Complex abnormality combinations between the scleritome and the sclerites of Chiton articulatus (Mollusca: Polyplacophora): new findings to the teratological classification

Publication date: Available online 26 January 2019Source: Zoologischer AnzeigerAuthor(s): Omar Hernando Avila-Poveda, Brenda Paola Ramirez-Santana, Pedro Martinez-Diaz, Jorge Saul Ramirez-Perez, Nancy C. Saavedra-Sotelo, Bibiana Vargas-Trejo, Carlos Alberto Amezcua-Gomez, Carlos Melendez-GaliciaAbstractTeratological diagnosis in polyplacophorans has mostly been based on primary structure (Chiton scleritome) with four types (hypermerism, hypomerism, coalescence and splitting), including some deformities in plates; however, diagnoses are hardly detailed for each sclerite. As part of a monthly research campaign conducted by a year investigating Chiton articulatus, we found several cases with a complex combination of abnormalities (chiton scleritome + sclerites) that complement the previous classification. Identification and diagnosis of abnormalities were assigned in terms of sclerite number, number of slits per side in the insertion area of intermediate sclerites and the merging grade between sclerites. Slit and slit-ray numbers were baseline to identify combination of abnormalities; the slit formula of Chiton articulatus is 13-18[I]/1[II-VII]/16-22[VIII]. We found four abnormality cases with combinations among them: a) perfect hypomerism, b) heterogeneous coalescence, c) homogeneous coalescence, d) imperfect hypermerism. Heterogeneous coalescence was most common abnormality, with a different merging degree between sclerites and with specimens showing combinations of abnormal s...

Source: A Journal of Comparative Zoology - January 26, 2019 Category: Zoology Source Type: research