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3 - Shoulder joint and inner ear of Tachypteron franzeni, an emballonurid bat from the Middle Eocene of Messel
- Edited by Gregg F. Gunnell, Duke University, North Carolina, Nancy B. Simmons, American Museum of Natural History, New York
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- Book:
- Evolutionary History of Bats
- Published online:
- 05 June 2012
- Print publication:
- 29 March 2012, pp 67-104
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Summary
Introduction
Over 600 Middle Eocene bat specimens have been excavated from the Messel pit (Grube Messel, near Darmstadt, Germany), and seven species have been described thus far. Many of the fossils are preserved as complete skeletons, often with soft body outlines and gut contents. Six of the bat species represent three extinct families, whereas Tachypteron franzeni can be assigned to the extant family Emballonuridae (Storch et al., 2002). T. franzeni is known only from two specimens; however, these are extraordinarily well preserved, including the shoulder joints and inner ears, so this had already been recognized in the original description of T. franzeni, and these close resemblances to extant emballonurids led to the conclusion that T. franzeni had already evolved similar bioacoustic specializations and a similar flight style to modern taxa.
The shoulder joints of bats are sophisticated structures showing remarkable morphological variation. Miller's (1907) investigations on the differentiations of the shoulder within the Microchiroptera were continued by the studies of other authors (Vaughan, 1970; Strickler, 1978; Hermanson and Altenbach, 1983).
Three different types of shoulder joint can be distinguished within the Chiroptera: the primitive morphology of the shoulder joint with a globular humeral head and corresponding glenoid cavity, as seen in Megachiroptera and Rhinopomatidae; a derived shoulder joint with an oblong humeral head and a single trough-like articular surface on the scapula, found in members of the superfamilies Emballonuroidea, Rhinolophoidea and Noctilionoidea; a derived shoulder joint with a secondary articulation between the tuberculum majus and a secondary articular facet on the dorsal side of the scapula, as seen in the remaining families. Their distribution within the order gives evidence of parallel evolution of the derived types (Schlosser-Sturm and Schliemann, 1995). The morphological modifications of the derived joints are interpreted as a functional response to a biomechanical demand connected with flight (Norberg, 2002), i.e., to limit pronation of the humerus during the downstroke of the wing beat cycle, realized in two different mechanical ways (Schlosser-Sturm, 1982; Altenbach, 1987; Schliemann and Schlosser-Sturm, 1999). Because movement restriction was described for the primitive type as well (Bergemann, 2003), functional interpretations are still a matter of controversy.
9 - Late Miocene mammals from Central Europe
- from PART II - Miocene mammalian successions
- Edited by Jorge Agustí, Institut de Paleontologia M. Crusafont, Sabadell, Spain, Lorenzo Rook, Università degli Studi di Firenze, Italy, Peter Andrews
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- Book:
- Hominoid Evolution and Climatic Change in Europe
- Published online:
- 15 December 2009
- Print publication:
- 07 October 1999, pp 165-190
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Summary
Introduction
The Vallesian and Early Turolian constitute a period of considerable faunal changes in Central Europe and even show a complete faunal turnover in some families. On the genus level, this period represents the time when the Middle Miocene fauna – still predominant during MN 9 – vanishes and immigrants appear which provide a modern stamp and often include ancestors of the extant fauna. Zone MN 10 is actually the crucial period of the faunal turnover. Therefore, the biostratigraphical subdivision does not follow the same standard throughout the present range charts: zone MN 9 is not further subdivided although there is not much doubt that Götzendorf takes a position pretty close to the MN 9 – MN 10 boundary (see Rögl et al., 1993) while Hammerschmiede and Vösendorf occupy a more basal position within MN 9. On the other hand zone MN 10, although obviously a rather short period in absolute chronology, is subdivided for micromammals into an earlier and later component in order to assess faunal changes during that critical interval. The penecontemporaneous Early Turolian localities Eichkogel and Dorn-Dürkheim 1 are listed for micromammals separately to provide a basis for inferences about latitudinal differences.
Large mammals
There are six groups of Vallesian macromammal sites known from Central Europe that are geographically, stratigraphically, and/or taphonomically different. All are located south of the Main River (Fig. 9.1).