A method for preparing a dried skeleton specimen of a cartilaginous fish

Abstract

This invention discloses a method for preparing dried cartilaginous fish skeleton specimens, aiming to address the common technical pain points in existing cartilaginous fish skeleton specimen preparation techniques, such as easy shrinkage and deformation of cartilage tissue, narrow applicable size range, lengthy production cycle, high chemical toxicity, or high operational difficulty. This method, through optimized process design, comprises five core steps: material processing, bleaching, dehydration, shaping, and specimen treatment. Combined with safe and non-toxic conventional materials, it successfully achieves standardized preparation of dried specimens of medium to large-sized complete cartilaginous fish skeletons with a snout length of over 20 cm. This invention not only significantly shortens the production cycle, but also uses safe, non-toxic, and environmentally friendly materials such as hydrogen peroxide, ethanol, and mixed desiccants, generating no harmful waste. Furthermore, it has a wide range of applications, efficiently preparing skeleton specimens of various cartilaginous fish such as rays and sharks, and can be extended to the preparation of fish ocular bones and cartilaginous tissue specimens of reptiles and mammals. It has extremely high practical value and broad prospects for promotion in fields such as biological teaching, scientific research display, and species resource preservation.

Description

Technical Field This invention relates to the field of animal skeleton specimen preparation technology, specifically to a method for preparing dried cartilaginous fish skeleton specimens, which is particularly suitable for drying and shaping medium to large cartilaginous fish skeletons and can be widely used in biological teaching, scientific research experiments, natural history museum displays, and species resource preservation. Background Technology

[0001] Cartilaginous fish, a special type of vertebrate, have skeletons entirely composed of cartilage. Compared to bony fish, cartilaginous tissue is highly hydrophilic, loosely structured, and less resilient. Their skeletal specimens provide a direct visual representation of their morphological and structural characteristics, holding irreplaceable value in fields such as biological education, scientific research, species conservation, and biodiversity surveys. However, precisely because of the unique physicochemical properties of cartilaginous tissue, cartilage is highly susceptible to shrinkage, deformation, and cracking during traditional dried specimen preparation due to uneven moisture loss. This results in distorted specimen morphology and an inability to preserve the original physiological structure, making the preparation of dried cartilaginous fish skeletal specimens far more difficult than that of bony fish.

[0002] Currently, the industry primarily relies on two methods for preparing cartilaginous fish skeleton specimens: plastination and tissue clearing. Plastination involves using chemical reagents such as paraformaldehyde and epoxy resin to penetrate and solidify cartilage tissue. While this method can preserve the skeletal morphology relatively well, the reagents used are highly toxic and corrosive, posing a serious threat to the health of operators. Furthermore, the discarded reagents can pollute soil and water environments. This technique is also complex, requiring extremely precise control of the operating environment, temperature, and humidity, making it difficult to produce and costly, hindering large-scale and standardized application. Tissue clearing, on the other hand, involves dehydration, clearing, and staining. While it can preserve the morphology and structure of the cartilage, this technique is only suitable for small or juvenile cartilaginous fish with a snout length of less than 20 cm. It has very poor adaptability to medium and large cartilaginous fish with a snout length of more than 20 cm, and the entire production cycle is lengthy, typically requiring several weeks or even months, failing to meet the practical needs for rapid, mass-produced specimens.

[0003] Therefore, developing a method for preparing dried skeletal specimens that can fundamentally solve the problem of shrinkage and deformation of dried cartilage tissue, is suitable for medium and large cartilaginous fish, has a short production cycle, uses safe and non-toxic materials, and is easy to operate has become a technical challenge that urgently needs to be overcome in the field of animal specimen preparation. It is of great significance to promoting the development of cartilaginous fish research and biological teaching and display. Summary of the Invention

[0004] The purpose of this invention To address the shortcomings of existing cartilaginous fish skeleton specimen preparation techniques, such as easy shrinkage and deformation of cartilage tissue, narrow applicability, long production cycle, high chemical toxicity, high operational difficulty, and high cost, this invention provides a method for preparing dried cartilaginous fish skeleton specimens. By optimizing process combinations and selecting safe materials, this method achieves safe, rapid, and high-quality preparation of dried cartilaginous fish skeleton specimens, while also expanding the applicability of the method to meet the specimen preparation needs in different scenarios.

