Proceratium goliath

The type series was collected in disturbed wet lowland rain forest under a fragment of rotten log.

Identification
A member of stictum clade and to the goliath group, and differing from its sister species Proceratium tio, in the worker, by the following two characters: propodeal teeth smaller, ventral process of the petiole at most shortly triangular instead of distinct and spiniform. P. goliath is the largest species of the stictum group.

Distribution
Known from Costa Rica, Honduras and Nicaragua.

Distribution based on Regional Taxon Lists
Neotropical Region: Costa Rica, Honduras.

Nomenclature

 *  goliath. Proceratium goliath Kempf & Brown, 1968: 94, figs. 1, 2 (w.) COSTA RICA. Baroni Urbani & De Andrade, 2003b: 115 (m.).

Worker
Baroni Urbani and de Andrade (2003) - Head slightly longer than broad, with gently convex sides. Vertex convex in full face view. Clypeus broad, convex, protruding anteriorly and surrounding the whole antennal insertions. Anteromedian margin of the clypeus with a notch. Frontal carinae very far each other, strongly diverging posteriorly and not covering the antennal insertions. Lateral expansions of the frontal carinae broad, convex and slightly raised. Frons concave medially. Genal carinae marked. Head, ventrally, with a pair of superficially impressed longitudinal sulci delimited externally by the genal carinae. Gular area impressed. Eyes present, composed by clearly convex facet, and placed slightly below the mid-line of the head. Scapes not reaching the vertexal margin. Funicular joints 2-10 broader than long. Last funicular joint as long as the sum of joints 7-10. Mandibles with 3-4 denticles before the apical tooth. Palp formula 4,3.

Mesosoma convex in side view and slightly longer than the head (mandibles included). Promesonotal and propodeal sutures very weakly impressed. Promesopleural and meso-metapleural sutures impressed on the ventral half only. Basal face of the propodeum declivous posteriorly. Declivous face of the propodeum flat; sides of the declivous face carinale. Each side between basal and declivous faces of the propodeum separate by a broad, subtriangular angle. Propodeal lobes truncate and apically convex. Propodeal spiracle tumuliform and placed over mid height in lateral view.

Petiole slightly longer than broad, with the sides diverging anteriorly and convex posteriorly in dorsal view. Anterior border of the petiole gently concave and strongly carinate. Ventral process of the petiole small, subtriangular. Postpetiole 1/4 shorter than length of the gastral tergite I (LT4), with a broad tumulus close to the middle of the posterior border in side view. Postpetiolar sternite anteromedially with a marked subtriangular projection. Posterior hall of the postpetiolar sternite convex. Constriction between postpetiole and gastral segment I impressed. Gastral tergite I strongly convex. Remaining gastral tergites and sternites slightly curved ventrally.

Legs slender. All tibiae with a pectinate spur. Spurs of the fore legs with a basal spine. Fore basitarsi slightly longer than the mid ones. Hind basitarsi about 1/8 shorter than hind tibiae. Second tarsomere of mid and hind legs longer than the third and fourth tarsomeres, and slightly shorter than pretarsus. Fourth tarsomere of fore legs slightly longer than tarsomeres 1-3. Pretarsal claws simple. Arolia small but present.

Sculpture. Head, mesosoma, petiole and postpetiole irregularly foveolate-punctate and sparsely granulate. Gaster smooth and with, minute piligerous punctures. Legs with dense piligerous punctures.

Body covered by hairs of three main types: (1) short, dense, subdecumbent on the whole body, suberect and sparse on the funicular joints; (2) long, suberect or subdecumbent, relatively dense on the whole body, absent on the scapes and funicular joints; (3) shorter than hair type (I), dense and decumbent on the funicular joints only. In addition, the funicular joints bear thick, appressed, short, sparse hairs and the scapes sparse, subdecumbent hairs slightly shorter than hair type (2).

Colour brownish-red, legs lighter.

Measurements in mm and Indices: TL 6.22-6.72; HL 1.44-1.54; HW 1.36-1.44; EL 0.10; SL 1.04-1.12; WL 1.80-1.92; PeL 0.72-0.80; PeW 0.62-0.68; HFeL 1.44-1.52; HTiL 1.16-1.25; HBaL 1.02-1.10; LS4 0.17-0.24; LT4 1.16-1.32; CI 93.5-94.6; SI 70.3-72.2; IGR 0.15-0.18.

