Strumigenys godeffroyi group

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Strumigenys godeffroyi group Bolton (2000)

Species

Austral

Malesian-Oriental-East Palaeartic

Malagasy

Worker Diagnosis

Austral

Apical fork of mandible of 2 spiniform teeth; with 1-3 (usually 2) intercalary denticles that most frequently arise from the dorsal surface of the apicoventral tooth, near its base. A single preapical tooth present, spiniform, at least as long as width of mandible where it arises and usually at least as long as maximum width of mandible. MI 40-52.

Anterior clypeal margin more or less transverse or very shallowly evenly concave across its width; never deeply indented.

Scape slender, subcylindrical to weakly dorsoventrally flattened, moderate to very long; SI 66-100.

Apical antennomere not spindle-shaped, not constricted basally.

Ventrolateral margin of head without a preocular impression or notch; with head in profile the dorsal and ventral outlines without impressions except for the shallow postbuccal groove.

Propodeal declivity usually with a narrow to moderate lamella whose posterior (free) margin is straight to concave; less commonly with a broad and conspicuous lamella whose posterior margin is convex.

Spongiform appendages of waist segments all present; lateral lobe of petiole variable in size and extent.

Pilosity. Variable, see under the various subdivisions of the group and individual species descriptions.

Sculpture. In general with fine reticulate-punctate sculpture on entire head and dorsal alitrunk; the latter (especially pronotum) rarely with reduced sculpture. Side of alitrunk may be entirely reticulate-punctate, mostly to partially so, or entirely smooth. Gaster unsculptured except for basigastral costulae, which may be short.

Malagasy

Apical fork of mandible of 2 spiniform teeth; with 1-2 intercalary teeth or denticles. A single spiniform preapical tooth, that is longer than width of mandible where it arises, is present near the apicodorsal tooth. Mandible with the outer margins shallowly and evenly convex. MI 40-43.

Scape slender, subcylindrical. SI 73-80.

Ventrolateral margin of head without a preocular impression or notch; with head in profile the dorsal and ventral outlines without impressions except for the postbuccal groove.

Eye large, its maximum diameter exceeding the maximum width of the scape.

Propodeal declivity with a broad and conspicuous lamella whose posterior (free) margin is partially or entirely convex or straight.

Spongiform appendages of waist segments well developed.

Pilosity. Cephalic dorsum with curved narrowly spatulate ground-pilosity on anterior two-thirds; simple standing hairs present along occipital margin and 1-2 pairs at about highest point of vertex. Pronotal humeral hair present. Dorsal surfaces of promesonotum, petiole, postpetiole and gaster with simple standing hairs.

Sculpture. Head, alitrunk dorsum and petiole reticulate-punctate. Gaster unsculptured except for basigastral costulae.

Glands. Gland of scape near the apex on the ventral surface not apparent. Femoral gland bullae decreasing in size from hind femur where easily visible to the fore femur where it is minute to absent. Tibial gland bullae visible on mid and hind tibiae. Gland at base of calcar conspicuous. Tarsal gland bullae visible on at least first three tarsi, decreasing in size from basitarsus where it is elongate to the third tarsal segment where it is oval. Mesopleural gland visible and set in a narrow circular notch.

Malesian-Oriental-East Palaeartic

Apical fork of mandible of 2 spiniform teeth; usually with 2 (rarely otherwise) intercalary denticles that most frequently arise from the dorsal surface of the ventral fork tooth, at its base. A single preapical tooth present near the apex, spiniform, in full-face view always longer than width of mandible where it arises and usually at least as long as maximum width of mandible. Mandible linear, straight to conspicuously curved; MI 35-58.

Anterior clypeal margin transverse or evenly shallowly concave across its width, only rarely more deeply concave medially.

Scape slender, subcylindrical to weakly dorsoventrally flattened, short to very long; SI 54-107.

Apical antennomere usually unconstricted basally, in a very few species strongly constricted basally.

Ventrolateral margin of head without a preocular impression or notch; with head in profile the dorsal and ventral outlines without impressions except for the postbuccal groove.

Propodeal declivity usually with a broad and conspicuous lamella whose posterior (free) margin is partially or entirely convex or straight; less commonly with a narrow lamella whose posterior margin is concave and parallels the shape of the margin of the declivity.

Spongiform appendages of waist segments all present; lateral lobe of petiole very variable in size and extent.

Pilosity. Extremely variable, see under the various subdivisions of the group.

