#Fins

[chasingrainbowsforever]

~ Blue and Gray ~

#ocean #deep blue sea #blue #marine life #under the sea #sharks #blue gray #fins

[nemfrog]

Fossils of fish fins, showing their evolution. La terre avant le déluge. 1874.

Internet Archive

#paleobiology #fish #paleontology #fins #science illustration #black #shapes #nemfrog #1874 #19th century

[carmeltheslimy]

🪶🐟🔎

#carmelart #traditional #creature #blue #red #feathers #scales #texture #eyes #lashes #eyeballs #blonde #claws #fins #amphibian #bird #corvian #beak #teeth #watercolor

[lamneus]

sea noodle

Volp asked me to design a sea rayquaza   Other art sites wlo.link/@sifyro

Posted using PostyBirb

#reptile #dragon #rayquza #oc #fakemon #underwater #red_eyes #fins #blue_scales #fangs #glowing_scales #long_body #serpent

[heartnosekid]

mertiful_mermaid on ig

#stim #stimboard #mermaids #mermaid tails #sfw #orange #blue #white #underwater #swimming #fins #people #bubbles #hands #ishy gifs #postish

[cosmic-whorror]

Lonely red moon sea

#monster boyfriend #oc #long haired male #demon #sea dragon #merman #merfolk #fantasy #ocean #harp #horns #fins

[toacody]

Tibyra, Okotan Shark

Has a tendency to utter a certain vowel sound.

Source

Creator: Antak3000

#lego #bionicle #armor #armor plates #eyes #red #red eyes #fins #razor #razor fins #animal #animal shape #rahi #aquatic #aquatic rahi #aquatic creatures #aquatic animals #bionicle g2 #sea animals #shark #fish #big fish #jaw #okoto

[clockbreadcroi]

goodness jeepers. two costume illustrations... (wobbles had a second redesign AND third costume rename jesus christ)

#🥐; #cookie run #croissant cookie #🥞; #clockbreadcroi #WOBBLES #FINS

[i-should-have-studied]

Mod 2 General Topics

Types of Fins

Fins are thin, broad folds of integument internally supported by fin rays, they aid in locomotion in various ways depending on the type of fins.

There are 2 kinds of adult fish fins: unpaired median and paired lateral.

Unpaired median fins include 1-2 dorsal fins along the mid-dorsal line, a ventral anal fin behind the anus/cloaca and a caudal fin around the tip of the tail.

Paired lateral fins include pectoral fins anteriorly and pelvic fins posteriorly. Pelvic fins are called thoracic when located below the pectoral fins and abdominal when located just above the anus. Absent in some.

Under unpaired fins there are many types of caudal fins. Caudal fins are well developed in most fish because of its important contribution to forward propulsion during swimming. The 3 main types are: diphycercal, heterocercal, and homocercal.

Diphycercal Fins:

The most primitive, not exhibited by many living fish.

Vertebral column extends straight back to the tip of the tail, dividing the fin symmetrically and equally into the dorsal and ventral lobes.

Occurs in cyclostomes, primitive sharks, and lungfish.

Presence of diphycercal tail in developed fish is due to secondary modifications.

Heterocercal Fins:

Intermediate type.

The caudal fin is strongly asymmetrical.

Vertebral column bends upwards and reaches up to the tip of the more prominent dorsal lobe.

Characteristic in bottom feeders with a ventral mouth, the stroked of the large dorsal lobe directs the fish downwards.

Occurs in modern sharks.

The opposite, a large ventral lobe, is found in flying fish to propel them upwards. This type of fin is called hypocercal.

Homocercal Fins:

The most advanced type and the most common.

Characteristic of most higher bony fishes.

Externally symmetrical but internally asymmetrical.

The original dorsal lobe or epichordal is suppressed, the original ventral love is developed into a single or 2 symmetrical lobes.

Characteristic of fishes with a terminal mouth, its strokes force the fish straight forward.

Types of Scales

There are 5 types of dermal scales: Cosmoid, Placoid, Ganoid, Cycloid, and Ctenoid.

