Crematogaster schimmeri

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Crematogaster schimmeri
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Crematogastrini
Genus: Crematogaster
Species group: biroi
Species: C. schimmeri
Binomial name
Crematogaster schimmeri
Forel, 1912

Crematogaster schimmeri casent0907514 p 1 high.jpg

Crematogaster schimmeri casent0907514 d 1 high.jpg

Specimen Labels

One of a number of Crematogaster species in the subgenus Orthocrema that possesses a soldier caste.

Identification

Hosoishi and Ogata (2016) - In the worker this species can be distinguished from all other members of the Crematogaster biroi group by the distinct compound eyes, sculptured dorsal surface of head, and petiole squared with angulate anterolateral corners. This species is similar to Crematogaster reticulata, but can be distinguished from it by the propodeal spiracles touching metapleural gland bulla and squared petiole with angulate anterolateral corners.

Terayama (2009) assigned this species to the subgenus Decarema by having 10-segmented antennae. However, examinations of the type specimens reveals that the species has 11-segmented antennae and belongs to the subgenus Orthocrema (Hosoishi & Ogata, 2009a).

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Oriental Region: Taiwan (type locality).

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

Castes

In this and other species belonging to subgenus Orthocrema, a third caste exists that is intermediate in size, weight and morphology between winged queens and workers. These individuals are numerically few in the colonies, and lay many unfertilized eggs that are mostly eaten by larvae. Histology confirmed the lack of a spermatheca, hence sexual reproduction is impossible. Using scanning electron microscopy and ovarian dissections, Peeters et al. (2013) showed that this third caste is a patchwork of queen-like and worker-like traits. It is a soldier caste with a specialized trophic function.

Developed ovaries of a soldier of C. schimmeri. Photo by C.C. Lin
Developed ovaries of a C. schimmeri worker. Its ability to lay trophic eggs is much less than workers'. Photo by C.C. Lin
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Dorsal SEMs of thorax of three castes (Q: queen, S: soldier; W: worker). Note different sizes and degrees of fusion of flight sclerites. Photo by Johan Billen

Nomenclature

The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.

  • schimmeri. Crematogaster schimmeri Forel, 1912a: 69 (w.q.) TAIWAN. Combination in C. (Decacrema): Emery, 1922e: 132; in C. (Orthocrema): Hosoishi & Ogata, 2010: 2..

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.

Description

Worker

Hosoishi and Ogata (2016) - (n=5) HW 0.44–0.48; HL 0.45–0.49; CI 96–98; SL 0.38–0.40; SI 79–87; EL 0.12–0.13; PW 0.29–0.32; WL 0.50–0.54; PSL 0.08–0.10; PtL 0.14–0.17; PtW 0.15–0.17; PtH 0.11–0.14; PpL 0.11–0.12; PpW 0.16–0.18; PtHI 75–82; PtWI 88–107; PpWI 142–150; WI 107–113.

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 weakly 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 almost straight anterior margin in dorsal view, distinctly lower than pronotum in lateral view. Pronotal dorsum with 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 parallel sides and angulate shoulders anteriorly, longer than wide. Posterior portion of petiole with short process that is slightly higher than posterior margin of petiole disc in lateral view. Subpetiolar process developed as blunt 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 developed as acute process.

Integument essentially sculptured. Dorsal surface of head weakly sculptured reticulately. Mandibles with feeble rugulae and smooth interspaces. Clypeus weakly sculptured with longitudinal rugulae; longer rugulae extending to posterior clypeal margin. Anterolateral shoulders of pronotum with rugulae. Lateral surface of pronotum sculptured in higher portion, but relatively smooth and shining in lower portion. Pronotum and mesonotum with longitudinal rugulae and sculptured interspaces. Mesopleura sculptured, but relatively smooth in central areas. Rugula on higher portion of mesopleura extending to small pit of mesothoracic spiracles. Dorsal surface of propodeum sculptured. Dorsal and lateral surfaces of petiole sculptured. Dorsal and lateral surfaces of postpetiole sculptured.

Standing pilosity sparse. Dorsal face of head with several pairs (c. 9) of erect and stout long setae, and short and decumbent 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 some pairs (three to four) of short setae laterally. Scapes with decumbent to appressed setae. Mesosoma with five pairs of long erect and stout setae (ps1PN, ps2PN, psaMN, pspMN, and ps2PS) that are much longer than other erect setae. Posterolateral tubercles of petiole posteriorly with one pair of stout long setae. Postpetiole with three pairs of stout long setae on disc anterodorsally, anterolaterally and posteriorly. Fourth abdominal tergite with several pairs (c. 12) of erect and stout setae, and short appressed setae sparsely.

Body yellow. All flagellar segments yellow.

Type Material

Hosoishi and Ogata (2016) - Syntype workers, Pilam, Taiwan (H. Sauter) (Musee d'Histoire Naturelle Genève, examined). One syntype worker (middle specimen of three on one pin) in MHNG here designated Lectotype.

References