Procryptocerus mayri

In Costa Rica, Procryptocerus mayri and Procryptocerus batesi are nearly always found together, and they are restricted to wet montane forest. They occur commonly in cloud forest habitats, reach their peak abundances between 1000 and 1500 m, and drop out at lower elevations where other species of Procryptocerus become more abundant. The restriction to montane forest is vividly illustrated on the Osa Peninsula in southwestern Costa Rica. Most of the peninsula is well below 500 m elevation, but a few ridges in the center attain 700 m, where there is a very small patch of vegetation with the aspect of a cloud forest. In spite of nearly two year’s experience on the peninsula by one of us (J.T.L.), P. mayri and P. batesi were only found during a two-day trip to this cloud forest, where they were abundant on low vegetation. (Longino and Snelling 2002)

Identification
Longino and Snelling (2002) - Variation in Frontal Carinae. On most P. mayri from Costa Rica and the series from Valle Dept., Colombia, the portion of the frontal carina that curves mesad above the torulus is well separated from the torulus and remains relatively elevated (and higher than wide) to the point where it joins or parallels the lateral clypeal carina. On a few Costa Rican specimens, the types of P. mayri and P. reichenspergeri, specimens from Rancho Grande, Venezuela, and a specimen from Peru, the frontal carina tapers as it curves mesad and becomes little more than a raised line, no higher than wide, that crosses the dorsum of the torulus and approaches the lateral clypeal carina.

Based on separate collections of six P. mayri queens and six Procryptocerus batesi queens, there is a sculptural difference between the two species. Queens of P. mayri have the ventral half of the anepisternum smooth or longitudinally carinate. Queens of P. batesi have the anepisternum entirely areolate-foveate, with at most a narrow ventral strip smooth or with 1–2 longitudinal carinae.

See additional comments on this species complex under P. batesi.

Distribution based on Regional Taxon Lists
Neotropical Region: Brazil, Colombia, Costa Rica, Ecuador, Guatemala, Honduras, Mexico, Panama, Peru, Venezuela.

Biology
Longino and Snelling (2002) - The following nest data are extracted from field notes. All are from Costa Rica.

Rio Lagartos below Santa Elena de Monteverde (J. Longino). Riparian forest patch along stream. An acanthaceous gangly shrub (probably Justicia) overhanging stream had scattered workers on it. Two nests were in the lower branches of the plant, and the entrances pointed downwards and were easily seen from below. One nest was 49 cm long, entirely within a live, 14-mm-diameter branch, with a single, centrally located, circular entrance hole. The walls of the chamber were very smooth and clean. The second nest was in a live branch with a dead apex; 4 cm of the nest in live stem, 52 cm in dead. It had two lateral entrance holes 30 cm apart. A third branch, near the previous two, had an externally visible entrance hole identical to those of the Procryptocerus nests, but the branch contained a populous Camponotus nest. The entire contents of the two Procryptocerus nests were collected (Table 1). The nests contained workers, sexuals, and brood, but no colony queen, which suggests they were parts of a polydomous colony.

Wilson Botanical Garden (J. Longino). On 28 Feb 1989, small saplings of Cecropia obtusifolia were examined along a river bank in forest. The apical internodes contained founding Azteca queens, but the lower internodes contained colonies of other genera, most commonly Procryptocerus mayri and Heteroponera panamensis. Nests of Procryptocerus occupied single internodes, but some saplings contained more than one nest. The contents of six nests were recorded. A number of workers bore a peculiar pale patch on the first gastral tergite, where the integument appeared thin, deformed, and weakly sclerotized.

Monteverde, 1340 m (J. Longino). Wet forest edge; lone queen in soft rotten stick lodged in vegetation; a Camponotus nest was in the same stick.

Twenty-two kilometers North of Volcan Barba (J. Longino). Wet forest; nest containing workers, alate queens, males, and larvae in the live trunk of a tree sapling.

Rara Avis, 17 km South of Pto. Viejo (J. Longino). Wet forest; nest in live branch of melastome tree; entire nest collected; contained 11 workers, 5 worker pupae, 2 prepupae, 6 larvae, 2 eggs.

