Limb Reduction in the Scincid Lizard Genus Lerista. 2. Variation in the Bone Complements of the Front and Rear Limbs and the Number of Postsacral Vertebrae

Greer, Allen E.

doi:10.2307/1564221

Cited by 61 publications

(76 citation statements)

References 11 publications

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“…In these species, living on coastal dunes in western Maghreb and Gambia, the forelimbs show a proportionally greater degree of reduction than the hindlimbs, the external ear opening tends to be more or less obliterated by scales, and the caudal vertebrae are less numerous than the presacral ones. These morphological characters are shared by other skinks with similar ecology (i.e., Sphenops, Lygosoma, Scelotes and Lerista species), and this strongly suggests that they have an adaptive significance (see GANS 1985, GREER 1990. The other tendency, in adaptation to moving freely through long grass, is typical of the C. chalcides group which contains the most elongated and limb-reduced species of the genus.…”

mentioning

confidence: 93%

Body elongation and limb reduction in the genusChalcidesLaurenti 1768 (Squamata Scincidae): a comparative study

1995

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The present paper analyses the postcranial skeleton and limb reduction in some species of the genus Chalcides Laurenti 1768. Three morphotypes are identified, related to as many adaptive zones.The first type includes the most primitive species, pentadactyls, which PASTEUR (1981) placed in two groups: Chalcides ocellatus and C. thierryi. The most primitive phalange formula is found in species of the C. ocellatus group (2-3-4-4-3/2-3-4-5-3): it differs from the plesiomorphic condition of the Squamata (2-3-4-5-3/2-3-4-5-4) due to the loss of a phalange in the fourth digit of the forelimb and fifth digit of the hindlimb. The mean number of presacral vertebrae (PV) varies from 34.8 in C. sexlineatus to 40.9 in C. ragazzii bottegi (37.1 in C. viridanus, 38.3 in C. colosii, 38.1 in C. polylepis, 38.0 in C. ragazzii ragazzii, 38.5 in C. ocellatus and 39.4 in C. bedriagai). In species of the C. thierryi group, which are more slender than the preceding ones, the mean number of PV is greater (40.8 in C. pulchellus, 43.7 in C. thierryi); the phalange formula is 2-3-4-4-3/2-3-4-5-3 in C. pulchellus and 2-3-4-4-3/2-3-4-4-3 in C. thierryi.Species of the first morphological type generally live in open areas with short thick vegetation, rich in stones and vegetal detritus under which they can hide. Some species are also found in sandy coastal dunes where they show semifossorial habits (such as C. bedriagai), and in pre-desert areas (such as C. ocellatus).The second morphological type includes the psammophile and semifossorial species of the C. mionecton and C. mauritanicus groups. The C. mionecton group is distinguished by a pronounced elongation and narrowing of the body ( 4 7.1 PV in C. mionecton, 50.0 in C. armitagei), a marked limb reduction from pentadactyl (2-3-4-4-3 or 2-3-4-4-2/2-3-4-5-3) to tetradactyl (2-3-4-4-0/2-3-4-5-0) in C. mionecton and to tridactyl in C. armitagei (0-2-3-3-0/0-2-3-4-0), and a generally very small ear opening. The distinctly fossorial species of C. mauritanicus group has an even longer and narrower body (50. 7 PV), greatly reduced limbs didactyl anteriorly and tridactyl posteriorly (0-0-2-3-0 or 0-0-1-3-0/0-2-3-4-0), and a completely obliterated ear opening. Species of this morphological type live mainly in sandy coastal zones.The third morphological type, affiliated with the C. chalcides group, dwells exclusively on surface grassland and is never fossorial. The species of this type show the greatest degree of body elongation and limb reduction, ranging from the western Hypothetically, the tendency toward limblessness and acquisition of a serpentiform habitus in the genus Chalcides has followed two separate paths: one favouring subsurface locomotion in sandy coastal environments (species of the C. mionecton and C. mauritanicus groups), the other favouring locomotion in thick grass vegetation (species of the C. chalcides group).

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mentioning

confidence: 93%

Body elongation and limb reduction in the genusChalcidesLaurenti 1768 (Squamata Scincidae): a comparative study

1995

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“…In the bird wing, this digit, called the primary axis, develops in the posterior-most, fully formed digit position suggesting that it is digit IV, thus making the two anterior digits II and III (Mü ller and Alberch, 1990;Burke and Feduccia, 1997). Further supporting this diagnosis of digit identity, maintenance of digits II, III, and IV conforms to the more typical pattern of bilateral digit loss, with the loss of the last developing digits I and V preceding the loss of the earlier developing middle digits (Morse's Law; Morse, 1872;Sewertzoff, 1931;Greer, 1990Greer, , 1991Galis et al, 2001;Shapiro, 2002;Shapiro et al, 2003).…”

