Aphaenogaster lepida

Identification
Wheeler 1929 - The worker of this species seems to resemble that of Aphaenogaster tipuna from Formosa, to judge from Forel's description, but the male is very different in the structure of its epinotum and mesonotum, which does not overhang the head anteriorly. The worker is smaller than that of tipuna, with longer funicular joints and different sculpture.

Dong et al. (2020) - Workers of Aphaenogaster lepida and Aphaenogaster tipuna are morphologically similar. The most significant difference is in head coloration, the head of A. tipuna workers being entirely reddish (Fig. 5A) while it is black in A. lepida (Figs. 1, 2). However, while the colour differences are distinct in live and freshly collected material, discoloration can occur in both pinned specimens and alcohol-fixed material, especially in long-term preserved specimens. Unfortinately, this reduces the usefulness of this character in separating these taxa.

In contrast to workers, males are easily separated by differences in the shape of the mesonotum and propodeum. The mesonotum of A. lepida is smaller and lower (Figs. 3A, 3B) compared to that of A. tipuna, where it is larger and overhangs the posterior region of the head (Fig. 3C) (Wheeler, 1929). The propodeum in A. lepida is higher and essentially flat (Figs. 3A, 3B) while in A. tipuna it is lower and distinctly angular anteriorly (Fig. 3C).

Distribution based on Regional Taxon Lists
Oriental Region: Taiwan. Palaearctic Region: China, Republic of Korea.


 * Note that Korean records of this species were previously misidentified as Aphaenogaster tipuna (Dong et al., 2020).

Nomenclature

 * . Aphaenogaster (Attomyrma) lepida Wheeler, W.M. 1930a: 96.
 * Replacement name for Aphaenogaster (Attomyrma) silvestrii Wheeler, W.M. 1929g: 37. [Junior primary homonym of Aphaenogaster (Deromyrma) silvestrii Menozzi, 1929b: 282.]
 * Status as species: Chapman & Capco, 1951: 132; Brown, 1954d: 10; Bolton, 1995b: 70; Wu, J. & Wang, 1995: 114; Lin & Wu, 2003: 64; Terayama, 2009: 164; Guénard & Dunn, 2012: 40.
 * Senior synonym of funkikoensis (unnecessary third replacement name): Brown, 1954d: 10; Bolton, 1995b: 70; Terayama, 2009: 164.
 * Senior synonym of phillipi (unnecessary second replacement name): Brown, 1954d: 10; Bolton, 1995b: 70.
 * funkikoensis. Aphaenogaster funkikoensis Creighton, 1950a: 152 (footnote).
 * Unnecessary (third) replacement name for Aphaenogaster (Attomyrma) silvestrii Wheeler, W.M. 1929g: 37. [Junior primary homonym of Aphaenogaster (Deromyrma) silvestrii Menozzi, 1929b: 282.]
 * Junior synonym of lepida (first replacement name): Brown, 1954d: 10; Bolton, 1995b: 69; Terayama, 2009: 164.
 * phillipi. Aphaenogaster phillipi Menozzi, 1932b: 311 (footnote).
 * Unnecessary (second) replacement name for Aphaenogaster (Attomyrma) silvestrii Wheeler, W.M. 1929g: 37. [Junior primary homonym of Aphaenogaster (Deromyrma) silvestrii Menozzi, 1929b: 282.]
 * Junior synonym of lepida (first replacement name): Brown, 1954d: 10; Bolton, 1995b: 72.

Worker
Length 4-6 mm.

