Myrmecina curvispina

Collection notes show M. curvispina has been sampled from litters in rain forests and rubber plantations.

Identification
Okido, Ogata, and Hosoishi (2020) - A member of the gracilis complex (M. curvispina, Myrmecina gracilis and Myrmecina raviwonghei). Among these species, M. curvispina can be distinguished by having its smooth and shining first gastral sternum.

Zhou et al. (2008) - The new species resembles Myrmecina curtisi Donisthorpe, but differs from the latter in its obviously out-curved propodeal spines, smaller eyes, less convex dorsum of the alitrunk, and the acute and rectangular anteroventral pronotal angles.

Distribution
Guangxi Province, China.

Distribution based on Regional Taxon Lists
Oriental Region: Vietnam. Palaearctic Region: China.

Castes
Known only from the worker caste.

Nomenclature

 *  curvispina. Myrmecina curvispina Zhou, Huang & Ma, 2008: 286, figs. 1-3 (w.) CHINA.

Worker
Holotype. TL 3.43, HL 0.78, HW 0.80, C I 103, SL 0.63, SI 78, PW 0.59, AL 0.91, EL 0.09, PL 0.24, PH 0.24, PNW 0.24, PPL 0.15, PPH 0.26, PPW 0.28.

Head square, with broadly concave posterior margin, slightly convex sides and developed occipital carina. Mandibles massive triangular, masticatory margin armed with two big apical teeth followed by a row of small blunt teeth. Clypeus with anterior margin slightly concave, bearing a small projection in the middle. Frontal lobes slightly raised, divergent behind, without a narrow oval smooth space between them. Eyes small and long oval, situated laterally a little before the middle of head, consisting of less than ten ommatidia. Antennae 12-segmented; scape slightly curved, almost reaching occipital corner, cylindrical at base and increasing in breadth to apex; club 3-jointed, with apical segment longer than the two preceding ones combined. Alitrunk obviously convex above, gradually tapering posteriorly in dorsal view; anterior margin roundly convex with humeral corners distinctly angular; the anteroventral pronotal angle tooth-like, acute and rectangular in profile. Anterolateral corner of dorsum of propodeum with developed and acute triangular teeth; declivity concave; propodeal spines long, pointing backwards, divergent posteriorly, distinctly curved outwards at apex in dorsal view. Petiole quadrangular, not pedunculate, dorsal node with distinct cross ridge; subpetiolar process small, anteriorly situated and triangular; postpetiole transversely broad, shorter but broader than petiole. Gaster broadly oval.

Mandibles, clypeus, declivity of propodeum, legs, anterior surface of petiole and gaster smooth and shining. Antennal scape opaque, with indistinct longitudinal rugae. Head, alitrunk strongly longitudinally striate, petiole and postpetiole impressed with longitudinal hollows above and at sides. Body with sparse pale suberect hairs, which are a little more abundant on gaster. Pubescence absent except on the flagellum of the antennae. Body black; mandibles, clypeus, genae, antennae, propodeal spines, declivity, petiole and postpetiole (excluding the dorsum), lateral sides of the first gastral segment reddish brown, legs and gaster behind the first segment light reddish brown.

Okido, Ogata, and Hosoishi (2020) - TL 2.82-3.25, HL 0.67-0.77, HW 0.66-0.77, CI 98-102, SL 0.52-0.61, SI 77-83, PW 0.43-0.54, ML 0.70-0.83 (11 measured).

Head subrectangular, as long as broad in full-face view; median portion of occipital margin concave or straight; occipital corners rounded, not projected posteriorly. Masticatory margin of mandible bent at midlength (third small tooth or sixth tooth); apical tooth strong, third tooth robust, followed by 5 small teeth and a basal blunt tooth; small teeth frequently unclear; apical tooth completely fused with preapical tooth; apical tooth about twice as long as preapical tooth. Dorsal surface of clypeus strongly concave; median portion of anterior margin projected and concave with distinct three processes; lateral portion simple, lacking sharp ridge in front of antennal insertions. Anterior dorsal surface of labrum with paired distinct denticles. Frontal carinae virtually absent, indistinguishable from rugae on dorsum of head. Eyes small and not convex, varying in size with maximum diameter 0.06-0.11 mm and 4-6 ommatidia. Antennal scape short, just reaching posterolateral corner of head; antennal flange developed.

