Research Article |
Corresponding author: Benoit Guénard ( zeroben@gmail.com ) Academic editor: Michael Ohl
© 2016 Mark K. L. Wong, Benoit Guénard.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Wong MKL, Guénard B (2016) First confirmed record of the ant genus Myrmecina (Hymenoptera, Formicidae) from the Malay Peninsula: description of a new species and a key to Myrmecina species from Sundaland. Journal of Hymenoptera Research 50: 129-140. https://doi.org/10.3897/JHR.50.8652
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We present the first confirmed record of the little known and uncommon ant genus Myrmecina for the Malay Peninsula. Myrmecina magnificens sp. n., a new species displaying unique anteriorly pointing propodeal spines, is described from specimens of the worker caste collected in a selectively logged primary rainforest in Singapore. We also provide the first key to Myrmecina species of the Sundaland region.
Myrmecina , Southeast Asia, Malay Peninsula, Singapore, Leaf litter
Ants of the myrmicine genus Myrmecina are generally encountered in leaf litter samples where they live in small colonies of 30 to less than 150 individuals (
Pictures of specimens were obtained with an incorporated digital camera, Leica DFC450, mounted on a Leica M205C dissecting microscope through the Leica Application Suite V4 software. A total of 24 to 86 images were taken and stacked together. Measurements of specimens were taken in mm (accurate to 0.001mm and rounded to the nearest 0.01mm for presentation) with the Measure Tools function of the Leica Application Suite V4 software on imaged specimens after proper placement for each body part measured. Measurements and morphological terminology follow:
The abbreviations used for the measurements and indices are as follows:
HW Head Width. Maximum width of head in full-face view excluding the eyes.
HL Head Length. Maximum head length in full-face view, measured from the anterior-most point of the clypeal margin to the midpoint of a line drawn across the posterior margin of the head.
MaL Mandible Length. Maximum length of mandible from the anterolateral margin of clypeus at outer side of mandibular insertion to mandibular apex.
SL Scape Length. Scape length, excluding the basal radicle.
EL Eye Length. Maximum diameter of eye measured in lateral view.
TL Total Length. Maximum length of specimen measured from the tip of the mandibles to the tip of the abdominal segment VII, not including sting. Due to the position of the specimen, total length was measured as the sum of head length + thorax, petiole and postpetiole length + gaster length.
WL Weber’s length measured from the anterior-most point of the pronotal collar to the posterior-most point of the propodeal process.
PNH Pronotum Height. Maximum height of pronotum, measured in profile from the posterior base of the lateral sides of pronotum, where procoxa is attached, to the highest point of the pronotum.
PNW Pronotal Width. Maximum width of pronotum measured in dorsal view.
MW Mesonotal Width. Maximum width of the mesonotum measured in dorsal view.
PSL Propodeal Spine Length. Maximum length of propodeal spines measured in profile view from the tip of the propodeal spine to the closer outward margin of the propodeal spiracle.
PTL Petiole Length. Maximum diagonal length of petiole, measured in lateral view, from most anteroventral point of the peduncle, at or below the propodeal lobe, to most posterodorsal point at the junction with helcial tergite.
PTH Petiole Height. Maximum height of petiole, measured in lateral view from the highest (median) point of the node, orthogonally to the ventral outline of the node.
PTW Petiole Width. Maximum width of the petiole in dorsal view.
PPL Postpetiole Length. Maximum length of postpetiole, measured in lateral view.
PPH Postpetiole Height. Maximum height of postpetiole, measured in lateral view from the highest point of the node.
PPW Postpetiole Width. Maximum width of the postpetiole in dorsal view.
CI Cephalic Index. Calculated as: HW / HL ×100.
SI Scape Index. Calculated as: SL / HW ×100.
MaI Mandibular Index. Calculated as: MaL / HW ×100.
PI Petiolar Index. Calculated as: PTW / PTL ×100.
