Paraphaenogaster

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Paraphaenogaster
Temporal range: 34–5.3 Ma Priabonian, Late Eocene to Messinian, Late Miocene
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Stenammini
Genus: Paraphaenogaster
Dlussky, 1981
Type species
Paraphaenogaster microphthalmus, now Paraphaenogaster microphthalma
Diversity
22 fossil species
(Species Checklist, Species by Country)

The genus Paraphaenogaster was described by Dlussky (1981) based on males originating from Miocene sediments in Vishnevaya Balka, Stavropol in Russia.

Identification

Jessen (2020) - Paraphaenogaster resembles Aphaenogaster to a great extent, i.e. elongate head, 12-segmented antenna, high and arched alitrunk, pedunculate and high-noded petiole. The only criteria to separate Paraphaenogaster from Aphaenogaster are the lack or strong reduction of the cell rm.

For Enspel Formation fossils: Since workers and dealate females lack wings, and are missing the main distinguishing feature between the genera Aphaenogaster and Paraphaenogaster, it is, strictly speaking, impossible to allocate worker or dealate females to one or the other genera. This is the weakest point of creating a morphogenus based on the wing venation pattern. However, since the genus Paraphaenogaster is much better represented in Enspel than Aphaenogaster, fossil worker specimens were assigned to the genus Paraphaenogaster. Dlussky and Wedmann (2012) stated that it is almost impossible to prove the conspecificity of gynes and males of fossil ants. This is also the case here. There are no specific morphological characteristics that would allow me to state a conspecificity of male and gyne.

Distribution

This taxon is known from Aix-en-Provence, France (Late Oligocene); Bembridge Marls, Isle of Wight, UK (Priabonian, Late Eocene); Brunn-Vösendorf, Austria (Late Miocene); Enspel Formation, Rhineland-Palatinate, Germany (Oligocene), Chôjaburu, Iki Island, Japan (Middle Miocene); Kleinkems, Germany (Early Oligocene); Mokrina (Krottensee), Czech Republic (Late Burdigalian, Early Miocene); Oeningen, Switzerland (Messinian, Late Miocene); Parschlug, Austria (Serravallian, Miocene); Radoboj, Croatia (Burdigalian, Early Miocene); Shanwang, China (Early Miocene) and Vishnevaya Balka Creek, Stavropol, Russian Federation (Middle Miocene).

Castes

Nomenclature

The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.

  • PARAPHAENOGASTER [incertae sedis in Myrmicinae: Pheidolini]
    • Paraphaenogaster Dlussky, 1981: 68. Type-species: †Paraphaenogaster microphthalmus, by original designation.
    • [†Paraphaeogaster Hong, 1984: 8, incorrect subsequent spelling.]


Descriptions here of all castes from Jessen (2020).

Description

Worker

BL about 6–8 mm. Head elongate oval, CI around 90. Mandibles triangular with 7–8 teeth. Outer margin of mandible is evenly curved. Alitrunk elongate. In profile, promesonotum can be significantly higher than propodeum, pronotum can be separated from mesonotum by a clear promesonotal suture. Propodeal spines present. Petiole pedunculate, with rounded node.

Queen

BL between 9 and 12 mm. Head usually longer than wide. The occipital corners vary from flattened to well developed. Mandibles sub-triangular to triangular with more than 6 triangular teeth. Apical and sub-apical tooth larger, can be slightly curved. Antenna 12-segmented, no distinct club. High alitrunk with arched mesonotum. Wing venation with closed cells mcu and 1+2r. The vein 5RS reaches far to the distal edge of the forewing, it rarely reaches it completely. So in most species, cell 3r remains open. Cell rm is not developed, because vein rs-m is absent. Sometimes an unsclerotized, thin residue of the vein rs-m can still be detected. Vein 2r-rs short. The distal section of vein M does not branch off from vein RS near the junction 2r-rs/ RS, but much further proximal. Thus, the free distal ends of veins M and RS do not branch off from a common node (see also Radchenko and Perkovsky 2016; Perfilieva et al. 2017). Proximal part of vein M with distinct lumen, towards distal vein turns into a stronger sclerotized line. The distal part seems to be just a stronger sclerotized line, possibly to improve the wings stability, without having any supply function. This also applies for vein 2Cu and 3Cu. Only the proximal part of 2Cu has a distinct lumen.

Propodeum armed. Petiole with distinct peduncle, posteriorly ending in a high petiolar node. Petiolar node slightly tapered, rounded. Postpetiole with gradually arising and descending node, not pedunculate. Solid, high helcium articulates higher than mid length at posterior face of petiole. Constriction of postpetiole towards gaster differs, postpetiole can be wider than petiole.

Male

BL 7–12 mm (length of male Paraphaenogaster microphthalma was given as 12 mm. The males found in Enspel are between 7 and 10 mm long.) Eye diameter between 0.27 and 0.50 mm. (Eye diameter of 0.27 mm is an estimation for P. microphthalma based on the drawing, the eye diameter of the Enspel males are between 0.35 and 0.50 mm). High and arched mesonotum, moderate descending propodeum. Well-developed sub-triangular mandibles with 4–6 triangular-shaped teeth. For all species described here, the petiole is pedunculate without a high, distinct node. Petiole is slightly ascending towards distal. Postpetiole is mostly elongate with a more or less contricted helcium. Postpetiole can dorsally be dome-shaped. Petiole and postpetiole can be regularly or irregularly striated. Wing venation as gyne.

References