One kilometer North of La Ese (P. S. Ward). Roadside; nest in dead twig of Baccharis trinervis.

In summary, P. mayri nests in a variety of plant stems, most often live ones. Individual nests contain fewer than 100 workers, but the frequent lack of dealate queens in nests suggests polydomy. The small amount of brood relative to adult workers and the absence of any signs of stored food suggest a long-lived worker population with a low rate of worker production. The presence of queen pupae, callows, and fully sclerotized adults together in the same nest suggests a gradual production of sexuals, and probably their gradual release.

Nomenclature

 *  mayri. Procryptocerus mayri Forel, 1899c: 43 (footnote) (w.) COLOMBIA. See also: Kempf, 1951: 103. Senior synonym of reichenspergeri: Longino & Snelling, 2002: 19.
 * reichenspergeri. Paracryptocerus mayri st. reichenspergeri Santschi, 1921g: 98 (w.) BRAZIL. Combination in Procryptocerus: Kempf, 1951: 105. Junior synonym of mayri: Longino & Snelling, 2002: 19.

Longino and Snelling (2002) - Other South American Material Identified as P. mayri. The following specimens are all very similar to the type, with only slight differences in the degree of longitudinal versus clathrate sculpture on the face, and the color of the legs. Two specimens from Venezuela (Rancho Grande) have HW’s 1.95 mm and 2.12 mm and red legs. A specimen from Colombia, Dept. Valle, has HW 1.72 and black legs (two other specimens in this series are similar). One specimen from Colombia, Dept. Narino, has HW 1.748 and red legs. One specimen from Peru has HW 1.62 and dark red legs. The face sculpture on this specimen is somewhat shallower than the type. Additional specimens from Colombia, Ecuador, and Peru begin to blur the distinction between P. mayri and other forms in this complex. Further work is needed in this region.

Worker
Longino and Snelling (2002) - (n = 1, Costa Rica): HW 1.678 (range 1.309–1.532, mean 1.465, n 5 4), HL 1.585, SL 1.0452, EL 0.388, MeL 2.405, MeW 1.233, PrW 0.743, PrL 0.670, PrS 0.479, PrT 1.149, MTL 1.392, MFL 1.535, MFW 0.462, PtL 0.599, PtW 0.531, PpW 0.617, PtH 0.434, AL 2.106, AW 1.750.

Lectotype: HW 1.951, HL 1.789, SL 1.203, EL 0.481, MeL 2.556, MeW 1.370, PrW 0.931, PrL 0.624, PrS 0.486, PrT 1.11, MTL 1.606, MFL 1.707, MFW 0.535, PtL 0.617, PtW 0.521, PpW 0.593, PtH 0.490, AL 2.037, AW 1.890.

Head subtriangular in outline, margin of vertex roughly straight; frontal carina extends onto clypeus, separated from and passing above torulus as a continuous flange; torulus trough lacking; face sculpture composed of high, sharp, well-spaced rugae; spaces between rugae smooth and shining; rugae often anastomosing to form polygons, with little longitudinal orientation (clathrate sculpture); this condition grades into increasing degrees of longitudinal orientation of rugae, especially anteriorly; rarely, rugae may be almost entirely longitudinal and subparallel; clypeus at level of antennal insertions bent ventrad; clypeus with prominent median longitudinal carina, flanked with 1–4 longitudinal carinae on each side; lateral carinae of variable strength; genae varying from longitudinally rugose to coarsely foveate/areolate; genal bridge longitudinally rugose; mandibles coarsely to weakly striate; eyes nearly symmetrically convex; scape flattened with thick lateral margin distally, becoming narrower and more terete basally, then flaring into a basal flange; broad, flat surface of scape finely areolate, outer lateral margin with coarse rugae; margin of vertex obtuse, weak, obsolete medially; vertex shiny with coarse, longitudinal striae radiating from occiput (of highly variable strength).

