Dichotomius (Luederwaldtinia) subaeneus ( Castelnau, 1840 )

Montoya-Molina, Santiago & Vaz-De, Fernando Z., 2021, Taxonomic review of the Dichotomius (Luederwaldtinia) agenor species group (Coleoptera: Scarabaeidae: Scarabaeinae), European Journal of Taxonomy 734, pp. 1-64 : 44-47

Dichotomius (Luederwaldtinia) subaeneus ( Castelnau, 1840) Fig. 15 , Map 13

Copris subaenea Castelnau, 1840: 79 (original description).

Pinotus subaeneus – Luederwaldt 1929: 136. — Blackwelder 1944: 208.

Dichotomius subaeneus – Larsen 2011: 92.

Diagnosis

Dichotomius subaeneus is separated from other species in the group by the following combination of characters: copper colour. Sparse or absence of setae on body surface. Cephalic carina narrow, wider than high. Ventral clypeal process greatly emarginate. Pronotum not modified. Elytra striae displaying strong, well-imprinted punctuation separated between them by one time diameter of a puncture on elytral disc. Protibia apical spine bifurcate.

Material examined

Lectotype (♂, here designated) FRENCH GUIANA • ♂; “ SYNTYPE” [white, rounded with blue margin]/ “67·45” [white, p] /“364”

[grey, hw]/ “ subaeneus Dej. Cayenne ” [white, hw] / “ subaeneus Cast. J. Gillet. det. 1912” [white, phw] / “LECTOTYPE” [red with black margin, p]/ “ Copris LECTOT. subaenea Cast. det, F. Vaz-de- Mello, 2011”/ “NHMUK 010847024” [white, p]; BMNH.

Additional material

BRAZIL – Amazonas • 7 ♀♀; 90 km N Manaus; Nov. 1997; E. Andressen leg.; CEMT • 2 ♀♀; Res. Florest. Ducke, 26 km E of Manaus, Am. [Amazonas]; 4–12 Mar. 1966; W.D. Edmonds leg.; CEMT • 1 ♀; Manáos, Rio Negro, Amaz. [Amazonas]; 17 Dec. 1927; CEMT . – Pará • 1 ♀; Monte Dourado, Reserva do Pacanari ; 180 m a.s.l.; 0º38′ S, 52º34′ W; rainforest, dung pitfall trap; Apr.–May 2005; T.A. Gardner and M.I.M. Hernández leg.; CEMT • 2 ♂♂, 5 ♀♀; Monte Dourado, Reserva do Pacanari ; 180 m a.s.l.; 0º38′ S, 52º34′ W; rainforest, dung pitfall trap; Apr.–May 2005; T.A. Gardner and M.I.M. Hernández leg.; BMNH • 1 ♂; Tucuruis, 8.84, Rio Tocantins ; N. Degallier leg.; CEMT .

FRENCH GUIANA – Cayenne • 2 ♂♂, 1 ♀; Nouragues ; 155 m a.s.l.; 4º05′ N, 52º40′ W; Mar. 1997; F. Feer. leg.; CEMT • 1 ♂, 3 ♀♀; Nouragues Camp. ; 430 m a.s.l.; 4º37′9″ N, 53º24′32″ W; 6 Mar. 2011; Seag leg.; CEMT • 5 ♀♀; Saint Georges de L’ Oyapok ; 35 m a.s.l.; 3º54′ N, 51º48′ W; May 2014; F. Feer. leg.; CEMT . – Guyane • 1 ♂, 6 ♀♀; Sain Eugène, Barrage de Petit Saut ; 90 m a.s.l.; 4º52′ N, 53º4′ W; Dec. 1998; F. Feer leg.; CEMT . – Saül • 2 ♂♂, 2 ♀♀; Guyanne-Mission ; Oct.–Nov. 1969; Balachowsky-Gruner leg.; CEMT • 2 ♂♂, 6 ♀♀; Saint Laurent du Maroni, Bélvédère de Saül ; 326 m a.s.l.; 3º37′22″ N, 53º12′57″ W; 28 Feb. 2011; Seag leg.; CEMT • 1 ♀; St. Laurent ; Nov. 1991; P. Arnaud leg.; CEMT .

GUIANA • 1 ♂; Oronque and New River Head ; 1938; 1938-346; H. Bedding B.M; BMNH • 1 ♀; New River ; Mar.–May 1938; C.A. Hudson leg.; BMNH .

