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.

Taxonomic Notes
The record of Crematogaster 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.

Worker
Holotype. EL 0.22; HL 0.75; HW 0.80; LHT 0.57; PPL 0.12; PPW 0.20; PRW 0.45; PTH 0.17; PTL 0.22; PTW 0.32; SL 0.62; ML 0.90; Indices. CI 107; LBI 158; OI 28; PPI 63; PTHI 77; PTWI 145; SI 78. Paratype. EL 0.15–0.25; HL 0.65–0.87; HW 0.67–0.87; LHT 0.45– 0.57; PPL 0.12–0.18; PPW 0.17–0.25; PRW 0.40–0.55; PTH 0.12–0.25; PTL 0.12–0.25; PTW 0.27–0.42; SL 0.50–0.70; ML 0.75–1.0; Indices. CI 96–107; LBI 124–178; OI 22–31; PPI 59–81; PTHI 88–125; PTWI 145–267; SI 68–93 (N = 15).

Workers of the new species showing marked size variation in the two nests.

Head. Head as long as or little broader than long with convex sides and feebly concave posterior margin; antennae 12-segmented; in full-face view antennal scapes when laid back from their insertions reach or surpass posterior margin of head by the length of the first funicular segment; eyes of moderate size (OI 22–31), located nearly at mid-length of head in full-face view and with about 12 ommatidia in the longest row; anterior clypeal margin broadly convex. Mesosoma. Mesonotum in profile without a small tubercle on promesonotal suture; promesonotal suture feebly impressed; mesonotum convex in profile; median mesonotal carina absent; metanotal groove shallowly impressed but distinct; propodeal spines long, sharp and upward directed; propodeal spiracle circular, and located below the base of the propodeal spines; propodeal dorsum and propodeal spines forming a continuous concave curve in profile. Petiole. In profile petiole distinctly longer than high (PTHI 88–125; PTWI 145–267); approx. twice broader anteriorly than posteriorly in dorsal view; subpetiolar process well developed. Postpetiole. Postpetiolar node entire, not bilobed in dorsal view. Pilosity. Cephalic and clypeal surfaces with abundant scattered fine appressed pubescence; anterior clypeal margin and mandibles with abundant scattered long yellow hairs; antennae and legs with dense appressed pubescence; mesosoma without hairs; promesonotum and mesonotum dorsum with few appressed pubescence; petiole, postpetiole and the first three gastral tergites with appressed pubescence; few hairs on the terminal gastral segment. Sculpture. Mandibles longitudinally striated; clypeal surface smooth; area in front of eyes finely longitudinally striated; cephalic surface smooth; antennal fossae surrounded by fine and curved striolae; promesonotum side smooth; promesonotum dorsum faintly longitudinally rugulose; propodeal dorsum faintly longitudinally striated; mesopleura, petiole, and postpetiole distinctly densely punctate; metapleura faintly, irregularly striated; gastral tergites smooth. Color. Head, mesosoma, petiole, postpetiole, first gastral tergite, legs, and antennae uniform yellow, second half of gaster brown-yellow.

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).

Etymology
The patronymic epithet has been selected in honor of Bear Grylls, the survival instructor in recognition of his remarkable efforts in spreading the culture of survival globally.

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