Crematogaster roslihashimi

An endemic Malysian (peninsular eastern coast) member of a group of Crematogaster species associated with Macaranga plants in Sumatra, Borneo, and Peninsula Malaysia. This species is only known from a few collections.

Identification
Feldhaar et al. (2016) - A member of the Crematogaster decamera subgroup within the Crematogaster borneensis group. Worker: Propodeal spines absent, scape index (SI) > 0.7, head distinctly longer than wide (CI: 0.91), legs realtively long (RLEG 0.71-0.73). Queen: EL 0.3 – 0.32; REL < 0.28, OD1 > OW, Elongated head (CI < 0.9), PI ≤ 1.0.

The species is closely related to Crematogaster decamera based on mitochondrial DNA as well as nuclear DNA (EF-1a) (Feldhaar et al., 2003b; Feldhaar et al., 2010).

Distribution based on Regional Taxon Lists
Indo-Australian Region: Borneo, Malaysia.

Biology
Feldhaar et al. (2016) - Crematogaster roslihashimi is a very rare species endemic to a small region on the East coast of Peninsula Malaysia (near Kuantan) and is was found on only two wax-covered hosts of the section Pachystemon (Macaranga constricta, Macaranga hypoleuca).

Nomenclature

 *  roslihashimi. Crematogaster roslihashimi Feldhaar, Maschwitz & Fiala, 2016: 664, figs. 3.8, S1.8A-B (w.q.) MALAYSIA.

Worker
Paratype. CI 0.90, DPPW 0.18, DPW 0.19, EL 0.09, HL 0.61, HW 0.55, LHT 0.51, (LPS not measured, no spines), MTW 0.34, PI 1.06, REL 0.14, RLEG 0.72, SI 0.74, SL 0.41, (TL 2.8), WL 0.71.

(n=3) CI 0.90-0.91, DPPW 0.18-0.19, DPW 0.19-0.20, EL 0.09 -0.1, HL 0.61-0.65, HW 0.55-0.59, LHT 0.5-0.52, (LPS not measured, no spines), MTW 0.34-0.36, PI 1.02-1.07, REL 0.14-0.15, RLEG 0.71-0.73, SI 0.69-0.74, SL 0.41, (TL 2.8- 2.9), WL 0.69-0.73

Colour uniformly light to medium brown. Workers monomorphic in size. Total body length of workers 2.8 mm to 2.9 mm, but this is a measurement from a single mature colony only. Workers from incipient colonies are expected to be smaller. Head and gaster shiny with smooth surface, alitrunk slightly less shiny and faintly shagreened. All body parts bear appressed pubescent hairs. Long flexuous setae present on head gaster and abdomen: on head especially in frons, on gaster more on the posterior margins of tergites and sternites. Only few setae on alitrunk and one pair each on petiole and postpetiole. Head distinctly longer than wide and only slightly rounded on sides (CI: 0.90-0.91). Anterior clypeal margin slightly convex and with a row of long erect setae projecting anteriorly. Clypeus with a small median node. Occipital margin slightly concavely rounded, occipital lobes rounded. Mandibles relatively short and with four denticles, capable of closing tightly against the clypeus. Denticles increasing continuously in size from most proximate to most distal denticle. Surface of mandibles smooth, covered with short pubescent hairs. Antennae relatively long in comparison to head width (SI 0.69-0.74) and densely covered in short pubescent hair. Terminal two funicular segments forming a club.

Compound eyes elliptically-shaped and not protruding over margin of head in full-face view. Pronotum and mesonotum form a convex dome in profile. Anterodorsal surface of pronotum sloping downwards as steep as posterodorsal surface of mesonotum. Metanotal groove slightly notched and clearly developed, whereas the promesonotal suture barely visible and not prominent.

Propodeal spines always absent. A nodiform elevation may be present above the propodeal spiracle, albeit not very prominent. Slope of the posterior face of the propodeum similar to posterior slope of mesonotum and approximately 45°.

