Strumigenys mayri group

Strumigenys mayri group Bolton (2000)

Austral
Apical fork of mandible of 2 spiniform teeth; 1 or 2 intercalary small teeth or denticles present (usually 1). Mandible without preapical dentition or with a single preapical tooth or denticle present. MI 41-57.

Anterior clypeal margin with a narrow U-shaped or V-shaped median notch or impression or markedly concave; clypeus narrow anteriorly, anterior portion of head including clypeus usually drawn out and snout-like.

Scape slender, subcylindrical to weakly dorsoventrally flattened, often broadest in the basal third and tapering to the apex; moderate to very long, SI 75-146.

Apical antennomere strongly constricted basally and narrowly articulated with the preapical antennomere; apical antennomere spindle-shaped, preapical frequently barrel-shaped.

Ventrolateral margin of head with or without a preocular notch or deep narrow impression. With head in profile the dorsal and ventral outlines without impressions except for the postbuccal groove, or the ventral outline with a preocular concavity located posterior to the postbuccal groove.

Propodeal declivity usually has a narrow and inconspicuous lamella, frequently merely a carina or narrow flange, the posterior (free) margin of which is concave and closely parallels the shape of the margin of the declivity; less commonly the lamella broader and with a convex margin.

Spongiform appendages of waist segments all present or lateral lobe of petiole node very small to absent (mayri-complex).

Pilosity. Dorsolateral margin of head with one or two freely laterally projecting simple or flagellate long hairs. Cephalic dorsum with a transverse row of 4-6 erect hairs across the occipital margin and an erect, usually shorter, pair at or close to highest point of vertex. Pronotal humeral hair present but pronotum otherwise usually lacks standing hairs. Mesonotum with 1-2 pairs of erect hairs; standing hairs always present on first gastral tergite.

Sculpture. In general with fine reticulate-punctate sculpture on entire head and dorsal alitrunk, but sculpture on pronotal dorsum may be reduced or sometimes partially to largely effaced. Side of alitrunk with pleurae and propodeum usually entirely smooth, or at most with punctate sculpture around the periphery; less commonly the pleurae entirely reticulate-punctate or merely with a small clear patch on the katepistern um. Gaster unsculptured except for basigastral costulae, which may be short.

Malesian-Oriental-East Palaeartic
Apical fork of mandible of 2 spiniform teeth; usually with I intercalary denticle (none in Strumigenys leptorhina). A single preapical tooth present near the apex, short to spiniform (absent in Strumigenys rayma). Mandible straight to conspicuously curved; MI 41-57.

Anterior clypeal margin with a narrow U-shaped or V-shaped median notch or impression; clypeus very narrow anteriorly, anterior portion of head including clypeus drawn out and snout-like.

Scape slender, subcylindrical to weakly dorsoventrally flattened, usually broadest in the basal third and tapering to the apex; moderate to very long, SI 75-146.

Apical antennomere strongly constricted basally and narrowly articulated with the preapical; apical antennomere spindle-shaped, the preapical frequently barrel-shaped.

Ventrolateral margin of head with (mayri-complex) or without (feae-complex) a preocular notch or deep narrow impression. With head in profile the dorsal and ventral outlines without impressions except for the postbuccal groove, or the ventral outline with a preocular concavity.

Propodeal declivity with a narrow and inconspicuous lamella, frequently merely a carina or narrow flange, the posterior (free) margin of which is concave and closely parallels the shape of the margin of the declivity.

Spongiform appendages of waist segments all present or lateral lobe of petiole node very small to absent (mayri-complex).

Pilosity. Dorsolateral margin of head with one (most mayri-complex) or two (most feae-complex) freely laterally projecting simple or flagellate long hairs. Cephalic dorsum with a transverse row of 4-6 erect hairs across the occipital margin and an erect, usually shorter, pair at or close to highest point of vertex. Pronotal humeral hair present but pronotum otherwise usually lacking standing hairs. Mesonotum with 1-2 pairs of erect hairs and standing hairs always present on first gastral tergite.

Sculpture. In general with fine reticulate-punctate sculpture on entire head and dorsal alitrunk, but sculpture on pronotal dorsum may be reduced or sometimes partially to largely effaced. Side of alitrunk with pleurae and propodeum usually entirely smooth, or at most with punctate sculpture around the periphery; less commonly the pleurae entirely reticulate-punctate or merely with a small clear patch on the katepisternum. Gaster unsculptured except for basigastral costulae, which may be short.