Sculpture. In general with fine reticulate-punctate sculpture on entire head, dorsal alitrunk, or both; dorsal alitrunk (especially pronotum) sometimes, and dorsal head very rarely, unsculptured and smooth. Side of alitrunk may be entirely reticulate-punctate, partially so, or entirely smooth. Gaster usually unsculptured except for basigastral costulae, which may be short (sculptured only in Strumigenys degonya).

Notes

Austral

The diagnosis of the group is modified slightly from that given for the Malesian-Oriental- East Palaearctic fauna, as the Austral fauna is smaller and more compact. The artificial subdivisions of the group, established to deal with the large Malesian-Oriental-East Palaearctic fauna, are also utilised here, with slight modification for the Austral fauna.

At present 22 of the 53 known Austral Strumigenys species belong in this group. All are discussed below except for Strumigenys godeffroyi; itself. That species, very widespread in the Malesian and Oriental regions, was first recorded in Queensland by Forel (1915a) and in New Caledonia by Emery (1914b). It is described and discussed, along with its closest relatives, under the Malesian-Oriental-East Palaearctic fauna.

godeffroyi complex

Dorsal (outer) surface of hind basitarsus with one or more erect long filiform or flagellate fine hairs. Lateral spongiform lobe of petiole extensive; in profile and in dorsal view the lobe extends from posterior margin of node to level of anterior margin of node; in profile the lobe longer than deep.

smythiesii complex

Dorsal (outer) surface of hind basitarsus with one or more erect long filiform or flagellate fine hairs. Lateral spongiform lobe of petiole small, in profile lobe usually restricted to about the posterior quarter or less of the length of the node, only rarely slightly more extensive; in dorsal view the lobes not reaching level of anterior margin of node.

rojocala complex

Dorsal (outer) surface of hind basitarsus without erect long filiform or flagellate fine hairs. Pronotal humeral hair long and flagellate.

signeae complex

Dorsal (outer) surface of hind basitarsus without erect long filiform or flagellate fine hairs. Pronotal humeral hair not flagellate. (In Australian species a humeral hair is present that is simple, stiff and quite short, straight to feebly curved; no humeral hairs are present on the single known specimen of Strumigenys geryon.)

Malagasy

This diagnosis is modified from that given for the group in the Malesian-Oriental-East Palaearctic fauna, where there are 64 species, because only a single species occurs in the Malagasy region. In the subdivisions of the group noted there, Strumigenys agetos would fall into the signeae-complex as its hind basitarsus lacks erect flagellate hairs, its pronotal humeral hair is not flagellate, and flagellate hairs are absent from dorsal surfaces of the head, alitrunk and gaster.

S. agetos, known only from Mauritius (where it may be an introduction), is easily distinguished from all other species of the Malagasy region by its combination of subcylindrical scape, apical fork of left mandible with two intercalary denticles, mandible with a single preapical tooth, and the absence of a preocular notch in the ventrolateral margin of the head.

Malesian-Oriental-East Palaeartic

With 64 species, this is by far the largest and morphologically the most diverse group in the regions currently under consideration. The group contains some of the most commonly encountered and widespread species of the region and it also forms a major component of the Austral fauna.

The godeffroyi-group is closely related to the mayri group and numerous parallelisms and convergencies by various species in either group sometimes tend to make the boundaries between them obscure. In general, members of the mayri-group may be discriminated from the species included here in the godeffroyi-group as follows. Members of the mayri-group possess these characters in combination: the anterior clypeal margin has a narrow U-shaped or V-shaped median notch; the apical antennal segment is spindle-shaped, strongly constricted basally and very narrowly articulated with the preapical antennomere; the propodeal lamella is narrow and has a concave posterior (free) margin that in profile closely follows the shape of the declivity; the apical fork of the mandible usually has only one intercalary denticle (two is the usual number in the godeffroyi-group). Some species of the godeffroyi-group may show one, or very rarely two, of the foregoing mayri-group characters, but none shows them all.

To assist identification the godeffroyi-group is subdivided here into two subgroups and a number of species complexes, most of which are artificial. The criteria defining these are for convenience, designed solely to help confirm correct determination of individual species; they have no phylogenetic value as utilised in this system.

Subgroup A

Species in which the dorsal (outer) surface of the hind basitarsus bears one or more long erect filiform or flagellate fine hairs that are enormously longer than the maximum width of the basitarsus. (Apically curved or reclinate short ground-pilosity, simple to spatulate, is usually also present. Similar pilosity is usually repeated on basitarsi of other legs and may also be present on other leg segments.)

