Crematogaster crinosa is an extremely widespread and generalized species that prefers highly insolated habitats. It is common in seasonally dry areas, less common in wet forests. In wet forest habitats it is typically found in the high canopy or in disturbed areas. It may form monodominant populations in mangrove forests.
Colonies are large and polydomous and it is usually difficult to locate colony boundaries. Nests are found in almost any kind of cavity (figs. 1, 2, 4), and columns of workers move from nest to nest. Nests can be in live or dead branches, in small rotten knots, under bark flaps, in cavities in fence posts, opportunistically in ant plants, and thinly dispersed in multiple small bark cavities. Workers, brood, and alate sexuals are dispersed across nests. Small amounts of carton construction are used to form baffles inside of nest cavities and to restrict nest entrances, but large external carton nests are never constructed.
Although new alate queens are relatively common in nests, I have rarely encountered physogastric colony queens. In my collecting experience, I have never found a colony that was obviously polygynous, with many dealate queens dispersed in many nests. However, I am treating Forel's minutior as a synonym of crinosa, and minutior from St. Vincent Island in the West Indies forms large polygynous, polydomous colonies in coastal areas (Forel 1893).
In Colombia I observed the beginning of a nuptial flight just after dusk. I found a dense aggregation of males and workers under a bark flap, and the males were just beginning to fly.
Workers are omnivorous. They are attracted to protein and carbohydrate baits, they scavenge dead or injured insects, they visit extrafloral nectaries, and they tend Homoptera. When nests are disturbed they can be aggressive and will bite. Workers are continuously polymorphic, with a broad range of worker sizes.
I often find cockroach egg cases scattered in the nest chambers of C. crinosa (fig. 1), at a much higher density than in the environment generally. The nature of the relationship between cockroaches and the crinosa group would be worth investigation.
Ecological equivalents are torosa and rochai. I can detect very few behavioral or ecological differences among these species. Crematogaster crinosa is the only member of the group that regularly dominates mangrove habitats. Mangrove forests in Costa Rica are sometimes dominated by Azteca, sometimes by C. crinosa. I found a similar situation in the Santa Marta area of Colombia. I have only one record of rochai from mangroves (a voucher collection from Adams' studies of mangrove communities, Adams 1994), and I have no record of torosa from mangroves. Other than in mangroves, crinosa is less abundant relative to torosa or rochai. For example, a collecting trip to a wildlife refuge in southern Texas yielded 13 separate collections of torosa but only one of crinosa. In northwestern Costa Rica, torosa and rochai are far more abundant than crinosa. Based on museum collections, crinosa seems to be the most common member of the crinosa group on various Caribbean and Pacific islands.
Throughout the Neotropics, from southern Texas to Argentina and on numerous Caribbean islands.
Taxonomic history
Mayr, 1887 PDF: 627 (q.m.).Combination in Crematogaster (Orthocrema): Emery, 1922c PDF: 134.Combination in Crematogaster (Orthocrema): Blaimer, 2012c PDF: 55.Senior synonym of Crematogaster brevispinosa, Crematogaster chathamensis, Crematogaster minutior, Crematogaster recurvispina, Crematogaster sampaioi, Crematogaster schuppi, Crematogaster striatinota, Crematogaster townsendi and material of the unavailable name Crematogaster semisericea referred here: Longino, 2003a PDF: 49.Plate 3, 5
Crematogaster crinosa Mayr , 1862:767. Syntype workers: Brazil , Rio de Janeiro ( Novara ) [ NMW ] (examined). Mayr, 1887:627: description of queen, male. Emery, 1922:134: combination in C. (Orthocrema) .
