scholarly journals Diurnal refuge sharing between species of Cuban snakes of the genus Tropidophis (Squamata: Tropidophiidae)

2020 ◽  
pp. 1-2
Author(s):  
Javier Torres ◽  
Tomás Rodríguez-Cabrera

Snakes of the genus Tropidophis Bibron, 1840 have undergone an adaptive radiation in Cuba, where 16 out of the 27 Antillean species occur (Hedges 2002). With this high diversity, coexistence of four species is somewhat common (Rodríguez et al. 2013). Coexistence has been hypothesized to be possible due to differences in habitat use based on body shape (Rodríguez-Cabrera et al. 2016). Even with potential segregating echanisms, it is reasonable to expect certain levels of niche overlap. Herein we report three instances of diurnal refuge shared between species of Tropidophis.

2010 ◽  
Vol 8 (2) ◽  
pp. 299-310 ◽  
Author(s):  
Fernando Zaniolo Gibran

Based on a fish survey and preliminary underwater observations, 17 "morphotypes" were identified that characterize the morphological diversity found within 27 nektonic fish species sampled at São Sebastião Channel. Such "morphotypes" were studied using an ecomorphological approach, with the intention to investigate similarities and differences in shape and habits. Underwater field observations were also performed, to verify if the lifestyle of these species, such as vertical occupation of the water column and the habitat use, are in accordance with their distribution in the morphospace. The results, complemented with data from scientific literature on the taxonomy and phylogenies of these species, allowed discussing some of the typical cases of convergent and divergent evolution. Some of the ecomorphological clusters had no phylogenetic support although this is probably due to the environmental conditions in which theirs members have evolved. The body shape and fins positions of a fish clearly influence its ecological performance and habitat use, corroborating the ecomorphological hypothesis on the intimate link between phenotype and ecology.


2019 ◽  
Vol 127 (2) ◽  
pp. 479-492 ◽  
Author(s):  
Anna E Hiller ◽  
Michelle S Koo ◽  
Kari R Goodman ◽  
Kerry L Shaw ◽  
Patrick M O’Grady ◽  
...  

Abstract The role of the environmental niche in fostering ecological divergence during adaptive radiation remains enigmatic. In this study, we examine the interplay between environmental niche divergence and conservatism in the context of adaptive radiation on oceanic islands, by characterizing the niche breadth of four Hawaiian arthropod radiations: Tetragnatha spiders (Tetragnathidae Latreille, 1804), Laupala crickets (Gryllidae Otte, 1994), a clade of Drosophila flies (Drosophilidae Fallén, 1823) and Nesosydne planthoppers (Delphacidae Kirkaldy, 1907). We assembled occurrence datasets for the four lineages, modelled their distributions and quantified niche overlap. All four groups occupy the islands in distinct ways, highlighting the contrasting axes of diversification for different lineages. Laupala and Nesosydne have opposite environmental niche extents (broad and narrow, respectively), whereas Tetragnatha and Drosophila share relatively intermediate tolerances. Temperature constrains the distributions of all four radiations. Tests of phylogenetic signal suggest that, for Tetragnatha and Drosophila, closely related species exhibit similar environmental niches; thus, diversification is associated with niche conservatism. Sister species comparisons also show that populations often retain similar environmental tolerances, although exceptions do occur. Results imply that diversification does not occur through ecological speciation; instead, adaptive radiation occurs largely within a single environment.


The Auk ◽  
2000 ◽  
Vol 117 (1) ◽  
pp. 175-183 ◽  
Author(s):  
Scott F. Pearson ◽  
David A. Manuwal

Abstract Hybrid zones between Townsend's Warblers (Dendroica townsendi) and Hermit Warblers (D. occidentalis) in the Pacific Northwest are narrow relative to estimated dispersal distances and appear to be moving, with Townsend's replacing Hermits. We examined whether the habitat-transition and parental-fitness asymmetry models can explain why these zones are narrow and moving by comparing habitat variables associated with warbler territories in the Washington Cascades hybrid zone. Habitat variables did not differ among phenotypes, suggesting that the habitat-transition model cannot explain the narrow and dynamic nature of this hybrid zone. Habitat characteristics of Hermit Warbler territories did not differ inside versus outside the hybrid zone, also suggesting that this zone is not associated with a region of habitat transition. The lack of difference in habitat use could be the result of comparing variables that are not important to pairing success. However, warblers tended to select territories on west-southwest aspects. South aspects in the southern Washington Cascades are dominated by Douglas fir (Pseudotsuga menziesii) and true fir, which is a habitat selected by female warblers when choosing among territories and males. The parental-fitness asymmetry model does not necessarily make predictions about habitat use within the hybrid zone but predicts the superiority of one parental species over the other. However, if significant overlap occurs in habitat use or niche (as in these warblers), then competition between parental species is likely to occur. To determine whether these species compete, we mapped 12 warbler territories and monitored an additional 94 territories throughout the breeding season and found that all males with neighbors compete for and hold exclusive territories. Thus, the pattern of habitat use and territoriality is consistent with the parental-fitness asymmetry model.