Mesonotal lobes short, acute, upturned; propodeal suture broadly, shallowly impressed, not breaking sculpture; anterolateral propodeal lobes absent; degree of margination between dorsal and lateral faces of propodeum variable; length of propodeal spines variable; propodeal spines vary from pointing straight back to being widely divergent; pronotum reticulate rugose, coarsely areolate anteriorly; in some specimens rugae somewhat longitudinally parallel on mesonotum; dorsal face of propodeum reticulate rugose to longitudinally striate; posterior face of propodeum meeting dorsal face at obtuse angle; posterior face of propodeum varies from completely smooth and shining with one or two transverse striae between bases of propodeal spines to mostly covered with coarse transverse striae; side of pronotum and katepisternum and side of propodeum with coarse longitudinal striae; becoming irregular on anepisternum and near dorsolateral pronotal margin; posterior surface of forefemur entirely smooth and shining; outer surface of metatibia coarsely rugose.

Ventral margin of petiole flat to weakly concave with low anterior right-angled tooth; anterodorsal face of petiole shiny with coarse to faint transverse striae (completely smooth in a few specimens); posterodorsal face areolate-foveate (weakly longitudinally rugose in some specimens); postpetiole with a long, gently sloping anterior face, a broad, rounded summit near the posterior margin, and a steeply sloping posterior face; ventral margin of postpetiole short with a prominent, acute anterior tooth; dorsum of postpetiole coarsely foveate-rugose (weakly longitudinally rugose in some specimens); first gastral tergite smooth and shining or occasionally with faint rugae anteriorly near petiolar insertion; first gastral sternite largely microreticulate, nearly smooth; second gastral tergite with faint, dense, granular sculpture.

Abundant flexuous setae on face, mesosomal dorsum (>20 on central area of promesonotum, not including those on lateral margins), petiole and sparse, whitish pubescence under the erect setae or lacking underlying pubescence; color shining black, legs black or occasionally red.

The type of P. mayri differs from Costa Rican material primarily by being larger. Also, the face is more uniformly striate, less clathrate. The legs are red.

Queen
Longino and Snelling (2002) - (n = 1, Costa Rica): HW 1.95, HL 1.78, SL 1.19, EL 0.47, MeL 2.88, MeW 1.69, MTL 1.59, PtL 0.72, PtW 0.58, PpW 0.71, PtH 0.55, AL 2.34, AW 2.04.

Characters of the head, legs, petiole, postpetiole, and gaster similar to worker.

Pronotum and anterior portion of mesoscutum coarsely areolate-foveate. On the posterior half of the mesoscutum and on the scutellum the interspaces become increasingly aligned as longitudinal rugae between the foveae. Dorsal face of propodeum with a variable extent of the median area vermiculate-longitudinally rugose, lateral margins areolate-foveate. Dorsal half of posterior face with 3–4 strong transverse carinae, ventral half smooth and shining. Pronotal sculpture extends onto sides, grading into wavy longitudinal carinae. Most of katepisternum and side of propodeum longitudinally carinate. Ventral half of anepisternum longitudinally carinate or smooth, dorsal half areolate-foveate, like pronotum.

Type Material
Longino and Snelling (2002) - Lectotype worker: Colombia (Landolt) (two workers examined). Kempf 1951:103–104, fig. 11, 28, 56, 68 (redescription of worker, designation of lectotype).

Neither of the two workers at MHNG bore a Kempf lectotype label. One worker was subsequently borrowed, detailed measurements were made, and a Lectotype label was added.

References based on Global Ant Biodiversity Informatics

 * 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.
 * INBio Collection (via Gbif)
 * Kempf, W.W. 1972. Catalago abreviado das formigas da regiao Neotropical (Hym. Formicidae) Studia Entomologica 15(1-4).
 * Longino J. T. and Snelling R. R. 2002. A taxonomic revision of the Procryptocerus (Hymenoptera: Formicidae) of Central America. Contributions in Science (Los Angeles) 495: 1-30
 * Longino J. et al. ADMAC project. Accessed on March 24th 2017 at https://sites.google.com/site/admacsite/