Character applies to: godeffroyi-complex, mjoebergi-complex, smythiesii-complex.

Complexes of Subgroup A

godeffroyi complex

With all the following characters in combination.

1 Dorsal (outer) surface of hind basitarsus with one or more long erect flagellate hairs.

2 Lateral spongiform lobe of petiole extensive; in dorsal view and in profile the lobe extends from posterior margin of the node to level of anterior margin of node; in profile the lobe longer than deep.

3 Apicoscrobal hair flagellate; without a second flagellate hair posterior to this.

4 Pronotal humeral hair flagellate.

5 Mesonotum with a pair of erect flagellate hairs.

6 Hind femur with at least one long erect fine hair on its dorsal surface, in the basal third of its length.

7 Pilosity of first gastral tergite usually flagellate, rarely long-filiform.

8 Ground-pilosity on cephalic dorsum simple to narrowly spatulate, inclined anteriorly.

9 Pleurae and side of propodeum reticulate-punctate (4 species) or smooth (13 species), see below.

Most species of this complex have the pleurae and side of the propodeum smooth but in four species these sclerites are entirely reticulate-punctate. A sculptured lateral alitrunk is universal in the mjoebergi-complex and also occurs in isolated species elsewhere in the group. However, such species fail to conform entirely with the other characters listed above. The extralimital species that approach the godeffroyi-complex most closely are Strumigenys dyak (mjoebergi-complex) and the smythiesii-complex species of the fauna of China, Taiwan and Japan (Strumigenys hispida, Strumigenys lichiaensis, Strumigenys liukueiensis, Strumigenys solifontis). In all of these the lateral spongiform lobe of the petiole is relatively large and approaches the dimensions normal for the godeffroyi-complex, but in these species the mesonotal pilosity consists of one to several pairs of stiffly erect simple hairs, not a single long flagellate pair.

Comparisons of species within this complex are discussed below as follows.

1 Species with pleurae and side of the propodeum entirely reticulate-punctate: asrochia, conjusatrix, indagatrix, strigatella, see notes under Strumigenys confusatrix.

2 Species with pleurae and side of the propodeum smooth. Pair of erect hairs closest to midline on occipital margin long, fine and abruptly angled anteriorly or looped: berkalial, chimaera, eumekes, minutula, nanzanensis, vassago, see notes under Strumigenys nanzanensis.

3 Species with pleurae and side of the propodeum smooth. Pair of erect hairs closest to midline on occipital margin short, stiff and erect, straight or very shallowly evenly curved: geminata, godeffroyi, juliae, lewisi, nytaxis, peraucta, uberyx, see notes under Strumigenys godeffroyi.

Yoshimura and Onoyama (2007) - We found that both S. lewisi and S. kumadori (a sibling species separated from S. lewisi) have three intercalary teeth which consist of apical two small teeth and a basal, smaller denticle. Bolton’s notes as a difference between the godeffroyi-group and Strumigenys mayri-group, that two is the usual number of intercalary teeth in the godeffroyi-group (Bolton, 2000). Some species having three intercalary teeth are recorded in other species group in Bolton (2000), i.e. Strumigenys horvathi-group and Strumigenys koningsbergeri-group, but neither diagnosis of the group agreed with characters of S. kumadori and S. lewisi. The number of the intercalary teeth is an important character to separate species group, therefore further study will be needed.

In addition, the usual state of hairs on apicoscrobe and mesonotum in S. lewisi did not agree with those of godeffroyi-complex in subgroup A of the godeffroyi-group, although the complexes were practically subdivided by Bolton (2000) to assist identification. Workers in the godeffroyi-complex have flagellate hairs on both the apicoscrobe and mesonotum, but this state was found in only S. kumadori. Both of the hairs are filiform in S. lewisi. Other character states of S. lewisi agree with godeffroyi-complex, and hence none of the species-complexes agree with the combination of the characters in S. lewisi.

mjoebergi complex

With all the following characters in combination.

1 Dorsal (outer) surface of hind basitarsus with one or more long erect filiform or flagellate hairs.

2 Lateral spongiform lobes of petiole usually small, in dorsal view the lobes not reaching level of anterior margin of node; in profile lobe usually restricted to about the posterior quarter or less of the length of the node, only rarely more extensive (see below).

3 Pleurae and side of propodeum either entirely reticulate-punctate or at most with a small smooth patch on katepisternum.

4 Dorsolateral margin of head rarely with a flagellate apicoscrobal hair, sometimes without a hair or with one present that may be short and simple or finely filiform and evenly curved; never with a flagellate hair closer to occipital corner.