[0005] Technical solution To achieve the above-mentioned objectives, this invention adopts the following technical solution: by precisely controlling the process parameters of each step and optimizing the material combination, a standardized process for producing dried cartilaginous fish skeleton specimens is formed: A method for producing dried cartilaginous fish skeleton specimens includes five core steps: material processing, bleaching, dehydration, shaping, and specimen treatment. The specific operational details of each step are as follows: 1. Material processing Select live or recently deceased cartilaginous fish individuals, prioritizing common cartilaginous fish with intact skeletal structures such as manta rays and sharks. The snout length should be at least 20 cm to ensure the specimens are suitable for medium to large-sized cartilaginous fish. First, thoroughly rinse the cartilaginous fish's body surface and abdominal cavity with clean water to remove mud, dirt, and internal organs and digestive residue. Then, gently peel away the epidermis and muscle tissue along the skin texture with a scalpel, avoiding damage to the cartilage structure. The pelvic girdle, due to its relatively unified skeletal structure without direct bone connections, requires separate and meticulous separation. Carefully peel away the attached muscle and fascia with tweezers, ensuring the pelvic girdle cartilage remains intact. Place the pre-treated cartilaginous fish in a constant temperature water bath at 90℃±2℃ for 5 minutes. The high temperature rapidly denatures and coagulates the muscle tissue proteins, reducing the adhesion between the muscle and cartilage matrix and facilitating rapid separation. After removal, allow it to cool naturally to below 30℃ at room temperature to prevent cartilage deformation from brushing at high temperatures. Next, using a brush, carefully brush away the muscle tissue from the body surface and bone crevices along the skeletal growth lines, from head to tail and from trunk to fins. The brushing should be gentle, preserving the gill structure as completely as possible. Then, carefully peel away the connective tissue and residual fascia between the gill filaments with pointed tweezers to fully expose the white gill cartilage, ensuring the specimen's morphological integrity. If some muscle tissue remains embedded in the bone crevices or tightly adhered, it can be repeatedly soaked in hot water at 90℃±2℃ for 2-3 minutes to soften the muscle before brushing again. Throughout the process, strictly control the force applied to ensure the cartilaginous skeletal structure remains intact without breakage or damage.

[0006] 2. Bleaching Rinse the cartilaginous fish skeleton, after removing all muscle tissue and fascia, repeatedly with clean water 3-4 times to thoroughly remove any remaining muscle debris, tissue mucus, and impurities. After draining the surface water, immerse it in a pre-prepared 5%-10% hydrogen peroxide solution and let it stand at room temperature for approximately 2 hours to bleach. During the bleaching process, gently turn the skeleton over every 30 minutes to ensure that both sides and crevices are fully in contact with the hydrogen peroxide solution for uniform bleaching, avoiding uneven coloring. Strictly control the bleaching time and hydrogen peroxide concentration; too high a concentration or too long a time will corrode the cartilage tissue, causing it to become brittle and prone to cracking, while too low a concentration will not achieve the desired whitening effect. The final bleaching time is until the skeleton surface is a clean, uniform white color, free of impurities and dullness.

[0007] 3. Dehydration After bleaching, the bone is removed and quickly rinsed with clean water to remove the hydrogen peroxide solution adhering to the surface. It is then drained and immediately placed in a 60%-75% medical ethanol solution for gradient dehydration, with the dehydration time strictly controlled to 2 hours. During dehydration, the cartilage condition needs to be observed regularly. The bone is removed every 40 minutes to observe surface changes. Dehydration is considered complete when the cartilage surface appears uniformly white, feels non-slippery to the touch, and no liquid oozes out when pressed. This concentration of ethanol quickly absorbs residual moisture in the cartilage tissue, laying the foundation for subsequent shaping and drying, while preventing the cartilage tissue from becoming brittle and cracking due to excessively high ethanol concentrations. Ethanol also has a certain bactericidal and disinfecting effect, preventing mold growth in subsequent steps.

