Are ontogenetic shifts in diet linked to shifts in feeding mechanics? Scaling of the feeding apparatus in the banded watersnake Nerodia fasciata

AbstractThe feeding apparatus of the fringed turtle Chelus fimbriatus (Schneider, 1783) was studied to elucidate the feeding mechanics of an aquatic feeding specialist that has never been investigated in detail before, regarding gross morphology. The skull and hyoid apparatus as well as associated musculature were examined by computer tomography and dissection; the tongue was examined by scanning electron microscopy. The flat skull, the possibility to enormously depress the mandible combined with a cheek-like development, the large, ossified hyoid apparatus, and a well-distensible esophagus enable the turtle to produce an enormous suction force the prey is inhaled with. The jaw adductors are poorly developed in relation to other turtles and thus help keep the skull shape flat; nevertheless, they are able to generate high velocities and exhibit some new performance lines. The hyoid musculature is as well-developed as the hyoid apparatus itself, promoting the high depression velocity that is necessary for good feeding performance. The tongue is nearly reduced and lacks dorsal morphological differentiations. Taking all the morphological features into account, C. fimbriatus is an extremely well-adapted turtle making this species a very interesting object of investigation.

Download Full-text

Long-term monitoring provides insight into estuarine top predator (Carcharhinus leucas) resilience following an extreme weather event

Marine Ecology Progress Series ◽

10.3354/meps13269 ◽

2020 ◽

Vol 639 ◽

pp. 169-183

Author(s):

P Matich ◽

BA Strickland ◽

MR Heithaus

Keyword(s):

Habitat Use ◽

Acoustic Telemetry ◽

South Florida ◽

Behavioral Variability ◽

Catch Per Unit Effort ◽

Ontogenetic Shifts ◽

Carcharhinus Leucas ◽

Acute Disturbance ◽

Cold Snap

Chronic environmental change threatens biodiversity, but acute disturbance events present more rapid and immediate threats. In 2010, a cold snap across south Florida had wide-ranging impacts, including negative effects on recreational fisheries, agriculture, and ecological communities. Here, we use acoustic telemetry and historical longline monitoring to assess the long-term implications of this event on juvenile bull sharks Carcharhinus leucas in the Florida Everglades. Despite the loss of virtually all individuals (ca. 90%) within the Shark River Estuary during the cold snap, the catch per unit effort (CPUE) of age 0 sharks on longlines recovered through recruitment within 6-8 mo of the event. Acoustic telemetry revealed that habitat use patterns of age 0-2 sharks reached an equilibrium in 4-6 yr. In contrast, the CPUE and habitat use of age 3 sharks required 5-7 yr to resemble pre-cold snap patterns. Environmental conditions and predation risk returned to previous levels within 1 yr of the cold snap, but abundances of some prey species remained depressed for several years. Reduced prey availability may have altered the profitability of some microhabitats after the cold snap, leading to more rapid ontogenetic shifts to marine waters among sharks for several years. Accelerated ontogenetic shifts coupled with inter-individual behavioral variability of bull sharks likely led to a slower recovery rate than predicted based on overall shark CPUE. While intrinsic variation driven by stochasticity in dynamic ecosystems may increase the resistance of species to chronic and acute disturbance, it may also increase recovery time in filling the diversity of niches occupied prior to disturbance if resistive capacity is exceeded.

Download Full-text

Jaw Apparatus and Feeding Mechanics of Typhlops (Ophidia: Typhlopidae): a Reconsideration

Russian Journal of Herpetology ◽

10.30906/1026-2296-1997-4-2-120-127 ◽

2011 ◽

Vol 4 (2) ◽

pp. 120-127 ◽

Cited By ~ 3

Author(s):

Nikolai N. Iordansky

Keyword(s):

Lower Jaw ◽

Jaw Apparatus ◽

Feeding Mechanics ◽

Cranial Kinesis

The cranial kinesis and movements of the lower jaw in Typhlops are analyzed, with special emphasis placed on the functions of the jugomandibular ligament. The musculature of the Typhlops jaw apparatus is described. The role of movements of the quadrato-mandibular and palato-maxillary systems in feeding mechanics and functioning of the jaw apparatus muscles is discussed.

Download Full-text

Morphological basis of the feeding mechanics in the shingle-back lizardTrachydosaurus rugosus (Scincidae, Reptilia)

Journal of Morphology ◽

10.1002/jmor.1051810303 ◽

1984 ◽

Vol 181 (3) ◽

pp. 271-295 ◽

Cited By ~ 21

Author(s):

Lawrence E. Wineski ◽

Carl Gans

Keyword(s):

Morphological Basis ◽

Feeding Mechanics

Download Full-text

Brachial supporting structure of Spiriferida (Brachiopoda)

Journal of Paleontology ◽

10.1017/jpa.2020.106 ◽

2020 ◽

pp. 1-15

Author(s):

Zhiwei Yuan ◽

Wen Guo ◽

Dan Lyu ◽

Yuanlin Sun

Keyword(s):

Mantle Cavity ◽

Family Type ◽

Type I ◽

Type Ii ◽

Feeding Apparatus ◽

Single Family ◽

Supporting Structure ◽

Type Iii ◽

Type Iv ◽

Evolutionary Lineages

Abstract The filter-feeding organ of some extinct brachiopods is supported by a skeletal apparatus called the brachidium. Although relatively well studied in Atrypida and Athyridida, the brachidial morphology is usually neglected in Spiriferida. To investigate the variations of brachidial morphology in Spiriferida, 65 species belonging to eight superfamilies were analyzed. Based on the presence/absence of the jugal processes and normal/modified primary lamellae of the spiralia, four types of brachidium are recognized. Type-I (with jugal processes) and Type-II (without jugal processes), both having normal primary lamellae, could give rise to each other by losing/re-evolving the jugal processes. Type-III, without jugal processes, originated from Type-II through evolution of the modified lateral-convex primary lamellae, and it subsequently gave rise to Type-IV by evolving the modified medial-convex primary lamellae. The evolution of brachidia within individual evolutionary lineages must be clarified because two or more types can be present within a single family. Type-III and Type-IV are closely associated with the prolongation of the crura, representing innovative modifications of the feeding apparatus in response to possible shift in the position of the mouth towards the anterior, allowing for more efficient feeding on particles entering the mantle cavity from the anterior gape. Meanwhile, the modified primary lamellae adjusted/regulated the feeding currents. The absence of spires in some taxa with Type-IV brachidium might suggest that they developed a similar lophophore to that in some extant brachiopods, which can extend out of the shell.

Download Full-text

The taxonomy and apparatus structure of the Silurian distomodontid conodont <i>Coryssognathus</i> Link & Druce, 1972

Journal of Micropalaeontology ◽

10.1144/jm.12.2.241 ◽

1993 ◽

Vol 12 (2) ◽

pp. 241-255 ◽

Cited By ~ 8

Author(s):

C. Giles Miller ◽

Richard J. Aldridge

Keyword(s):

Feeding Apparatus ◽

Crown Tissue

Abstract. Collections of discrete conodont elements from the Upper Whitcliffe Formation of the Welsh Borderland indicate a septimembrate plan for the feeding apparatus of Coryssognathus, comprising Pa, Pb, Pc, M, Sa/Sb, Sb and Sc elements. Each element is paired, and relative frequencies suggest that there was a total of 16 elements in the apparatus, including two indistinguishable pairs of Sc elements. Associated small coniform elements appear to represent discrete denticles of crown tissue that were sequentially incorporated into multidenticulate elements during ontogeny.

Download Full-text