Redescription

Male

MEASUREMENTS. Length: 20.8 mm. Dorsal and ventral surface copper to dark copper, shiny with olive green reflection. Body with setae sparse or absent.

HEAD. Anterior surface rugose extending posteriorly not reaching base of cephalic carina. Cephalic carina narrow, wider than high; anterior surface smooth with scattered punctures. Median tubercle one and half times as high as lateral tubercles which are rounded apically. ( Fig. 15A ). Ventral clypeal process greatly emarginate ( Fig. 2C ).

PRONOTUM. Twice as wide as long and as wide as elytra. Anterior disc declivity weak. Pronotal medial disc shiny, with fine well-impressed punctures. Antero-lateral fossae with ocellate punctures. Ocellate punctures along anterior and posterior margins, never on lateral. Hypomeral disc smooth, without punctures; external margin bearing single row of organized long setae visible in dorsal view.

ABDOMEN. Prosternum surface microsculpture shagreened, glabrous.Mesosternum surface microsculpture shagreened with ocellate setigerous punctures, setae short. Metepisternum surface smooth, displaying setigerous punctures. Metasternum antero-medial edge with superficial weak marked punctuation next to apical margins of mesocoxa ( Fig. 15D ); ocellate punctation restricted mainly to lateral edges, few setigerous punctures near metepisternal suture. Ocellate punctures along anterior margins of each sternite, denser in lateral areas and medially vanished. Pygidium surface displaying well-impressed simple punctures, basal margin with wide ocellate punctures.

ELYTRA. Interstriae smooth, shiny with fine randomly separated punctures. Striae well delimited and distinctly punctate, punctures wider than striae and separated by twice diameter of a puncture on elytral disc.

LEGS. Metacoxa glabrous, fore calcar bifurcate ( Fig. 15C ).

PARAMERES AND LAMELLA COPULATRIX. As in Fig. 15 E–F.

Morphological variation

Females ( Fig. 15B )

As males except for the following characters:

HEAD. Clypeus elongate. Anterior surface completely rugose, interocular surface with well-impressed flat punctures separated by twice diameter of a puncture. Cephalic carina quadri-dentate, triangular in shape. Median tubercles located forward lateral tubercles.

PRONOTUM. Shiny, with fine well-impressed punctures, denser on antero-lateral sides.

ABDOMEN. Prosternum antero-medial edge with vertical rugosity.

LEGS. Profemur distal setae dense.

Remarks

This species is easily distinguished by its copper colour and sparse pilosity. As with D. belus , the protibial calcar spine is bifurcate. Luederwaldt (1929) mentioned the similarity of these two species to D. cuprinus ( Felsche, 1901) and transferred it from the inachus group to the carbonarius group. After a detailed inspection of the lectotype and other specimens, we suggest that this species belongs to the D. agenor species group based on the shape of the cephalic carina.

Figures

Fig. 15. Dichotomius subaeneus (Castelnau, 1840). A–B. Dorsal habitus. A. ♂. B. ♀. C. Lateral view of the aedeagus. D. Protibial calcar spine bifurcate. E. Ventral view of the aedeagus. F. Lamella copulatrix. G. Metasternum pilosity sparse, some few setae on the lateral edges.

Fig. 2. General characters that help differentiate the species of the Dichotomius (Luederwaldtinia) agenor species group. A–D. Ventral clypeal process. A. Cordate as in D. agenor (Harold, 1869). B. Truncate as in D. sagittarius (Harold, 1869) stat. rev. C. Bifurcate as in D. belus (Harold, 1880). D. Cylindrical as in D. henripittieri sp. nov. E–F. Hypomeral characters. E. Medial disc smooth, lateral margin with multiple rows of setae as in D. amplicollis (Harold, 1869). F. Medial disc punctate, lateral margin with single row of setae as in D. tristis (Luederwaldt, 1923). G–H. Metasternum characters. G. Setigerous punctures from the medial and lateral edges joining throughout the margin of the mesocaxa as in D. enioi sp. nov. H. Setigerous punctures from the medial and lateral edges not joining throughout the margin of the mesocaxa as in D. centralis (Harold, 1869). I–J. Elytra interstriae. I. Smooth as in D. amplicollis. J. Shagreened as in D. agenor.