Stereocephalus agostii, Matějíček, 2017

Matějíček, Jan, 2017, A new specIes of the genus Stereocephalus Lynch, Į 8 8 4 from Paraguay (Coleoptera StaphylInIdae PaederInae), Biodiversity Journal 9 (1), pp. 65-68 : 6-7

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Stereocephalus agostii

n. sp.

Stereocephalus agostii n. sp.

( Figs. 1 View Fig – 3 View Figures 2–12 )

TYPE MATERIAL. Holotype: Male, [Label 1] “ Paraguay 02.10.2005 Cordillera Piraretá Carlos Aguilar lgt. ” [Label 2] “ Holotypus Stereocephalus agostii sp. n. Matějíček det. 2 0 1 7 ”. Paratypes (2): female, “ Paraguay 02.10.2005 Cordillera Piraretá Carlos Aguilar lgt. ”; female “ Paraguay 15-10-2005 Cordillera Departamento, Naranjo, Carlos Aguilar lgt ” .

Specimens included in this study are deposited in the private collections of the author.

TYPE LOCALITY. Paraguay: Departamento Cordillera, Salto Piraretá , 25°30’S, 56°55’W. GoogleMaps

DIAGNOSIS. The posterior portion of the ventral sclerite of the aedeagus has the form of a clublike, single pointed miner’s pick (Fig. 3) with a short poll or striking head; the pick is moderately long and anteriorly directed. This poll pick configuration separates the males of S. agostii n. sp. from all congeneric species.

DESCRIPTION OF HOLOTYPE. Length 5.5 mm. Body dark reddish brown. Antennae pale reddish brown. Legs yellowish brown. Dorsum of head ( Fig. 1 View Fig ) densely punctate, punctures umbilicate; dorsum of head strongly shining between punctures and with two, polished, glabrous, transverse, median spots. Head longer than wide; postocular lateral margin feebly rounded; basal angles strongly rounded. Eyes moderately large and slightly protuberant. Pronotum ( Fig. 1 View Fig ) slightly longer than wide; surface moderately and densely punctate, with moderately wide, midlongitudinal, glabrous strip, and short, narrow, glabrous strip laterad of median strip. Elytra ( Fig. 1 View Fig ) densely punctate; punctures of dorsal surface arranged in longitudinal rows. Abdominal segments with moderately dense pubescence; terga III to VII with dense ground sculpture across base and polished from near middle to apical margin. Sternum VII with truncate posterior margin. Sternum VIII damaged, with median emargination, only apical curve of emargination visible; depth and width of emargination unknown.

Aedeagus with median lobe, in ventral view (Fig. 2), tapered from just beyond posterior margin of basal foramen to about apical third then parallel to apex; ventral surface moderately compressed to form broad ridge with weakly developed midlongitudinal carina beginning just beyond basal foramen and extending apically apex of median ridge; apex of median ridge strongly rounded in ventral view; median ridge in lateral view, ending abruptly and sharply ascending (Fig. 3); apical sixth of median lobe in ventral view parallel-sided to pointed apex; apical sixth of median lobe, in lateral view, with form of head of poll pick (Fig. 3); head of pick about one-tenth of length of median lobe, ventral edge carinate and broadly convex in lateral view; point of pick well separated from apex of median ridge; poll of pick small and strongly rounded. Base of median lobe and internal sac unavailable for study because of damage.

VARIABILITY. The two females paratype are larger than the male, respectively measuring 5.8 mm and 6.2 mm. External characters the same as the holotype male.

ETYMOLOGY. Named in honour of our colleague and my friend Mauro Agosti (1 9 7 0–2 0 1 7) (Brescia, Italy), an excellent specialist in Carabidae .

DISTRIBUTION. Known only from two localities in Cordillera Departamento, in southern Paraguay

east of Asunción.

REMARKS. The base of the aedeagus and the surfaces surrounding the emargination of sternum VIII of the holotype were severely damaged. However, the apical portion of the aedeagus of S. agostii n. sp. is so distinct that there is no doubt of the validity and defining features of the new species. The apical portion of the left mandible is broken off, but still attached to the mounting plate.