Crematogaster suehiro

This species inhabits developed forests and nests in dead twigs on trees.

Identification
Hosoishi and Ogata (2016) - A member of the Crematogaster quadriruga group. We have not examined the types of C. suehiro, but the original description and figures closely match the specimens examined. In the worker this species can be distinguished from all other members of the Crematogaster quadriruga group by the distinct compound eyes, propodeal spiracles small and apart from metapleural gland bulla, and petiole tapering anteriorly in dorsal view. This species is similar to C. quadriruga, but can be distinguished from it by the longitudinal rugulae on the clypeus extending to the bottoms between frontal carinae and petiole tapering anteriorly.

In the original description of Crematogaster miroku, Terayama (2013) separated the species from Crematogaster osakensis by the carinate dorsolateral corners of mesonotum and smooth and shining mesopleuron. However, the original description and character states mentioned by him match well with C. suehiro. Additionally longer scape (SI 96) in holotype of C. miroku also suggests the affinity with C. suehiro (SI 94–100) rather than C. osakensis (SI 77–84). In a key to Japanese Crematogaster species (Terayama, Kubota & Eguchi, 2014), C. miroku was separated from C. suehiro by the petiole with convex sides and slightly broader posteriorly, but he mentioned ‘Petiole.., widest at posterior end’ in the original description (Terayama, 2013). Those slight differences are treated as variation within one species, C. suehiro until additional characters including molecular data are available.

Distribution
Southern parts of Japan (Ishigaki Island, Okinawa Island).

Distribution based on Regional Taxon Lists
Palaearctic Region: Japan.

Nomenclature

 *  suehiro. Crematogaster suehiro Terayama, 1999f: 726 JAPAN [not seen]. Senior synonym of miroku: Hosoishi & Ogata, 2016: 598.
 * miroku. Crematogaster miroku Terayama, 2013: 12, figs. 23-25 (w.) JAPAN. Junior synonym of suehiro: Hosoishi & Ogata, 2016: 598.

Worker
Hosoishi and Ogata (2016) - (n=6) HW 0.46–0.52; HL 0.47–0.51; CI 96–102; SL 0.46–0.50; SI 94–100; EL 0.12–0.14; PW 0.30–0.33; WL 0.54–0.6; PSL 0.11–0.13; PtL 0.18–0.20; PtW 0.16–0.18; PtH 0.14–0.15; PpL 0.12–0.14; PpW 0.17–0.19; PtHI 74–79; PtWI 85–90; PpWI 123–158; WI 106–112.

Workers monomorphic. Head subquadratic in full-face view. Mandibles with four teeth arranged at an equal distance, apical and subapical teeth large, basal two teeth smaller. Anterior clypeal margin convex in medial portion. Compound eyes distinctly projecting beyond lateral margins of head in full-face view. Scapes reaching posterolateral corners of head.

Pronotal collar with weakly concave anterior margin in dorsal view, distinctly lower than pronotum in lateral view. Pronotal dorsum without distinct ridges laterally. Mesonotal dorsum with lateral ridges. Pronotum and mesonotum in lateral view not clearly forming continuous dorsal outline. Metanotal groove in dorsal view transverse, almost straight in median portion, forming deep concavity that is laterally margined by lamellate ridges. Propodeal spiracles oval, situated at posterolateral corners of propodeum, touching metapleural gland bullae. Propodeal spines developed, longer than diameter of propodeal spiracles, in dorsal view directed posteriad.

Petiole in dorsal view with subparallel sides and narrow anteriorly, longer than wide. Posterior portion of petiole without distinct process in lateral view. Subpetiolar process weakly developed as small process. Postpetiole in lateral view with weakly convex dorsum, as high as petiole, in dorsal view slightly wider than petiole, weakly bilobed posteriorly but without longitudinal sulcus. Subpostpetiolar process undeveloped, but venter of postpetiole convex.

Integument essentially smooth and shining. Dorsal surface of head smooth and shining. Mandibles with feeble rugulae and smooth interspaces. Clypeus generally smooth and shining, but with one distinct pair of longitudinal longer rugulae and one pair of shorter rugulae laterally; longer rugulae extending to posterior clypeal margin. Dorsal and lateral surfaces of pronotum smooth and shining; anterolateral shoulders of pronotum without rugulae. Mesopleura smooth and shining. Dorsal surface of propodeum generally smooth and shining, but with one longitudinal rugulae anteriorly. Dorsal and lateral surfaces of petiole smooth and shining. Dorsal and lateral surfaces of postpetiole smooth and shining.

Standing pilosity sparse. Dorsal face of head with erect setae sparsely. Clypeus with two pairs of long setae in anterior portion, one directed upward and the other downward. Anterior clypeal margin with one pair of long setae medially and short setae laterally. Scapes with suberect setae. Mesosoma with five pairs of long erect and stout setae [ps1PN, ps2PN, psaMN, pspMN (also one pair of short setae medially), and ps1PS] that are much longer than other erect setae. Posterolateral tubercles of petiole posteriorly with two pairs of stout long setae. Postpetiole with four pairs of setae on disc anterodorsally, anterodorsally and posteriorly. Fourth abdominal tergite with erect setae abundantly, and short decumbent setae sparsely.

Body yellow. All flagellar segments yellow.

Queen
Paratype - Head length 0.70 mm; head width 0.70 mm; scape length 0.58 mm; cephalic index 100; scape index 82; Weber's length of alitrunk 1.38 mm; petiole length 0.45 mm; petiole height 0.25 mm; dorsal petiole width 0.30 mm; total length 1.1 mm.

Head, alitrunk, petiole, postpetiole, and 1st gastral segment yellow; 2nd to terminal segments of gaster brown.

Lateral margins of petiole converging toward the base in dorsal view. Head and alitrunk smooth and shining; petiole with micropunclate sides and smooth dorsum; postpeliole smooth; gaster smooth and shining.

Type Material
Holotype Worker. Banna-dake, Ishigaki-jima. Okinawa Pref., VII I. 1994, H. Takamine leg. Paratypes 2 workers, 1 female, 1 intercaste, same data as holotype; 3 workers, Omoto-dake. Ishigaki·jima, 16. III. 1984, M. Morisita leg.