(Mackay, W.P. & Mackay, E.E., 2010)
From Mackay and Mackay (2010): The nest of the type series was in a log with brood and a single male (July).
From Mackay and Mackay (2010): The worker of Rasopone cernua is nearly identical to that of Rasopone pergandei, differing in being slightly smaller and in possessing the ventrally directed angle on the posterior edge of the subpetiolar process, which is absent in R. pergandei. Rasopone cernua is similar to R. pergandei in having a longitudinal depression in the middle of the clypeus and having relatively long antennal scapes, which extend past the posterior lateral margin of the head. The petiole of R. cernua is narrower than that of R. pergandei with a shorter dorsal face.
Rasopone cernua could also be confused with the larger Rasopone conicula. It can be easily separated by the form of the subpetiolar process (the ventrally directed angle is absent in R. conicula). Additionally R. conicula lacks the longitudinal depression on the clypeus and the scape barely reaches the posterior lateral margin of the head. The shape of the petiole of R. cernua is very similar to that of R. conicula.
The male of R. cernua is similar to those of R. conicula and R. pergandei, but differs in color (concolorous reddish brown compared to the males of the other two species, in which the pronotum and scutum are lighter in color). Rasopone cernua is also much smaller and has the ventrally directed angle on the subpetiolar process, which is absent in the males of the other two species.
The angle on the subpetiolar process of R. cernua is similar to that found in the ferruginea and rubra species complexes and appears to simply be bent downward and not as posteriorly as in the other two species complexes. The process suggests a relationship of the constricta species complex with the other two species complexes.
Known only from Only known from the type locality: Napo, Ecuador.
Distribution based on Regional Taxon Lists
Distribution based on AntMaps
Distribution based on AntWeb specimens
Check data from AntWeb
Specimens were collected in a rain forest with clay soil. (Mackay and Mackay 2010)
The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.
- cernua. Pachycondyla cernua Mackay & Mackay, 2010: 242, figs. 46-48, 200, 369-375 (w.m.) ECUADOR. Combination in Rasopone: Schmidt & Shattuck, 2014: 210.
Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.
The worker is a small (total length 6 mm) dark reddish brown specimen with lighter reddish brown appendages. The five apicalmost mandibular teeth are well developed, followed by two or three smaller teeth and basally by small denticles. The anterior mar-gin of the clypeus is broadly convex; a longitudinal medial depressed area is present in the middle of the clypeus. The head is nearly rectangular-shaped, with the sides nearly parallel and only slightly narrowed anterior to the eyes. The posterior margin is nearly straight. The head length is 1.2 mm, the head width 1 mm. The eyes are small (maximum diameter 0.2 mm) located about one diameter from the anterior margin of the head (side view). The antennal scape (1.0 mm) extends approximately the first funi-cular segment past the posterior lateral corner of the head. The pronotal shoulder is swollen and forms a longitudinal raised area, but a carina is not developed. The mesosoma is only slightly depressed at the metanotal suture; the propodeal spiracle is circular. The anterior face of the petiole is nearly straight and vertical, the posterior face is broadly rounded and a short dorsal face is present. The subpetiolar process consists of a swollen rounded lobe anteriorly and a small downwardly directed angle posteriorly. The anterior face of the postpetiole is slightly concave and the dorsal face forms an abrupt acute angle. The stridulatory file and arolia are absent. The metasternal process is fang-like as viewed from the side and has two slender lobes when viewed from behind.
Erect hairs are sparse, with a few on the mandibles, clypeus, malar area, along the posterior margin of the head; fine but erect hairs are scattered on the scape, erect hairs are present on the ventral surface of the head, the dorsum of the mesosoma, dorsum of the petiole, subpetiolar process and all surfaces of the gaster. Most hairs on the legs are appressed, but a few are raised from the surface, including on the tibiae. Fine golden pubescence is present on the head, dorsum of the mesosoma, anterior face of the petiole and all surfaces of the gaster.
The dorsal surface of the man-dible is finely and evenly striate, with the few scattered punctures near the teeth, most other surfaces are covered with scattered punctures and dull to weakly shining; the side of the pronotum, dorsal half of the side of the propodeum, the posterior face of the petiole, as well as the dorsum of the gaster are slightly more shiny than the remainder of the surfaces.
Queens are not known for this species
The mandibles are tiny, but have well-developed depressions near the bases. The surface of the clypeus is swollen and slightly overhangs the mandibles, when viewed from the side. The head length is 0.95 mm, the head width 0.85 mm. The eyes are large, the maximum diameter (viewed from side) is 0.55 mm, the eye is located approximately ½ of its diameter from the lateral ocellus. The diameter of the median ocellus is 0.11 mm, located approximately one dia-meter from the lateral ocellus (viewed obliquely from above and from the side), which has a diameter of 0.12 mm. The Mayrian furrows are moderately well developed, but do not meet medially; the parapsidal sutures are well developed. The propodeal spiracle is nearly circular, but appears elongated due to the surrounding peritreme (cuticular swelling around the spiracle). The petiole is narrow when viewed in profile with the anterior face slightly concave and sloping at approximately 45°, the posterior face is slightly convex; the two faces meet at a rounded apex. The subpetiolar process is similar to that of the worker, with a well-developed thickened lobe anteriorly and the ventrally directed angle posteriorly. The anterior face of the postpetiole is broadly rounded into the dorsal face. The wing is typical of the genus, except that the third discoidal cell is somewhat elongated.
Erect hairs are sparse, with a few on the mandibles and maxillary palps, a pair of obvious hairs on the clypeus; the malar area and the dorsal and ventral surfaces of the head are without erect hairs. The dorsum of the mesosoma is nearly without erect hairs, the apex of the petiole and the lobe of the subpetiolar process have a few erect hairs, many hairs on the gaster are erect or suberect. The hairs on the legs are all appressed. Appressed pubescence is sparse, with a few hairs on the head and mesosoma; the appressed hairs on the gaster are more numerous.
Most surfaces are rough, dull and punctate, the side of the pronotum, the lateral edges of the scutum and gaster are weakly shining.
The males were not associated with workers, but the similarities of the subpetiolar process and the distribution strongly suggest they are conspecific.
Ecuador, Napo, near Dureno, 287m, 20-vii-2005, W&E Mackay # 21270; 0°4’40.8”N 76°43’50.5”W. Holotype worker (Museum of Comparative Zoology) and 9 paratype workers (California Academy of Sciences, CWEM, IAVH, Los Angeles County Museum of Natural History, Museu de Zoologia da Universidade de Sao Paulo, Museum of Comparative Zoology, QCAZ, National Museum of Natural History).
From Latin, cernuus, meaning drooping or facing earthward, referring to the posterior edge of the subpetiolar process.
- Mackay, W. P., and E. E. Mackay 2010. The Systematics and Biology of the New World Ants of the Genus Pachycondyla (Hymenoptera: Formicidae). Edwin Mellon Press, Lewiston. Information from this publication is used with permission from the authors.
- Schmidt, C.A. & Shattuck, S.O. 2014. The higher classification of the ant subfamily Ponerinae (Hymenoptera: Formicidae), with a review of ponerine ecology and behavior. Zootaxa 3817, 1–242 (DOI 10.11646/zootaxa.3817.1.1).