{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,24]],"date-time":"2026-07-24T10:04:05Z","timestamp":1784887445872,"version":"3.55.0"},"reference-count":44,"publisher":"Wiley","issue":"1","license":[{"start":{"date-parts":[[2026,3,18]],"date-time":"2026-03-18T00:00:00Z","timestamp":1773792000000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2026,3,18]],"date-time":"2026-03-18T00:00:00Z","timestamp":1773792000000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/doi.wiley.com\/10.1002\/tdm_license_1.1"}],"funder":[{"DOI":"10.13039\/501100002322","name":"Coordena\u00e7\u00e3o de Aperfei\u00e7oamento de Pessoal de N\u00edvel Superior","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100002322","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Journal of Fish Biology"],"published-print":{"date-parts":[[2026,7]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>\n                    Reports of teratogenic embryos in elasmobranchs have been documented in multiple species, with proposed aetiologies including environmental disturbances, genetic mutations, predation, exposure to endocrine\u2010disrupting compounds and maternal stress. Nevertheless, complex congenital malformations such as bicephaly remain exceptionally rare, particularly among freshwater stingrays of the family Potamotrygonidae. The present study constitutes the first record of bicephaly in the genus\n                    <jats:italic>Potamotrygon<\/jats:italic>\n                    , documenting multiple congenital anomalies in two embryos from a single litter. One female embryo exhibited incomplete fusion of the anterior margin of the right pectoral fin, a malformation previously reported in batoid fishes. The second case involved a male parapagus bicephalic twin; internal examination demonstrated duplicated brains and hearts, as well as partially individualized gastrointestinal tracts, whereas the reproductive and urinary systems were shared. Skeletal assessment revealed discrete chondrocrania and precaudal vertebrae, with spinal fusion occurring at the transitional caudal region. The underlying causes of these anomalies remain unresolved. Two primary hypotheses are discussed: (1) genetic alterations, including misexpression of critical developmental regulators such as Sonic hedgehog (Shh), which has been implicated in cephalic duplication and fin malformations; and (2) maternal physiological stress, potentially linked to anthropogenic factors such as recurrent capture events, which may disrupt embryogenesis. This report broadens the spectrum of known teratological conditions in freshwater elasmobranchs and underscores the importance of further research into the mechanistic basis of congenital anomalies in this group.\n                  <\/jats:p>","DOI":"10.1111\/jfb.70394","type":"journal-article","created":{"date-parts":[[2026,3,18]],"date-time":"2026-03-18T10:07:03Z","timestamp":1773828423000},"page":"257-263","update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Occurrence of multiple congenital anomalies in\n                    <i>Potamotrygon amandae<\/i>\n                    (Elasmobranchii, Potamotrygoninae) embryos, including the first report of bicephaly"],"prefix":"10.1111","volume":"109","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-1455-0014","authenticated-orcid":false,"given":"Douglas","family":"de Castro Ribeiro","sequence":"first","affiliation":[{"name":"UNESP, Universidade Estadual Paulista Departamento de Biologia e Zootecnia, Laborat\u00f3rio de Paleontologia e Evolu\u00e7\u00e3o de Ilha Solteira  Ilha Solteira Brazil"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0002-2071-0758","authenticated-orcid":false,"given":"Raquel Lopes","family":"Queiroz","sequence":"additional","affiliation":[{"name":"UNESP, Universidade Estadual Paulista Departamento de Biologia e Zootecnia, Laborat\u00f3rio de Estudos em Fisiologia Animal  Ilha Solteira Brazil"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4382-9575","authenticated-orcid":false,"given":"Cristi\u00e9le","family":"da Silva Ribeiro","sequence":"additional","affiliation":[{"name":"UNESP, Universidade