Zootaxa ◽  
2016 ◽  
Vol 4208 (5) ◽  
pp. 401 ◽  
Author(s):  
SIMON WEIGMANN ◽  
DAVID A. EBERT ◽  
PAUL J. CLERKIN ◽  
MATTHIAS F.W. STEHMANN ◽  
GAVIN J.P. NAYLOR

A new deep-water catshark, Bythaelurus bachi, is described based on 44 specimens caught on the southern Madagascar Ridge in the southwestern Indian Ocean. The new species is the only stout-bodied Bythaelurus with oral papillae in the region and is distinguished from all congeners by the plain beige to light gray-brown coloration, high diversity in dermal denticle morphology, and presence of composite oral papillae. Despite resemblance in body shape, Bythaelurus bachi n. sp. is distinguished from its closest congener, B. naylori Ebert & Clerkin, 2015, by the presence of numerous large, partially composite papillae on the tongue and roof of the mouth (vs. papillae lacking), plain light coloration (vs. medium to dark brown ground color, light fin edges and a distinctly dark dusky-colored snout), only slightly enlarged dermal denticles on the anterior upper caudal-fin margin (vs. dermal denticles distinctly enlarged), a higher diversity in dermal denticle morphology in general, and smaller maximum size and size at maturity. The distinction of both species is also supported by molecular results. The new species differs from all other congeners in the western Indian Ocean in the stout body shape of large specimens, coloration, larger size, as well as several morphometrics, including larger claspers, longer eyes and dorsal fins, and shorter pelvic—anal and pelvic—caudal spaces. The genus is reviewed, a key to its species given. 


PLoS ONE ◽  
2014 ◽  
Vol 9 (11) ◽  
pp. e112085 ◽  
Author(s):  
Kimmo Kalevi Kahilainen ◽  
William Paul Patterson ◽  
Eloni Sonninen ◽  
Chris Harrod ◽  
Mikko Kiljunen

2016 ◽  
Vol 53 (1) ◽  
pp. 34-40
Author(s):  
Robin L. Sissons ◽  
Michael W. Caldwell ◽  
Carol A. Evenchick ◽  
Donald B. Brinkman ◽  
Matthew J. Vavrek

Although the Jurassic was a period of high diversity in ichthyosaurs, only a small number of specimens have been recorded from Canada to date. We describe here a new occurrence of an ophthalmosaurid ichthyosaur from a shallow marine depositional environment within the Bowser Basin of northern British Columbia. Based on vertebral diameters and the size of the humerus, the ichthyosaur was relatively large compared to other contemporaneous forms, yet possessed teeth that were small for its body size. As well, the height to length ratio of the preserved vertebrae suggests it may have had a more elongate, less regionalized body shape. Although indeterminate at a generic level, the presence of Late Jurassic ichthyosaurs in nearshore waters of northwestern North America further demonstrates their cosmopolitan distribution.


The Auk ◽  
2003 ◽  
Vol 120 (3) ◽  
pp. 680-699
Author(s):  
Robert H. Day ◽  
Alexander K. Prichard ◽  
Debora A. Nigro

Abstract We compared habitat use and niche overlap in the closely related seabirds Kittlitz’s (Brachyramphus brevirostris) and Marbled (B. marmoratus) Murrelets in nearshore waters of Prince William Sound, Alaska, in 1996–1998, and examined the relationship between near shore habitat use and morphology of those two species. Within bays, the distribution of Kittlitz’s Murrelet groups diverged the most from randomness for the variables habitat type (preferring [i.e. using significantly more than what is available] glacial-affected and glacial-stream-affected habitats), distance to shore (preferring areas 51–100 m from shore), and water clarity (preferring highly turbid water), whereas the distribution of Marbled Murrelet groups diverged the most from randomness for the variables habitat type (preferring glacial-unaffected habitats), ice cover (preferring areas of no ice), and sea-surface temperature (SST) (preferring temperatures = 6°C). The probability of a group of birds being Kittlitz’s Murrelets was determined most strongly by water clarity. Kittlitz’s Murrelet groups were more common in the more heavily glaciated College and Harriman fjords than in the other two bays and more common in early and midsummer than in late summer; the reverse was true for Marbled Murrelet groups. Marbled Murrelet groups had the least niche overlap with Kittlitz’s Murrelet groups in water clarity, SST, and site, whereas Kittlitz’s Murrelets had the least overlap with Marbled Murrelets in habitat type and water clarity. Similarly, Kittlitz’s Murrelet groups occurred in water significantly more turbid than did Marbled Murrelet groups in two of four habitat types. Kittlitz’s Murrelets had eyes (as indicated by orbit diameter) that were significantly larger in proportional size than Marbled Murrelets. We propose that these two species are specialized for foraging in different water types, with specialization of the Kittlitz’s Murrelet for turbid water of glacial origin leading to optical specialization.


2020 ◽  
Vol 287 (1931) ◽  
pp. 20201053
Author(s):  
S. T. Friedman ◽  
S. A. Price ◽  
K. A. Corn ◽  
O. Larouche ◽  
C. M. Martinez ◽  
...  

Colonization of novel habitats can result in marked phenotypic responses to the new environment that include changes in body shape and opportunities for further morphological diversification. Fishes have repeatedly transitioned along the benthic–pelagic axis, with varying degrees of association with the substrate. Previous work focusing on individual lineages shows that these transitions are accompanied by highly predictable changes in body form. Here, we generalize expectations drawn from this literature to study the effects of habitat on body shape diversification across 3344 marine teleost fishes. We compare rates and patterns of evolution in eight linear measurements of body shape among fishes that live in pelagic, demersal and benthic habitats. While average body shape differs between habitats, these differences are subtle compared with the high diversity of shapes found within each habitat. Benthic living increases the rate of body shape evolution and has led to numerous lineages evolving extreme body shapes, including both exceptionally wide bodies and highly elongate, eel-like forms. By contrast, we find that benthic living is associated with the slowest diversification of structures associated with feeding. Though we find that habitat can serve as an impetus for predictable trait changes, we also highlight the diversity of responses in marine teleosts to opportunities presented by major habitats.


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