Male
Baroni Urbani and de Andrade (2003) - (tentative attribution, previously undescribed). Head about as long as broad. Vertex convex. Clypeus anteromedially gently convex and with a superficial notch on the anterior border. Frontal carinae little developed, parallel, not hiding the antennal socket and far each other. Space between the frontal carinae with a deep concavity on the center. Ocelli large. Compound eyes very large and on the anterior half of the head sides. Scapes at most reaching the anterior border of the anterior ocellus. First funicular joint about 1/2 of the length of the second joint; second joint slightly longer than joints 3-9, about as long as joints 10-11, and about half of the length of the last joint. Mandibles slender, edentate except for a swelling before the apical pointed tooth. Palp formula probably 4,3.

Mesosoma robust. In profile pronotum perpendicular, mesonotum gently convex, scutellum convex and higher than mesonotum. Mesonoturn separated from the scutellum by a deep sulcus. Scutellum medially with a deep, longitudinal sulcus. Metanotum with a thick, median spine. Propodeurn with differentiate basal and declivous faces. Basal and declivous faces separated laterally by an angle. Basal face medially with a deep sulcus prolonging up to the anterior third of the declivous face. Declivous face anteriorly higher than posteriorly. Posterior part of the declivous face with carinate sides.

Petiole elongate, about 1/5 longer than broad, little convex dorsally. Anterior border of the petiole carinate and gently concave medially. Subpetiolar process absent but with a longitudinal carina. Postpetiole with the sides broadening posteriorly in dorsal view. Postpetiolar sternite anteromedially with a marked triangular carina.

Gastral tergite I strongly convex. Remaining gastral tergites and sternites curved ventrally.

Legs long and slender. Hind tibiae slightly longer than the hind basitarsi. Fore basitarsi shorter than mid basitarsi.

Fore wings of our type 5, hind wings of our type 2 as defined in the description of the genus.

Sculpture. Head, mesosoma, petiole and postpetiole irregularly foveolate-punctate, the foveae sparser on the mesopleurae, larger on the metapleurae. Propodeal dorsum with additional irregular rugosities. Gastral tergite I with similar sculpture as on the postpetiole but the foveae more superficial and absent on the sides. Legs smooth, tibiae and tarsi strongly punctate, the punctures denser on the tarsi.

Body covered by hairs of three main types: (1) short, dense, subdecumbent on the whole body, suberect and very sparse on the funicular joints; (2) long, suberect or subdecumbent, relatively dense on the whole body, absent on the scapes and funicular joints; (3) shorter than hair type (1), dense and decumbent on the funicular joints only. In addition, the funicular joints bear thick, appressed, short, sparse hairs and the scapes sparse, subdecumbent hairs shorter than hair type (2).

Colour. Dark brown-red with lighter legs.

Measurements in mm and Indices: TL 5.73-5.95; HL 0.98; HW 1.00-1.04; EL 0.40-0.42; SL 0.49-0.50; WL 1.96-2.10; PeL 0.62-0.67; PeW 0.49-0.50; HFeL 1.16-1.24; HTiL 1.12-1.24; HBaL 1.08-1.16; LS4 0.33-0.37; LT4 1.14-1.18; CI 102.0-106.1; SI 50.0-57.1; IGR 0.29-0.31.

Type Material
Baroni Urbani and de Andrade (2003) - Type locality Costa Rica. Type material five workers (holotype and paratypes) labeled "R. Toro Amarillo, vic. Guapiles, Costa Rica, 25 Feb - 9 March 1966, W L Brown", Holotype in, paratypes in MCZC and , all examined.

References based on Global Ant Biodiversity Informatics

 * Brown W. L., Jr. 1974. A remarkable new island isolate in the genus Proceratium (Hymenoptera: Formicidae). Psyche (Camb.) 81: 70-83.
 * Dattilo W. et al. 2019. MEXICO ANTS: incidence and abundance along the Nearctic-Neotropical interface. Ecology https://doi.org/10.1002/ecy.2944
 * Fernández, F. and S. Sendoya. 2004. Lista de las hormigas neotropicales. Biota Colombiana Volume 5, Number 1.
 * Kempf, W.W. 1972. Catalago abreviado das formigas da regiao Neotropical (Hym. Formicidae) Studia Entomologica 15(1-4).
 * Longino J. T. L., and M. G. Branstetter. 2018. The truncated bell: an enigmatic but pervasive elevational diversity pattern in Middle American ants. Ecography 41: 1-12.
 * Longino J. T., and R. K. Colwell. 2011. Density compensation, species composition, and richness of ants on a neotropical elevational gradient. Ecosphere 2(3): 16pp.