In dorsal view petiole and postpetiole approximately the same width or petiole slightly broader. Anterodorsal surface of petiole broadly flattened. Both petiole and postpetiole round in dorsal view. Subpetiolar process usually absent. Petiole and postpetiole wide in comparison to MTW (MTW/DPW: <1.8; in all other species >1.8 and usually larger than 1.9).

Queen
Holotype. CI 0.84, DPPW 0.45, DPW 0.45, EL 0.3, HL 1.13, HW 0.95, LHT 0.81, MTW 0.83, OD1 0.11, OD2 0.05, OW 0.07, PI 1.0, REL 0.27, RLEG 0.43, ROD 0.12, ROD2 0.05, SI 0.6, SL 0.57, (TL 5.8), WL 1.9.

(n=4) CI 0.84-0.89, DPPW 0.46-0.5, DPW 0.45-0.48, EL 0.3- 0.32,HL 1.10-1.15, HW 0.95-1.02, LHT 0.81, MTW 0.8-0.87, OD1 0.11-0.16, OD2 0.05-0.08, OW 0.07-0.09, PI 0.96-1.0, REL 0.27-0.28, RLEG 0.43-0.46, ROD 0.12-0.17, ROD2 0.05- 0.08, SI 0.57-0.64, SL 0.57-0.61, (TL 5.8-6.1), WL 1.73-1.9

Queens small, 5.8 to 6.1 mm in total body length and uniformly medium to dark brown in colour. Surface of head, gaster and alitrunk not structured but densely covered in pubescent hairs. Long flexuous setae present on head gaster and abdomen: on head especially in frons, on gaster more on the posterior margins of tergites and sternites. A row of long erect setae pointing anterior present on the clypeus. Mandibles relatively short, capable of closing tightly against the clypeus.

Head distinctly longer than wide (CI: 0.84-0.89). Sides of the head straight and not becoming narrow towards the clypeus. Occipital margin of the head convex. Occipital lobes rounded. Anterior clypeal margin slightly convex. Terminal four segments of funiculus forming a distinct antennal club. Funiculus covered densely in pubescent hair so that borders between antennal segments barely visible. Antennal scrobes strongly developed, with an acute and marked dorsal margin; the frontal carinae short.

Compound eyes only slightly oval-shaped from lateral view and maximum head width with compound eyes only slightly wider than HW. Compound eyes small relative to head length spanning one third or less of HL (REL 0.27-0.28). Maximum diameter of compound eyes 0.3 to 0.32 mm. Ocelli relatively small in diameter. The two lateral ocelli widely spaced and the median ocellus always smaller in diameter than the distance between the two lateral ocelli.

Mesoscutum convexly rounded anterodorsally. Mesoscutellum nearly in horizontal plane in lateral view. Propodeum flattened dorsally and then drops off steeply posterior of the propodeal spiracle. Mesoscutum relatively short, stretching out over approximately a third of the alitrunk in lateral view. In dorsal view, the posterior margin of the propodeum forms a straight line and the mesonotum is broadly triangular. Propodeum not armed with spines. Petiole in dorsal view rounded and node approximately as wide as long. Petiole slightly less wide than postpetiole (PI≤1.0). In lateral view the petiole and postpetiole nodiform. Petiole and postpetiole broad in relation to MTW (MTW/DPW 1.69-1.78; in all other Macaranga-associated Decacrema MTW/DPW rarely <2.0).

Type Material
Holotype. Queen (to be deposited in, provisional specimen number 22UM-Q) (U. Maschwitz) on 2.12.1996 in Kuantan from Macaranga constricta. Paratype. Worker collected from the same colony (to be deposited in SMNK, provisional specimen number 22UM-W).

Determination Clarifications
The species was formerly called Crematogaster msp. 9 in publications by our group (Fiala et al., 1999).