a puncture. Eyes round, separated by 2.2 longitudinal diameters of an eye. Pronotum 1.87 times as wide as long; anterior angles slightly acute, posterior ones obtuse, rounded. Surface with dual punctation; large punctures separated by 3–4 diameters of a puncture on disc, and large punctures disappear on sides. Elytra 1.3 times as long as wide and 2.5 times as long as pronotum, with two lateral striae. Both striae reach only metasternum and run forwards as rows of punctures. Elytral surface with dual punctation where punctures are arranged in dense rows and separated by 1.5–2 puncture diameters. Small punctures are very dense. Mesosternum without hook. Metasternum without carina. Surface with dual punctation; large punctures rather sparse, arranged evenly on surface. Fore tibiae with two complete grooves, middle tibiae with a complete groove. Length 2.5 mm. T. sublatus belongs to the group of Tricorynus without mesosternal hook and metasternal carina, and with small eyes (eyes separated by more than two diameters of an eye). T. sublatus differs from the species of the group by short body and very short pronotum (body 1.75–1.85 times as long as wide, pronotum 1.5–1.7 times as wide as long in the species: T. aguilari Toskina, 1993, T. deminutus Toskina, 2017, T. flavicornis sp. n., T. fuligineus Toskina, 2000, T. nigroaquilus sp. n., T. ovatipunctatus Toskina, 2000, T. piceus Toskina, 2000, T. virgulatus sp. n.).
T. virgulatus is brown. Pubescence grey, fine, partly suberect. Body 1.8 times as long as wide. Frons convex; surface with dual punctation, large punctures separated by one puncture diameter. Eyes round, separated by 2.3 longitudinal diameters of an eye. Pronotum 1.5 times as wide as long; anterior angles rectangular, posterior ones obtuse, rounded, narrowly flattened. Surface with dual punctation; large punctures separated by 2–3 diameters of a puncture on the disc, and they are denser on anterior angles. Elytra 1.4 times as long as wide and 2.16 times as long as pronotum, with two lateral striae; lower stria reaches the basal margin of elytron, upper stria goes on only to metasternum and continues to basal margin as puncture row. Two more punctures rows are above upper stria. Elytral surface slightly costate, that is emphasized with pubescence. Surface with dual punctation, large punctures arranged in longitudinal rows, where they are separated by one puncture diameter. Mesosternum without hook. Metasternum without carina. Surface with fine and dense punctation in the centre, and smaller and sparser to sides, disappearing in upper angles of metasternum. There is a small tubercule with pit in the middle of metasternum. Fore tibiae with two grooves, upper groove shortened. Middle tibiae with a complete groove. Upper margins in grooves with setae. Surface of 3rd abdominal sternite covered with large punctures separated by 2–3 puncture diameters. Length 2.6 mm. T. virgulatus differs from the other species of Tricorynus by slightly costate elytra and tubercle with pit on the middle of metasternum.
We compared our new species of the genus Tricorynus from Paraguay with species described by M. Pic from Brazil (T. brasiliensis (Pic, 1902), T. convexus (Pic, 1902), T. minutissimus (Pic, 1904), T. rudepunctatus (Pic, 1904), T. thecaoides (Pic, 1904), T. distinctus (Pic, 1905), T. goyosensis (Pic, 1905), T. instriatipennis (Pic, 1923), T. fulvopilosus (Pic, 1927), T. reitteri (Pic, 1927), T. subplicatus (Pic, 1927), T. unisulcatus (Pic, 1927), T. caudatus (Pic, 1928)). T. caudatus only was found in the Paraguayan collection.