Crematogaster brevispinosa Mayr , 1870a:403. Holotype worker: Colombia , S. Fé de Bogotá ( Lindig ) [ NMW ] (examined). Wheeler, G. C. and Wheeler, J. 1952:260: description of larva. Santschi, 1918:182: combination in C. (Orthocrema) . NEW SYNONYMY
Crematogaster brevispinosa var. minutior Forel , 1893:399. Syntype worker, queen: Antilles Islands, Saint Vincent ( H. H. Smith ) [ MHNG ] (examined). Emery, 1922:134: combination in C. (Orthocrema) . Forel, 1897:300: race of brevispinosa . NEW SYNONYMY
Crematogaster brevispinosa var. schuppi Forel , 1901a:299. Syntype worker, queen: Brazil , Rio Grande do Sul , Porto Alegre ( Schupp ) [ MHNG ] (examined). Emery, 1922:134: combination in C. (Orthocrema) . NEW SYNONYMY
Crematogaster brevispinosa var. striatinota Forel , 1912:211. Syntype worker: Colombia , Magdalena , Rio Frio near Santa Marta , from the wood of a steamboat from Magdalena ( Forel ) [ MHNG ] (examined). NEW SYNONYMY
Crematogaster brevispinosa r. recurvispina Forel , 1912:212. Syntype workers: Brazil , Rio de Janeiro ( Sampaio, Naegeli ) [ MHNG ] (examined). Emery, 1922:134; Santschi, 1925:230: combination in C. (Orthocrema) . NEW SYNONYMY
Crematogaster brevispinosa r. sampaioi Forel , 1912:213. Syntype worker, queen, male: Brazil , Rio de Janeiro ( Sampaio ) [ MHNG ] (examined). Emery, 1922:134: combination in C. (Orthocrema) . NEW SYNONYMY
Crematogaster (Orthocrema) brevispinosa st. sericea var. semisericea Santschi , 1923:249. Worker: Argentina , Formosa , Guayculec ( Joergensen ) [ NHMB ] (examined). Unavailable name.
Crematogaster (Orthocrema) brevispinosa subsp. townsendi Wheeler, W.M. 1925:25. Syntype worker: Peru , Piura ( Townsend ) [ MCZC ] (examined). NEW SYNONYMY
Crematogaster (Orthocrema) brevispinosa subsp. chathamensis Wheeler, W.M. 1933:58. Lectotype worker: Galapagos Islands, Chatham Island , 17 Apr 1932 ( Willows ) [California Academy of Sciences No. 3689 ] (workers from same series at MCZ examined) . NEW SYNONYMY
Range
Throughout the Neotropics, from southern Texas to Argentina and on numerous Caribbean islands.
Description of worker (Costa Rica)
Color red brown to black; workers usually with pronounced size polymorphism.
In face view head subquadrate, wider than long in larger workers, with emarginate posterior margin; mandibles coarsely striate, striae faint to pronounced; clypeus smooth and shiny or faintly granular or finely longitudinally striate; scapes short, in face view not attaining posterior margin of head when laid back; terminal three segments of antenna gradually lengthening and broadening, becoming increasingly densely pubescent, terminal two segments very much larger, so that antennal club appears two-segmented; scapes with short appressed pubescence, sometimes subdecumbent, never erect, with no differentiated long erect setae (occasionally a long seta on very large workers); face with sparse appressed to subdecument pubescence and sparse short erect setae; face smooth and shining or with variably developed fine longitudinal striation, most common on anterior face and space between eye and antennal insertion, occasionally extending posteriorly and medially, but always with at least median strip sublucid.
Promesonotal profile forming a single, somewhat flat-topped convexity; in large workers promesonotal suture visible, a dorsolateral arch that extends far forward, showing that dorsal pronotum is short and much of promesonotal dorsum composed of mesonotum (approaching queen condition); in small workers promesonotal suture effaced, visible only as oblique anterolateral impressions; propodeum with short but distinctly differentiated dorsal face, such that propodeal suture distinctly visible in lateral view as v-shaped impression; propodeum with long sloping posterior face; propodeal spines short, upturned; promesonotal dorsum and dorsal face of propodeum faintly punctate with varying development of longitudinal or transversely whorled rugulae or striations, lateral carinulae bridge propodeal suture, rarely forming a small triangular denticle; posterior face of propodeum smooth and shining or faintly microareolate; lateral pronotum with faint microsculpture; katepisternum and lateral propodeum faintly punctate to microareolate; promesonotum and bases of propodeal spines with highly variable number but usually abundant short stiff flattened setae; femora and tibiae with appressed to subdecumbent pubescence, no erect setae.
Petiole in lateral view subtriangular, often with slightly concave ventral margin, with strongly developed, anteriorly projecting, acute anteroventral tooth; side faintly granular or microareolate; dorsal face of petiole smooth and shining to faintly microareolate, about as wide as long, subquadrate or more often with convex sides, widest about one third distance from anterior margin, with one or more stiff setae on posterolateral tubercles; postpetiole with no ventral tooth, in dorsal view globular to subquadrate, usually slightly broader than long, rarely with faintly impressed posteromedian sulcus, with four or more stiff setae; fourth abdominal tergite smooth and shining or faintly microareolate, with abundant vestiture of short, stiff, flattened, erect setae, evenly distributed over surface of tergite (not clustered or concentrated anterolaterally).
