Crematogaster sisa

Rarely collected but appears to be an endemic high elevation Madagascar species.

Identification
Blaimer (2010, 2012c) - A member of the Crematogaster hova group. This species is easily distinguished morphologically by its uniquely shaped subpetiolar process in form of an acute tooth.

Distribution
Madagascar: Only known from two localities in the rugged and isolated Manongarivo massif (Blaimer 2010).

Distribution based on Regional Taxon Lists
Malagasy Region: Madagascar.

Biology
Collections of foraging workers were made while sifting litter and beating vegetation in montane rainforest habitats at 1580 and 1860 m. No nest collections have yet been recorded for this species, thus reproductives and natural history are entirely unknown. (Blaimer 2010)

Nomenclature

 *  sisa. Crematogaster sisa Blaimer, 2010: 29, figs. 33, 39 (w.) MADAGASCAR.

Worker
Measurements (n=10). HW 0.89–1.14; HL 0.81–1.08; EL 0.21–0.27; SL 0.73–0.84; WL 0.91–1.12; SPL 0.16–0.24; PTH 0.16–0.23; PTL 0.24–0.31; PTW 0.26–0.35; PPL 0.17–0.22; PPW 0.24–0.33; LHT 0.71–0.90; CI 1.05–1.17; OI 0.22–0.28; SI 0.78–0.90; SPI 0.17–0.21; PTHI 0.65–0.83; PTWI 0.91–1.24; PPI 1.33–1.53; LBI 1.23–1.30.

Medium to large species (HW 0.89–1.14, WL 0.91–1.12).

Masticatory margin of mandibles with 5 teeth; posterior margin of head straight or medially depressed, laterally forming gentle round corners; 1–3 ocelli sometimes present on large workers; antennal scapes just surpassing posterior margin of head; midline of eyes situated at midline of head in full face view.

Pronotum laterally angular; promesonotal suture usually complete, and distinctly and broadly impressed, continuing laterally to mesopleural spiracle and thereby constricting mesonotum in relation to pronotum; dorsum of promesonotum more or less flat in lateral view; antero-medial portion of mesonotum slightly raised with respect to pronotum, but not tuberculate; dorsum of mesonotum flat, lateral portion broadly angular; mesonotum postero-laterally angular or tuberculate, and with a distinct to indistinct posterior face; propodeal spines small to medium sized (SPI 0.17–0.21), half as long to as long as width between their bases, evenly tapering, straight or weakly down-curved, in dorsal view weakly diverging; petiole in dorsal view trapezoidal or suboval, weakly lobed or rounded, laterally weakly carinate, with weak postero-lateral tubercle; dorsum of petiole weakly concave; subpetiolar process articulated as acute and distinct antero-ventral tooth, but rarely may be present as only a minute tooth.

Type Material
Holotype worker. Madagascar: R.S. Manongarivo, -14.02167, 48.41833, 1580m, 27.x.1998, sifted litter (leaf mold, rotten wood), montane rainforest, B.L.Fisher#1970(49)-2 (CASENT0193556) (deposited in ).

Paratypes. 4w, same locality and collection data as holotype (B.L.Fisher#1970(49)-2, CASENT0193557, CASENT0193542 and CASENT0193543; #1972(11)-1, CASENT0193009) (deposited in, , , ).

Etymology
“Sisa” is Malagasy for “remnant” and this species is named in allusion to its isolated distribution. “Sisa” is used in this combination as a noun in apposition.

References based on Global Ant Biodiversity Informatics

 * Blaimer B. B. 2012. Acrobat ants go global  Origin, evolution and systematics of the genus Crematogaster (Hymenoptera: Formicidae). Molecular Phylogenetics and Evolution 65: 421-436.