Crematogaster gryllsi

The microhabitat of Crematogaster gryllsi in the type locality (Fayfa Mountains) is the humid leaf litter under Acacia and Calotropis procera (Aiton) W. T. Aiton (Apocynaceae) trees. The specimens were collected by sifting leaf litter. The material from Raydah were collected by pitfall traps.

Identification
Crematogaster gryllsi is distinguished from related congeners by the combination of the following characters: Mesonotum in profile without a tubercle on promesonotal suture; propodeal dorsum and propodeal spines forming a continuous concave curve in profile; postpetiolar node entire, not bilobed dorsally; mesopleura, petiole, and postpetiole distinctly densely punctate; color uniform yellow, second half of gaster brown-yellow.

This distinct species immediately be separated from all Arabian Crematogaster species by the undivided postpetiolar node and the uniform yellow color. All other species have a divided postpetiolar node. Crematogaster gryllsi appears to be related directly to Crematogaster luctans from Kenya as it possesses an undivided postpetiolar dorsum as well. However, C. gryllsi can be separated by the following characters: metanotal groove shallowly impressed, propodeal dorsum and propodeal spines forming a continuous concave curve in profile; promesonotum side smooth; mesopleura distinctly densely punctate; whereas C. luctans has deeply impressed, U-shaped metanotal groove profile; convex propodeal dorsum in profile extending posteriorly to straight propodeal spines; mesosomal sides longitudinally striated.

Distribution based on Regional Taxon Lists
Afrotropical Region: Saudi Arabia.

Nomenclature

 *  gryllsi. Crematogaster gryllsi Sharaf & Hita Garcia, in Sharaf et al., 2019: 52, figs. 17A-C (w.) SAUDI ARABIA.

Type Material

 * Holotype: pinned worker, KSA: Fayfa, 17.29691N, 43.13500E, 837 m, 06.iv.2013 (Sharaf MR) (CASENT0872096, KSMA).
 * Paratypes: 29 pinned workers, same data as the holotype (28 w, KSMA, 1 w, CASENT0919794, CASC); Asir Province, Abha, Raydah, 18.195817N, 42.389083E, 1614 m, 31.vii.2015 (Al Dhafer et al.) (8 w, KSMA; 1 w, WMLC); Abha, Raydah, 18.19465N, 42.39485E, 1851 m, 08.vi.2014 (Al Dhafer et al.) (1 w, KSMA).

Taxonomic Notes
The record of C. luctans given by Collingwood (1985) was based on material collected from Fayfa Mountains where the species C. gryllsi was collected. Considering that the shape of the postpetiole is uncommon in the Arabian fauna and the initial identification of C. luctans was probably based on this character, it is highly likely that the record of C. luctans by Collingwood (1985) represents a misidentification. This hypothesis is further supported by the complete lack of any material of C. luctans in the WMLC. Therefore, the species was omitted from the list of Arabic species.

References based on Global Ant Biodiversity Informatics

 * Sharaf M. R., S. A. Aldawood, and F. Hita Garcia. 2019. Review of the Arabian Crematogaster Lund (Hymenoptera, Formicidae), synoptic list, distribution, and description of two new species from Oman and Saudi Arabia. ZooKeys 898: 27-81