The Taxonomic Status of the Louisiana Pine Snake (Pituophis melanoleucus ruthveni) and Its Relevance to the Evolutionary Species Concept

1995 ◽  
Vol 29 (2) ◽  
pp. 186 ◽  
Author(s):  
Steven B. Reichling
Keyword(s):  
Species Concept ◽  
Taxonomic Status ◽  
Pituophis Melanoleucus ◽  
Pine Snake

scholarly journals Cone-like rhodopsin expressed in the all cone retina of the colubrid pine snake as a potential adaptation to diurnality

2017 ◽  
Author(s):  
Nihar Bhattacharyya ◽  
Benedict Darren ◽  
Ryan K. Schott ◽  
Vincent Tropepe ◽  
Belinda S.W. Chang
Keyword(s):  
Cell Types ◽  
Rhodopsin Gene ◽  
Cone Opsin ◽  
Retinal Photoreceptor ◽  
Pituophis Melanoleucus ◽  
Summary Statement ◽  
Potential Adaptation ◽  
Pine Snake ◽  
Cone Opsins

AbstractColubridae is the largest and most diverse family of snakes, with visual systems that reflect this diversity, encompassing a variety of retinal photoreceptor organizations. The transmutation theory proposed by Walls postulates that photoreceptors could evolutionarily transition between cell types in squamates, but few studies have tested this theory. Recently, evidence for transmutation and rod-like machinery in an all cone retina has been identified in a diurnal garter snake (Thamnophis), and it appears that the rhodopsin gene at least may be widespread among colubrid snakes. However, functional evidence supporting transmutation beyond the existence of the rhodopsin gene remains rare. We examined the all cone retina of another diurnal colubrid,Pituophis melanoleucus, distantly related toThamnophis. We found thatP. melanoleucusexpresses two cone opsins (SWS1, LWS) and rhodopsin (RH1) within the eye. Immunohistochemistry localized rhodopsin to the outer segment of photoreceptors in the all-cone retina of the snake and all opsin genes produced functional visual pigments when expressedin vitro. Consistent with other studies, we found thatP. melanoleucusrhodopsin is extremely blue-shifted. Surprisingly,P. melanoleucusrhodopsin reacted with hydroxylamine, a typical cone opsin characteristic. These results support the idea that the rhodopsin-containing photoreceptors ofP. melanoleucusare the products of evolutionary transmutation from rod ancestors, and suggests that this phenomenon may be widespread in colubrid snakes. We hypothesize that transmutation may be an adaptation for diurnal, brighter-light vision, which could result in increased spectral sensitivity and chromatic discrimination with the potential for colour vision.Summary StatementThe all cone retina of the colubrid snake,Pituophis melanoleucuscontains a blue-shifted rhodopsin with cone opsin-like properties, which may have been adaptive in diurnal snakes.

scholarly journals Conservation and species lists: taxonomic neglect promotes the extinction of endemic birds, as exemplified by taxa from eastern Atlantic islands

1996 ◽  
Vol 6 (2) ◽  
pp. 181-196 ◽  
Author(s):  
C. J. Hazevoet
Keyword(s):  
Species Concept ◽  
Conservation Status ◽  
Morphological Differentiation ◽  
Taxonomic Status ◽  
Biological Species ◽  
Hierarchical Level ◽  
Conservation Priorities ◽  
Biological Species Concept ◽  
Clinal Variation ◽  
Phylogenetic Species Concept

SummaryWhen formulating conservation priorities, conservation biologists often rely on published lists of species-level taxa. This paper discusses the nature and taxonomic status of “species” and “subspecies” and different ways of defining “species”. Species are here taken to be terminal and evolutionarily independent units which are qualitatively diagnosable and reproductively cohesive; genealogical biodiversity is thus taken for what it is in the first place, namely the observable result of evolutionary history, an approach which has become known as the phylogenetic species concept (PSC). In contrast to the widely applied Mayrian or “biological” species concept (BSC), no inferences are made about how the degree of morphological differentiation of allopatric but seemingly closely related taxa translates in the absence or presence of reproductive isolation. Many diagnosably distinct endemic island taxa have traditionally been treated as “subspecies” of widespread “polytypic biological” species. At the same time, the “subspecies” category is also used to name arbitrarily delimited sections of intraspecific clinal variation. Thus, the “subspecies” category subjects entirely different evolutionary phenomena to the same hierarchical level through the use of trinomials. Nevertheless, and despite the discrepancy in ontological status among its contents, “subspecies” are usually considered to be of lower evolutionary and/or conservation status than “species” and this has resulted in low conservation priorities allotted to diagnosably distinct island endemics, many of which have traditionally been considered to be “merely Mayrian subspecies”. This has been recognized by some authorities who, because of the threatened status of certain island taxa, advocated treating them binomially in order to generate appropriate conservation measures to save them from extinction, without however justifying their action by any sort of phylogenetic reasoning. Although well intended and sometimes quite successful as regards the follow-up by conservationists, this demonstrates the arbitrary manner in which “species” can be defined under the BSC. Some examples of endemic taxa from eastern Atlantic islands are discussed, demonstrating the way “list thinking” and the lack of phylogenetic reasoning among conservationists translates into the presence or absence of conservation actions. Some of the criticisms of the PSC by adherents of the BSC are discussed. It is advocated that conservationists replace “list thinking” with “lineage thinking”.