[0008] 4. Shaping Prepare a rectangular or cubic container that can fully contain the cartilage specimen and has good sealing properties. The container material should preferably be corrosion-resistant and not easily deformed, such as plastic or glass. Place a layer of desiccant at least 2 cm thick at the bottom of the container. The desiccant can be any one of silica gel, perlite, or calcium chloride powder, or a mixture of silica gel, perlite, and calcium chloride powder in a 2:1:1 mass ratio. Silica gel and calcium chloride powder have highly efficient water absorption properties, quickly absorbing moisture from the cartilage and the environment. Perlite increases the looseness and breathability of the desiccant, preventing clumping and localized dampness, thus preventing cartilage tissue deterioration and deformation. Carefully place the dehydrated cartilage into a container, adjusting it to a pre-set posture such as natural swimming or fin-spreading, according to display requirements, to prevent posture deviation. Then, slowly pour in the mixed desiccant, ensuring that the desiccant completely buries the cartilage and its appendages such as fins and tail. During pouring, gently tap the side of the container to ensure that the desiccant fully fills the gaps in the cartilage, gills, and skeletal recesses. At the same time, gently adjust the temporary fixation device to keep the cartilage posture from shifting. After the desiccant surface is smoothed, cover it with a 0.5-1cm thick layer of foam or silicone cushioning pad, and then weigh it down with a weight that is 1.5-2 times the mass of the cartilage skeleton. The weight applies uniform pressure to prevent the cartilage from shrinking and deforming due to moisture loss during the drying process. Finally, seal the container and place it in a cool, dry, and well-ventilated environment for at least 4 days to ensure that any remaining moisture in the cartilage is completely absorbed by the desiccant, achieving stable fixation of the skeletal shape.

[0009] 5. Specimen processing After the cartilaginous skeleton is set and dried, open the sealed container and slowly pour out the desiccant. Remove the cartilaginous skeleton and gently brush away any remaining desiccant powder with a soft brush to ensure the skeleton surface is clean. For any remaining muscle tissue, fascia, or impurities on the skeleton surface, use a micro-grinding machine at a low speed to gently remove them. During grinding, the operator should keep the skeleton stable and control the grinding pressure to avoid over-grinding and damaging the cartilaginous structure, paying particular attention to protecting vulnerable areas such as the gills and fins. Finally, based on the physiological characteristics of the cartilaginous fish skeleton, use fine metal wire with a diameter of 0.3-0.5 mm to precisely connect and fix the skeletons of the head, trunk, tail, fins, and pelvic girdle. Use a small amount of 502 glue or AB glue to reinforce the joints, ensuring the specimen's morphology is stable and its structure is intact, ultimately creating a high-quality dried cartilaginous fish skeleton specimen.

[0010] Beneficial effects Compared with existing techniques for preparing cartilaginous fish skeletons, this invention has the following significant advantages: 1. Solving core technical challenges: This invention fundamentally solves the problems of shrinkage, deformation, and cracking caused by moisture loss during the drying of cartilage tissue through a combination of processes: "high-temperature precise separation (90℃ hot water denatures the muscle, reducing its adhesion to the cartilage) - gradient gentle dehydration (slow dehydration with 60%-75% ethanol to prevent subsequent desiccant adhesion) - desiccant embedding and pressure shaping (mixed desiccant absorbs moisture, and a heavy object applies uniform pressure to prevent deformation)". It can completely preserve the original physiological morphology and structural details of the cartilaginous fish skeleton, and is especially suitable for medium and large cartilaginous fish with a snout length of more than 20 cm, filling the gap in the field of dried specimen preparation of medium and large cartilaginous fish.

