Pachycondyla succinea

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Pachycondyla succinea
Temporal range: Middle Eocene
P. succinea male
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Genus: Pachycondyla
Species:
†P. succinea
Binomial name
†Pachycondyla succinea
(Mayr, 1868)
Synonyms
  • Ponera succinea
  • Euponera (Trachymesopus) succinea

Pachycondyla succinea is an

formicid subfamily Ponerinae described from fossils found in Europe. P. petrosa is one of three middle Eocene Pachycondyla species found in Baltic amber
.

History and classification

When described Pachycondyla succinea was known only from three queen fossils which were fossilized as

Bitterfeld ambers.[3][4]

Baltic amber is approximately forty six million years old, having been deposited during

Paratethys Sea, and the amber that is recovered from the region is thought to be redeposited from older sediments. The fossil record of Bitterfeld and Baltic amber insects is very similar with a number of shared species, and that similarity is noted in the suggestions of a single source for the paleoforest that produced the amber.[8] The amber deposits on the Danish coast, often referred to as Scandinavian amber, is of similar age to the other three European ambers, however a study of the ant fauna published in 2009 indicates Scandinavian amber has a fairly distinct ant assemblage.[1]

The species was first described in 1868 by Austrian entomologist Gustav Mayr based on three queens. He named the species and placed it into the genus Ponera as Ponera succinea.[9][1] The species was redescribed in 1915 by William Morton Wheeler based on a group of 21 queens, including one of Mayrs three original syntypes. Based on the queens examined, Wheeler moved the species to the genus Euponera as Euponera (Trachymesopus) succinea. The placement was unchanged until 1995 when Euponera was synonymized with Pachycondyla by Barry Bolton.[1][3] Pachycondyla was split into a number of genera in 2014 with most of the extant species being placed into other genera, but a series of fossil species including P. succinea were not moved. Schmidt and Shattuck in the revision of the genus noted that many of the fossil species were not moved due to specimens not being examined by them, and that the placement of the species was "undoubtedly incorrect".[10] Males of the species were first formally described in 2009, based on specimens preserved in Baltic and Bitterfeld ambers.[3]

P. succinea is one of three Pachycondyla species described from Baltic amber, the other two being P. baltica and P. gracillicornis. In addition to these species, one species is known from Rovno amber, P. conservata, and one species is known from Bitterfeld amber, P. tristis.[3]

Neotype
queen

Description

Closeup of male head

The queens have a body length of 4–6 mm (0.16–0.24 in), with dense pitting along all of the body excluding the

compound eyes, slightly bulged out with oval outlines, are placed far forward on the head, shortening the gena to shorter than the eye diameter. The antennae are composed of 12 segments, with the basal and tip segments longer than wide, while the rest are shorter than wide. The bottom most segment, the scape, is longer than the other antenna segments, but does not reach the rear edge of the head. There are six teeth on the chewing face of the mandibles, and no external tooth on the outer margin.[3]

The males are smaller than the queens, with a total body length between 3.5–4.5 mm (0.14–0.18 in) and an overall shiny exoskeleton. There are longitudinal ridges on the propodeum sides, while the petiole is smooth. There is dense pitting on the head and sparser pitting is present on the gaster and mesosoma. Many upright hairs are found on the gaster, petiole scale, upper surface of the mesosoma, and on the head. Decumbent hairs are present over the whole exoskeleton, showing most distinctly on the gaster, where the hairs are "several times" longer than that of the spacing between each hair.[3] The head is rounded in outline, with a convex rear edge and no distinct rear corners, but instead has a slight expansion of the anterior section and no frontal ridges are present. The eyes are kidney shaped, slightly bulging, and large, placed far forward on the head. The ocelli are also large, but smaller than the distance between each of the three.[3]

References

  1. ^
    S2CID 84191149
    .
  2. ^ Wheeler, W. M. (1915). "The ants of the Baltic amber" (PDF). Schriften der Physikalisch-Okonomischen Gesellschaft zu Konigsberg. 55 (4): 55–56.
  3. ^
    S2CID 84170960
    .
  4. doi:10.1515/vzoo-2016-0014
    .
  5. ^
    ISBN 978-0-9558636-4-6
    .
  6. ^ Henderickx, H.; Tafforeau, P.; Soriano, C (2012). "Phase-contrast synchrotron microtomography reveals the morphology of a partially visible new Pseudogarypus in Baltic amber (Pseudoscorpiones: Pseudogarypidae)". Palaeontologia Electronica. 15 (2, 17A, 11p): 1–11.
  7. S2CID 84073810
    .
  8. doi:10.2478/pjen-2013-0001
    .
  9. hdl:2027/hvd.32044107210734
    .
  10. PMID 24943802
    .

External links
Retrieved from "https://en.wikipedia.org/w/index.php?title=Pachycondyla_succinea&oldid=1099072011"