Aptinoma Fisher, 2009

Yoshimura, Masashi & Fisher, Brian L., 2011, A revision of male ants of the Malagasy region (Hymenoptera: Formicidae): Key to genera of the subfamily Dolichoderinae, Zootaxa 2794, pp. 1-34 : 9-10

publication ID	https://doi.org/ 10.5281/zenodo.276993
DOI	https://doi.org/10.5281/zenodo.5689421
persistent identifier	https://treatment.plazi.org/id/03F81D2F-900F-FFBF-FF0B-BC8BC6526733
treatment provided by	Plazi
scientific name	Aptinoma Fisher, 2009
status

Treatment

( Figs 2 View FIGURES 1 – 5 , 7 View FIGURES 6 – 10 , 11 View FIGURES 11 – 15 , 16 View FIGURES 16 – 23 , 17, 24 View FIGURES 24 – 28 , 30 View FIGURES 29 – 33 , 35 View FIGURES 34 – 38 , 42 View FIGURES 41 – 45 , 50 View FIGURES 49 – 51 , 56 View FIGURES 55 – 57 , 62 View FIGURES 62 – 66 , 67 View FIGURES 67 – 71 , 72 View FIGURES 72 – 76 , 77 View FIGURES 77 – 81 )

With characters of Dolichoderinae . All known males alate. Median hypostoma present ( Fig. 62 View FIGURES 62 – 66 ). Mandible triangular, but its basal angle indistinct. Basal and masticatory margins of mandible wholly covered with many serrate denticles ( Fig. 72 View FIGURES 72 – 76 ). Apical tooth on masticatory margin longer than subapical one. Palpal formula 6,3 (one specimen of A. mangabe dissected: Fig. 77 View FIGURES 77 – 81 ). Third maxillary palpal segment nearly as long as fourth. Labrum not bilobed, with single distal apex and concavity on its distal margin absent ( Fig. 67 View FIGURES 67 – 71 ). Antennal scape excluding its basal condyle shorter than length of flagellar segments 1+2 ( Fig. 2 View FIGURES 1 – 5 ). Pedicel conical. First and second flagellar segments straight. Axillae on mesonotum medially compressed, anterior and posterior margins not parallel. Petiolar node raised vertically, its anterior margin nearly as long as the posterior margin in lateral view ( Fig. 7 View FIGURES 6 – 10 ). Node not much expanded laterally. Petiole narrowly attached to abdominal segment III. Anterior surface of abdominal segment III with indentation that fits posterior surface of petiolar node. Pygostyles present.

Distal portion of abdominal sternum IX broadly spatulate ( Fig. 24 View FIGURES 24 – 28 ). Apicoventral portion of basimere with spine-like projection ( Fig. 30 View FIGURES 29 – 33 ). Harpago moderate in size, and widely separated from basimere by membranous region ( Figs 30 View FIGURES 29 – 33 , 35 View FIGURES 34 – 38 ). Harpago narrow in ventral view, without a distinct ventral face (as in Fig. 23 View FIGURES 16 – 23 ). Basal portion of aedeagus without any distinct ventral lobe ( Fig. 42 View FIGURES 41 – 45 ). Ventral margin of aedeagus with denticles.

Forewing not extremely elongate apical to wing stigma, its radial sector reaches costal margin, media and 2rsm recognizable apical to Rs+M, and 1m-cu present ( Fig. 50 View FIGURES 49 – 51 ). On hindwing, M+Cu, free sections of radial sector and cubitus almost vestigial, and cu-a weak but still present ( Fig. 56 View FIGURES 55 – 57 ).

Remarks. Genus Aptinoma is endemic to Madagascar and only males of Aptinoma mangabe are presently known. Fisher (2009) proposed the combination of a shorter scape compared with flagellomeres 1+2, a palpal formula of 6,3, and a raised petiolar node as a diagnostic set of characters for Aptinoma in the Malagasy region. Here we propose a character unique to Aptinoma that consistently separates this genus from the other genera and provide additional characters to separate Aptinoma from the other Malagasy dolichoderine genera.

Males of Aptinoma are distinguished easily from other Malagasy dolichoderine genera by an abdominal sternum IX which is distally broadly spatulate ( Fig. 24 View FIGURES 24 – 28 ). This character is so far globally unique to Aptinoma . In the Malagasy region, Technomyrmex and Tapinoma are superficially the most similar to Aptinoma . Aptinoma and Technomyrmex share the following unique characters: basal margin of the mandible wholly covered with serrate denticles and the concavity on the distal margin of the labrum reduced ( Figs 72, 76 View FIGURES 72 – 76 ). Aptinoma and Tapinoma share a unique projection on the apicoventral portion of the basimere ( Figs 29, 30 View FIGURES 29 – 33 ). The petiolar node in Aptinoma rises almost vertically, although the sternum is thickened posteriorly and the whole shape of the petiole seems to decline anteriorly ( Figs 7 View FIGURES 6 – 10 , 17 View FIGURES 16 – 23 ). Therefore, the petiolar node in Aptinoma is best described as vertical, not as declining anteriorly as described in Fisher (2009).

The phylogenetic analysis of Ward et al. (2010) gives the intra-tribal relationship of Tapinomini as ((( Aptinoma + Tapinoma ) + Liometopum Mayr ) + ( Axinidris Weber + Technomyrmex )). They propose two hypotheses for the evolution of the “highly reduced petiole” seen in Aptinoma , Tapinoma , and Technomyrmex . The question is whether the petiole evolved once at the root of Tapinomini or at least twice at the roots of ( Aptinoma + Tapinoma ) and Technomyrmex independently. If we limit the discussion to males, the present result, a vertical petiolar node in Aptinoma , supports the theory that an anteriorly-declined and reduced petiolar node evolved independently in Tapinoma and Technomyrmex , and that there has been no reversal in Aptinoma , Axinidris , and Liometopum .