[0011] 2. Safe, environmentally friendly, and low-cost: The materials used are all conventional chemical materials such as hydrogen peroxide, medical ethanol, silica gel desiccant, perlite, and calcium chloride. They are safe, non-toxic, and non-corrosive, posing no harm to the health of operators. Waste materials are easy to dispose of and will not pollute the environment. At the same time, the materials are readily available and inexpensive, and the mixed desiccant can be reused, which greatly reduces the cost of specimen preparation. The operation threshold is low, no professional high-end equipment is required, and it is easy to promote and apply on a large scale and in a standardized manner.

[0012] 3. Significantly shortened production cycle: The entire production process, from material processing to specimen formation, takes only 7-8 days (including more than 4 days for shaping and drying). Compared to the weeks or even months required for tissue transparency technology, the production efficiency is increased several times, which can quickly meet the urgent needs of teaching, scientific research and other scenarios for cartilaginous fish specimens and achieve mass production.

[0013] 4. Wide range of applications: The core technology of this invention can not only efficiently produce complete skeletal specimens of various cartilaginous fish such as rays, sharks, and silver sharks, but can also be flexibly extended to the production of dried specimens of fish eyeball bones, cartilage tissue of reptiles (such as lizards and turtles), and cartilage tissue of mammals (such as mice and rabbits). When applying it, only the process parameters need to be finely adjusted according to the size and structural characteristics of the cartilage to achieve the ideal effect. It is highly practical and has high promotional value. Detailed Implementation

[0014] Example 1: Preparation of dried skeleton specimen of the ray 1. Material Processing: Select live manta rays with a snout length of 25 cm. Rinse the body surface and abdominal cavity repeatedly with clean water to remove mud and sand. After opening the abdomen, carefully remove internal organs, digestive residue, and abdominal fascia. Gently peel away the epidermis and subcutaneous fat tissue along the skin texture with a scalpel. Separate the pelvic girdle separately and carefully peel away the attached muscles and fascia with pointed tweezers, ensuring that the pelvic girdle cartilage is intact. Place the processed manta ray in a 90°C constant temperature water bath for 5 minutes. After removing it, allow it to cool naturally to 25°C at room temperature. Use a brush to carefully brush away the muscle tissue on the body surface and in the bone gaps along the skeletal texture from head to tail and from trunk to fins, preserving the gill structure intact. Then, use tweezers to peel away the connective tissue between the gill filaments to fully expose the gill cartilage. For the remaining muscle embedded in the bone gaps at the tail, soak it again in 90°C hot water for 3 minutes, remove it, and continue to brush it. Finally, obtain a complete and unbroken manta ray cartilage skeleton.

[0015] 2. Bleaching: Rinse the cleaned cartilaginous skeleton of the ray with clean water 4 times to remove surface muscle debris and impurities. After draining the water, put it into an 8% hydrogen peroxide solution and let it stand at room temperature for 2 hours to bleach. During this period, gently turn it over once every 30 minutes to ensure even bleaching. After bleaching, take it out, rinse it with clean water, and drain the surface water.

[0016] 3. Dehydration: Place the bleached ray skeleton in a 70% medical ethanol solution for 2 hours to dehydrate it. Take it out and observe it every 40 minutes during this period. When the cartilage surface turns white evenly, feels non-slippery to the touch, and no liquid seeps out when pressed, take it out and drain the ethanol.

[0017] 4. Shaping: Prepare a rectangular plastic airtight container. Lay a 2.5cm thick layer of mixed desiccant at the bottom of the container. The mixed desiccant consists of 40g silica gel desiccant, 20g perlite, and 20g calcium chloride powder. Place the dehydrated ray skeleton into the container and adjust it to a natural swimming posture. Temporarily fix the fins and tail with thin wire. Slowly pour in the mixed desiccant to completely bury the skeleton. Gently tap the side of the container to fill the gaps between the skeleton and the gills with the desiccant. After smoothing the surface, cover it with a 0.8cm thick foam cushioning pad and weigh it down with a 300g weight (the ray skeleton weighs about 180g). Seal the container and place it in a cool, dry, and well-ventilated environment for 5 days to shape and dry.

