Corresponding author: Christopher Woolley (
Academic editor: P. Stoev
A full description is given of the first scarabaeid beetle documented from the Mesozoic (Late Cretaceous) of Africa (Orapa, Botswana). Brief and partial descriptions of this beetle have appeared in two previous review papers of fossils from the Orapa Diamond Mine. This work represents an updated analysis and interpretation of the fossil based on character comparison and phylogenetic analysis. The new genus and species,
Woolley C (2016) The first scarabaeid beetle (Coleoptera, Scarabaeidae, Melolonthinae) described from the Mesozoic (Late-Cretaceous) of Africa. African Invertebrates 57(1): 53–66. doi:
Compression fossils of insects from the Orapa Diamond Mine (Central District, Botswana,
The insects’ burial and preservation is thought to have come about through the infilling of a crater lake by mass flows of epiclastic material from the crater’s sides (
The presence of deciduous leaves, together with a southerly shift in the present-day distributions of several taxa:
The Orapa collection holds two fossil specimens belonging to the superfamily
The described specimen (BP/2/18654) is housed in the collection at the Evolutionary Studies Institute, University of the Witwatersrand.
From Old English
The placement of the fossil beetle within the superfamily
The specimen differs from
Of the subfamilies of the
The presence of minor pronotal or cephalic armature cannot be discounted and pronounced dimorphic features are not present in all tribes (e.g.
From Mesozoic taxa the specimen differs from
The paucity of apomorphies (
Systematic phylogeny: Phylogenetic analysis was performed using the character set from
Strict consensus of six most parsimonious trees showing characters (above) and state (below). Bootstrap support values are given in parentheses (tree length=275 steps, ensemble consistency index ensemble retention index
List of 27 characters identified in the Orapa fossil for phylogenetic analysis (Fig.
Character # and state | Character and states |
---|---|
4 (1) | Eyes canthus: (0) absent; (1) present |
7 (1) | Antenna club: (0) not lamellate; (1) lamellate |
9 (2) | Antenna club: (0) 1-segmented; (1) 2-segmented; (2) 3-segmented; (3) 4-segmented; (4) 5-segmented; (5) with 6 or more segments |
10 (0) | Antennal club: (0) loose; (1) compact |
11 (1) | Antennal club: (0) not or slightly flattened; (1) distinctly flattened |
12 (0) | Antennal club: (0) not preceded by cupule; (1) preceded by cupule |
13 (0) | Apex of labrum: (0) subtruncate to slightly convex; (1) strongly convex, narrowly rounded or acute; (2) slightly concave or emarginate; (3) deeply emarginate or bilobed; (4) trilobed or with several lobes or teeth |
14 (1) | Mandibular apex: (0) not or slightly and gradually curved mesally; (1) moderately to strongly, gradually curved mesally; (2) strongly and abruptly curved mesally |
15 (0) | Mandibular apex: (0) unidentate, truncate or rounded; (1) bidentate or biolobed; (2) multidentate or multilobed |
22 (2) | Prothorax widest: (0) anteriorly; (1) at middle; (2) posteriorly |
23 (2) | Sides of prothorax: (0) more or less straight; (1) moderately to strongly curved; (2) straight posteriorly, curved anteriorly; (3) sinuate; (4) variously lobed |
25 (1) | Anterior angles of pronotum: (0) absent or not produced forward; (1) distinctly produced forward |
26 (2) | Anterior angles of pronotum: (0) absent, right or rounded, not produced; (1) produced and broadly rounded or obtusely angulate; (2) produced and narrowly rounded or acute |
27 (1) | Posterior angles of pronotum: (0) absent or broadly rounded; (1) obtuse or right; (2) moderately to strongly acute |
39 (0) | Scutellum: (0) well developed; (1) highly reduced; (2) absent or not visible |
46 (0) | Metacoxae: (0) contiguous or narrowly separated; (1) widely separated |
54 (0) | Metafemur (0) not much wider than mesofemur; (1) much wider than mesofemur |
55 (0) | Mesotibia: (0) not strongly widened; (1) strongly widened, widest at or near apex; (2) strongly widened, widest well before apex |
56 (1) | Preapical surfaces of mesotibia: (0) without ridges or combs; (1) with transverse or oblique ridge or combs |
57 (0) | Outer apical angles of mesotibia: (0) simple or slightly produced, without lobe, teeth or spines; (1) with one or more straight or outwardly facing teeth or spines: (2) with rounded lobe or process bearing spines |