Measurements
HL 0.801, 0.616, 1.052; HW 0.869, 0.701, 1.156; HC 0.837, 0.664, 1.123; SL 0.537, 0.454, 0.697; EL 0.175, 0.147, 0.252; A11L 0.248; A11W 0.138; A10L 0.097; A10W 0.113; A09L 0.055; A09W 0.078; A08L 0.034; A08W 0.066; WL 0.844, 0.688, 1.146; SPL 0.134, 0.095, 0.168; PTH 0.174, 0.142, 0.203; PTL 0.239, 0.206, 0.343; PTW 0.253, 0.224, 0.323; PPL 0.198, 0.182, 0.254; PPW 0.246, 0.205, 0.328; CI 108, 114, 110; OI 22, 24, 24; SI 67, 74, 66; PTHI 73, 69, 59; PTWI 106, 109, 94; PPI 124, 113, 129; SPI 16, 14, 15; ACI 0.64.
Queen
A normal queen (dorsal face of propodeum drops steeply from postscutellum and much of propodeum appears ventral to scutellum and postscutellum, Fig. 1) with general shape, sculpture, and pilosity characters of the worker; size characters as in Figures 4 and 5.
Biology
Crematogaster crinosa is an extremely widespread and generalized species that prefers highly insolated habitats. It is common in seasonally dry areas, less common in wet forests. In wet forest habitats it is typically found in the high canopy or in disturbed areas. It may form monodominant populations in mangrove forests.
Colonies are large and polydomous and it is usually difficult to locate colony boundaries. Nests are found in almost any kind of cavity, and columns of workers move from nest to nest. Nests can be in live or dead branches, in small rotten knots, under bark flaps, in cavities in fence posts, opportunistically in ant plants, and thinly dispersed in multiple small bark cavities. Workers, brood, and alate sexuals are dispersed across nests. Small amounts of carton construction are used to form baffles inside of nest cavities and to restrict nest entrances, but large external carton nests are never constructed.
Although new alate queens are relatively common in nests, I have rarely encountered physogastric colony queens. In my collecting experience, I have never found a colony that was obviously polygynous, with many dealate queens dispersed in many nests. However, I am treating Forel's minutior as a synonym of crinosa , and minutior from St. Vincent Island in the West Indies forms large polygynous, polydomous colonies in coastal areas (Forel 1893).
In Colombia I observed the beginning of a nuptial flight just after dusk. I found a dense aggregation of males and workers under a bark flap, and the males were just beginning to fly.
Workers are omnivorous. They are attracted to protein and carbohydrate baits, they scavenge dead or injured insects, they visit extrafloral nectaries, and they tend Homoptera. When nests are disturbed they can be aggressive and will bite. Workers are continuously polymorphic, with a broad range of worker sizes.
Ecological equivalents are torosa and rochai . I can detect very few behavioral or ecological differences among these species. Crematogaster crinosa is the only member of the group that regularly dominates mangrove habitats. Mangrove forests in Costa Rica are sometimes dominated by Azteca , sometimes by C. crinosa . I found a similar situation in the Santa Marta area of Colombia. I have only one record of rochai from mangroves (a voucher collection from Adams' studies of mangrove communities, Adams 1994), and I have no record of torosa from mangroves. Other than in mangroves, crinosa is less abundant relative to torosa or rochai . For example, a collecting trip to a wildlife refuge in southern Texas yielded 13 separate collections of torosa but only one of crinosa . In northwestern Costa Rica, torosa and rochai are far more abundant than crinosa . Based on museum collections, crinosa seems to be the most common member of the crinosa group on various Caribbean and Pacific islands.