[0018] 5. Specimen Processing: Open the container, pour out the mixed desiccant, remove the ray skeleton, brush off the desiccant powder adhering to the surface with a brush, and gently polish the small amount of muscle impurities remaining on the back and fins with a micro grinder at low speed. Then, using a 0.4mm diameter fine metal wire, precisely connect and fix the entire skeleton and pelvic girdle according to the physiological structure of the ray skeleton. Use a small amount of hot melt glue to reinforce the joints. Finally, a dried ray skeleton specimen with complete shape, uniform color, and no shrinkage or deformation is obtained, which can be directly used for biological teaching and display.

[0019] Example 2: Preparation of dried skeleton specimen of the sharp-nosed oblique-toothed shark 1. Material Processing: Select fresh sharp-snout sharks with a snout length of 30 cm. Rinse the body surface and abdominal cavity thoroughly with clean water, removing internal organs, epidermis, and muscle tissue. The pelvic girdle is processed separately and meticulously, separating attached muscles and fascia to avoid cartilage damage. The sharp-snout shark skeleton is heated in 90℃ hot water for 5 minutes, then removed and allowed to cool naturally to 30℃. Use a soft brush to clean the muscle tissue from the body surface and bone crevices, preserving the gills intact. Use tweezers to remove the connective tissue from the gills. For any tightly adhered residual muscle at the jawbone, soak it again in 90℃ hot water for 2 minutes to soften it, then thoroughly clean it with a brush, ensuring the skeleton remains intact and free of residual muscle.

[0020] 2. Bleaching: Rinse the cleaned sharp-nosed shark skeleton three times with clean water, then bleach it in a 10% hydrogen peroxide solution at room temperature for 2 hours, turning it regularly to ensure even bleaching. After bleaching, remove the skeleton, rinse it with clean water, and drain.

[0021] 3. Dehydration: Place the bleached shark skeleton in a 75% medical ethanol solution and dehydrate for 2 hours until the cartilage surface turns white and no longer feels slippery. Remove and drain the ethanol.

[0022] 4. Shaping: Select a glass sealed container of appropriate size, and lay a 3cm thick layer of desiccant (perlite) at the bottom of the container. Place the dehydrated sharp-nosed shark skeleton into the container, adjust it to a fin-spreading posture and temporarily fix it. Pour in the mixed desiccant to completely bury the skeleton, gently tap the container wall to make the desiccant fill evenly, level the surface, cover it with a silicone cushioning pad, and press it with a 500g weight (the sharp-nosed shark skeleton weighs about 280g). Seal the container and let it dry for 6 days.

[0023] 5. Specimen Processing: Pour out and recover the mixed desiccant, remove the skeleton of the sharp-nosed oblique-toothed shark, clean off the surface desiccant powder, remove residual impurities with a micro-grinding machine, connect and reinforce the various bone parts with fine metal wire, and complete the specimen preparation. The specimen is stable in posture, has an intact cartilage structure, shows no deformation or shrinkage, and has a uniform white color, meeting the high standards required for scientific research display and museum exhibition.

[0024] Example 3: Preparation of dried skeleton specimen of black-striped silver shark Material processing: Select individual black-striped silver sharks with a snout length of 25 cm. Rinse the body surface and abdominal cavity repeatedly with clean water to remove mud and sand. Open the abdomen to remove internal organs, digestive residue, and fascia, focusing on separating the pelvic girdle cartilage (which has no direct skeletal connection and requires meticulous dissection of muscles and connective tissue). Place the processed silver shark whole in hot water at 90℃±2℃ for 5 minutes, remove it and let it cool naturally to room temperature. Use a soft brush to clean the muscle tissue on the body surface and in the crevices along the skeletal texture, preserving the gill structure intact. For the tightly adhered residual muscles at the jawbone, soak for 2 minutes and continue brushing until a complete and unbroken cartilaginous skeleton is obtained.