Recognizing diversity in blennioid fish nomenclature (Teleostei: Blennioidei)

Zootaxa ◽  
2009 ◽  
Vol 2120 (1) ◽  
pp. 3-14 ◽  
Author(s):  
PHILIP A. HASTINGS ◽  
VICTOR G. SPRINGER
Keyword(s):  
Conservation Biology ◽  
Species Concept ◽  
Taxonomic Status ◽  
Distinct Species ◽  
Valid Species ◽  
Compelling Evidence ◽  
Phylogenetic Species ◽  
Species Status ◽  
Phylogenetic Species Concept ◽  
Evolutionary Pathways

Species inventories for macroecology, biogeography and conservation biology rely upon accurate lists of valid species. In order to provide a more uniform taxonomic treatment for blennioid fishes, we evaluated the taxonomic status of 21 species with currently recognized subspecies. In six cases we found no compelling evidence for recognizing these nominal forms as distinct species. However, in 15 cases, evidence exists for elevating 17 subspecies to full species status based on currently used criteria for delimiting fish species. This evidence includes the existence of significant phenotypic and/or genetic differences supporting the hypothesis that they are on distinct evolutionary pathways in accordance with a phylogenetic species concept. Known distributions of affected species are modified accordingly. Most of these elevated species are separated from their closest relatives by well-known biogeographic barriers.

Home Range Size and Habitat Selection in the Florida Pine Snake (Pituophis melanoleucus mugitus)

Copeia ◽  
2012 ◽  
Vol 2012 (4) ◽  
pp. 706-713 ◽  
Author(s):  
Gabriel J. Miller ◽  
Lora L. Smith ◽  
Steve A. Johnson ◽  
Richard Franz
Keyword(s):  
Habitat Selection ◽  
Home Range ◽  
Home Range Size ◽  
Range Size ◽  
Pituophis Melanoleucus ◽  
Pine Snake

Notes on Variation and Range of the Louisiana Pine Snake, Pituophis melanoleucus ruthveni Stull (Reptilia, Serpentes, Colubridae)

1976 ◽  
Vol 10 (3) ◽  
pp. 252 ◽  
Author(s):  
Robert A. Thomas ◽  
Billy J. Davis ◽  
M. R. Culbertson
Keyword(s):  
Pituophis Melanoleucus ◽  
Pine Snake

Electrophoretic and morphometric analyses of two sibling species pairs in Trachyphloeus (Coleoptera: Curculionidae)

1991 ◽  
Vol 22 (2) ◽  
pp. 159-170
Author(s):  
V. Simonsen ◽  
V. Loeschcke ◽  
V. Mahler ◽  
L.S. Jermn
Keyword(s):  
Sibling Species ◽  
Species Concept ◽  
Taxonomic Status ◽  
Distinct Species ◽  
Reliable Identification ◽  
Lack Of Information ◽  
Morphometric Analyses ◽  
Species Pairs ◽  
Parthenogenetic Reproduction ◽  
Morphological Differences

AbstractMisidentified specimens of Trachyphloeus bifoveolatus (Beck, 1817), T. angustisetulus Hansen, 1915, T. spinimanus Germar, 1824 and T. digitalis (Gyllenhal, 1827) are very frequent in weevil collections and reflect the ambiguous taxonomic status of some of these taxa. The taxonomic problems are a result of (1) sole use of traditional morphological differences, (2) the weevils' assumed parthenogenetic reproduction which prevents the use of Mayr's species concept, and (3) lack of information about their biology and genetics. Our present electrophoretic, morphometric and morphological analyses of live and dry-mounted samples of females from north and west Europe indicate that the four taxa are each genetically and morphologically distinct species. New keys which permit easy and reliable identification of the species are provided.

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