Chortastus minimus Hagedorn 1909

Chortastus minimus Hagedorn, 1909 (Figs 9–18) Chortastus minimus Hagedorn, 1909: 738. Chortastus medius Eggers, 1924: 100, syn. nov. Chortastus agnatus Eggers, 1935: 301, synonym by Browne, 1973. Chortastus sulcatus Eggers, 1935: 301, synonym by Browne, 1973 Chortastus brunneus Nunberg, 1967: 317, synonym of C. medius by Browne, 1973. Afrochramesus baguenai Schedl, 1971: 197, synonym of C. medius by Beaver, 1998. Type material. Syntypes: Cameroon [ZMHB]. Syntype of Chortastus medius: Congostaat [Democratic Republic of the Congo], Albertville [Kalemie] 1.XII.1918, R. Mayné, leg. [MRCA]. Lectotype of Chortastus agnatus: Cameroon, Conradt, leg. [USNM]. Holotype of Chortastus sulcatus: [Democratic Republic of the Congo], Sankuru, 1.IV.1925, ex Staudtia gabonensis, Lt. Ghesquière, leg. [MRCA]. Holoty,pe of Chortastus brunneus: [Democratic Republic of the Congo], Bas-Congo, Kimwenza, 1.IV.1956, R. P. Van Eyen, leg. [MRCA]. Other material. Congo-Brazzaville [Republic of Congo], Sibiti, leg. Endrödy-Younga, 27.11.1963 [NHMW]. Democratic Republic of the Congo, Mulongo, [Haut-Lomami], 20.5.1930, P. Gerard, leg. [NHMW]; Yangambi, 14.12.1951, K. E. Schedl, leg. [NHMW] and 17.VII.1952 [MRCA]. Diagnosis. Body length 1.6–2.7 mm, 2.1–2.2 × as long as wide. Male frons with long golden setae from vertex and near eye margin reaching near epistoma, female frons with very short erect setae evenly distributed over entire frons; pronotum and elytra with similar type of setae, on elytral interstriae in a single row or in variably confused multiple rows; interstriae 2 on declivity slightly impressed, smooth and glabrous, interstriae 3 on lower half of declivity with a slightly elevated blunt ridge. Distribution. Democratic Republic of the Congo, Republic of Congo, Cameroon, Angola. Host plant: Staudtia stipitata (Myristicaceae). Remarks. Comparison of (holo-) types of C. minimus, C. medius, C. sulcatus, C. brunneus and C. agnatus, and a paratype of C. baguenai revealed a gradual variation from smallest (minimus, agnatus and sulcatus) to medium (baguenai) to largest (medius), and from slightly more spaced setae (minimus and agnatus) to a little denser (sulcatus, brunneus and medius). Because all these species were described from nearby locations in the greater Congo basin, and that body size is known to vary a great deal in phloem feeding bark beetles, these intergrading types are inferred as conspecific.