[0025] Bleaching: Rinse the cleaned silver shark skeleton three times with clean water, put it into an 8% hydrogen peroxide solution, and let it stand at room temperature for 2 hours to bleach. During this time, turn it over every 30 minutes to ensure even bleaching. Once the skeleton surface is white and free of dark spots, take it out and drain it.

[0026] Dehydration: Place the bleached bones in a 70% medical ethanol solution and dehydrate for 2 hours, until the cartilage surface is uniformly white and no longer feels slippery to the touch. Then remove and drain.

[0027] Shaping: Use a sealed glass container. Lay a 2.5cm thick layer of mixed desiccant (silica gel: perlite: calcium chloride = 2:1:1) at the bottom. Place the dehydrated silver shark skeleton into the container, adjusting it to a natural swimming posture. Temporarily secure the fins and tail with thin metal wire. Slowly pour in the desiccant to completely bury the skeleton, gently tapping the sides of the container to fill any gaps and depressions. Cover the desiccant surface with a 0.8cm thick silicone cushioning pad, and weigh it down with a weight 1.8 times the mass of the skeleton (the silver shark skeleton weighs approximately 200g, corresponding to a 360g weight). Seal the container and place it in a cool, dry environment for 5 days to set and dry.

[0028] Specimen preparation: Open the container and pour out the desiccant. Use a soft brush to clean the surface powder. Use a micro grinder to gently grind away any remaining impurities at low speed. Finally, use a 0.4mm diameter fine metal wire to connect the head, shoulder straps, and waist belt. Use a small amount of AB glue to reinforce the connection points. This completes the preparation of the dried skeleton specimen of the black-lined silver shark.

[0029] Other notes The method described in this invention is not only applicable to the standardized preparation of complete skeletal specimens of cartilaginous fish, but can also be flexibly adapted to the preparation of dried specimens of other types of cartilaginous tissue. When used for the preparation of fish ocular bones, the bone connection step can be omitted, and the process can be directly carried out according to the material processing, bleaching, dehydration, shaping, and cleaning procedures. Only the ocular bones need to be separated separately, and the heating time can be adjusted to 3 minutes and the bleaching time to 1.5 hours to obtain a dried ocular bone specimen with a complete morphology. For cartilaginous tissues of reptiles (such as lizards and turtles) and mammals (such as mice and rabbits), the core process of this method can be referred to, and the heating time (2-5 minutes), reagent concentration (5%-8% hydrogen peroxide concentration, 60%-70% ethanol concentration), and desiccant dosage can be adjusted according to the size of the cartilage. At the same time, the shaping and drying time can be shortened to 3-4 days, all of which can achieve ideal dried specimen effects, and the specimens are morphologically stable and do not shrink or deform, which can meet the needs of different scenarios.

