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核心技术专利：CN118964589B侵权必究

核心技术专利：CN118964589B侵权必究

Thorson T B, Wotton R M, Georgi T A

School of Life Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska 68588.

Biol Bull. 1978 Jun;154(3):508-16. doi: 10.2307/1541076.

Contrary to some reports, a rectal gland is present in strictly freshwater stingrays of South American rivers (Potamotrygon spp.). 2. The gland has the location and histological features of the salt-secreting rectal gland of marine elasmobranchs, but is much reduced in size and number of tubules. 3. Its residual function, if any, is unknown. 4. The rectal gland is associated with prominent myeloid lobes, here designated as rectomyeloid bodies. 5. In the absence of potamotrygonid fossils, the atrophied rectal gland is strong evidence of marine ancestry for the freshwater rays. 6. Both the reduced gland and the loss of urea retention in potamotrygonids are indicative of a long history of freshwater adaptation.

与一些报道相反，南美洲河流中的严格淡水魟（Potamotrygon属）存在直肠腺。2. 该腺体具有海洋软骨鱼类分泌盐分的直肠腺的位置和组织学特征，但在大小和小管数量上大大减少。3. 其残余功能（如果有的话）尚不清楚。4. 直肠腺与突出的髓叶相关，此处称为直肠髓体。5. 在没有淡水魟化石的情况下，萎缩的直肠腺是淡水魟海洋起源的有力证据。6. 淡水魟中缩小的腺体和尿素保留能力的丧失都表明其有长期适应淡水环境的历史。

Thorson T B, Wotton R M, Georgi T A

School of Life Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska 68588.

Biol Bull. 1978 Jun;154(3):508-16. doi: 10.2307/1541076.

Contrary to some reports, a rectal gland is present in strictly freshwater stingrays of South American rivers (Potamotrygon spp.). 2. The gland has the location and histological features of the salt-secreting rectal gland of marine elasmobranchs, but is much reduced in size and number of tubules. 3. Its residual function, if any, is unknown. 4. The rectal gland is associated with prominent myeloid lobes, here designated as rectomyeloid bodies. 5. In the absence of potamotrygonid fossils, the atrophied rectal gland is strong evidence of marine ancestry for the freshwater rays. 6. Both the reduced gland and the loss of urea retention in potamotrygonids are indicative of a long history of freshwater adaptation.

与一些报道相反，南美洲河流中的严格淡水魟（Potamotrygon属）存在直肠腺。2. 该腺体具有海洋软骨鱼类分泌盐分的直肠腺的位置和组织学特征，但在大小和小管数量上大大减少。3. 其残余功能（如果有的话）尚不清楚。4. 直肠腺与突出的髓叶相关，此处称为直肠髓体。5. 在没有淡水魟化石的情况下，萎缩的直肠腺是淡水魟海洋起源的有力证据。6. 淡水魟中缩小的腺体和尿素保留能力的丧失都表明其有长期适应淡水环境的历史。