PPI Postpetiolar Index. Calculated as: PPW / PPL ×100.
Abbreviations of the type depositories and others are as follows:
LKCNHM Lee Kong Chian Natural History Museum, Singapore.
SBSHKU Insect Biodiversity and Biogeography Laboratory, School of Biological Sciences, The University of Hong Kong, Hong Kong SAR.
Worker from SINGAPORE, Seletar Trail, Central Catchment Nature Reserve, 1.395141°N, 103.802595°E, 47m, 02.IX.2015, leaf litter, leg. Mark K. L. Wong, label “MW020915-L1.1” (ANTWEB1009004) deposited in LKCNHM.
Four workers in total (ANTWEB1009005, ANTWEB1009006, ANTWEB1009007, ANTWEB1009008), all with the same collection data as holotype (deposited at SBSHKU).
Holotype: HL 0.98 mm; HW 1.12 mm; MaL 0.63 mm; SL 0.90 mm; EL 0.20 mm; WL 1.37 mm; PNW 0.71 mm; PNH 0.62 mm; MW 0.65 mm; PSL 0.24 mm; PTL 0.36 mm; PTW 0.32 mm; PTH 0.35 mm; TL 4.42 mm (stinger not included); PPL 0.23 mm; PPW 0.34 mm; PPH 0.39 mm; CI 114, SI 80, MaI 56, PI 88, PPI 149.
Paratypes (n=4): HL 0.94–0.98 mm; HW 1.06–1.11 mm; MaL 0.55–0.63 mm; SL 0.89–0.91 mm; EL 0.20–0.21 mm; WL 1.22–1.36 mm; PNW 0.70–0.74 mm; PNH 0.57–0.62 mm; MW 0.61–0.65 mm; PSL 0.23–024 mm; PTL 0.34–0.36 mm; PTW 0.29–0.31 mm; PTH 0.31–0.33 mm; TL 4.36–4.57 mm (stinger not included); PPL 0.22–0.24 mm; PPW 0.32–0.35 mm; PPH 0.34–0.36 mm; CI 113–116, SI 80–86, MaI 51–57, PI 83–87, PPI 141–151.
Head. Head in full-face view slightly shorter than wide (CI 113–116) and maximum HW occurs behind the eyes, sides convex, occipital corners triangular, occipital margin strongly convex (Fig.
Mesosoma. In profile view, dorsal outline of promesonotum flat to broadly convex, sloping along anterodorsal part of propodeum (Fig.
Metasoma. In profile view (Fig.
Sculpture. Sculpturing on head and thorax running longitudinally. Sculpture on head parallel on its middle portion and divergent on the sides and posterior portions. Groove on head with latitudinal sculptures present on most of its length. In profile view, sculpture on thorax presenting a complex pattern with parallel or and convergent sculptures (Fig.
Pubescence. Almost all of body covered in abundant erect long hairs (0.2–0.25 mm) with the exception of the propodeal junction and ventral surface of the petiole where pubescence is absent.
Coloration. Most of head, mesosoma and gaster black; antenna, clypeus and mandibles dark red to dark brown; legs, posterior portion of propodeum light amber to light brown; pubescence and margins of gastral tergites yellow to light gold.
Castes. Male and gyne castes unknown.
The species epithet is derived from the English word ‘magnificent’, referencing the beautiful appearance of this species, which makes it truly magnificent to behold. The species epithet is a noun, and thus invariant.
Southeast Asia. Only known from Singapore.
Almost nothing is known about the ecology of M. magnificens. All specimens were collected from a selectively logged lowland primary rainforest. Based on the collection methods used to collect several workers (N=5), we suspect that M. magnificens probably forages within the leaf litter and topsoil. This is based on our collection of the species via a Berlese extraction of sifted leaf litter and topsoil, as well as from a subterranean pitfall trap baited with tuna and buried at a depth of 5 cm underground. No other conspecifics were found in similar traps buried at greater depths (i.e. 15, 20, 25 cm) within the same locality.
