Dichotomius (Cephagonus) baiano Nunes & Vaz-de-Mello 2019, new species

2.3.: Dichotomius (Cephagonus) baiano new species (Figure 22)

Diagnosis. distinguished from the other species in the group by the following combination of characteristics: males ’ cephalic carina longer than wideı rounded at apex (like D. seag of the same group); anterior pronotal marginı including anterior excavationı bearing deeply impressed punctures (as in D. fissus); pronotal margin serrate (as in D. filgueirasi and D. fernandosilvai of the same group); males ’ pronotal disc with two rounded lobes at anterior mid-portion and 5) elytra having distinct striate microsculpture (viewed under 20x magnification) (Figure 13 (c-e)).

● HOLOTYPEı male: BRASIL: Bahia. Iguaí. 14³38 ʹ 32 ” Sı 40³08 ʹ 51 ” W. Q36. Floresta. Pitfall. 5-18-i-2012. CMP Leite [at CEMT].

● PARATYPES: same data of Holotype [1 Ƌı 1 ♀ at CEMT]; same data but 14³38 ʹ 13 ” Sı 40 ³08 ʹ 30 ” W [74 ƋƋı 80 ♀♀ at CEMT]; same data but 14³38 ʹ 32 ” Sı 40³08 ʹ 51 ” [52 ƋƋı 61 ♀♀ at CEMT]; same data but 14³38 ʹ 33 ” Sı 40 ³09 ʹ 51 ” W [74 ƋƋı 50 ♀♀ at CEMT]; same data but 14³39 ʹ 31 ” Sı 40 ³09 ʹ 09 ” W [24 ƋƋı 18 ♀♀ at CEMT]; Jaguaripe. 13³11 ʹ 32 ” Sı 39 ³00 ʹ 06 ” W. 58 mosl. Pitfall. ii-2011. CMP Leite [2 ♀♀ at CEMT]; Santa Teresinha. Serra da Jibóia. iv-2009. AF Brito [3 ♀♀ at CEMT]; Ubaíra. 13³05 ʹ 55 ” Sı 39 ³40 ʹ 03 ” W. 416 mosl. Pitfall. xi-2011. CMP Leite [8 ƋƋı 3 ♀♀ at CEMT]; same data but 13³06 ʹ 29 ” Sı 39 ³39 ʹ 35 ” W [4 ƋƋı 4 ♀♀ at CEMT]; same data but 13³07 ’ Sı 39³39 ʹ [5 ƋƋı 8 ♀♀ at CEMT]; Wenceslau Guimarães. 13³32 ʹ 27 ” Sı 39 ³42 ʹ 39 ” W. Pitfall. i-2011. CMP Leite [3 ♀♀ at CEMT].

Description (holotype). BL: 22 mmı PW: 15 mm. Colour: blackı shiny on pronotumı brownı silky-shiny on elytra. Head: fronto-clypeal surface smooth. Inter-ocular and genal surface finely punctuate. Gena borders straight. Cephalic carina taller than wideı rounded at apex. Pronotum: borders serrateı especially after medio-lateral pronotal pit. Pronotal disc shinyı lacking punctuation and with two rounded lobes at anterior portion. Anterior portionı including excavation and anterior angles with fineı deeply impressed punctures (under 25x magnification)ı equally spaced. Posterior margin with a single-defined row of ocellate punctures. Metasternum: sides and anterior portion of anterior lobe covered by dense red setae. Setigerous punctures equally spacedı where present. Elytra: striae weakly impressed with weak punctures. Punctures separated by twice their diameter. Striae expanding at the baseı forming small foveae. Interstriae flatı having distinct striate microsculpture (viewed under 30x magnification) that gives a silky aspect to the discı that has a brownı matt colour. Abdomen: glabrousı punctures of anterior margin of ventrites interrupted medially. Aedeagus (Figure 22 (d-f)): parameraı apexes dorsally roundedı parallel; longitudinal excavation present taking 2/3 of the paramera length; basal-rounded excavations present. Laterallyı subtle declivity towards apex. Ventrallyı each side of the base producing a foveae; mid-section of sclerotised portion constrained; subgenital plate rounded at the base and strongly emarginated at apex.

Morphological variation. males BL: 17 – 23 mmı PW: 8 – 15 mm. Females BL: 16 – 23 mmı PW: 9 – 15 mm. Some males may have a slight bifurcation at the apex of cephalic carina. Females distinguishable from the males by the following: Head: fronto-clypeal surface transversely wrinkled. Cephalic carina transversalı forming a weak pair of tubercles. Pronotum: punctures coarser than those of the males but with the same distribution pattern. Pronotal borders strongly serrated. Elytra: striae deeply impressedı punctures separated by twice their diameter. Abdomen: sixth ventrite bearing a pair of triangular projections which reach the apical margin of the pygidium (Figure 9 (b)).

Distribution. Brazilı south of the state of Bahia (Figure 20).

Etymology. baianoı noun in appositionı is the gentilic for those originated from Bahiaı Brazil.