Cephalotes rohweri

These ants nest in branches and limbs of oaks (Quercus spp.) and Yellow Paloverde (Parkinsonia microphylla). Food consists of honeydew and small arthropods.

Identification
A member of the wheeleri clade differing from all the other species of the clade in the worker by the head and mesosoma irregularly foveolate-rugulose and by the infuscate frontal carinae, in the soldier and in the gyne by the dense foveae on the head and by the presence of hairs around the disc. (de Andrade and Baroni Urbani 1999)

Identification Keys including this Taxon

 * Key to Cephalotes Workers
 * Key to US Cephalotes species

Distribution
United States: Southern AZ, may occur in western NM. Mexico.

Distribution based on Regional Taxon Lists
Nearctic Region: United States. Neotropical Region: Mexico.

Biology
Cephalotes rohweri prefers to nest in canyon bottoms or on foothills at elevations 2,800 to 3,700 feet. There are seldom more than seventy-five workers in a colony. Colonies have a single queen. Workers often forage on the ground.

Nomenclature

 * . Cryptocerus (Cyathocephalus) rohweri Wheeler, W.M. 1916f: 32, fig. 2 (s.w.) U.S.A. (Arizona).
 * Type-material: lectotype soldier (by designation of Kempf, 1958a: 129), paralectotype soldiers, paralectotype workers (numbers not stated).
 * [Note: Wheeler described the species from 2 soldier and 2 worker syntypes in MCZC, but he added that other syntypes with the same data were present in USNM.]
 * Type-locality: lectotype U.S.A.: Arizona, Santa Catalina Mts, Buckman Canyon (Chrisman); paralectotypes with same data.
 * Type-depositories: USNM (lectotype); MCZC, MZSP, USNM (paralectotypes).
 * Smith, M.R. 1947a: 35 (q.).
 * Combination in Cryptocerus (Cryptocerus): Smith, M.R. 1947a: 34;
 * combination in Paracryptocerus (Harnedia): Smith, M.R. 1951a: 825;
 * combination in Zacryptocerus: Smith, D.R. 1979: 1403;
 * combination in Cephalotes: De Andrade & Baroni Urbani, 1999: 568.
 * Status as species: Emery, 1924d: 310; Wheeler, W.M. 1942: 208; Smith, M.R. 1947a: 34 (redescription); Creighton, 1950a: 297; Smith, M.R. 1951a: 825; Kempf, 1958a: 129 (redescription); Creighton & Nutting, 1965: 59; Smith, M.R. 1967: 360; Snelling, R.R. 1968a: 9 (in key); Hunt & Snelling, 1975: 22; Smith, D.R. 1979: 1403; Bolton, 1995b: 427; De Andrade & Baroni Urbani, 1999: 568 (redescription); Mackay & Mackay, 2002: 79.
 * Distribution: Mexico, U.S.A.

Worker
Kempf (1958) - Total length (only one specimen measured) 5.2 mm; maximum length of head 1.28 mm; maximum length of thorax 1.43 mm. Black; the following ferruginous: mandibles, part of frontal carinae, apex of femora and tibiae, tarsites II-V.

Head opaque, trapezoidal. Occipital corners not lobate, nor obliquely truncate, forming merely an obtuse angle. Occipital border straight and transverse. Dorsal face, excepting the rather flat, posteriorly very thick and scarcely translucid frontal carinae, and the declivous clearly limited clypeus, convex, finely and sharply punctate, coarsely foveolate, the pits wanting on the frontal carinae and on the clypeus. Lower face coarsely reticulate-rugose and foveolate.

Thorax opaque. Anterior border convex in the middle, slightly concave toward the sides. Scapular angle incorporated in the lateral pronotal crest, the latter tridentate, the anterior two teeth close together, triangular, the third tooth, forming the posterior corner of the crest, subrectangular. Promesonotal suture absent. Sides of mesonotum unarmed, immarginate. Mesoepinotal suture absent. Each side of epinotum with a slender spine, pointing laterad and slightly upward and caudad. In profile the dorsum of the thorax noticeably sloping behind pronotum, the latter convex and ascending. The entire thorax sharply punctate. Dorsum reticulate-rugose, the meshes elongate on mesonotum. Declivous face with longitudinal striae. Laterotergite of pronotum reticulate-rugose and foveolate. Pleura longitudinally rugose.

Peduncular segments opaque, their dorsal face mostly longitudinally rugose. Body of petiole subglobose, its anterior face vertically truncate; from each side of the petiole at some distance from the anterior border, arises a slender, log, slightly curved and pointed spine, pointing obliquely caudad and upward. Postpetiole with anteriorly broad, posteriorly more constricted body. A slender, longer, more recurved and pointed spine arising from each side, next to the anterior border. Dorsum of postpetiole, as seen in profile, nearly flat.