Dorsal outline of mesosoma slightly convex in profile. Pronotum without denticle on dorsolateral portion; anterior portion marginate; anterior ventrolateral portion with denticle directing forward and downward. Furrow between pronotum and mesoepisternal projection more or less broad. Eumetanotal spine present but small. Propodeal spine elongate, directing backward, extending over vertical posteriormost limit of propodeum in profile; apex of spines curved upward distinctly. Propodeal lobe low. Propodeal spiracle large, situated near posterior margin of propodeum, apart from margin by its diameter. Petiole short, slightly longer than high in profile, and slightly longer than broad in dorsal view; small but distinct dorsal crest located at midlength in profile; subpetiolar process small, usually forming acute anterior apex. Postpetiole slightly broader than petiole in dorsal view; dorsal outline flattened or slightly convex in profile; ventral outline distinctly projected with acute anterior apex.

Anterior margin of gaster concave in dorsal view; first gastral sternum simple without median longitudinal ridge.

Head with thin rugae longitudinally; ventrolateral portion smooth and shining. Dorsal surface of mandible sometimes appears paired yellow spots. Clypeus smooth and shining. Mesosoma with thin rugae longitudinally on dorsal and lateral portion. Forecoxa smooth and shining. Petiole and postpetiole with a few distinct rugae. First gastral tergum punctured or rugulose weakly dorsally. First gastral sternum smooth and shining. Head with sparse and long pilosity on dorsum. Mesosoma with sparse and long pilosity on dorsum, hairs of pronotum slightly shorter than propodeal spine. Dorsal pilosity of petiole as long as that of mesosoma. Petiole without hairs on ventral surface. Postpetiole with 2-4 hairs on ventral surface. Body black, mandibles, antennae and legs yellowish brown, forecoxae reddish brown.

Type Material
Holotype: worker, Maoershan Natural Reserve, Xing'an County, Guangxi Province, P. R. China (25°54' N, 110°30' E), August 22, 1998, Coll. By Shanyi Zhou. The type specimen is deposited in the Insect Collection, College of Life Sciences, Guangxi Normal University, Guilin, China.

Etymology
This new species is named from the Latin words “curvus” and “spina” referring to its curved propodeal spines.

References based on Global Ant Biodiversity Informatics

 * Alcantara M. J., S. Modi, T. C. Ling, J. Monkai, H. Xu, S. Huang, and A. Nakamura. 2019. Differences in geographic distribution of ant species (Hymenoptera: Formicidae) between forests and rubber plantations: a case study in Xishuangbanna, China, and a global meta-analysis. Myrmecological News 29: 135-145.
 * Fontanilla A. M., A. Nakamura, Z. Xu, M. Cao, R. L. Kitching, Y. Tang, and C. J. Burwell. 2019. Taxonomic and functional ant diversity along tropical, subtropical, and subalpine elevational transects in southwest China. Insects 10, 128; doi:10.3390/insects10050128
 * Guénard B., and R. R. Dunn. 2012. A checklist of the ants of China. Zootaxa 3558: 1-77.
 * Liu C, B. Guénard, F Hita Garcia, S. Yamane, B. Blanchard, and E. Economo. New records of ant species from Yunnan, China. Submitted to Zookeys
 * Zhou S., J. Huang, and L. Ma. 2008. Two new species of the ant genus Myrmecina (Hymenoptera: Formicidae), with a key to Chinese species. Sociobiology 52(2): 283-291.
 * Zhou Shanyi, Jianhua Huang, and Libin Ma. 2008. Two new species of the ant genus Myrmecina (Hymenoptera; Formicidae), with a key to chinense species. Sociobiology 52(2): 283-291.