Myrmica nungesseri

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

Identification

Jessen (2020) - differs from the other Myrmica species described here (Myrmica schaefersi) mainly by the combination of its oval head shape with flattened occipital corners, and its sub-triangular mandibels. In addition, the prescutellum is consistent in length without any median contriction, as it is the case in M. schaefersi. Metapleura are posteriorly formed slightly bell-bottomed, covering partly hind coxae.

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.

  • nungesseri. †Myrmica nungesseri Jessen, 2020: 29, figs. 11f, g (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: 4.83, HL: 1.34, HW: 1.18*, ED: 0.26, GeL: 0.29, ML: 0.76, MML: 0.38, SL: 1.0, AL: 2.09, ScuL: 0.75, ScutL: 0.66 (incl. prescutellum), HiTL: 0.99, PL: 0.51, PH: 0.47, PPL: 0.50, PPW: 0.51, HeH: 0.32, G1W: 1.46. Indices: CI: 87.91, SI: 85.0, IED/HL: 19.78, IHL/AL: 64.01.

Position: Head from dorsal, alitrunk, petiole from dorsolateral, postpetiole and parts of gaster from dorsal. No wings.

Colour: Medium brown; clypeus, mandibles, antenna, tarsi dark brown.

BL about 6.92. Head longer than wide. Relatively small eyes are located below head mid length. The middle parts of the eyes are missing. Circumocular sulcus strongly sclerotized. Median part of clypeus seems to be convex, with longitudinal striae following the convex shape. Clypeus anterior margin smooth, median slightly tapered. Mandibles only partly preserved. Shape is elongated to almost triangular, with approximately five teeth. Apical and subapical tooth slightly curved and longer than the others. Apical tooth longer than sub-apical tooth. Scape reaches posterior margin of head. Scape slightly curved at base. Antenna with 12 segments, funiculus with 4-segmented club. Basal funicular segment longer than funicular segments 2–5. Head sculptured with longitudinal widely spaced striae. Alitrunk with flat scutum, prescutellum and scutellum. Posterior margin of scutellum and metanotum are strongly sclerotized, dark brown in colour. Scutum, prescutellum and scutellum with distinct wide apart longitudinal striae respectively longitudinal rugose. Propodeal spines are not obtained, but due to photographic analysis; there is strong evidence of the existence of long spines. Distinct transverse striae posteriorly at descending face of propodeum. Tibial spurs with long comb at fore legs, another simple tibial spur also preserved at left hind leg. Petiole almost sessile, with short peduncle. Node with rounded top, not tapered. The impression of a subpetiolar spine could be caused by other body parts lying below petiole. Postpetiolar node wide. Helcium broadly connected almost with complete petiole posterior face. Postpetiole is broadly connected with first gastral segment. Postpetiole widest at posterior margin. Sutures between petiole and postpetiole tergites and sternites distinct. Gaster is not complete. A wing is wrapped around gaster. First gastral sternite is disarticulated from postpetiole. First gastral segment seems to be relatively longer than in ‘’Myrmica schaefersi’’. Ridges arranged in a semicircle can be identified at the anterior margin of the first gastral tergite. This structure is associated with the stridulation organ.

Type Material

Holotype: NHMM-PE2001/5066-LS, gyne. Enspel Oilshale, Rhineland-Palatinate, Germany. Enspel Formation, Upper Oligocene, MP 28; (24.56–24.79 Ma, Mertz et al. 2007), layer S16.

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 Kai Nungesser, who supervised the scientific collections of the Enspel fossils.

References