Comparative morphology of labial cartilages in sharks (Chondrichthyes, Elasmobranchii)

Klimpfinger, Claudia; Kriwet, Jürgen

doi:10.1080/24750263.2020.1844323

Cited by 5 publications

(6 citation statements)

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“…However, the presence of labial cartilages was not recovered as a synapomorphy for sharks in our analysis. Although labial cartilages were reported in many modern shark species [ 103 , 140 , 210 – 212 ], they are also well-known from Hybodontiformes [ 211 , 213 – 215 ], Holocephali [ 211 ] as well as Paleozoic chondrichthyans such as Helicoprion [ 216 ], Trisychius [ 217 ], and Debeerius [ 218 ]. The presence of labial cartilages in such a variety of different chondrichthyan taxa, paired with the fact that many groups are predating modern sharks indicates that the reconstruction of labial cartilages as a synapomorphy for modern sharks in Villalobos-Segura et al [ 59 ] was merely a product of outgroup choice and taxon sampling (which focused on batomorphs, in which labial cartilages are only known from Torpediniformes and Rhinopristiformes [ 59 , 87 , 219 , 220 ]).…”

Section: Discussionmentioning

confidence: 99%

Systematics and Phylogenetic Interrelationships of the Enigmatic Late Jurassic Shark Protospinax annectans Woodward, 1918 with Comments on the Shark–Ray Sister Group Relationship

et al. 2023

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The Late Jurassic elasmobranch Protospinax annectans is often regarded as a key species to our understanding of crown group elasmobranch interrelationships and the evolutionary history of this group. However, since its first description more than 100 years ago, its phylogenetic position within the Elasmobranchii (sharks and rays) has proven controversial, and a closer relationship between Protospinax and each of the posited superorders (Batomorphii, Squalomorphii, and Galeomorphii) has been proposed over the time. Here we revise this controversial taxon based on new holomorphic specimens from the Late Jurassic Konservat-Lagerstätte of the Solnhofen Archipelago in Bavaria (Germany) and review its skeletal morphology, systematics, and phylogenetic interrelationships. A data matrix with 224 morphological characters was compiled and analyzed under a molecular backbone constraint. Our results indicate a close relationship between Protospinax, angel sharks (Squatiniformes), and saw sharks (Pristiophoriformes). However, the revision of our morphological data matrix within a molecular framework highlights the lack of morphological characters defining certain groups, especially sharks of the order Squaliformes, hampering the phylogenetic resolution of Protospinax annectans with certainty. Furthermore, the monophyly of modern sharks retrieved by molecular studies is only weakly supported by morphological data, stressing the need for more characters to align morphological and molecular studies in the future.

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Section: Discussionmentioning

confidence: 99%

Systematics and Phylogenetic Interrelationships of the Enigmatic Late Jurassic Shark Protospinax annectans Woodward, 1918 with Comments on the Shark–Ray Sister Group Relationship

et al. 2023

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“…After reconstructing the jaws and LCs, we also compared our reconstructions to other reconstructions published in sharksrays.org to check for similarities and aberrations and added those species for which we did not have scans (29 species). For LC identifications, we employed the definitions of LCs of Klimpfinger and Kriwet [26], who numbered LCs as 1, 2, 2.1, 3, and 3.1 (Table 1; Figure 1). We also established a dichotomous identification key for the different morphotypes of LCs (Figures 2-5).…”

Section: Morphological Descriptionsmentioning

confidence: 99%

“…Their origin and function have been discussed for over 100 years (e.g., [20][21][22][23][24][25]), but since 2001, it is well established that LCs support suction during feeding in sharks [8]. Still, not all LCs enable suction [26], but a certain number and size is necessary to form an efficient tunnel for generating a suction flow. The objective of this work is to provide precise descriptions of the number, position, structure, and orientation of LCs in different shark species.…”

Section: Introductionmentioning

confidence: 99%

“…The objective of this work is to provide precise descriptions of the number, position, structure, and orientation of LCs in different shark species. Previously, Klimpfinger and Kriwet [26] introduced a general identification system for LCs in sharks and arranged extant shark families according to their jaw and LC structure into eight morphotypes (groups A to H). The present study represents an extension of this work providing novel information about the morphology and variability of LCs in sharks and installing a dichotomous identification key for different morphotypes of LCs.…”

Section: Introductionmentioning

confidence: 99%

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Morphological Variability and Function of Labial Cartilages in Sharks (Chondrichthyes, Elasmobranchii)

Klimpfinger,

Kriwet

2023

Biology

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(1) Background: Labial cartilages (LCs), as their name suggests, lie in the folds of the connective tissue, the lips, framing the gape of elasmobranch chondrichthyans. As such, these cartilages lie laterally to the jaws and marginal teeth. They are considered to influence the ability of creating suction during the feeding process. As past studies have shown, LCs in sharks are as diverse as their varied feeding techniques and differ between species in number, size, shape, and position. This allows establishing parameters for inferring the feeding and hunting behaviors in these ecologically important fishes. (2) Methods: We present a study of LCs based on the CT scans of more than 100 extant shark species and, therefore, represent at least one member of every living family within the Euselachii, excluding batoids. (3) Results: Accordingly, sharks without labial cartilages or that have only small remnants are ram feeders or use pure biting and mainly occupy higher trophic levels (tertiary and quaternary consumers), whereas suction-feeding sharks have higher numbers (up to five pairs) of well-developed LCs and occupy slightly lower trophic levels (mainly secondary consumers). Species with unique feeding strategies, like the cookie-cutter shark (Isistius brasiliensis, an ectoparasite), display distinct shapes of LCs, while generalist species, conversely, exhibit a simpler arrangement of LCs. (4) Conclusions: We propose a dichotomous identification key to classify single LCs into different morphotypes and propose combinations of morphotypes that result in suction feeding differing in strength and, therefore, different hunting and feeding strategies. The conclusions of this study allow to infer information about feeding strategies not only in extant less-known sharks but also extinct sharks.

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“…— ?Regan (1908: 42 – ‘In the British Museum four specimens’) [in fact six have been registered prior to 1908 (1856, 1865, 1868, 1891, 1898, 1900)], Leigh-Sharpe (1926: 307, 313-314, fig. 6), Bini (1967: 107), Kamminga et al (2017: figshare) and Klimpfinger & Kriwet (2020: 747, fig. 4E). Info .…”

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confidence: 98%

An inventory of Bramble sharks Echinorhinus brucus (Bonnaterre, 1788) (Elasmobranchii, Echinorhinidae) in natural history collections worldwide for conservation status assessment

Mollen,

Iglésias

2023

Zoosystema

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Comparative morphology of labial cartilages in sharks (Chondrichthyes, Elasmobranchii)

Cited by 5 publications

References 35 publications

Systematics and Phylogenetic Interrelationships of the Enigmatic Late Jurassic Shark Protospinax annectans Woodward, 1918 with Comments on the Shark–Ray Sister Group Relationship

Systematics and Phylogenetic Interrelationships of the Enigmatic Late Jurassic Shark Protospinax annectans Woodward, 1918 with Comments on the Shark–Ray Sister Group Relationship

Morphological Variability and Function of Labial Cartilages in Sharks (Chondrichthyes, Elasmobranchii)

An inventory of Bramble sharks Echinorhinus brucus (Bonnaterre, 1788) (Elasmobranchii, Echinorhinidae) in natural history collections worldwide for conservation status assessment

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