World Library  
Flag as Inappropriate
Email this Article

Species group

Article Id: WHEBN0003965780
Reproduction Date:

Title: Species group  
Author: World Heritage Encyclopedia
Language: English
Subject: Ring species, Papilio helenus, Papilio polytes, Papilio dravidarum, Papilio castor, Papilio prexaspes, Papilio nephelus, Papilio fuscus, Papilio demodocus, Papilio aegeus
Collection:
Publisher: World Heritage Encyclopedia
Publication
Date:
 

Species group

A species group is an informal taxonomic rank into which an assemblage of closely related species within a genus are grouped because of their morphological similarities[1][2] and their identity as a biological unit with a single monophyletic origin.[3]

Use

The use of the term reduces the need to use a higher taxonomic category in cases with taxa that exhibit sufficient differentiation to be recognized as separate species but possess inadequate variation to be recognized as subgenera. Defining species groups is a convenient way of subdividing well-defined genera with a large number of recognized species. The use of species groups have enabled systematists to consolidate polytypic species species into nominal species which in turn can be grouped into the larger array of the species group.[3]

Range

In regards to whether or not members of a species group share a range, sources differ. A source from Iowa State University Department of Agronomy says that members of a species group usually have partially overlapping ranges but do not interbreed with each other.[1] A Dictionary of Zoology (Oxford University Press 1999) describes a species group as complex of related species that exist allopatrically and explains that this "grouping can often be supported by experimental crosses in which only certain pairs of species will produce hybrids."[2] The examples given below may support both uses of the term "species group."

Arthropod examples

Vertebrate examples

  • Brachygobius, a small genus of gobies which are popular as aquarium fish, are informally divided by taxonomists into two species groups. The dwarf "Brachygobius nunus species group" contains Brachygobius nunus, Brachygobius aggregatus, and Brachygobius mekongensis while the bigger "Brachygobius doriae species group" contains the bigger species of Brachygobius doriae, Brachygobius sabanus, and Brachygobius xanthomelas.[10]
  • The chameleon Brookesia minima has been characterized as belonging to a species group with other "Madagascan Dwarf Chameleons" such as Brookesia dentata, Brookesia tuberculata, and other new or unidentified species such as a recently described chameleon from Tsingy de Bemaraha Strict Nature Reserve.[11]
  • Peromyscus, a genus of deer mice, has been divided into subgenera Peromyscus and Haplomylomys and these subgenera are subdivided further into thirteen species groups.[3]
  • Recent cytogenetic studies have shown that the Middle East Blind Mole Rat (Spalax ehrenbergi) may actually be a species group containing several cryptic species that can be distinguished by chromosome numbers.[12]

Other uses

The term "species group" is also used in a different way so as to describe the manner in which individual organisms group together. In this non-taxonomic context one can refer to "same-species groups" and "mixed-species groups." While same-species groups are the norm, examples of mixed-species groups abound. For example, zebra (Equus burchelli) and wildebeest (Connochaetes taurinus) can remain in association during periods of long distance migration across the Serengeti as a strategy for thwarting predators. Cercopithecus mitis and Cercopithecus ascanius, species of monkey in the Kakamega Forest of Kenya, can stay in close proximity and travel along exactly the same routes through the forest for periods of up to 12 hours. These mixed-species groups are cannot be explained by the coincidence of sharing the same habitat. Rather, they are created by the active behavioural choice of at least one of the species in question.[13]

See also

References

This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 


Copyright © World Library Foundation. All rights reserved. eBooks from Project Gutenberg are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.