Please use this identifier to cite or link to this item:
https://www.arca.fiocruz.br/handle/icict/43411
Type
ArticleCopyright
Open access
Collections
- IOC - Artigos de Periódicos [12642]
Metadata
Show full item record
BIOMPHALARIA OBSTRUCTA (MORELET, 1849): A STUDY OF TOPOTYPIC SPECIMENS (MOLLUSCA: PULMONATA: PLANORBIDAE)
Planorbidae
Planorbis orbiculus
Mollusca
Planorbis retusus
México
Taxonomia
Planorbidae
Mollusca
Planorbis orbiculus
Planorbis retusus
Mexico
Taxonomy
Paraense, W. Lobato | Date Issued:
1990
Author
Affilliation
Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Departamento de Malacologia. Rio de Janeiro, RJ, Brasil.
Abstract
A description of Biomphalaria obstructa (Morelet, 1849), based on specimens collected at its type locality - isla del carmen, state of Campeche, Mexico - is presented. The Shell is small, 13 mm in diameter, 3.5 mm in width and with 5.75 whorls in the largest specimen, thin, moderately lustrous and translucent, horn-colored. Whorls increasing regularly (neither slowly nor rapidly) in diameter, rounded on the periphery side, bluntly angular on the left. Suture well-marked, deeper on the left. Right side widely concave, with first whorl deeply situated and partly hidden by the next. Left side shallower than right one, largely flattened, with first whorl plaintly visible. Aperture roundly heart-shaped, usually in the same plane as the body whorl but somewhat deflected to the left (less frequently to the right) in some specimens. Peristome sharp, seldom blunt; a distinct callus on the parietal wall. A number of young shells develop one set (seldom more) of apertural lamellae which tend to be resorbed as the shell grows. Absence of renal ridge. Ovotestis with about 70 mostly unbrached diverticula. Seminal vesicle beset with well-developed knoblike to fingerlike diverticula. Vaginal pouch more or less developed. Spermatheca club-shaped when empty, egg-shaped when full, and with intermediate forms between those extremes. Spermathecal body usually somewhat longer than the duct. Prostate with 7 to 20 (mean 12.06 ± 2.51) usually short diverticula which give off plumpish branches spreading out in a fan shape and overlapping to some extent their immediate neighbors. Foremost prostatic diverticulum nearly always partially or completely inserted between the spermathecal body and the uterine wall. Penial sheath consistently narrower and shorter than the prepuce. Muscular coat of the penis consisting of an inner longitudinal and an outer circular layers. Ratios between organ lengths: caudal to cephalic parts of female duct = 0.55 to 1.37 (mean 0.85 +- 0.17); cephalic parte of female duct to penial complex = 1.36 to 2.81 ((mean 1.90 +- 0.33); penial sheath to prepuce = 042 to 0.96 (mean 0.67 +- 0.13). Comparison with Morelet s type specimens of Planorbis orbiculus and P. retusus points to the identity of those nominal species with B. obstructa.
Keywords in Portuguese
Biomphalaria obstructaPlanorbidae
Planorbis orbiculus
Mollusca
Planorbis retusus
México
Taxonomia
Keywords
Biomphalaria obstructaPlanorbidae
Mollusca
Planorbis orbiculus
Planorbis retusus
Mexico
Taxonomy
Share