TY - JOUR

T1 - Structure of sperm, spermatozeugmata and 'lateral organs' in the bivalve Arthritica (Galeommatoidea: Leptonidae)

AU - Jespersen, Åse

AU - Lützen, Jørgen

N1 - KEYWORDS Arthritica • reproduction • sperm structure • spermatozeugmata • sperm storage • lateral organs

PY - 2009

Y1 - 2009

N2 - The position and structure of paired 'lateral organs' in the foot of Arthritica semen and Arthritica bifurca might indicate a chemosensory function. In both species part of the organ is also glandular. In A. semen the glandular epithelium is detached piecemeal and, probably by means of the foot, is moved to and grafted upon the gills of the same individual. The transferred epithelia appear as disk-shaped actively secretory 'gill bodies' which, attached to the abfrontal side of the inner demibranch, replace the ordinary unciliated gill epithelium. The secretion is liberated into the suprabranchial chamber, which serves as a marsupium, but its function is uncertain. Arthritica semen is a protandric hermaphrodite and produces very large ova that undergo a direct development that results in a non-planktonic lecithotrophic crawling juvenile stage. The sperm cells have filiform nuclei that are straight in the euspermatozoa and more or less helicoidal in what is considered to represent paraspermatozoa. By a process of aggregation, spermatozeugmata are formed which consist exclusively either of euspermatozoa or paraspermatozoa. Spermatozoa are stored in the oviduct in A. semen but in paired seminal receptacles in A. bifurca.

AB - The position and structure of paired 'lateral organs' in the foot of Arthritica semen and Arthritica bifurca might indicate a chemosensory function. In both species part of the organ is also glandular. In A. semen the glandular epithelium is detached piecemeal and, probably by means of the foot, is moved to and grafted upon the gills of the same individual. The transferred epithelia appear as disk-shaped actively secretory 'gill bodies' which, attached to the abfrontal side of the inner demibranch, replace the ordinary unciliated gill epithelium. The secretion is liberated into the suprabranchial chamber, which serves as a marsupium, but its function is uncertain. Arthritica semen is a protandric hermaphrodite and produces very large ova that undergo a direct development that results in a non-planktonic lecithotrophic crawling juvenile stage. The sperm cells have filiform nuclei that are straight in the euspermatozoa and more or less helicoidal in what is considered to represent paraspermatozoa. By a process of aggregation, spermatozeugmata are formed which consist exclusively either of euspermatozoa or paraspermatozoa. Spermatozoa are stored in the oviduct in A. semen but in paired seminal receptacles in A. bifurca.

U2 - 10.1111/j.1463-6395.2008.00332.x

DO - 10.1111/j.1463-6395.2008.00332.x

M3 - Journal article

VL - 90

SP - 51

EP - 67

JO - Acta Zoologica

JF - Acta Zoologica

SN - 0001-7272

IS - 1

ER -