Paraphaenogaster bizeri

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Paraphaenogaster bizeri
Temporal range: Oligocene Enspel Formation, Rhineland-Palatinate, Germany
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Genus: Paraphaenogaster
Species: P. bizeri
Binomial name
Paraphaenogaster bizeri
Jessen, 2020

Identification

Jessen (2020) - Characterised by its combination of BL 11-12 mm, its posteriorly wide head, narrowing towards the front, its rounded and distinct occipital corners, and its relatively small eyes. Its head is sculptured with regular, relatively fine striae, including the clypeus. It differs from Paraphaenogaster tertiaria by its head shape, eyes position and shape of the lateral parts of the anterior clypeal margin. The head shape of P. tertiaria is characterised by “….parallel sides and rounded occipital margin, without occipital angles” (Dlussky and Putyatina 2014, p: 273). It differs from Paraphaenogaster jurinei regarding its size and head shape (see also Dlussky and Putyatina 2014, p. 271).

Distribution

This taxon was described from Enspel Formation, Rhineland-Palatinate, Germany (Oligocene).

This species and other fossil ants were collected as part of yearly excavation campaigns between 1995 and 2013 conducted by the Directorate General for Cultural Heritage Rhineland-Palatinate, Directorate Archaeology, Department of Earth History.

Castes

Nomenclature

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

  • bizeri. †Paraphaenogaster bizeri Jessen, 2020: 12, figs. 5a, b (q.) GERMANY.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.

Description

Queen

Holotype BLw/ oG: 7.80, HL: 2.05, HW: 2.14, ED: 0.35, GeL: 0.85, ML: 1.18, MML: 0.74, SL: 1.73, AL: 3.12, FWL: 8.23, ScuL: 1.36, ScutL: 0.56, HiTL: 2.08, PL: 1.15, PPL: 0.75, PPW: 0.88, G1W: 3.06. Wing venation: 2M+Cu: 0.91, 1Cu: 0.82, 1M: 0.62, m-cu: 0.62, 1RS+M: 0.49, 2RS+M: 0.47. Indices: CI: 104.44. SI: 80.83, IED/ HL: 17.26, IHL/AL: 65.55, Imcu: 58.93, I2RS+M/1RS+M: 96.97, I2RS+M/m-cu: 108.85, I2RS+M/2M+Cu: 51.61.

Position: Head, alitrunk, petiole, postpetiole, first gastral tergite dorsal. Worth mentioning is the fact that left mandible is extremely arched because of a surface distortion in the sediment.

Colour: Black. Alitrunk, petiole, postpetiole, and gaster pyritized.

BL about 11.5. Head slightly wider than long, with rounded occipital corners. Head tapers anteriorly. Median part of anterior clypeus margin is smooth and follows strongly convex curve. Ridges of striae are reaching anterior margin. The posterior margin of the head shows median a small pointed depression. Frontal carinae reaching back to about mid length of eyes. Frontal lobes do not cover antennal condyle completely. All dorsal parts of head, completely sculptured with constant longitudinal, fairly fine striae, at occiput it turns to a reticulate pattern. Frons wide. Mandibles sub-triangular. Masticatory margin with about 8 triangular shaped teeth, all about the same size. Apical tooth not preserved, but signs in the sediment indicate a bigger apical tooth. Eyes located at midlength of head. Eyes diameter is only about 17% of head length. Scape reaches posterior margin of head. Antenna with 12 segments. No differentiated club. Alitrunk partly pyritized. Scutellum is transverse oval with tapered ends. Well-developed metanotum. Posterior margin of metanotum distinctly thickened. Scutum longitudinally striated. Scutellum with coarse longitudinal ridges. Propodeum with transversal striation at posterior declivity continuing vertical at lateral parts of propodeum. Propodeal spines not preserved, but according to photograph analysis very likely.

Petiole with long, stout peduncle and a dinstinct high petiolar node. Peduncle appears ventrally and laterally slightly concave. Peduncle lateral with two long ridges and a groove in between. Postpetiole wide, with distinct node. Anterior face of node moderately ascending, rounded top. Posterior face of node much shorter, gradually descending. Helcium articulates ventrally at less then mid length of posterior face of petiole. Wing venation with closed cells mcu, 1+2r, and 3r. Vein rs-m weak, not distinct, sclerotization at junction with vein 4M only. Shape of cell mcu trapezoid. Vein 5RS does reach the apical margin of wing, but it is very weakly sclerotized in its distal part. Additional incomplete vein is leaving proximally from 2-3rs. In all other respects, the description of the genus applies. First gastral tergite large, with homogenous slightly rugose surface sculpturing.

Type Material

Holotype: NHMM-PE1997/5991-LS, winged gyne. Enspel Oilshale, Rhineland- Palatinate, Germany. Enspel Formation, Upper Oligocene, MP 28; (24.56–24.79 Ma, Mertz et al. 2007), layer S14 o.

Abbreviation of specimen numbers:NHMM= Naturhistorisches Museum Mainz; PE = Palaeontology Entomology; 2009 = found in 2009; 6281 = running inventory number of the year; LS = Landessammlung (State Collection). Information on the layer is given. They refer to the standard profile in Felder et al. (1998).

Currently stored in the Directorate General for Cultural Heritage Rhineland-Palatinate, Directorate Archaeology, Department Earth History, Mainz, Germany. In the long term, they will be deposited in the “Typothek” of the State Collection of Natural History Rhineland-Palatinate/Museum of Natural History Mainz, Mainz, Germany (NHMM).

Etymology

Honouring Thomas Bizer, Mainz, Germany, who managed the photographic repository of the Enspel excavations and did the image processing for many Enspel papers, published by the staff of the General Department for the Conservation of the Cultural Heritage of Rhineland Palatinate, Department Archaeology/History of the Earth, Mainz (Germany).

References