Vicinopone

A monotypic African genus, the arboreal Vicinopone conciliatrix is known from relatively few collections.

Identification
Bolton and Fisher (2012) - In major details of morphology, striking contrasts between Vicinopone and all species of Simopone include the following (the state considered apomorphic is italicised).

1 Palp formula is 3,2 in Vicinopone, as opposed to 6,4 or more rarely 5,3 in Simopone.

2 Antennae have 12 antennomeres in Vicinopone, as opposed to 11 antennomeres in Simopone.

3 Scape, when laid straight back, reaches the posterior margin of the eye in Vicinopone, as opposed to the anterior margin of the eye in Simopone (SI 57–67 in Vicinopone, SI 33–56 in Simopone).

4 Ocelli are absent in Vicinopone, as opposed to present in Simopone.

5 Eyes are shifted very far forward in Vicinopone, as opposed to being near or behind the midlength in Simopone (EP 0.32–0.41 in Vicinopone, EP 0.68–1.91 in Simopone).

6 A differentiated posterior (occipital) surface to the head occurs in Vicinopone, as opposed to the lack of such a surface in Simopone.

7 Pre-occipital carina (that extends down the posterolateral margin of the head and onto the ventral surface) runs right across the ventral surface to intersect the ventral midline in Vicinopone, as opposed to the carina terminating well before it approaches the ventral midline in Simopone.

8 Metabasitarsus lacks a ventral glandular groove in Vicinopone, as opposed to the universal presence of such a groove in Simopone.

9 AII (petiole) tergite in dorsal view is elongate and barrel-shaped in Vicinopone, as opposed to flattened and laterally marginate in Simopone (AIIW/AIIL 0.68–0.75 in Vicinopone, AIIW/AIIL 0.79–1.30 in Simopone). 10 Cinctus of AIV is cross-ribbed in Vicinopone, as opposed to smooth in Simopone.

Distribution
Known from Democratic Republic of Congo, Gabon, Ghana, Tanzania and Uganda.

Species richness
Species richness by country based on regional taxon lists (countries with darker colours are more species-rich). View Data



Biology
The only species of the genus is arboreal. Its rarity in collections may be a reflection of its actual abundance across its wide range but more likely than not it is completely arboreal hence the species, (and as the sole member of the Vicinopone, the genus) is not commonly encountered. The only known queens are two dealates collected from the same nest, suggesting polygyny. Workers are variable in size with larger workers having larger eyes.

Nomenclature

 *  VICINOPONE  [Cerapachyinae: Cerapachyini]
 * Vicinopone Bolton & Fisher, 2012: 72. Type-species: Simopone conciliatrix, by original designation.

Worker

A monotypic Afrotropical genus of arboreal cerapachyine ants, with size-variable workers. With the shared characters of Cerapachyini listed in the introduction and also with the following combination of characters. An undoubted apomorphy of the genus is in italics.

1 Palp formula 3,2 (by dissection). Maxillary palp very short: with mouthparts retracted the apex of the maxillary palp, when extended back on underside of head, does not reach the posterior margin of the buccal cavity.

2 Antenna with 12 segments, gradually incrassate apically; apical antennomere large but subcylindrical, not swollen and bulbous.

3 Scape short (SI 56–67), when laid straight back in full-face view reaching the level of the posterior margin of the eye.

4 Eyes large (EL/HW 0.31–0.45), located very far forward on the head so that the posterior eye margin is in front of the midlength of the head.

5 Ocelli absent.

6 Clypeus more or less flat between the elevated frontal lobes; frontal carinae short, extending back to level of anterior margins of eyes only because the eyes are located so far forward.

7 Parafrontal ridges present but short and weak because of proximity of eye to front of head.

8 Head capsule with a short, vertical posterior surface above the occipital foramen; this surface separated from the vertex by a low, arched, transverse carina.

9 Head capsule, in ventral or ventrolateral view, with a carina that extends down the posterolateral margin and onto the ventral surface, which it crosses to meet its opposite number at the ventral midline; this carina is anterior to, and separate from, that which borders the occipital foramen.

10 Mesosoma dorsally with very feeble, shallow transverse concavities that represent the last vestiges of the promesonotal suture and metanotal groove; in some both are functionally absent. Dorsum and declivity of propodeum separated by a carina.

11 Mesopleuron without a strongly developed transverse sulcus; a vestige may remain in large workers.

12 Mesotibia without spurs.

13 Metatibia with a single, pectinate spur.

14 Metatibial gland absent (at least no external orifice or indication is present).

15 Metabasitarsus ventrally without a longitudinal glandular groove.

16 Pretarsal claws each with a single, small, preapical tooth on its inner surface.

17 Propodeal lobe in profile large and broad-based, rounded apically, continuous above with a narrow lamella that ascends the margin of the propodeal declivity.

18 AII (petiole) elongate, barrel-shaped, not marginate laterally and with a transverse carina that separates anterior and dorsal surfaces but without a similar carina posteriorly; the dorsum curves evenly down to the posterior foramen. Side of AII with a weak, oblique longitudinal carina above the level of the spiracle.

19 AIII postpetiolate, more voluminous than AII but the same length in dorsal view. AIII distinctly smaller than AIV.

20 Prora of AIII merely a curved carina that separates the anterior face of the poststernite from the lateral and ventral surfaces.

21 Pretergite of AIV in dorsal view strongly constricted with respect to posttergite of AIV.

22 Cinctus of AIV cross-ribbed.

23 Tergite of AIV without a pair of slightly depressed, subovate glandular patches on the posterior half.

24 Pygidium with its apical margin evenly curved and equipped with a continuous row of minute denticles that are all approximately equal in size.

Queen

The queen is worker-like except that ocelli are present and the mesosoma has a full complement of flight sclerites. Therefore all the worker characters listed above, except for numbers 5 and 10, occur here. Venation unknown as the two queen specimens are dealate and were captured in a single nest, which implies that the species is probably polygynous.