1. Cosmoid Scales:

Does not occur in living fish, only fossilized fishes.

2. Placoid Scales:

Characteristic of sharks.

Each scale has a backwardly directed spine arising from a round or rhomboidal basal plate embedded in dermis.

Spine is enamel-like and basal plate is of dentine-like bony material.

A pulp cavity inside the spine opens through basal plate.

Placoid scales are closely set together in skin; giving a sandpaper like texture.

3. Ganoid Scales:

Thick, rhomboidal, or diamond shaped plates closely fitted side by side. Tile like, provide a bony armor to the fish, might overlap in some.

Characteristic of holosteans.

4. Cycloid Scales:

Thin, flexible. translucent plates. Circular in outline and thicker in the center.

Marked with several concentric lines of growth which can be used to determine age.

They overlap each other, each scale is embedded in a small pocket of dermis.

Found in lung fishes, carp, cod, etc.

5. Ctenoid Scales:

Similar to cycloid scales in form, structure, and arrangement.

But is more firmly attached, their free hind parts with are not overlapped, bear numerous small comb-like teeth or spines.

Characteristic of modern higher teleosteans like perch and sunfish.

There are some intermediate types of scales found in between cycloid and ctenoid, and some fish like flounder have both.

Neoteny and Paedogenesis

Neoteny refers to the retention of a larval or embryonic trait in the adult body. For example the retention of larval gills in adult salamanders.

Paedogenesis refers to the development of gonads and or production of young by an immature larval animal. Examples are scattered in several groups or animals such as gall fly, liver fluke, and salamanders.

Neoteny emphasizes the retention of larval traits in the adult body while paedogenesis stresses the development of adult like gonads in the larval body.

The best example of neoteny and paedogenesis is ambystomata. Normally they live through an aquatic larval stage and transform into an air-breathing terrestrial adult. However, under certain circumstances, the larvae does not undergo metamorphosis, retains it's gills and aquatic nature, but becomes sexually mature. This sexually mature larval stage with external gills is called an axolotl.

For a while axolotls were thought to be an entirely separate genus, Siredon.

Environmental factors affect metamorphosis in many ways. Abundance of food, cold temp., and insufficient iodine may cause failure of metamorphosis and paedogenesis. This is known because drying of swamps, lack of food, and rise in temp induce axolotls to metamorphose. When treated with thyroxine or TSH, they lose their gills and become adults.

There are 3 types of neoteny, partial, intermediate and total.

Partial neoteny is then metamorphosis is delayed due to temporary ecological or physiological changes, seen in tadpoles over winter.

Intermediate neoteny is when the organism is sexually reproductive and can undergo metamorphosis under the correct conditions, seen in axolotl.

Total neoteny is when they remain larval throughout. Even after treatment of thyroxine, they fail to metamorphose. Seen in Siren.

Parental Care in Amphibians

Parental care is the act of looking after the eggs or young until they are independent enough to defend from predators.

Amphibians exhibit various types of parental care in two broad groups: Protection by nests, nurseries, or shelters and direct caring by parents.

Protection by nests, nurseries, or shelters:

1. Selection of site: Many amphibians lay their eggs in protected moist microhabitats. Some frogs and toads lay eggs on land near water. Many tree frogs lay their eggs on leave and branched overhanding water by gluing their eggs, they fall into water free of predators when hatched. Some tree frogs deposit eggs in water that accumulates in epiphytic tropical plants, free from aquatic predators.

2. Defending eggs or territories: Male green Rana frogs maintain territories and attack small intruders to protect the eggs. Both male and female Mantophryne frogs guard the eggs. The male actually sits over and holds the gelatinous envelope containing 17 eggs.

3. Direct Development: In some frogs such as Hyla, the eggs hatch directly into little frogs, thus avoiding the chance of larval mortality. In the red backed salamander, the hatchlings are miniature adults.

