Crematogaster ransonneti Mayr, 1868

Hosoishi, Shingo, 2020, Taxonomic review of the Crematogaster ransonneti-group in Asia, with description of a new species from Malaysia (Hymenoptera: Formicidae: Myrmicinae), Raffles Bulletin of Zoology 68, pp. 759-768 : 767

Crematogaster ransonneti Mayr, 1868

( Fig. 5 )

Crematogaster ransonneti Mayr, 1868: 287 , worker. Combination in Crematogaster (Acrocoelia) : Emery, 1922: 151. Combination in Crematogaster (Crematogaster) : Bolton, 1995: 166; Blaimer, 2012a: 55.

Type material examined. 2 syntype workers ( NHMW), Sri Lanka, Yerbury , coll. G. Mayr, no collection date.

Diagnosis of worker. Dorsal surface of head smooth and shiny. Pronotum smooth. Propodeal spine long. In dorsal view petiole diamond-shaped, broader in the middle portion. Postpetiole weakly bilobed posteriorly, but without longitudinal median sulcus.

Measurements and indices: NHMW syntype workers (n = 2). HW 0.95–0.97; HL 0.95–0.97; CI 99–100; SL 0.82– 0.87; SI 87–90; EL 0.19; PW 0.55–0.56; WL 1.1–1.2; PSL 0.21–0.23; PtL 0.33–0.34; PtW 0.31–0.35; PtH 0.18–0.20; PpL 0.17–0.18; PpW 0.24–0.26; PtHI 55–61; PtWI 94–106; PpWI 142–144; WI 73–78.

General description of worker. Head as broad as long in full-face view, posterior margin almost straight, posterior corner rounded. Frontal carina extending to ⅓ length of head. Occipital carina developed. Mandible with four teeth, apical and subapical teeth large. Anterior clypeal margin convex in median portion. Compound eyes slightly projecting beyond lateral margins of head in full-face view. Scape reaching posterior corner of head. Antennal club 3-segmented.

Pronotum without distinct ridges on dorsolateral margin. In lateral view, mesonotum posteriorly with weak longitudinal ridges. Mesonotum slightly higher than pronotum in lateral view. Metanotal groove straight in dorsal view, forming a deep concavity between mesonotum and propodeum. Metapleural gland opening slit-shaped. Propodeal spiracles dorsoventrally oval, its horizontal diameter larger than vertical diameter, located on posterolateral corner of propodeum in lateral view. Propodeal spines long, directed posterolaterally in dorsal view.

Petiole diamond-shaped and broadest at mid-length in dorsal view; spiracle situated at midportion between dorsal and ventral margin of petiole in lateral view, directed laterally. Subpetiolar process undeveloped. Postpetiole weakly bilobed, but without longitudinal median sulcus in dorsal view. Petiole wider than postpetiole in dorsal view.

Sparsely hirsute with erect setae. Scape with abundant suberect setae. Dorsal face of head with suberect setae. Clypeus with suberect setae; one pair of longer setae directed medially on anteriormost portion. Anterior clypeal margin with two pairs of longer setae, mixed with some shorter setae on the sides. Mesosoma with sparse longer erect setae, mixed with shorter decumbent setae. Fourth abdominal tergite with sparse suberect to decumbent setae.

Dorsal surface of head smooth and shiny. Clypeus generally smooth, but indistinct rugulae anteriorly. Promesonotum smooth and shiny, but posterior mesonotal ridge with feeble rugulae. Lateral surface of pronotum smooth and shiny. Mesopleuron weakly sculptured. Lateral surface of propodeum smooth and shiny. Propodeal dorsum and declivity smooth and shiny.

Body colour reddish-brown.

Distribution. This species is known from India (Karnataka [Kanara], Sikkim) ( Bingham, 1903) and Sri Lanka ( Fig. 1 ).

Notes. This species is similar to C. keris , but can be distinguished by the smooth and shiny surface of gena and promesonotum.

Figures

Fig. 5. Crematogaster ransonneti, NHMW syntype worker from Sri Lanka (HW, 0.95; WL, 1.07). A, body in lateral view; B, full-face view of head; C, dorsal view of mesosoma; D, dorsal view of petiole and postpetiole.

Fig. 1. Distribution map of Crematogaster cornuta, C. keris, and C. ransonneti. Open circle = C. cornuta; open square = C. keris; open triangle = C. ransonneti.