Die bedeutung hirnmorphologischer Merkmale für die taxonomie der placentalen säucer

Abstract

Traits of the central nervous system have up to now played only a minor role in taxonomic practice. Based on the macromorphology of the brain in several mammalian orders, the present paper gives the methodological assumptions that should be taken in account when characteristics of the brain are used taxonomically. The conclusions that may be drawn from an analysis of such traits for a taxonomic division of certain orders are discussed. The extent to which some clearly anagenetic processes are taxonomically significant in the development of the central nervous system, as well as how the concepts of evolutionary and consequent genealogical systematics have impinged upon the taxonomic utilization of cerebral traits are also analysed.

Anatomical correlates and nomenclature of the chiropteran endocranial cast

“…This flocculus is located medioventrally compared to the paraflocculus, which is consistent with what is illustrated by Larsell & Dow (1935). Moreover, a cerebellar structure distinguishes from the paraflocculus on the frontal plane of the stereotaxic atlas of the Rousettus aegyptiacus brain (Schneider 1966: e.g Hackethal (1981) also illustrates in most species a medioventral flocculus, of varying size. Contrary to Maugoust & Orliac (2021), we consider that the flocculus can be visible on the external aspect of the chiropteran brain.…”

“…McDaniel (1976) also describes extensively the external morphology of the brain of phyllostomid bats -even if it concerns one particular group in my clade of interest, its methodology may stand. Hackethal (1981) reviews what has been done regarding the cerebral and cerebellar morphology in whole mammals, order by order; if its discussion about the cerebral morphology in bats is a summary and a discussion of the previous works, his work about cerebellar morphology is way more complete, with numerous figures and an impressive anatomical content discussed family by family. These works highly complete the review of Baron et al (1996, the main work used for bats brain by Maugoust & Orliac [2021]), who compiled a large dataset of brain metrics and shortly discussed about the brain of bats in an evolutionary framework.…”

“…Together, these two works give a large anatomical basis to work with. Then, several other studies worked on these grounds to complete anatomical observations and homologies (Buchanan & Arata 1969, Kallen 1977, Wible 1984, 1987, Diamond 1991, Wible & Davis 2000 Schneider (1957Schneider ( , 1966, Henson (1970) and Hackethal (1981) for the identification of the nervous structures, and Tandler (1899), Grosser (1901) and subsequent works for the identification of vascular structures. We use Anglicized terms of the Nomina Anatomica Veterinaria (NAV, 2017) or of the Latin terms of the previously cited articles if missing in the NAV.…”

“…The specificities of bats ecology necessarily reflect on their central nervous system, and the brain has therefore been widely studied. Several works looked at the general morphology and diversity of the brain, with comparisons between and within chiropteran families (Schneider 1957, 1966, Henson 1970, McDaniel 1976, Hackethal 1981, Baron et al 1996, Neuweiler 2000. However, most studies have focused on volumes and sub-volumes of the brain in order to correlate neural volumes to ecological traits (e.g., Mann 1961, Stephan & Pirlot 1970, Jolicoeur et al 1984, Hutcheon et al 2002, Safi et al 2005, Dechmann & Safi 2009.…”

“…Other studies stated and/or showed that the brain reflects well on the inner braincase of small-and medium-sized mammals (Orlov 1961, Dechaseaux 1962, Kochetkova 1978). However, with global size decrease, bony structures and soft tissues get thinner and imprints left on endocasts get shallower, even though the thickness of meninges also decreases (e.g., Hackethal 1981), making the brain vs. endocast comparison process more difficult. Direct correspondence between endocranial form and brain shape in bats was questioned by Schneider (1957).…”