Head subelliptical, nearly 1 1/3 times as long as broad, regularly rounded and narrowed, but not constricted behind the eyes, without posterior corners, the posterior border formed by the marginate occipital articulation. Eyes rather small, moderately convex, situated at the middle of the sides of the head. Mandibles large, flattened, with straight external borders, the long apical borders with three well-developed apical and several short, indistinct basal teeth. Clypeus convex posteriorly, its anterior border rather broadly emarginate in the middle and sinuate on each side. Frontal area very distinct, rounded-triangular. Antennae long and slender; scapes extending about 2/5 their length beyond the posterior border of the head; funicular joints 1-7 subequal, twice as long as broad, the four terminal joints longer and larger, forming a distinct club. Thorax slender; pronotum bluntly bituberculate on each side, somewhat flattened above; convex in profile; promesonotal suture strongly impressed. Mesonotum rather straight, sloping downward and backward from a projecting, transverse, medially emarginate ridge at its anterior end; mesoepinotal constriction short and acute; the base of the epinotum long, straight and horizontal in profile, except at the extreme anterior end where it rises abruptly from the mesoepinotal suture, nearly twice as long as the rather steep declivity, the spines slender, blunt, shorter than their distance apart at the base and directed backward, outward and slightly upward. Petiole longer than high through the node, which is about as long as the peduncle and rising rather abruptly from it, somewhat conical, narrowed above. Postpetiole half again as broad as the petiole, longer than broad, broadened behind, with a well- developed, somewhat transverse node, as high as that of the petiole. Gaster elongate-elliptical. Legs long and slender, the femora somewhat thickened in the middle.

Shining; mandibles subopaque, sharply longitudinally striate; clypeus and upper surface of head irregularly longitudinally rugulose. On the latter the rugules are most numerous near the eyes, the front smoother and more shining; cheeks and sides of gula with a few scattered elongate foveolre. Pronotum smooth and shining in the middle, vaguely and delicately rugulose on the sides; meso-epinotum less shining and somewhat longitudinally punctate-rugulose, the epinotal declivity smooth and shining. Gaster with scattered piligerous punctures. Scapes subopaque, finely striate and sparsely punctate.

Hairs glistening white, obtuse, coarse, sparse and erect on the body, on the appendages line, short and appressed, except on the femora which bear several suberect hairs on their flexor surfaces. Pubescence absent.

Deep reddish brown or blackish; mandibles, thorax, legs, clubs; of antennae and peduncle of petiole red.

Male
Length 3.5 - 4 mm.

Head decidedly longer than broad through the eyes, flattened above and below; subtrapezoidal behind the eyes, which are moderately convex and half as long as the sides. Ocelli small. Cheeks very short. Mandibles with six well-developed teeth. Clypeus very convex, its anterior border thick and slightly impressed in the middle. Frontal area large and very distinct; frontal groove deeply impressed in front of the anterior ocellus. Antennal scapes cylindrical, slightly curved, four times as long as broad; funiculi long, resembling those of the worker in the proportions of the basal joints, but the four terminal joints forming the club are each strongly constricted at the base. Thorax lung, very broad and high through the wing-insertions. Pronotum very short and broad, its posterior lateral borders extending out on each side beyond the mesonotum. Mesonotum convex, especially in the middle anteriorly where it overhangs the pronotum though not as much as' in some other species of the genus. Seen from above the mesonotum is subpentagonal and distinctly broader than long, Scutellum convex and projecting. Epinotum fully 1 1/2 times as long as broad, as broad behind as in front, feebly and transversely constricted in the middle; in profile much lower than the mesonotum, its dorsal surface slightly convex, gradually sloping backward and downward; with a slight median impression and terminating behind in two stout, blunt, backwardly directed teeth, which are as long as broad at their bases; the declivity short and sloping, less than a third as long as the base. Petiole and postpetiole similar to those of the worker, but with lower nodes. Hind femora and tibiae constricted at the base, bent, bow-shaped, the bending opposite in the two segments, the femora being concave on the extensor, the tibiae on the flexor side. The metatarsi also exhibit a distinct sigmoidal flexure. Wings with two complete cubital, a closed submarginal and a rather large discoidal cell.

Smooth and shining, except the mandibles, head, scutellum and posterior portion of the mesonotum, which are finely and rather superficially punctate or reticulate and somewhat more opaque.

Pilosity similar to that of the worker but shorter and finer.

Piceous black; clubs of antennre, pronotum and legs paler. Wings faintly tinged with brown, with brown veins and dark brown stigma.

Type Material
Described from fourteen workers and four males taken at Funkiko, Formosa.

References based on Global Ant Biodiversity Informatics

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 * Terayama, M. 2009. A synopsis of the family Formicidae of Taiwan (Insecta; Hymenoptera). The Research Bulletin of Kanto Gakuen University 17: 81-266.
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