Melanophilharmostes tuber Grebennikov, 2022

Grebennikov, Vasily V., 2022, Phylogenetic placement of a new Melanophilharmostes Paulian, 1968 pill scarab (Coleoptera: Hybosoridae: Ceratocanthinae) from Cameroon: molecular results decipher misleading morphology, Zootaxa 5087 (3), pp. 441-450 : 446

Melanophilharmostes tuber Grebennikov , new species

Figs 1–5 .

Type locality. Cameroon, Mt. Cameroon, 4.0681ºN, 9.0717ºE, 233m.

Type material. Holotype (deposited in the Canadian National Collection of Insects , Arachnids , and Nematodes, Ottawa, Canada), female, “ CAMEROON, Mt. Cameroon, 4.0681, 9.0717, 233m, 28.xii.2015, sift. CM09 , V. Grebennikov.”, “CNCCOLVG00009477” . Paratype (deposited in the Canadian National Collection of Insects , Arachnids, and Nematodes), not sexed, “ CAMEROON, Mt. Kupe, 4.8193, 9.7075, 1525m, 29.xii.2015, sift. CM13 , V. Grebennikov.”, “CNCCOLVG00009488” .

Description. Holotype maximal body length (in rolled position, Fig. 1A ): 2.5 mm (paratype: 2.5 mm), maximal body width ( Fig. 1 ): 2.2 mm (paratype: 2.3 mm). Head distinctly convex, clypeal disc gibbose. Interocular bridge completely subdividing each eye into smaller dorsal and larger ventral parts ( Fig. 2E ); antenna with seemingly 10 antennomeres ( Fig. 2F , not dissected to make exact count); head, pronotum, and elytra with deep and dense microsculpture (horseshoe-shaped and comma-shaped), as well as with sparse, short, and distinct pilosity; surface of pronotum uneven, with bumps and depressions ( Fig. 2A ); each elytron with notable lateral longitudinal sharp carina interrupted in posterior part ( Figs 2B, D ); hind wings fully developed; distal fork of vein CuA present; distal expansion of vein MP 1+2 cannot be verified using single available wing ( Fig. 2D ). Male genitalia unknown. DNA data of holotype: MW899169 (COI) and MW845067 (28S); DNA data of paratype: MW899176 (COI), MW845087 (ITS2), and MW845074 (28S).

Diagnosis. Within the Synarmostes group of four Afrotropical genera (including Madagascar and Comoros), this species can be immediately recognised by any of its four diagnostic characters: (1) head distinctly convex with clypeal disc gibbose ( Fig. 2F ), (2) bumpy pronotum, (3) notably developed longitudinal carina on each elytron, and (4) deep and dense microsculpture on the head, pronotum, and elytra.

Distribution. This species is known from two Cameroonian localities about 100 km apart: Mt. Cameroon (233 m) and Mt. Kupe (1523 m).

Natural History. Both specimens were collected by sifting forest leaf litter in rainforest.

Derivation of name. The species epithet is the Latin noun meaning “a hump, bump, swelling, protuberance”, with reference to the peculiarly bumpy pronotum of the new species distinguishing it from all its congeners; it is used as a noun in apposition.

Figures

FIGURE 1. Melanophilharmostes tuber Grebennikov, new species.A–E: habitus of the conglobate holotype, dorsal (A), anterior (B), left lateral (C), ventral (D), and posterior (E) views; F: habitat of paratype on Mt. Kupe; G: distribution of M. tuber.

FIGURE 2. Melanophilharmostes tuber Grebennikov,new species, holotype, habitus (A–C; right mesothoracic andmetathoracic legs removed), hind wing (D), antenna (E), and head (F–G).

FIGURE 3. Habitus of select sequenced specimens of Melanophilharmostes and Pseudopterorthochaetes, dorsal view; images are to scale. Note pilosity on pronota and elytra distinguishing both genera. Melanophilharmostes tuber Grebennikov, new species is immediately recognisable by possessing three unique characters: uneven pronotal surface, lateral elytral carina, and exceptionally deep microsculpture on the head, pronotum, and elytra.

FIGURE 4. Habitus of select sequenced specimens of Melanophilharmostes and Pseudopterorthochaetes, lateral view; images are to scale.

FIGURE 5. Maximum likelihood tree of Ceratocanthinae pill scarabs (Coleoptera: Hybosoridae) reconstructed by RAxML from the three-fragment concatenated matrix. Non-target clades are collapsed (see Grebennikov 2021 for their details). Except for the aberrant position of the Melanophilharmostes terminal 9604, M. tuber Grebennikov, new species, is inside monophyletic Melanophilharmostes, sister to monophyletic Pseudopterorthochaetes. Both genera are inside the monophyletic Synarmostes group of four genera. Habitus images are to scale; small black arrows indicate imaged specimens.