External Morphology Species ID and Musculoskeletal System Flashcards
What is the basic terminology used in marine turtle morphology?
dorsal, ventral, anterior, posterior, medial, lateral, proximal, distal, and deep.
How are marine turtle families classified?
Cheloniidae and Dermochelyidae based on their anatomical features.
What characterizes the Cheloniidae family?
extensively roofed skull, well-developed rhamphothecae, secondary palate, non-retractile head, flippers with elongated digits.
What is unique about the Dermochelyidae family?
extreme reduction of bones in carapace and plastron, lack claws and shell scutes.
What is a rhamphotheca?
keratinous beak that covers the upper and lower jaws of Cheloniidae.
What are the shells of Cheloniidae composed of?
bone covered with keratinous scutes.
What are the different scutes found on a Cheloniid’s carapace?
costal, nuchal, marginal, vertebral, supracaudal.
What distinguishes the carapace of Dermochelyidae?
leathery shell composed of skin overlying a mosaic of thin bony plates.
How do scales and scutes differ in sea turtles?
Scales are thickened areas of the epidermis that cover the skin, while scutes are keratinous plates covering the skeletal shell.
What is the positioning of the prefrontal scales in Cheloniid turtles?
Prefrontal scales are located on the head of Cheloniid turtles, covering the dorsal and lateral areas.
How many pairs of lateral scutes do loggerheads and olive ridleys have?
Loggerheads have five pairs of lateral scutes, while olive ridleys have six pairs.
What distinguishes the head of Dermochelyids from Cheloniids?
The head of Dermochelyids appears covered with smooth skin, whereas Cheloniids have large scales covering the dorsal and lateral head.
How many claws do Chelonia mydas and Natator depressus have?
Chelonia mydas has one claw located on one digit, while Natator depressus also has one claw.
What is the significance of the rhamphotheca’s morphology?
aids in identifying species based on their diet and jaw structure.
Describe the skeleton structure of marine turtles.
skull, axial skeleton, appendicular skeleton.
What are the components of a turtle’s appendicular skeleton?
flippers, pectoral girdles, and limb bones.
What anatomical structure supports the forelimb of sea turtles?
humerus, radius, ulna, carpals, metacarpals, phalanges.
What are the two primary types of bone in turtle appendicular skeletons?
bone and cartilage.
How does the skeletal anatomy of leatherback sea turtles differ from other turtles?
extensive vascular channel in cartilage ends; unique chondo-osseous bone formation.
What is the typical growth rate of leatherback sea turtles?
approximately 76 grams per day, reaching sexual maturity in around nine years.
What muscles are primarily involved in swimming for marine turtles?
pectoralis major, deltoideus, supracoracoideus muscles
What does the plastron consist of in marine turtles?
four pairs of bones: epiplastron, hyoplastron, hypoplastron, and xiphiplastron.
How does the appendicular skeleton differ between turtles and other reptiles?
Turtles have shoulder and pelvic bones located inside the ribs, differentiating them from other reptiles.
What is the role of scleral ossicles in a turtle’s skull?
provide structural support for the eyes in a turtle’s skull.
Describe the growth dynamics of Hard-shelled marine turtles compared to leatherbacks.
Hard-shelled marine turtles grow at an average rate of 16-22 grams per day, while leatherbacks grow substantially faster at around 76 grams per day.
How do the auditory structures differ between cheloniids and dermochelyids?
Cheloniids have distinct auditory structures accommodating their environmental needs, whereas dermochelyids show adaptations for their deep-diving lifestyle.
Identify the primary function of the deltoideus muscle in turtles.
facilitates swimming by assisting in limb movement.
How does the body shape of the leatherback sea turtle support its lifestyle?
Its streamlined body shape allows it to be a long-distance migrant and deep-diving species.
What anatomical features help identify different turtle species?
color patterns, scale arrangement, jaw structure, and carapace shape
What do the various scutes on a Cheloniid’s plastron signify?
provide taxonomic information and serve as landmarks for locating various body parts.
Describe the positioning of the femoral scutes in Cheloniids.
Femoral scutes are located on the underside of the turtle, contributing to its plastron structure.
What adaptation do leatherback sea turtles have for fast growth?
Leatherback sea turtles exhibit specialized vascularization in their cartilage that promotes rapid growth.
How is the appendicular skeleton of turtles structured in terms of muscle attachment?
supports swimming and various other movements.
In terms of locomotion, how important are the forelimbs for sea turtles?
critical role in propulsion and steering during swimming.
What role does the skeletal morphology play in distinguishing various turtle species?
The skeletal morphology, including features such as skull shape and bone density, is crucial for species differentiation.
What key characteristics of oceanic turtles aid their identification?
presence and structure of carapace scutes, head scales, and rhamphotheca characteristics.
What factors influence the sexual maturity timeline of leatherback sea turtles?
Growth rates, environmental conditions, and biological health
How do the species of turtle relate to their external morphology?
The external morphology, including shell shape, size, and scute arrangement, correlates with the specific adaptations and habitats of each turtle species.
What is a distinctive feature of the carapace in Eretmochelys imbricata?
narrow pointed snout with distinctive shell structures that help in species identification
What is the role of fat layers in the carapace of Dermochelyids?
provide insulation and buoyancy, aiding in their deep-diving capabilities.
