The Persian dwarf snake is wrongly classified as one species, scientists say. New research shows it is composed of six different species, a finding which might be important for the conservation of the snake.
Well, the new finding might be important for the conservation of the snake but, together with many other instances, it isn’t doing much for a science-based use of the term “species.”
The research, which was published in the Zoological Journal of the Linnean Society, revealed that the Persian dwarf snake is not a single species at all. It is composed of 6 different species, wrongly classified as the species Eirenis persicus. A molecular clock analysis revealed that the divergence and diversification of the E. persicus species group mainly correspond to Eocene to Pliocene orogeny events subsequent to the Arabia-Eurasia collision.
The six species are Eirenis nigrofasciatus, Eirenis walteri, Eirenis angusticeps, Eirenis walteri, Eirenis mcmahoni and Eirenis occidentalis. Except for E. occidentalis, which is a completely new discovery by the researchers, these species were already described between 1872 and 1911. However, during the last half of the previous century, herpetologists considered them as a single species with some difference in color and pattern, because the overall morphology is quite similar. More.
The fact that the very concept of “species” is such a mess, with no sign of taking the matter in hand, is the sort of thing that causes some to call biology the “social sciences of the sciences.”* Apparently, the hallowed popular status of On the Origin of Species is enough warrant for comfort with chaos.
See also: Single jaw finds three species to be one
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Here’s the abstract:
The Persian dwarf snake Eirenis (Pseudocyclophis) persicus (Anderson, 1872) has a wide distribution range in south-western Asia. This species group was comprehensively studied here using traditional biometry, geometric morphometrics, ecological niche modelling, and genetics. Our analyses revealed that E.?persicus is split into two clades. A western clade, bearing at least two different species: E.?persicus, distributed in south-western Iran, and an undescribed species from south-eastern Turkey and western Iran. The eastern clade consists of at least three species: Eirenis nigrofasciatus, distributed across north-eastern Iraq, and western and southern Iran; Eirenis walteri, distributed across eastern Iran, southern Turkmenistan, and western and southern Pakistan, and Eirenis angusticeps, distributed in north-eastern Pakistan. Ecological niche modelling revealed that the distribution of the species in the western clade are mainly affected by winter precipitation, and those in the eastern clade are mainly affected by the minimum temperature of the coldest month. A molecular clock analysis revealed that the divergence and diversification of the E.?persicus species group mainly correspond to Eocene to Pliocene orogeny events subsequent to the Arabia–Eurasia collision. This study confirms that specimens with the unique morphology of having 13 dorsal scale rows on the anterior dorsum, occurring in the Suleiman Mountains in central Pakistan, can be referred to Eirenis mcmahoni (Wall, 1911). However, at this moment we have insufficient data to evaluate the taxonomy of this species. © 2015 The Linnean Society of London Open access – Mahdi Rajabizadeh, Zoltán T. Nagy, Dominique Adriaens, Aziz Avci, Rafaqat Masroor, Josef Schmidtler, Roman Nazarov, Hamid Reza Esmaeili, Joachim Christiaens. Alpine-Himalayan orogeny drove correlated morphological, molecular, and ecological diversification in the Persian dwarf snake (Squamata: Serpentes:Eirenis persicus). Zoological Journal of the Linnean Society, 2015; DOI: 10.1111/zoj.12342