Mystrium camillae

According to the revision of Mystrium in the Indo-Australian region (Bihn and Verhaagh 2007), Mystrium camillae is widely distributed in the Indomalaya, and Australian regions: from Australia to Brunei, China, India, Indonesia, Malaysia, Myanmar, Papua New Guinea, the Philippines and Singapore. We find that specimens currently determined as M. camillae display remarkable morphological variation, some of which appears not to be intra-specific but rather due to differences among species. For example, we found a small-sized queen with vestigial wings in Indonesian material, workers with longer setae on the anteromedial portion of the clypeus in specimens from New Guinea, a large queen with simple setae on the pronotal dorsum in specimens from China, and a strange yellow male from Australia. A reexamination of the species boundaries of Mystrium camillae based on a detailed comparative study using comprehensive colony samples from each local region is needed. (Yoshimura and Fisher 2014)

Identification
The following character combination differentiates Mystrium camillae from all its congeners in the Indo-Australian region: the apex of each mandible distinctly expanded and rounded in lateral view, with a more or less triangular and caudally directed tip on the inner side; outer face of labrum entirely covered with a weakly developed, irregular rugoreticulum; maxillary palps 4-segmented; the second segment of the maxillary palp shorter than the basal (first) segment and less than half as broad as the basal segment; antennal segment III shorter than twice its width; each anterolateral corner of the head produced into a short, nearly triangular, pointed spine; dorsum of head with rugose-reticulate cuticular sculpture and spatulate hairs; minute compound eyes; petiolar node not broader than twice its length measured in dorsal view. (Bihn & Verhaagh 2007)

Distribution
Widely distributed in the Indo-Australian region and neighboring countries. Recorded from Australia, Brunei Darussalam, China, India, Indonesia, Malaysia, Myanmar, New Guinea, the Philippines, Singapore and Vietnam.

Distribution based on Regional Taxon Lists
Australasian Region: Australia. Indo-Australian Region: Borneo, Indonesia, Malaysia, New Guinea, Philippines, Singapore. Oriental Region: India, Myanmar, Vietnam. Palaearctic Region: China.

Biology
Mystrium camillae occurs in well-developed forests but sometimes forest edges and second growth vegetation, and nests under stones and wood fragments. Workers are brown or brick red and dull, bear spatulate hairs, and are often clad in soil. These features make them difficult to detect when their nests are exposed. (Eguchi et al. 2014)

Nomenclature

 * . Mystrium camillae Emery, 1889b: 491, pl. 10, figs. 1-3 (w.q.) MYANMAR.
 * Type-material: lectotype worker (by designation of Yoshimura & Fisher, 2014: 47), 4 paralectotype workers.
 * Type-locality: lectotype Myanmar (“Birmania”): Bhamo, iv.1886 (L. Fea); paralectotypes with same data but dated either vi.1885, or iv.1886.
 * [Note: Yoshimura & Fisher, 2014: 47, observe that the original syntype queen could not be found.]
 * Type-depositories: MSNG (lectotype); MHNG, MNHN, MSNG (paralectotypes).
 * Wheeler, G.C. & Wheeler, J. 1952a: 113 (l.); Tjan, et al. 1986: 57 (k.).
 * Status as species: Dalla Torre, 1893: 15; Emery, 1895k: 454; Forel, 1900c: 54; Emery, 1900d: 661; Bingham, 1903: 36; Emery, 1911d: 23; Wheeler, W.M. & Chapman, 1925: 55; Menozzi, 1929d: 535 (redescription); Chapman & Capco, 1951: 24; Wilson, 1958a: 150; Brown, 1960a: 170; Baltazar, 1966: 234; Taylor & Brown, 1985: 35; Taylor, 1987a: 47; Bolton, 1995b: 287; Bihn & Verhaagh, 2007: 2 (redescription); Pfeiffer, et al. 2011: 32; Guénard & Dunn, 2012: 23; Yoshimura & Fisher, 2014: 47; Bharti, Guénard, et al. 2016: 18.
 * Senior synonym of javana: Brown, 1960a: 170; Bolton, 1995b: 287; Bihn & Verhaagh, 2007: 2; Yoshimura & Fisher, 2014: 16.
 * Senior synonym of oculatum: Bihn & Verhaagh, 2007: 3; Yoshimura & Fisher, 2014: 16.
 * Distribution: Australia, Brunei, China, India (+ Andaman Is, Nicobar Is), Indonesia (Irian Jaya, Java, Sumatra), Malaysia (Peninsula, Sabah, Sarawak), Myanmar, Papua New Guinea, Philippines (Luzon), Singapore.
 * javana. Mystrium camillae subsp. javana Karavaiev, 1925a: 73, fig. 1 (w.) INDONESIA (Java).
 * Type-material: 2 syntype workers.
 * Type-locality: Indonesia: Java, Kalkberg (= limestone mountain), nr Tjampea, Nr 2389 (W. Karawaiew).
 * Type-depository: SIZK.
 * Subspecies of camillae: Chapman & Capco, 1951: 24.
 * Junior synonym of camillae: Brown, 1960a: 170; Bolton, 1995b: 287; Bihn & Verhaagh, 2007: 2; Yoshimura & Fisher, 2014: 16.
 * oculatum. Mystrium oculatum Xu, 1998c: 161, figs. 1, 2 (w.) CHINA (Yunnan).
 * Type-material: holotype worker, 23 paratype workers.
 * Type-locality: holotype China: Yunnan, Mengla County, Menglun Town, Bakaxiaozhai (21.9°N, 101.2°E), 840 m., 8.iii.1996, no. A96-318 (Z. Xu).
 * Type-depository: SFCY.
 * [Misspelled as coulatum by Zhou & Ran, 2010: 102.]
 * Status as species: Zhou & Ran, 2010: 102.
 * Junior synonym of camillae: Bihn & Verhaagh, 2007: 3; Yoshimura & Fisher, 2014: 16.

Type Material


Bihn & Verhaagh (2007):
 * Syntype worker and queen: Myanmar (as “Birmania”: Bhamo (Fea) MSCN, not examined.
 * Mystrium camillae Emery subsp. javana syntype worker: Java, limestone mountain near Tjampea, no. 2389, 2 workers on the ground, under leaves (Karawaiew) (not examined).
 * Mystrium oculatum holotype worker: China: Yunnan Province, Mengla County, Menglun Town, Bakaxiaozhai (Xu Zheng-hui) SWFC (not examined).

Description
Worker

Bingham 1903: Reddish yellow the whole insect, even on the mandibles, antenna; and legs, very closely and somewhat coarsely punctured, rugose and granulate; pilosity very short, rather sparse, in no way hiding the sculpture; head slightly wider in front than posteriorly, the sides straight from the base of the mandibles for about two-thirds of their length, then a little bent inwards towards the posterior lateral angles; mandibles slightly twisted, above longitudinally grooved. For the rest, the characters as in the genus.

Length: 3.3 - 4.5 mm

Measurements and indices (Workers): HL 0.81–1.75, HW 0.85–1.64, CI 88–105, SL 0.50–1.00, SI 54– 64, ML 0.52–1.75, WL 0.91–1.49, PW 0.47–0.80 (n = 31) (Bihn & Verhaagh 2007).

Queen

Bingham 1903: Closely resembles the worker; larger and more massive; sculpture of the head and thorax, colour and pilosity as in the worker, the apical margin of the 1st, 3rd and 4th abdominal segments above smooth, slightly shining. For the rest, the characters as given for the genus.

Length: ~ 7 mm

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