Claims

1. A method for preparing dried cartilaginous fish skeleton specimens, characterized in that, The process includes the following steps: Selecting fresh cartilaginous fish, rinsing them thoroughly with clean water, and then removing the internal organs, skin, and attached muscle tissue. The pelvic region of the cartilaginous fish, due to its relatively unconnected skeletal structure, requires separate and meticulous separation. After initial processing, the entire cartilaginous fish is placed in hot water at 90°C±2°C for 5-10 minutes to rapidly separate the muscle tissue from the cartilage. After removal, it is allowed to cool naturally at room temperature. Then, using a soft brush, the muscle tissue on the body surface and in the skeletal crevices is carefully brushed away along the skeletal texture, preserving the gill structure as much as possible. Finally, using pointed tweezers, the connective tissue and residual fascia at the gills are carefully peeled away, clearly exposing the white gill cartilage. If some muscle tissue remains tightly adhered and difficult to remove completely, the skeleton can be repeatedly soaked in hot water at 90°C±2°C for 2-3 minutes until the muscle is fully softened before continuing cleaning. Ensure the entire process is thorough. The cartilaginous skeleton is intact and without fractures or damage. Bleaching: Rinse the cartilaginous fish skeleton, from which all muscle tissue has been removed, repeatedly with clean water 3-4 times to remove surface impurities and tissue debris. Then immerse it in a 5%-10% hydrogen peroxide solution and let it stand at room temperature for about 2 hours until the skeleton surface is white and free of localized darkening. Dehydration: After rinsing, remove the bone and drain the hydrogen peroxide solution adhering to the surface. Immediately immerse it in a 60%-75% medical ethanol solution for gradient dehydration treatment. The dehydration time should be controlled at 2 hours. During the dehydration process, observe the cartilage condition regularly. When the cartilage surface turns uniformly white and feels non-slippery to the touch, the dehydration is considered complete. Shaping: Prepare a container that can completely contain the cartilage specimen and has good sealing performance. Pre-lay a desiccant layer at least 2 cm thick at the bottom of the container. The desiccant can be any one of silica gel desiccant, perlite, or calcium chloride powder. Carefully place the dehydrated cartilage into a container, adjust it to the preset display posture, and temporarily fix it. Then, slowly pour in the desiccant, ensuring that the desiccant completely buries the cartilage and all its attached structures. During pouring, gently tap the side of the container to ensure that the desiccant fully fills the gaps and depressions in the cartilage, while maintaining the cartilage's posture. After the desiccant surface is smoothed, place a suitable weight on top to apply even pressure to the cartilage and prevent deformation during the drying process. Seal the container and place it in a cool, dry environment for embedding and drying for at least 4 days, until the remaining moisture in the cartilage is completely absorbed by the desiccant. Specimen processing: Open the container and slowly pour out the desiccant, remove the cartilaginous skeleton, brush off the desiccant powder adhering to the surface with a soft brush, and then gently polish the remaining small amount of muscle tissue, fascia and impurities on the skeleton surface with a micro polisher. Control the polishing force and speed during polishing to avoid damaging the cartilage structure. Finally, use fine metal wire to precisely connect and fix the skeleton of each part, such as the head, trunk, tail, fins and pelvic girdle, according to the physiological structure characteristics of the cartilaginous fish skeleton, to form a complete dried cartilaginous fish skeleton specimen.

2. The manufacturing method according to claim 1, characterized in that, The cartilaginous fish is one or more of the following: ray, shark, etc., and the anal snout length of the cartilaginous fish is not less than 20 cm, ensuring that the skeleton of medium and large cartilaginous fish can be stably formed by this method without obvious shrinkage or deformation.

3. The manufacturing method according to claim 1, characterized in that, The desiccant can be any one of silica gel desiccant, perlite, or calcium chloride powder, or it can be a mixture of silica gel desiccant, perlite, and calcium chloride powder in a mass ratio of 2:1:

1. This ratio can balance water absorption efficiency and air permeability, so that it can quickly absorb moisture while avoiding local dampness that could lead to cartilage degeneration and deformation.

4. The manufacturing method according to claim 1, characterized in that, In the shaping step, the mass of the weight is 1.5-2 times the mass of the cartilage and bone, and the weight is indirectly pressed onto the surface of the desiccant through a buffer pad. The buffer pad is a foam pad or a silicone pad with a thickness of 0.5-1cm to avoid the weight directly contacting the cartilage and causing structural damage.

5. The manufacturing method according to claim 1, characterized in that, The method can also be applied to the preparation of dried specimens of ocular bone from bony fish, cartilage tissue from reptiles, and cartilage tissue from mammals. When applying this method, the heating time, reagent concentration, amount of desiccant, and setting time can be adjusted according to the size and structural characteristics of the cartilage.