Comments
Members of the crinosa complex are among the most frequently encountered Neotropical ants, particularly in open or seasonally dry habitats. They are geographically variable and taxonomically difficult, and species boundaries are poorly defined (see Taxonomic Notes on C. crinosa and Related Forms). Crematogaster crinosa , rochai , and torosa are three very similar species that occur together in Costa Rica. They are difficult to distinguish and workers may not always be clearly identified. All three have the face with sparse erect setae over short appressed pubescence, the mesosomal dorsum and fourth abdominal tergite with short, stiff erect setae (or erect setae absent), the dorsal face of the petiole short with convex sides, and the propodeal spines short and upturned. Crematogaster crinosa can be differentiated from rochai throughout the range, because crinosa has a dense, even covering of erect setae on the fourth abdominal tergite, while rochai completely lacks these setae or has only a small cluster on each anterolateral humerus. Distinguishing crinosa from torosa is more difficult. In Costa Rica, torosa also has abundant erect setae on the fourth abdominal tergite, but these are usually clustered laterally and anterolaterally, leaving a median strip free of setae. Also, crinosa always has a long, sharp anteroventral petiolar process, while torosa more often has a short, blunt or squared-off process. Crematogaster crinosa can also be confused with erecta and moelleri , but these have flexuous erect setae on the pronotal humeri.
The workers of recurvispina are small, with few setae on mesosoma and fourth abdominal tergite, and a strong anteroventral petiolar tooth. These may just be small workers of crinosa . A brief examination of the schuppi types revealed a queen and a minim worker. The queen had a strong anteroventral petiolar tooth, was abundantly setose, and had a quadrate head. It is probably crinosa . The other synonymies are all based on examination of medium-size to large workers that match the general features of crinosa as defined here.
Throughout the tropical and subtropical Americas, highly insolated habitats are often dominated by Crematogaster with the following characters:
· Colonies large and polydomous.
· Workers with pronounced size polymorphism.
· Head of large workers emarginate posteriorly.
· Scapes short, not attaining posterior margin of head when laid back (SI <75).
· Dorsal face of petiole short, nearly as broad as or broader than long, subquadrate or more often with strongly convex sides, usually widest at midlength.
· Postpetiole lacking ventral tooth; in dorsal view globular to subquadrate, as wide as or wider than long, and sometimes with faint longitudinal median impression.
· Face with short appressed pubescence and variable number of short erect setae, never with abundant long flexuous setae.
· Setae of mesosomal and gastral dorsum always short, flattened, and stiff, never long and flexuous.
I refer to these as the crinosa complex, because Mayr's C. crinosa is the oldest described taxon that exhibits these characters. Habitats where these ants are dominant include mangroves, seasonal dry forests, savanna, the upper canopy of wet forests, scrub and thorn forests, and anthropogenic habitats such as pasture edges, roadsides, and urban areas. The habitats where they are absent or show greatly reduced abundance are wet forest interiors and montane areas. In many ways this group is intermediate between other Neotropical Crematogaster and the Crematogaster s.s. that dominate the North American temperate zone. Wet forest Crematogaster tend to have the petiole elongate, widest posteriorly, and tapering anteriorly. The crinosa complex shows a shortening and broadening of the petiole, and a shift of the widest portion to midlength or even more anteriorly. Crematogaster s.s. continues this trend, such that the dorsal face of the petiole has broad anterolateral lobes, is definitely widest anteriorly, and tapers posteriorly. Many rainforest Crematogaster have the postpetiole globular. The postpetiole of the crinosa complex may be globular or slightly bilobed. The postpetiole of Crematogaster s.s. is strongly bilobed with a pronounced median sulcus. Many rainforest Crematogaster have abundant long flexuous setae on the face and fourth abdominal tergite, heads that are more rounded posteriorly, and long scapes that extend to or beyond the vertex margin. The crinosa complex and Crematogaster s.s. are essentially identical in the short pubescence on the face, the generally sparse erect setae, and the short scapes. Given the prevalence of elongate petiole with posterior node among the most generalized myrmicines, the shortening and broadening of the petiole within Crematogaster is probably apomorphic. Paralleling these morphological transitions is a habitat transition from moderate to increasingly harsh environmental conditions. The pattern may reflect a phylogenetic history in which the crinosa complex was derived from a rainforest ancestor and moved out into open areas, dry areas, and the subtropics. Subsequently, under this scenario, Crematogaster s.s. was derived from a crinosa complex ancestor and moved across the frost line and into the temperate zone. The pattern could also be generated by parallel responses to natural selection, with the similarities between the crinosa complex and Crematogaster s.s. being due to similar adaptive responses to dry conditions. Also, the widespread occurrence of Crematogaster s.s. in the Old World has not been incorporated into this scenario, and begs investigation.
Other Neotropical species that share the general habitus of the crinosa complex but have long flexuous hairs are erecta , moelleri , stollii , and crucis . These are all more associated with rain forest and montane forest, compared to crinosa-group species.
