Dolichoderus scabridus species group

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Based on Dill 2002.

Species

Oriental species

Australian species

Distribution

Identification

This group is well defined by means of the alveolate surface sculpturing and the typical propodeal spines. In addition, it is well characterized by the shape of the head (narrow convex portion of the posterior margin) and the very long scape (fig. III-73 , fig. III-74: SI). The long and very straight spines differ from the more horn-like and curved spines of several species of the cuspidatus group.

Description

Worker

(fig. III-34): Medium-sized to large species. Head and most parts of the alitrunk alveolate, the honeycomb-like cavities are ± deep and shining, each bearing a single hair; the separating rims finely punctate and matt. Entire body surface with long, erect hairs; pubescence lacking or dense (Australian species). Head about as wide as long, sub-oval; posterior margin weakly emarginate, this concave portion distinctly narrower than clypeus; scape slender and long (SI around 130); pronotum unarmed; mesonotum slightly convex, its anterior margin distinct, its posterior margin indistinct; propodeum bearing a pair of long, ± straight, pointed spines, pointing upwards, backwards, and slightly sidewards (figs . III-34b·c). Petiole scale ± bulky.

Queen

(only known of Dolichoderus beccarii) (fig. III-35): Similar to workers, but winged with a large, strongly convex flight thorax and distinctly separated sclerites. Posterior edges of propodeum expanded to short spines that are much shorter than those of the workers.

Males have yet to be collected.

Notes

Apart from the two described Oriental species beccarii and Dolichoderus indrapurensis, there are three Australian species belonging to this group (Dolichoderus angusticornis, Dolichoderus scabridus, and Dolichoderus ypsilon). Thus, the scabridus group is identical with Wheeler’s (1935a) subgenus Diceratoclinea (synonymized by Shattuck 1992). Rather than to any other Oriental species groups, the scabridus group is morphologically closer to several Australian species which had been grouped by Wheeler (1935a) in the subgenus Acanthoclinea (Dolichoderus clarki, Dolichoderus dentatus, Dolichoderus doriae, and Dolichoderus extensispinus; subgenus synonymized by Shattuck 1992). These species differ from those of the scabridus group basically by the presence of an additional pair of spines on the pronotum. Consequently, the Oriental species of the scabridus group represent a zoogeographical link between the two faunal regions. However, they seem to be restricted to the perhumid rainforest belt (Peninsular Malaysia, Sumatra, and Borneo) and do not occur North of the Isthmus of Kra.

Related Pages

References