Crematogaster raptor

Dataset
The Crematogaster (Hymenoptera, Formicidae, Myrmicinae) of Costa Rica.: Rank
SPECIES

Classification

kingdom
Animalia: phylum
Arthropoda: class
Insecta: order
Hymenoptera: family
Formicidae: genus
Crematogaster: species
Crematogaster raptor

biology_ecology

Biology Crematogaster raptor occurs in lowland wet forest habitats. I first collected the species in Corcovado National Park on the Osa Peninsula. In a study of visitors to the extrafloral nectaries of a Passiflora species, the new shoots of one plant were always occupied by this species of Crematogaster. After following activity on this plant for two years, I traced the workers back to their nest. The nest was a small mass of carton wedged between a rotten stick and a live stem, about 1.5 m above the ground. This collection yielded workers only. I encountered a second colony while collecting on Cerro Tortuguero on the north Atlantic coast. Workers and brood were densely packed in a dead, square-stemmed vine. The vine, 2 - 3 cm diameter, was fragmented and nothing but a thin papery shell. Also associated with the fragmented vine was a globular carton nest about 10 cm wide. The carton was mainly a shell with a few internal partitions, and was bare of epiphytes. Workers were tending Homoptera on various branches around the nest. In addition to workers and brood, I found two teneral winged queens and a male in the carton nest. At La Selva Biological Station, the species is known from a single queen. Adrienne Nicotra discovered a small single-queened colony of C. carinata in a live stem of Siparuna tonduziana (Monimiaceae). Coinhabiting this nest was a single dealate queen of C. raptor. This observation, along with the shininess of the queen and the strongly falcate mandibles, suggest temporary social parasitism as a mechanism of colony founding. The only other collection of C. raptor is stray workers taken during nocturnal collecting in forest along the Rio Pacuare, at 200 m elevation.

description

Description of worker Color dark red brown to black. Mandibles striate, shiny; clypeus weakly emarginate anteriorly, convex dorsally, shiny; face smooth and shiny; scapes with a combination of erect and subdecumbent setae, setae abundant, of variable length, longest erect setae longer than width of scape; terminal three segments of antenna enlarged, forming distinct three-segmented club; face with abundant erect flexuous white setae; in full face view abundant setae projecting from posterior margin and sides of head. In lateral view, promesonotum forming a single, somewhat flat-topped convexity, rising steeply anteriorly, dropping steeply posteriorly, and slightly impressed at promesonotal suture; propodeal suture deep and broad, v-shaped; dorsal and posterior faces of propodeum distinct; propodeal spines in the form of broad, low, nearly right angles rather than spiniform, the vertex of the angle forming a variably developed short acute tooth; side of pronotum and dorsolateral propodeum smooth and shiny; katepisternum and ventrolateral propodeum with variably developed faint areolate rugose sculpture; promesonotal dorsum and dorsal face of propodeum with faint irregular rugae and etchings, sublucid; posterior face of propodeum smooth and shiny; promesonotum and dorsal face of propodeum with abundant whitish erect flexuous setae of variable lengths, no setae on posterior face of propodeum; legs with abundant erect and suberect setae. Petiole robust, in side view trapezoidal, with microareolate sculpture; anteroventral tooth well-developed, deep, forming a strong right to slightly obtuse angle; dorsal face rectangular, longer than wide, slightly wider posteriorly than anteriorly, smooth and shiny, with row of setae across posterior margin; postpetiole with very small ventral tooth, blunt to acute; postpetiole in dorsal view subquadrate, wider than long, posterior margin emarginate, with longitudinal median sulcus; fourth abdominal tergite smooth and shiny; postpetiole and fourth abdominal tergite with abundant whitish erect flexuous setae. Measurements Holotype: HL 0.671, HW 0.689, HC 0.618, SL 0.639, EL 0.157, WL 0.791, SPL 0.070, PTH 0.205, PTL 0.287, PTW 0.226, PPL 0.185, PPW 0.226, CI 103, OI 23, SI 95, PTHI 71, PTWI 79, PPI 122, SPI 9. Other specimens: HL 0.630, 0.627, 0.685; HW 0.663, 0.667, 0.708; HC 0.596, 0.591, 0.617; SL 0.598, 0.595, 0.631; EL 0.147, 0.168, 0.182; A 11 L 0.279; A 11 W 0.139; A 10 L 0.145; A 10 W 0.114; A 09 L 0.074; A 09 W 0.080; A 08 L 0.051; A 08 W 0.060; WL 0.733, 0.752, 0.788; SPL 0.078, 0.074, 0.081; PTH 0.196, 0.181, 0.217; PTL 0.251, 0.265, 0.314; PTW 0.200, 0.205, 0.259; PPL 0.182, 0.159, 0.192; PPW 0.211, 0.139, 0.243; CI 105, 106, 103; OI 23, 27, 27; SI 95, 95, 92; PTHI 78, 68, 69; PTWI 80, 77, 82; PPI 116, 87, 127; SPI 11, 10, 10; ACI 0.86. Queen In lateral profile dorsal face of propodeum sloping obliquely from postscutellum, such that most of propodeum is posterior to scutellum (in contrast to normal queens, in which dorsal face of propodeum drops steeply from postscutellum and much of propodeum appears ventral to scutellum and postscutellum, Fig. 1); entire body (head, mesosoma, petiole, postpetiole, fourth abdominal tergite, appendages) polished, very smooth and shiny; mandible smooth and shiny, subfalcate, basal and masticatory margins not differentiated, masticatory margin with a large, sharp apical tooth preceded by a series of small denticles; anterior margin of clypeus emarginate; clypeus flat; antennal club three-segmented; scapes with abundant long erect setae; face, mesosomal dorsum, petiole, postpetiole, fourth abdominal tergite, and legs with abundant long erect white setae, those on tibiae particularly long, much longer than width of tibia; dorsal face of pronotum perpendicular, at right angle to anterior collar, recessed beneath mesonotum; propodeal spines absent; petiole trapezoidal in lateral view, with ventrally directed, triangular, anteroventral tooth; dorsal face subrectangular, slightly longer than wide; posterodorsal face longer than typical of other Crematogaster, portion of petiole posterior to dorsal face forming a cylinder about two thirds length of dorsal face; postpetiole with short, acute ventral tooth; postpetiolar dorsum globular (unlike worker), dorsally convex and posterior margin rounded, not emarginate; size characters as in Figures 4 and 5.

description

Plate 2, 8

discussion

Comments The salient feature of this species is the greatly reduced propodeal spines, which are no more than low tumosities or ridges. The only other Costa Rican species with such reduced propodeal spines is montezumia, which has a partially punctate face and appressed tibial pilosity. In contrast, raptor has a shiny face and erect tibial pilosity. This species is very similar to indefensa Kempf 1968. It shares with indefensa a lack of propodeal spines and a shiny queen with falcate mandibles. It differs in the presence of abundant flexuous setae and a more robust petiole. Crematogaster indefensa is known from a 1000 m elevation site in Bolivia.

distribution

Range Costa Rica.

etymology

Etymology This species is named after the raptorial nature of the queen mandibles.

Name

Homonyms: Crematogaster raptor