Thaumatomyrmex paludis

Kempf (1975) - The holotype was found in an abandoned birds nest on a tree, on a small island periodically subjected to submersion, and the Manaus specimen was taken while climbing the trunk of a tree. The presence of strays in such situations appears to be characteristic of a great many ant species of the Amazon and Orinoco fauna and by no means constitutes a peculiarity of the present species.

Identification
Kempf (1975): This species belongs to the ferox-group, characterized by the entirely smooth and highly polished integument of the body, the lack of a pair of close-set setae on center of c1ypeus, and the presence of only two setae on each side of declivous face of propodeum. The closest relation is Thaumatomyrmex zeteki, with which it shares the subquadrate head and short mandibles, but from which it differs in the following features: mandibles lacking the small tooth on base of proximal spines which do not cross each other when mandibles are closed and pressed against the c1ypeus; intermediate mandibular spines only half as long as apical ones; the larger eyes with their greatest diameter equaling or even surpassing one third of head length; the lack of a metanotal suture and groove, the mesonotum and propodeum being continuous and forming in profile an evenly and very broadly rounded curvature; inferior part of sides of declivous face only indistinctly carinate; petiolar node in side-view biconvex, subconical, with an acutely rounded apex and with a distinct though not sharp transverse margination separating dorsally and laterally the anterior face from the posterior face of the node. Also the interfrontal, scape and hind femur indices have constantly higher values in paludis (3 specimens seen) than in zeteki (3 specimens seen), but the respective ranges are contiguous, so that in individual cases they might not give much help.

The other species of the ferox-group, Thaumatomyrmex ferox, Thaumatomyrmex atrox and Thaumatomyrmex manni, have all a distinct metanotal groove and suture, much broader heads and longer mandibles.

Key to Thaumatomyrmex

Distribution based on Regional Taxon Lists
Neotropical Region: Brazil, Colombia, Venezuela.

Nomenclature

 *  paludis. Thaumatomyrmex paludis Weber, 1942b: 68, figs. 1, 2 (w.) VENEZUELA. Junior synonym of ferox: Longino, 1988: 38. Revived from synonymy: Fernández, 2008: 211 (in key); Jahyny, Lacau, et al. 2008: 336 (in key). See also: Kempf, 1975b: 114.

Worker
Kempf (1975): holotype - TL 3.8 (3.7-4.1) mm; HL 0.75 (0.73-0.81) mm; HW 0.77 (0.73-0.80) mm; CI 103 (98-103); ML 0.60 (0.60-0.72) mm; MI 89 (89-94); IfW 0.53 (0.52-0.57) mm; IfI 69 (69-72); SL 0.58 (0.58-0.71) mm; SI 78 (78-87); WL 1.12 (1.12-1.27) mm; PnW 0.53 (0.53-0.56) mm; HfL 0.77 (0.77-0.91) mm; HfI 100 (100-113); PW 0.58 (0.58-0.68) mm. Black; mandibles, frontal lobes, antennae, trochanters and basal third of femora, apical four tarsomeres of all legs yellowish brown; remainder of femora, tibiae and tarsomere I, and three apical segments of gaster somewhat darker brown. Integument smooth, shining and highly polished except for the following: Dorsum of base of mandible to origin of apical spine finely striolate; frontal lobes finely rugulose; semicircular rugulae around antennal socket; antennal scape finely and superficially rugulose-punctate; neck of thorax transversely rugulose; femora and tibiae with stronger and sparse piligerous punctures, otherwise smooth and shining; tarsomeres densely reticulate-punctate, opaque. Hairs in general as in Thaumatomyrmex mutilatus (their distribution shown in Figs. 15 and 24), but honey-yellow in color, slightly finer, and less distinctly truncate at apex; lacking a pair of close-set setae on disc of c1ypeus, and the lateral submarginate border of propodeum bears only two setae, the lowermost arising from the top of the nearly obsolete inferior carinule.

Head about as long as broad, occipital corners more narrowly rounded than in mutilatus, its greatest length between two parallels drawn through the anteriormost tip of frontal lobes and the posteriormost point of the occipital carinule which is visible in full-face vicw; the mandibular acetabula scarcely stalked and hardly projecting. Mandibles (Fig. 30), when closed, not at all (or just a little) projecting beyond maximum width of head in front of eyes, the base of the proximal spines without a tooth, the tips of the same spines not crossing when appressed against the c1ypeus; intermediate spine half as long as chord length of apical spine. Frontal lobes narrower than in mutilatus, narrowly rounded in front, without a somewhat constricted and pointed apex. Frontal area and suture vestigial. Maximum length of genae in full-face view in front of eyes not much longer than one half of the diameter of the latter. Eyes relatively large, their greatest diameter slightly over one third of head length, with about 13-14 facets in a row across the same diameter. Funicular segments II-VI of antennae conspicously broader than long. Thorax (Fig. 24) with the pronotum evenly vaulted in both directions, the antero-inferior corner subangulate. Mesonotum and propodeum continuous, lacking a metanotal suture or groove; basal and declivous face of propondeum very evenly and continuously rounded in profile, the lateral carinule on inferior part of alteral border of declivous face short and indistinct. Spiracle of propodeum, when seen from above, not drawn out in the fashion of a broad and low cone (i. e. the area surrounding the aperture not raised). Petiole somehow similar to that of mutilatus, its apex almost pointed when seen in profile, and with a more or less distinct yet not sharply marked transverse margination between the anterior and posterior face of node, both dorsally and on sides. Subpctiolar process posteriorly dentate. Dorsum of tergum I of gaster not overhanging the vertical anterior surface, both not forming an acute angle in profile.

Type Material
VENEZUELA, Delta Amacuro: on a small, nameless island, submersed at high tide, cast of Isla Tórtola, February 2, 1935, N. A. Weber leg. 1 female (holotype), in an abandoned birds nest (Weber collection: MCZ type 32304); examined.