{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,31]],"date-time":"2026-07-31T01:01:06Z","timestamp":1785459666307,"version":"3.56.0"},"reference-count":50,"publisher":"Wiley","issue":"3","license":[{"start":{"date-parts":[[2026,3,16]],"date-time":"2026-03-16T00:00:00Z","timestamp":1773619200000},"content-version":"vor","delay-in-days":15,"URL":"http:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/"},{"start":{"date-parts":[[2026,3,1]],"date-time":"2026-03-01T00:00:00Z","timestamp":1772323200000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/doi.wiley.com\/10.1002\/tdm_license_1.1"}],"content-domain":{"domain":["onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Journal of Morphology"],"published-print":{"date-parts":[[2026,3]]},"abstract":"<jats:title>ABSTRACT<\/jats:title>\n                  <jats:p>\n                    The axolotl (\n                    <jats:italic>Ambystoma mexicanum<\/jats:italic>\n                    ) is an endemic amphibian of the order Urodela, which has the ability to reproduce while retaining its larval characteristics. The primary objective of this study was to outline the stages of gonadal development leading to sexual maturity. Gonads from both male and female larvae, aged 4\u201312 months, were histologically processed and characterized according to their developmental stage. Histological analysis of the ovaries revealed that larvae aged 4\u20138 months were immature. At 9 and 10 months, the oocytes showed early signs of maturity, characterized by an increase in volume, yolk accumulation, and the presence of cortical pigment at one cellular pole. At 12 months, mature oocytes are predominant, as indicated by a significant increase in size and the migration of the germinal vesicle toward the pigmented animal pole. Male larvae have immature gonads at 4\u20135 months of age. By 7 to 8 months, the beginning of the spermatogenic process is evident, regionalizing the testis in a cephalocaudal and lateromedial direction. In 9\u2010month\u2010old males, the spermiation process begins, becoming dominant by 10 months. In 12\u2010month\u2010old males, a clear regionalization of the testis is evident; while spermiation continues in the caudal and medial regions, spermatogenesis restarts in the more cephalic and dorsal areas. This early and accelerated gametogenesis in males signifies a gonadal maturity that occurs sooner than in females, which reflects a process of heterochrony. The relatively early attainment of sexual maturity for both sexes, a direct result of their paedomorphic condition, is an advantageous adaptive strategy.\n                  <\/jats:p>","DOI":"10.1002\/jmor.70118","type":"journal-article","created":{"date-parts":[[2026,3,16]],"date-time":"2026-03-16T08:05:32Z","timestamp":1773648332000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Gonadal Development in Larvae of the Paedomorphic\n                    <i>Ambystoma mexicanum<\/i>\n                    (Amphibia: Urodela)"],"prefix":"10.1002","volume":"287","author":[{"given":"Jessica Luc\u00eda","family":"S\u00e1nchez\u2010Ortiz","sequence":"first","affiliation":[{"name":"Laboratorio de Biolog\u00eda Tisular y Reproductora, Departamento de Biolog\u00eda Comparada, Facultad de Ciencias Universidad Nacional Aut\u00f3noma de M\u00e9xico M\u00e9xico City M\u00e9xico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0005-9063-8394","authenticated-orcid":false,"given":"Eva","family":"Mendoza\u2010Cruz","sequence":"additional","affiliation":[{"name":"Laboratorio de Biolog\u00eda Tisular y Reproductora, Departamento de Biolog\u00eda Comparada, Facultad de Ciencias Universidad Nacional Aut\u00f3noma de M\u00e9xico M\u00e9xico City M\u00e9xico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3538-8709","authenticated-orcid":false,"given":"Maricela","family":"Villagr\u00e1n\u2010SantaCruz","sequence":"additional","affiliation":[{"name":"Laboratorio de Biolog\u00eda Tisular y Reproductora, Departamento de Biolog\u00eda Comparada, Facultad de Ciencias Universidad Nacional Aut\u00f3noma de M\u00e9xico M\u00e9xico City M\u00e9xico"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2026,3,16]]},"reference":[{"key":"e_1_2_10_2_1","doi-asserted-by":"publisher","DOI":"10.1655\/06-005.1"},{"key":"e_1_2_10_3_1","first-page":"25","volume-title":"Developmental Biology of the Axolotl","author":"Armstrong J. 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