5 Pronotal humeral hair flagellate, simple, or short and stout.

6 Hind femur without long erect fine hairs on its dorsal surface.

7 Mesonotum usually without flagellate hairs (a short pair present in two species).

Only in dyak does the lateral lobe of the petiole node extend forward until close to the anterior margin of the node; this species appears to form a link with the species of the godeffroyi-complex. However, in dyak there are no flagellate hairs on the dorsolateral margin of the head, on the alitrunk or on the first gastral tergite; this quickly distinguishes dyak from members of the godeffroyi-complex, where flagellate hairs are conspicuous in all these locations.

Of the seven species in this complex five are known to be arboreal and have only been collected from forest trees, either by insecticide fogging or by hand (epyna, mjoebergi, nesteryx, phoenix, zagan). One other, phytibia, known only from the type-series, was discovered on plants intercepted in quarantine. Only dyak belongs to the leaf litter fauna.

smythiesii complex

Dorsal (outer) surface of hind basitarsus with one or more long erect filiform or flagellate hairs but otherwise not satisfying all criteria of the two foregoing species-complexes.

The 16 species of this complex are grouped together for convenience. The pseudodiagnosis, “not members of any other complex within the group”, is very unsatisfactory but is the best that can be achieved at present. In general, recognition of species placed here depends upon the following.

1 The pleurae and side of the propodeum are always unsculptured, entirely smooth and shining.

2 The godeffroyi-complex character combination, presence of flagel late hairs on mesonotum coupled with lateral spongiform lobe on petiole that extends the entire length of the node, does not occur.

For purposes of identification the 16 species can be divided as follows.

1 Those species in which the dorsolateral margin of the head has a second freely laterally projecting flagellate hair, closer to the occipital corner than the apicoscrobal hair; pronotal humeral hair is also flagellate (habropilosa, hypoturba): discussed under Strumigenys habropilosa.

2 Those species lacking a second flagellate hair posterior to the apicoscrobal and with the pronotal humeral hair flagellate (chernovi, datryx, ekasura, hastur, lichiaensis, panaulax, smythiesii, tenitecta, trada): discussed under Strumigenys lichiaensis.

3 Those species lacking a second flagellate hair posterior to the apicoscrobal and with the pronotal humeral hair stiff and simple, straight or at most only evenly shallowly curved (hispida, jepsoni, liukueiensis, solifontis): discussed under Strumigenys solifontis.

4 The isolated Fijian species Strumigenys scelesta.

Subgroup B

Species in which the dorsal (outer) surface of the hind basitarsus lacks erect filiform or flagellate hairs. (Apically curved or reclinate short ground-pilosity, simple to spatulate, is usually present. Pilosity similar on all legs.)

Character applies to: rojocala-complex, signeae-complex.

Complexes of Subgroup B

rofocala complex

Dorsal (outer) surface of hind basitarsus lacks erect flagellate hairs; pronotal humeral hair long and flagellate.

signeae complex

Dorsal (outer) surface of hind basitarsus lacks erect flagellate hairs; pronotal humeral hair not flagellate (humeral hair may be fine and simple, remiform, spatulate, short and stout, or rarely absent). Flagellate hairs always absent from dorsal surfaces of head, alitrunk and gaster.

For purposes of identification the 20 species included here may be divided as follows.

1 Fijian species with scrobe absent behind eye, propodeal declivity with a narrow carina (no lamella) and node of petiole long and low, in profile with anterior face much shorter than dorsum (mailei, praejecta, sulcata, tumida): discussed under Strumigenys mailei.

2 Species without the character combination of 1, above; without a pronotal humeral hair; dorsal surfaces of head, alitrunk and frequently also first gastral tergite lacking standing hairs (esrossi, degonya, forficata, ortholex): discussed under Strumigenys forficata.

3 Species without the character combination of 1, above; with a stiff pronotal humeral hair; dorsal surfaces of head and body with standing hairs present; metapleuron plus side of propodeum mostly or entirely smooth (ahares, izepara, signeae, sublaminata, uichancoi, valejor, virgila): discussed under Strumigenys signeae.

4 Species without the character combination of 1, above; with a stiff pronotal humeral hair; dorsal surfaces of head and body with standing hairs present; metapleuron plus side of propodeum mostly or entirely reticulate-punctate (gabarys, gamegyn, halpas, mocsaryi, sytaria): discussed under Strumigenys mocsaryi.

References