With the exception of M. sulcata for which body size was not recorded in the species description, the new species M. magnificens can quickly be distinguished from other Myrmecina species in the Sundaland region by its large overall size (TL 4.2–4.6 mm) and its distinctly long and forward-pointing propodeal spines. While M. nesaea, M. semipolita, M. sulcata and M. undulata also possess relatively long propodeal spines, their spines are posteriorly oriented. The other two species, M. bandarensis and M. butteli have relatively short propodeal spines, and are also notably smaller in their overall sizes (TL 1.9–2.2 mm), which by comparison would be approximately half that of M. magnificens.
Myrmecina bandarensis Forel, 1913 (Sumatra)
Myrmecina butteli Forel, 1913 (Sumatra)
Myrmecina magnificens sp. n. (Singapore)
Myrmecina nesaea Wheeler, 1924 (Sumatra) – described from gyne only
Myrmecina semipolita Forel, 1905 (Java)
Myrmecina sulcata Emery, 1887 (Java)
Myrmecina undulata Emery, 1900 (Borneo, Sumatra)
A new key to Myrmecina species from Sundaland based on descriptions of the worker caste was developed from scrutinizing the respective taxonomic descriptions for the worker caste of M. butteli (
1 | In profile view propodeal spines pointing posteriorly | 2 |
– | In profile view propodeal spines pointing anteriorly; large sized species (TL > 4 mm) (Singapore) | M. magnificens sp. n. |
2 | In profile view propodeal spines small with length shorter than or equivalent to basal width | 3 |
– | In profile view propodeal spines distinct with length exceeding basal width | 4 |
3 | In profile view pro-mesonotum weak to moderately convex (Fig. |
M. bandarensis Forel |
– | In profile view pro-mesonotum strongly convex; in full-face view anterior edge of clypeus slightly concave (Sumatra) | M. butteli Forel |
4 | In full-face view clypeus with distinctly concave anterior edge (Borneo, Sumatra) | M. undulata Emery |
– | In full-face view clypeus with straight anterior edge | 5 |
5 | In profile view pro-mesonotum strongly convex (Fig. |
M. sulcata Emery |
– | In profile view pro-mesonotum weakly convex; propodeal spines with length slightly exceeding basal width and pointing posteriorly at a nearly horizontal angle | 6 |
6 | Pilosity on entire body long and white in colour (Sumatra) | M. nesaea Wheeler (Described from gyne only) |
– | Pilosity on entire body short and yellow in colour (Java) | M. semipolita Forel |
Photographs of M. bandarensis from AntWeb (CASENT0908953, photos by Will Ericson) in a full-face view showing large eyes and straight anterior edge of clypeus b profile view, close-up of thorax showing weak to moderately convex pro-mesonotum and short propodeal spine. Original illustration of M. sulcata in profile view c with close-up of thorax showing strongly convex pro-mesonotum and long propodeal spine pointing posteriorly at approximate forty-five degree angle (from
Myrmecina magnificens represents the first Myrmecina species described from the Malay Peninsula and completes the distribution of the genus in the Sundaland region. Although several records of Myrmecina have been reported from ecological work in this region, most of them have not been formerly identified. For example, many unidentified Myrmecina species were previously reported from Peninsular Malaysia: Negeri Selemban and Selangor provinces in Malaysia (
The independent research work of the first author (MW) was partially supported by the generous contributions of numerous donors through experiment.com/antsofsingapore. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. We are grateful to staff of the National Biodiversity Centre Singapore for their support with research permits. We would also like to thank Ying Luo and Lily Ng from the University of Hong Kong for their assistance with specimen handling and imaging. The authors would like to thank Brian Fisher and the team of Antweb.org for providing free access to the pictures. Finally, we thank Himender Bharti for his valuable comments on a previous version of the manuscript.