58 (1) | Outer edge of protibial: (0) simple or rounded to carinate but without lobes or teeth except at apex; (1) with one or more distinct lobes or teeth |
59 (2) | Outer apical angle of protibial: (0) simple or slightly produced, without lobe, teeth or spines; (1) with one or more straight or outwardly facing teeth or spines; (2) with rounded lobe or process sometimes bearing spines |
60 (2) | Protibial spurs: (0) single; (1) double; (2) absent |
61 (1) | Preapical surfaces of metatibia (0) without ridges or combs (1) with transverse or oblique ridge or combs |
62 (0) | Metatibial articular area: (0) not to only moderately expanded, narrowly oval or oblique; (1) greatly expanded, broadly oval to circular and flattened |
63 (1) | Metatibial spurs: (0) subequal in length and form; (1) differing distinctly in length; (2) differing distinctly in form |
64 (3) | Number of abdominal ventrites: (0) 3; (1) 4; (2) 5; (3) 6; (4) 7 |
66 (0) | First ventrite: (0) not completely divided by metacoxae; (1) divided into 2 or 3 parts of metacoxae |
The close relationship between
A combining of Greek
medium-sized oval body, mandibles and labrum exposed beyond clypeus, left mandible short, dentate with single acute apical tooth, broad subapical tooth and distinct molar region, outer margin abruptly angled mesally, clypeus trapezoidal, eye partially divided by genal lobe, antennal club with three lamellae, lamellae elongate and narrow, pronotum broad, protibia with single lateral tooth mesally, metatibia with single transverse carina mesally, metatibial apex with 2 spurs, spurs adjacent, unequal in length, ‘inner’ spur extending just beyond tarsomere 1, ‘outer’ spur extending just beyond tarsomere 2, tarsomeres 1, 2, broad, not elongate, metatibia with single transverse carina mesally, metatibial apex with 2 spurs, spurs adjacent, unequal in length, ‘inner’ spur extending to tarsomere 2, ‘outer’ spur extending to tarsomere 3, tarsomeres 1, 2, broad, not elongate, mid and hind coxae contiguous, six visible sternites, terminal sternite exposed beyond elytra, median lobe of aedeagus absent/reduced, parameres long relative to basal piece.
(mm). body length from mandible apex to terminus of abdomen, 11.64; mandible length, 0.77; labrum length, 0.26; labrum width, 0.72; clypeal width 1.64; width between eye orbits, 1.69; Length of lamellae, 0.69; pronotal width, 4.71; humeral width, 4.87; elytron length, 6.25; elytron width, 2.82; profemur width, 1; profemur length, 2.15; protibial length, 1.97; mesofemur width, 0.92; mesotibial length, 1.59; mesotibial width at apex, 0.51; mesotibial spur length, inner 0.38, outer 0.87; length of mesotarsal segment 2, 0.36; Width of mesotarsal segment 2, 0.26; metafemur width, 0.92/1.02; metatibial length, 2.31; metatibia width at apex, 0.71; metatibial spur length, inner 0.87, outer 1.33; length of metatarsus, 2.31; length of metatarsal segments 1, 0.4; 2, 0.38; 3, 0.46; 4, 0.38; 5, 0.61 (without claws 0.41) ; length of metatarsal segments 2, 0.31; 3, 0.21; 4, 0.13; 5, 0.13; length of basal piece 0.76; length of parameres 0.71.
BP/2/18654 BOTSWANA: Central District: Orapa Diamond Mine,
Characters which pose some uncertainty in their interpretation are the mouthparts and the distal portion of the protibia. The mandibles and labrum of the Orapa fossil clearly extend beyond the clypeus which is considered the plesiomorphic condition (
The apex of the protibia (Figs
– aedeagus – antennal lamellae – basal lobe of mandible – clypeus – genal lobe – labrum? – mandible – metasternum – mesocoxa – mesopisternum – metacoxa – metepisternum – parameres – procoxa – protarsus I? – tentorium?
Alternatively, the form of protibae taken ‘as is’ could be a ‘spade-like’ fossorial adaption, possibly for digging in soft earth or sand. Some sand-inhabiting
The form of the left mandible (Fig.
According to estimated divergence times given by
In summary, evidence is presented in support of the Orapa specimen as a basal member of the sub-family
The work was funded by the DST-NRF Centre of Excellence in Palaeosciences funding initiative. I am grateful to Prof Marion Bamford, Dr Riaan Stals and the Wits Research Office for respectively providing equipment, specimens for comparative study, and additional research-related funding in support of this work.