Estadual Paulista Departamento de Biologia e Zootecnia, Laborat\u00f3rio de Estudos em Fisiologia Animal  Ilha Solteira Brazil"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2026,3,18]]},"reference":[{"key":"e_1_2_10_2_1","doi-asserted-by":"publisher","DOI":"10.1677\/joe.0.1380275"},{"key":"e_1_2_10_3_1","first-page":"357","article-title":"Morphological abnormality in a diamond stingray, Dasyatis dipterura (Jordan & Gilbert, 1880) (Chondrichthyes: Dasyatidae), from the Gulf of California, Mexico","volume":"52","author":"Blanco\u2010Parra M. P.","year":"2011","journal-title":"Cahiers de Biologie Marine"},{"key":"e_1_2_10_4_1","doi-asserted-by":"publisher","DOI":"10.1017\/S1755267209000414"},{"key":"e_1_2_10_5_1","doi-asserted-by":"publisher","DOI":"10.1017\/S0025315422000996"},{"key":"e_1_2_10_6_1","doi-asserted-by":"publisher","DOI":"10.1590\/S1679-87592015082206304"},{"key":"e_1_2_10_7_1","doi-asserted-by":"publisher","DOI":"10.1206\/0003-0090(2004)284<0001:FSOTGR>2.0.CO;2"},{"key":"e_1_2_10_8_1","first-page":"45","article-title":"Malformaciones en la raya \u00e1guila chilena Myliobatis chilensis (Myliobatidae): implicancias para el desarrollo y la movilidad","volume":"27","author":"C\u00e9spedes C.","year":"2023","journal-title":"Scientific Cultura"},{"key":"e_1_2_10_9_1","doi-asserted-by":"publisher","DOI":"10.2960\/J.v35.m502"},{"key":"e_1_2_10_10_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1095-8649.2010.02890.x"},{"key":"e_1_2_10_11_1","doi-asserted-by":"publisher","DOI":"10.3109\/10520297709116780"},{"key":"e_1_2_10_12_1","doi-asserted-by":"publisher","DOI":"10.1111\/jfb.14799"},{"key":"e_1_2_10_13_1","doi-asserted-by":"publisher","DOI":"10.1017\/S1755267210001120"},{"key":"e_1_2_10_14_1","unstructured":"Gama C. S.(2013).Diversidade e ecologia das arraias de \u00e1gua doce (Chondrichthyes: Potamotrygonidae) da reserva biol\u00f3gica do Parazinho (Doctoral thesis Universidade Federal da Para\u00edba Brazil)."},{"key":"e_1_2_10_15_1","doi-asserted-by":"publisher","DOI":"10.1590\/S1676-06032007000100023"},{"key":"e_1_2_10_16_1","volume-title":"Nomina Anatomica Veterinaria","author":"Gasse H.","year":"2017"},{"key":"e_1_2_10_17_1","first-page":"157","article-title":"Four dicephalous specimens of blue shark, Prionace glauca, from Japan","volume":"28","author":"Goto M.","year":"1981","journal-title":"Japanese Journal of Ichthyology"},{"key":"e_1_2_10_18_1","doi-asserted-by":"publisher","DOI":"10.1071\/MF13198"},{"key":"e_1_2_10_19_1","first-page":"509","article-title":"Record of a diprosopus monster of blue shark (Prionace glauca) from Chile","volume":"29","author":"Hevia\u2010Hormaz\u00e1bal V.","year":"2011","journal-title":"International Journal of Morphology"},{"key":"e_1_2_10_20_1","doi-asserted-by":"publisher","DOI":"10.3856\/vol48-issue1-fulltext-2317"},{"key":"e_1_2_10_21_1","doi-asserted-by":"publisher","DOI":"10.1590\/S1676-06032007000300020"},{"key":"e_1_2_10_22_1","first-page":"1","article-title":"Morphological, craniodental, and molecular characterization of Platyrrhinus guianensis (Chiroptera, Phyllostomidae) and second record for Brazil","volume":"114","author":"Lima A. C. S.","year":"2024","journal-title":"Serie Zoologia"},{"key":"e_1_2_10_23_1","doi-asserted-by":"publisher","DOI":"10.1590\/S1679-62252013000400001"},{"key":"e_1_2_10_24_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.repbio.2012.09.001"},{"key":"e_1_2_10_25_1","doi-asserted-by":"publisher","DOI":"10.53499\/sfjeasv1n4-003"},{"key":"e_1_2_10_26_1","doi-asserted-by":"publisher","DOI":"10.1007\/s11356-021-12546-0"},{"key":"e_1_2_10_27_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1095-8649.2006.01238.x"},{"key":"e_1_2_10_28_1","doi-asserted-by":"publisher","DOI":"10.1002\/(SICI)1097-4687(199810)238:1<1::AID-JMOR1>3.0.CO;2-D"},{"key":"e_1_2_10_29_1","doi-asserted-by":"publisher","DOI":"10.3856\/vol39-issue1-fulltext-19"},{"key":"e_1_2_10_30_1","doi-asserted-by":"publisher","DOI":"10.1111\/jfb.12102"},{"key":"e_1_2_10_31_1","unstructured":"Oldfield R. 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