Taxonomy within the crinosa complex is difficult. The following is a synopsis of character systems that vary within the crinosa complex:
The face and clypeus may be largely smooth and shining, or with varying degrees of granular to finely longitudinally striate sculpture that extends from the anterior portion of the head. Often the clypeus, malar spaces, and space between eyes and antennal insertions is finely striate. These striae may extend up the sides of the head and medially, to the point where only a thin median strip remains smooth and shiny. In some cases the entire face is uniformly striate, causing a sericeous luster or mat surface.
The position and strength of the promesonotal suture varies. In some cases the promesonotum forms a uniformly curved convex profile, with the promesonotal suture not visible in profile or dorsally. In other instances the mesonotum is enlarged and the pronotal dorsum shortened, such that the remnants of the promesonotal suture can be seen as oblique impressions laterally, but the suture is effaced in dorsal view. In very large workers the suture may be entire but strongly arching anteriorly, such that the pronotal dorsum is very short (approaching the condition in the queen). Finally, the mesonotum may be less enlarged relative to the pronotum, and the promesonotal suture visible as an impression that more evenly divides the promesonotum. In lateral view this results in a promesonotal profile that is more flat-topped.
The dorsal face of the propodeum, which is always very short relative to the posterior face, may drop steeply to the propodeal suture, such that the juncture of the dorsal and posterior faces is strongly produced as an anteroposteriorly compressed ridge. In some cases the dorsal and posterior faces meet at an obtuse angle, such that in lateral view there is a distinct v-shaped propodeal suture, a subhorizontal dorsal face, then a sloping posterior face. In some cases the dorsal and posterior faces are in the same plane, such that the propodeal suture appears very shallow with no posterior wall, and the propodeum forms a single declivity from the propodeal suture to the petiolar insertion. The transition is like a wrinkle in a rug being gradually smoothed out.
The anteroventral petiolar tooth may be long, narrowly acute, and sharp. If long and sharp, it may project anteriorly, with the entire ventral margin of the petiole, including the tooth, in the same plane, or the ventral margin of the tooth may curve resulting in an upwardly concave ventral margin. Alternatively, the tooth may be reduced to a nearly right angle.
The fourth abdominal tergite may have an even vestiture of erect setae over the entire surface. In other cases the setae are clustered anterolaterally, often leaving a medial strip bare. The tergite may be completely bare, or with only 1-3 setae anterolaterally.
The above character variation is continuous rather than discrete, and all combinations of characters seem to occur. However, variation is not random, and clusters of correlated characters occur that suggest distinct sympatric species. Within Costa Rica, for which abundant material is available, I have come to the conclusion that there are three sympatric species: crinosa , torosa , and rochai . However, occasional specimens exhibit combinations of characters that blur the distinctions. I have not discovered characters that are uniformly diagnostic. These three "character clusters" seem to occur widely in the Neotropics. For example, abundant collections from southeast Texas in the USA almost all match torosa , but one collection exhibits all the characters of crinosa , suggesting that two species are sympatric there. However, among the other collections I have been able to examine from scattered localities in the Neotropics, many show combinations of characters that do not match one of these three. As in other complex taxa, there is probably a combination of widespread lineages and narrow endemics. Additional collections and character analysis will be necessary to gain a clearer picture.
Given the ecological prevalence and the large character variation in the complex, many taxonomic names have been generated. In an attempt to bring some order to the nomenclature and to prepare the way for future taxonomic work, I summarize below the available names I associate with the crinosa complex (or remove from the complex). No new synonymy is proposed, but many changes in status are made to eliminate trinomials and liberate names from the various assumed relationships to other species. Species are either discussed separately or grouped by salient characters.
Caaguazú , Canindeyú , Central, Concepción , Ñeembucú , Pte. Hayes, San Pedro (ALWC, BMNH, IFML, INBP, JTLC, LACM, NHMB). Literature records: Cordillera, Itapúa , “Paraguay” (s. loc.) (Emery 1896b, Emery 1906c, Forel 1901a, Forel 1909, Forel 1911b, Forel 1912c).
Crematogaster crinosa is a species of ant in tribe Crematogastrini.[1] It was described by Mayr in 1862.[1]
Crematogaster crinosa is a species of ant in tribe Crematogastrini. It was described by Mayr in 1862.