Gaster oval, opaque, finely and sharply punctured throughout. Postpetiole insertion not emarginate, anterolateral borders immarginate. First tergite finely and densely longitudinally rugose on the sides.

Standing hairs pointed, short, sparingly scattered over dorsum of head, thorax, peduncle and gaster, also on sternites, more oblique, but not decumbent, on legs. Silvery scalelike hair minute on posterior portions of head disc, larger and more conspicuous on cheeks, dorsum of thorax, laterotergite of pronotum, dorsum of peduncular segments, lacking on gaster, but present on apical half of extensor face of femora. All foveolae on dorsum of head bear a small decumbent hair, visible only under high magnification.

de Andrade and Baroni Urbani (1999) - Measurements (in mm) and indices: TL 4.04-5.54; HL 0.96-1.28; HW 1.04-1.36; EL 0.26-0.35; PW 0.92-1.22; PeW 0.46-0.60; PpW 0.55-0.65; HBaL 0.44-0.56; HBaW 0.09-0.12; CI 106.2-111.6; PI 111.5-115.5; PPeI 192.8-214.0; PPpI 167.3-192.8; HBaI 19.2-21.4.

Soldier
Kempf (1958) - Total length (one specimen only measured) 6.9 mm; maximum length of head 1.85 mm; maximum length of thorax 1.82 mm. Black; the following fuscous-ferruginous: anterolateral portions of head (variable in extent, always much infuscated), extreme tip of last funicular segment, knees and tarsites II-V

Head supopaque, surmounted by a slightly elongate disc (52:47), the borders of which are evenly rounded anteriorly, except for the supramandibular excision, subparallel and rather straight on the sides, then abruptly, yet not forming a sharp angle, curved mesad, to join the scarcely convex, subtruncate occipital border. Floor of disc moderately excavated anteriorly, shallowly excavated laterally, scarcely behind, having in the center a little prominent convexity. Occipital lobes subrectangular. Clypeal sutures obsolete. Lateral border of lower face of head not distinctly marginate. Integument of head finely reticulate-punctate, more superficially and densely on dorsum, more coarsely on lower face. Likewise densely covered with large, rounded foveolae, the intervals between the foveolae not as broad as the diameter of the pits.

Thorax opaque. Anterior border convex in the middle, slightly concave toward the sides. Anterior corner sharply dentate, the lateral border of the pronotum subparallel and crenulate in front of the carina, converging, rather straight behind the carina, not forming a prominent corner when joining the mesonotum. Transverse carina sharply marginate and somewhat crenulate, broadly yet shallowly excised in the middle. Promesonotal suture vestigial. Lateral lobes of mesonotum scarcely projecting, broad, rounded, immarginate. Mesoepinotal suture distinct. Anterior and posterior corner of basal face of epinotum rounded, not angulate. On each side, somewhat in front of the posterior corner, a strong, prominent spine, pointing mainly laterad. Sculpture of thorax as that of head, the foveolae sparser, except on basal face of epinotum. Bottom of foveolae rather shiny. Foveolae very sparse and irregularly dispersed on sides of the thorax, which also present reticulate rugosities. Declivous face without macrosculpture.

Peduncular segments opaque, dorsally reticulate-rugose and foveolate, their shape and lateral processes as in worker, but their bodies are more transverse, broader, and the spines are shorter. Postpetiole much broader than petiole.

Gaster dorsally opaque, ventrally more shining. Postpetiolar insertion very little emarginate. Anterolateral borders of gaster immarginate, never crested. First tergite heavily and densely punctate, with fine, longitudinal, dense rugosities, fading out caudad, before reaching the half. Sculpture of sternite identical but more superficial.

Standing hairs long and pointed at tip around the rim of cephalic disc anterolaterally, shorter and sparingly on dorsum of thorax, peduncle, and gaster, and on the sternites. Oblique on legs. Decumbent hair in foveolae of head and thorax usually very fine and scarcely visible, scalelike, silvery and glittering only on posterior border of basal face of epinotum, on peduncular segments, none on legs and gaster.

de Andrade and Baroni Urbani (1999) - Measurements (in mm) and indices: TL 6.82-7.44; HL 1.60-1.72; HW 1.72-1.84; EL 0.36; PW 1.68-1.88; PeW 0.62-0.72; PpW 0.76-0.88; HBaL 0.48-0.57; HBaW 0.12-0.16; CI 106.9-109.5; PI 97.8-102.4; PPeI 255.5-272.5; PPpI 209.1-223.8; HBaI 24.5-28.6.