4. Foam Nests: Many amphibians convert copious mucous secretion into nests for young. Japanese tree frogs dig a hole or tunnel into which eggs are left in a frothy mass to avoid desiccation. During rain, the hatching tadpoles are washed down the slopping tunnel into pond or river water for further development. Some frogs lay eggs in nests of foam floating on water. The female emits a huge amount of mucus that she can beats into foam with her hindlegs to lay eggs in. When tadpoles hatch they drop from foam into water.

5. Mud nests: Brazilian tree frog, Hyla, the male frog digs little holes in the mud of shallow water for the female frog to lay eggs in. The nest is 30cm in diameter and 5-8cm deep. Tadpoles hatch within this safe place and develop until they are large enough to defend themselves.

6. Tree nests: The South American Tree frog, Phyllomedusa, lays eggs in a folded leaf nest with margins glued together with cloacal secretions. The tadpoles when formed fall straight into water below.

7. Gelatinous bags: Salamandrella, a small aquatic salamander, deposits 50-60 small eggs in a gelatinous bag which is fastened to aquatic plants.

Direct Carrying By Parent

1. Coiling around eggs: In certain caecilians like Ichthyophis, the female lays large eggs in burrows in damp soil and carefully guards them by coiling her body around them until they hatch.

2. Transferring tadpoles to water: Some species of small frogs in tropical Africa and South America deposit their eggs on ground. Once the tadpoles hatch, they fasten themselves to the back of one of the parents with their sucker like mouth so they can be transported to water.

3. Eggs glued to body: Many amphibians carry the eggs glued to their body. In the Sri Lankan tree frog, the eggs are glued to the belly of the female. In the European midwife toad, Alytes, the mall entangles the eggs around his hindlegs so he can carry them with him until they are ready to hatch. When the time comes they release the tadpoles into the nearest water body.

4. Eggs in back pouches: In a group of tree frogs called marsupial frogs, the female carries the eggs on her back. Either in an open oval depression, a closed pouch, or individual pockets. The eggs develop into miniature frogs before leaving their mother's back.

5. Organs as brooding pouches: Males of the terrestrial South American Darwin's frog, Rhinoderma, pushes at least 2 fertilized eggs into his large vocal sacs. There they undergo complete development to emerge out as fully formed froglets.

6. Viviparity: Some anurans are ovoviviparous. They reatain eggs in the oviducts and the female gives birth to living young. For example African toads give birth to little frogs.

#zoology #vertebrates #fish #frog #neoteny #parental care #fins #scales #notes #biology #exam season #please help #amphibians #axolotl

[babanasaur]

Fullbody Lazosaurus

-

#dragon #wings #fins #fire #tail #scales #babanasaurart

[chasingrainbowsforever]

~ Aqua and Gray ~

#fins #water #turquoise #aqua #aqua gray #splash

[vintagequeer-oceansoul]

#my drawings #mermay #mermay 2023 #merman #plus size #bbm #polynesian #digital art #underwater #tattoo #fins #mermaid #beard #merfolk

[carmeltheslimy]

🍐🫐🍠

#fruits #berries #green #yellow #blush #red #yam #blueberry #tail #fins #face #mask #creature #traditional #watercolor #carmelart #onion #aura #halo #crown #twins #clothing #hood #veil #headdress

[lamneus]

Emo fish

Cine https://x.com/sifyro/status/1707519638513328349?s=20 -------------- 🚨Get pinged for YCH's , Commission openings Here   ✏️Itaku   💕Merch ✏️Follow me on twitch ✏️Commission Info 💕Patreon   Other art sites wlo.link/@sifyro

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#vaporeon #pokemon #feral #cigar #smoking #existencial_crisis #fins #meme #tagme

[phiori]

Vaporeon

#vaporeon #pokemon #gijinka #kemono #fanart #illustration #big tail #tail #fins #blue #water

[thomaswaynewolf]

#arches #arches national park #Moab #Utah #sandstone #fins #adventure #travel #my photo #southwest #desert #mountains #photography #aesthetic #landscape #Colorado plateau #devils garden