Systematics of lagomorphs

• Type: Chapter or Part of a Book
• Date: 2018

Authors

J. Melo Ferreira (Author) Other; Paulo Célio Alves (Author) FCUP

Book

Title: Lagomorphs: Pikas, Rabbits, and Hares of the World

Pages: 9-12

ISBN: 9781421423418; 9781421423401

Publisher: Johns Hopkins University Press

Indexing

Scopus - 6 Citations

Other information

Authenticus ID: P-00Q-0Y7

Abstract (EN): during rapid radiations, or of secondary hybridization between populations that maintain some or high levels of reproductive isolation, the key criterion of the biological species concept (Mayr 1942; Coyne and Orr 2004). Another common difficulty is geographic separation, which tends to foment classification of distinct species even if the common history is very recent. The complex nature of species delimitation, coupled with our ability to merge important amounts of information from different disciplines, led to the creation of the notion of integrative taxonomy to define species (Dayrat 2005). This approach seeks consensus among distinct disciplines and attempts to use the evolutionary perspective to understand mechanisms of species divergence and resolve disagreements (Pante et al. 2015). The pragmatic definition of species thus remains complex, multidimensional, and provisional, and corresponds to the best understanding of the biology and evolution of the organisms under study. Difficulties and Progress in Lagomorph Systematics Lagomorphs comprise more than 90 species, distributed in 2 families, Ochotonidae and Leporidae. The family Ochotonidae is composed of a single genus, Ochotona, known as pikas. The leporids are composed of 11 genera, 10 known as rabbits and 1 as hares (Lepus). Most rabbit genera (Brachylagus, Bunolagus, Caprolagus, Oryctolagus, Pentalagus, Poelagus, and Romerolagus) are monotypic. Taxonomy and systematics are often considered to be synonymous. However, taxonomy is a branch of biology concerned with identifying, naming, and classifying organisms, whereas systematics includes both taxonomy and the relatedness over time in the form of a tree of life (phylog eny). Thus, systematics aims to classify and name biodiversity components according to evolutionary patterns. One of the major challenges of systematics is species delimitation as the basic unit of the classification of biodiversity. Because evolution is a continuous process and species as taxonomic entities are discrete units, this task remains fairly controversial among specialists. From the initial naturalist perspective, when morphology was generally used as the sole guide for species classification, to the present, when our ability to collect massive amounts of information from natural populations is unprecedented, this debate has resulted in numerous attempts to create simple definitions using objective criteria (see, e.g., Avise 2004 for a summary of species concepts). While for deep levels of divergence different concepts tend to agree in the identification of species, for closely related natural populations that lie in the so- called gray zone of species divergence, different criteria result in distinct classifications (De Queiroz 2007), generating obvious difficulties for taxonomy. In addition, even within species concepts, the continuous makeup of population diversification and the peculiarities of each situation create substantial difficulties inherent to the evolutionary process. For example, extensive sharing of characters among sister species is expected in cases of speciation 3 Systematics of Lagomorphs josé melo- ferreira and paulo c. alves 1709048_int_cc2015.indd 9 15/9/2017 15:59 10¿¿ Systematics of Lagomorphs Thus, most lagomorph species are included in only 3 genera: Ochotona (29), Sylvilagus (18), and Lepus (32). While there are some inconsistencies in the phylogenetic relationships at a generic level, namely, among the rabbit group (Matthee et al. 2004), the main systematic concerns are among the species within genera. These controversies are mainly related to evolutionary history (rapid radiation, local adaption, and hybridization) and ecological features (inhabiting a great variety of environments, including the arctic, deserts, grasslands, or tropical and boreal forests), coupled with extensive lack of information on many of the species within Ochotona, Sylvilagus, and Lepus. Rapid Radiations During most of the past 45 million years, lagomorphs were much more common on the planet than today (López- Martínez 2008). The fossil record shows that around 78 genera and more than 200 species inhabited both the Old World and North America, suggesting that lagomorphs underwent numerous explosive radiations during their evolution. This led to complete replacement and diversification of genera and species over very short periods of time. At the generic level, lagomorphs initially spread rapidly in Asia and North America during the Eocene, and later to Europe during Late Eocene¿Early Oligocene, and then to Africa in the Late Oligocene¿ Early Miocene. The most recent diversification occurred during the Pliocene, with a subsequent decline during the Quaternary (López- Martínez 2008). A similar pattern of rapid radiations is seen at the species level. At the end of Miocene, e.g., the formation of the steppe zone in Eurasia allowed the rapid diversification of the genus Ochotona (see, e.g., Erbajeva and Zheng 2005). Likewise, diversification of leporids was explosive (Hibbard 1963), and within the genus Lepus extant. © 2018 Johns Hopkins University Press.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 4