Queen
de Andrade and Baroni Urbani (1999) - Head disc present. Posterior two thirds of the head dorsum almost flat, with a broad, little protruding central tumulus. Anterior third of the head moderately concave. Frontal carinae broadly expanded anteriorly, converging posteriorly and connected by a convex carina on the vertex. Vertexal angles round and crenulate. Eyes convex and not hidden by the disc in dorsal view. Anterior clypeal border concave. Mandibles with a lateral carina and partially hidden by the frontal carinae.

Mesosoma flat in side view. Humeral angles with an obtuse tooth anteriorly, straight posteriorly. Pronotal carina marked and superficially interrupted in the middle. Promesonotal suture impressed. Propodeum differentiated in basal and declivous face; basal face weakly convex dorsally, with convex sides; declivous face little concave on the middle.

Petiole distinctly differentiated in anterior and posterior faces; anterior face vertical, posterior face slightly convex and with unarmed sides. Postpetiole broadly convex, with a small lateral denticle on one side only of the sole available specimen.

Gaster without lateral margin, with protruding anterior border.

Legs. Fore coxae with anterior tumulus. Mid and hind femora without angle or denticles. Mid and hind basitarsi without broad base and not compressed laterally.

Sculpture. Head, mesosoma and pedicel deeply punctate and covered by deep foveae broader than their interspaces, suboval and denser on the pedicel. Frontal carinae punctate and with foveae sparser, smaller and shallower than in the other parts of the head. Sides of the fore femora, ventral part of the mesopleurae and dorsal part of the metapleurae punctate, with superficial and sparse foveae. Posterior half of the declivous face of the propodeum, legs and gaster reticulate-punctate, the same structure is present but very superficial on the ventral part of the first gastral sternite which is shining. Outer face of the tibiae with oval and superficial foveae. Anterior fourth of the first gastral tergite and sides of the anterior half of the first gastral sternite with anastomosing rugosities and rare foveae. Few irregular rugosities on the meso- and metapleurae.

Pilosity and colour as in the soldier.

Measurements (in mm) and indices: TL 7.92-8.24; HL 1.60-1.64; HW 1.64-1.72; EL 0.36; PW 1.60-1.68; PeW 0.55-0.56; PpW 0.66-0.78; HBaL 0.64; HBaW 0.14; CI 102.5-104.9; PI 102.4-102.5; PPeI 285.7-305.4; PPpI 205.1-254.5; HBaI 21.9.

Male
de Andrade and Baroni Urbani (1999) - We did not see males of this species although they are likely to be represented in some collection. There is no formal description of this sex in the literature, except for the drawings of the genitals given by Krafchick (1959). These drawings are based on material presumably preserved in the USNM and are accompanied by the following descriptive remarks deduced from the key and referred to both rohweri and Cephalotes texanus: “Basal ring entire. Paramere with the distal end rounded and ventral margins entire; notches, hooks, projections absent. Anterior ventral corner of paramere rounded or with a small point. Anterior margin of the IX sternum pointed or rounded. Point absent from corner of volsellar lobe. IX sternum with the lateral and mesal apodemes simple. Digitus a short and broad hook. Penis valve longer than wide.”

Type Material
Worker, soldier. Type locality: Buehman Canyon, Santa Catalina Mountains (Arizona). Type material: lectotype soldier in the U. S. National Museum, Washington, D. C., syntypes workers and soldiers in the U. S. National Museum, Washington, D. C.,, (Kempf, 1958 a: 129), examined in part.

References based on Global Ant Biodiversity Informatics

 * Creighton W. S., and W. L. Nutting. 1965. The habits and distribution of Cryptocerus rohweri Wheeler (Hymenoptera, Formicidae). Psyche (Cambridge) 72: 59-64.
 * Johnson R. Personnal Database. Accessed on February 5th 2014 at http://www.asu.edu/clas/sirgtools/resources.htm
 * Smith M. R. 1947. Ants of the genus Cryptocerus F., in the United States. Proceedings of the Entomological Society of Washington 49: 29-40.
 * Vásquez-Bolaños M. 2011. Lista de especies de hormigas (Hymenoptera: Formicidae) para México. Dugesiana 18: 95-133
 * de Andrade, M.L. & C. Baroni Urbani. 1999. Diversity and Adaptation in the ant genus Cephalotes, past and present. Stuttgarter Beitrage zur Naturkunde Serie B 271. 893 pages, Stuttgart