TY - JOUR

T1 - The structure of the muscular and nervous systems of the female Intoshia linei (Orthonectida)

AU - Slyusarev, G.S.

AU - Starunov, V.V.

PY - 2016

Y1 - 2016

N2 - The systematic position of the Orthonectida remains enigmatic. According to a classical point of view, they are placed together with Dicyemida in the phylum Mesozoa. Traditionally, orthonectids are regarded as rather primitive organisms, lacking digestive, muscular, and nervous systems. Here, using confocal laser scanning microscopy (CLSM) and immunohistochemical methods, we describe the musculature and serotoninergic nervous system of female adults of Intoshia linei (Orthonectida). The whole muscular system consists of 4 longitudinal and 9–11 circular muscle cells. The general muscular topography corresponds to the typical pattern for small-sized annelids or flatworms. Immunohistochemistry reveals six serotonin-like cells, which form part of a small nervous system comprising only 10–12 total cells based on nuclear counts. This is the first finding of a serotoninergic nervous system in orthonectids. Our analysis of muscular and neural organization in Orthonectida reveals significant differences from Diciemyda and aligns it more closely with the Lophotrochozoa.

AB - The systematic position of the Orthonectida remains enigmatic. According to a classical point of view, they are placed together with Dicyemida in the phylum Mesozoa. Traditionally, orthonectids are regarded as rather primitive organisms, lacking digestive, muscular, and nervous systems. Here, using confocal laser scanning microscopy (CLSM) and immunohistochemical methods, we describe the musculature and serotoninergic nervous system of female adults of Intoshia linei (Orthonectida). The whole muscular system consists of 4 longitudinal and 9–11 circular muscle cells. The general muscular topography corresponds to the typical pattern for small-sized annelids or flatworms. Immunohistochemistry reveals six serotonin-like cells, which form part of a small nervous system comprising only 10–12 total cells based on nuclear counts. This is the first finding of a serotoninergic nervous system in orthonectids. Our analysis of muscular and neural organization in Orthonectida reveals significant differences from Diciemyda and aligns it more closely with the Lophotrochozoa.

KW - Mesozoa

KW - Orthonectida

KW - muscular system

KW - nervous system

KW - confocal microscopy

KW - immunohistochemistry

U2 - 10.1007/s13127-015-0246-2

DO - 10.1007/s13127-015-0246-2

M3 - Article

VL - 16

SP - 65

EP - 71

JO - Organisms Diversity and Evolution

JF - Organisms Diversity and Evolution

SN - 1439-6092

IS - 1

ER -