Section: Overview Of the Digit Identity Evidence: Conflicts And Propomentioning

confidence: 80%

“…Among tetrapods, with the exception of urodeles, loss of digits occurs in a predictable pattern (Morse's Law), that is digit I > V > II > III > IV (Morse, 1872;Sewertzoff, 1931;Greer, 1990Greer, , 1991Shapiro, 2002). This pattern of digit reduction is thought to reflect a developmental constraint imposed by the pattern and sequence of digit formation (Holder, 1983) such that loss of digits occurs in the reverse order of appearance during development (i.e., the ''first in, last out'' rule; Alberch and Gale, 1985;Shapiro, 2002).…”

Section: Embryological Evidencementioning

confidence: 99%

Identity of the avian wing digits: Problems resolved and unsolved

Young

Bever

Wang

et al. 2011

Developmental Dynamics

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Controversy over bird wing digit identity has been a touchstone for various ideas in the phylogeny of birds, homology, and developmental evolution. This review summarizes the past 10 years of progress toward understanding avian digit identity. We conclude that the sum of evidence supports the Frame Shift Hypothesis, indicating that the avian wing digits have changed anatomical location. Briefly, the derivation of birds from theropod dinosaurs and the positional identities of the avian wing digits as 2, 3, and 4 1 are no longer in question. Additionally, increasing evidence indicates that the developmental programs for identity of the wing digits are of digits I, II, and III. Therefore, the attention moves from whether the digit identity frame shift occurred, to what the mechanisms of the frame shift were, and when in evolution it happened. There is considerable uncertainty about these issues and we identify exciting new research directions to resolve them. Developmental Dynamics 240:1042-1053,

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“…Only three other species of Lerista, L. connivens, L. miopus and L. varia, have the combination of forelimb with a nubbin or stump, two digits on the hindlimb, free eyelid and interparietal fused to the frontoparietals. Lerista lineopunctulata differs from L. connivens in a more developed forelimb (a stump 0.7-1.2% SVL vs. usually a depression only or a nubbin no more than 0.6% SVL), a reduced hindlimb (up to 14% SVL vs. 13-23% SVL, 7-10 subdigital lamellae on longest toe, homologous to digit IV, see Greer (1987Greer ( , 1990 vs. 11-14, 5-7 supradigital scales on longest toe vs. 8-11), more supraciliaries (5 vs. 4) and colour pattern (brown-grey dorsally with lines of dark brown spots, pattern fading laterally vs. two irregular lines of dark brown enclosing a paler brown vertebral stripe and a solid dark brown upper lateral stripe). From L. miopus, it differs in a more developed forelimb (a stump 0.7-1.2% SVL vs. usually a depression only or a nubbin no more than 0.7% SVL) and more distinct colour pattern (lines of dark brown spots vs. often so indistinct as to appear patternless).…”

Section: Systematicsmentioning

confidence: 99%

“…Research has shown the development of limblessness within this genus to have occurred a number of times and is an unusually plastic condition, with a variety of conditions sometimes occurring within the same species (Amey & Worthington Wilmer 2014;Skinner 2010). The value of this situation in the study of limb loss has long been recognised (Benesch & Withers 2002;Greer 1987Greer , 1990Greer , 1992Lee et al 2013;Skinner 2010).…”

Section: Introductionmentioning

confidence: 99%

Taxonomy of the Sand Sliders of Western Australia’s central coast (genus Lerista, Squamata: Scincidae): recognition of Lerista miopus (Günther, 1867)

Amey

Edwards

2017

Zootaxa

723

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The Dotted-Line Robust Slider, Lerista lineopunctulata (Duméril & Bibron, 1839), is widely distributed along the western coast of Western Australia. An investigation of diversity within this taxon showed a clear split between northern and southern populations in the vicinity of Jurien. Accordingly, Lerista lineopunctulata is restricted to the southern population while the northern is recognised as Lerista miopus (Günther, 1867). Both taxa are redescribed and diagnosed and a neotype for L. miopus is designated.

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Limb Reduction in the Scincid Lizard Genus Lerista. 2. Variation in the Bone Complements of the Front and Rear Limbs and the Number of Postsacral Vertebrae

Cited by 61 publications

References 11 publications

Body elongation and limb reduction in the genusChalcidesLaurenti 1768 (Squamata Scincidae): a comparative study

Body elongation and limb reduction in the genusChalcidesLaurenti 1768 (Squamata Scincidae): a comparative study

Identity of the avian wing digits: Problems resolved and unsolved

Taxonomy of the Sand Sliders of Western Australia’s central coast (genus Lerista, Squamata: Scincidae): recognition of Lerista miopus (Günther, 1867)

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