Austral
The diagnosis of the group is modified slightly from that given for the Malesian-Oriental-East Palaearctic fauna. In general the Austral members of the mayri-group may be recognised thus: anterior clypeal margin with a U-shaped or V-shaped median notch or impression; apical antennal segment spindle-shaped, strongly constricted basally and narrowly articulated with the preapical antennomere (as Figs 532-535); mandible usually with a single intercalary tooth or denticle (two present only in Strumigenys varanga).

Three Austral species of this group (Strumigenys ferocior, Strumigenys mayri, Strumigenys racabura), which all belong to the mayri-complex, also occur in the Malesian region and are discussed under the Malesian-Oriental-East Palaearctic fauna. The other six are solely Australian (Strumigenys anetes, Strumigenys dysanetes, Strumigenys orthanetes, Strumigenys paranetes, Strumigenys philiporum, Strumigenys varanga) and are derived from the feae-complex, though the massively hypertrophied spongiform appendages of philiporum and the much-reduced preapical mandibular dentition of the first four of this last group tend to distract attention from the relationship.

Malesian-Oriental-East Palaeartic
Members of the widely distributed mayri-group, which contains 21 species in this region, may generally be recognised by the following combination of characters.

Apical fork of the mandible has only one intercalary denticle between the two fork teeth, the anterior clypeal margin has a narrow U-shaped or V-shaped median notch or impression, the apical antennal segment is spindle-shaped, strongly constricted basally and narrowly articulated with the preapical antennomere, and the propodeal lamella is narrow to vestigial and has a concave posterior (free) margin that in profile closely follows the shape of the declivity.

The group is considerably expanded from the original concept of Brown (1973c), and falls into two almost equally sized complexes of species.

feae complex
Strumigenys barylonga, Strumigenys ecliptacoca, Strumigenys exilirhina, Strumigenys feae, Strumigenys fixata, Strumigenys formosensis, Strumigenys kraepelini, Strumigenys leptorhina, Strumigenys rallarhina, Strumigenys separa, Strumigenys stenorhina

Ventrolateral margin of head immediately in front of eye either straight or merely narrowing, or forming a long and very shallow concavity; without a strongly incised preocular notch or impression. With head in ventral view the surface immediately in front of the eye without a transverse impression or trench that extends toward the midline. Usually two freely laterally projecting long hairs are present on the upper scrobe margin, one at or near the level of the eye, the other apicoscrobal. (This arrangement is modified only in leptorhina and fixata; in the former one hair occurs in the apicoscrobal position and a second is present posterior to this, in the latter only the apicoscrobal is present.) With petiole in profile the lateral spongiform lobe is located posteriorly, generally triangular in shape and usually conspicuous. Posterior transverse collar of petiole node usually complete and distinct (lateral lobe very small and rounded, and posterior collar absent only in ecliptacoca).

Most species of this complex are found in the Oriental region proper. A few occur in the East Palaearctic and others are distributed through the Malay Peninsula and the islands of Sumatra, Java and Borneo. Only separa and ecliptacoca have yet been discovered as far east as Seram and New Guinea respectively. The first named species appears to form an intermediary between the two complexes as it combines most of the characters of the feae-complex with some of the characters and the small size usual in species of the mayri-complex.

mayri complex
Strumigenys akhtoi, Strumigenys ferocior, Strumigenys fricta, Strumigenys hoplites, Strumigenys mayri, Strumigenys missina, Strumigenys montu, Strumigenys nysu, Strumigenys racabura, Strumigenys rayma

Ventrolateral margin of head immediately in front of eye with a strongly incised preocular notch or impression. With head in ventral view the preocular notch usually forms the apex of a transverse impression or trench in the ventral surface of the head capsule that extends toward the midline. This ventral preocular depression is posterior to, and separated from, the postbuccal groove. In most species the apicoscrobal is the only long hair on the dorsolateral margin of the head; in only two (fricta, rayma) is a second such hair present, just behind the level of the eye. With petiole in profile the lateral spongiform lobe is low on the side, usually very small or vestigial (rarely absent), only rarely conspicuous. Posterior transverse collar of petiole node usually represented by a mere carina or vestigial, only rarely complete and distinct.

The majority of species in this complex are restricted to New Guinea. A couple of species have extended their range into Australia (Queensland) but only mayri has yet been found on the islands to the west of New Guinea where its range extends to Sulawesi.

Members of the complex break down into two unequal sets, based on the presence or absence of erect flagellate hairs on the hind basitarsi.

Species with such hairs present: montu, nysu, racabura, discussed under montu.

Species with such hairs absent: akhtoi, ferocior, fricta, hoplites, mayri, missina, rayma, discussed under akhtoi.