Species

accounts

No common name

Rhopalura ophiocomae

FAMILY Rhopaluridae

TAXONOMY

Rhopalura ophiocomae Giard, 1877, Wimereux, France.

OTHER COMMON NAMES None known.

PHYSICAL CHARACTERISTICS

Reaches length of 0.01 in (260 pm) in females, 0.005 in (130 pm) in males. This genus is characterized by sexual dimorphism, the demarcation of the body into regions being much sharper in males than in females. Males possess conspicuous crystalline inclusions in some epidermal cells. In females, the numerous oocytes form a compact mass that occupies most of the body; in males, the sperm mass is located in the middle third of the body.

DISTRIBUTION

Widely distributed. The usual host species, Amphipholis squa-mata, occurs off the coasts of France, Great Britain, and Italy, and Washington and California in the United States.

HABITAT

The perivisceral coelom are closely associated with the walls of the genital bursae or the gut of a parasitized brittle star.

BEHAVIOR

Generally swims by a spiraling motion.

FEEDING ECOLOGY AND DIET

May absorb nutrients in the host cytoplasm.

REPRODUCTIVE BIOLOGY

In males, the genital pore is located between epidermal rings 12 and 14; in females, in ring 19. The male and female may bring their genital pores together long enough for sperm transfer to be effected.

CONSERVATION STATUS

Not listed by the IUCN.

SIGNIFICANCE TO HUMANS None known. ♦

No common name

Ciliocincta sabellariae

FAMILY

Rhopaluridae

TAXONOMY

Ciliocincta sabellariae Kozloff, 1965, San Juan Archipelago, Washington, United States.

OTHER COMMON NAMES None known.

PHYSICAL CHARACTERISTICS

Body length of females up to 0.01 in (270 pm); usually 38 or 39 rings of epidermal cells. Males up to 0.005 in (130 pm); usually 30 rings of epidermal cells. This genus is characterized by slight sexual dimorphism. Males are smaller than females, but the arrangement of epidermal cells and the pattern of cilia-tion are similar in both sexes. Males have no crystalline inclusions in epidermal cells comparable to those of male Rhopalura. In females, oocytes are in a single series.

DISTRIBUTION

The host is the sabellid polychaete Sabellaria cementarium, which occurs in the San Juan Archipelago, off the coast of the state of Washington, in the United States.

HABITAT

Epidermal tissues of the body wall and dorsal cirri of the parasitized polychaete.

BEHAVIOR

Generally swims in a spiral motion.

FEEDING ECOLOGY AND DIET

May absorb nutrients in the host cytoplasm.

REPRODUCTIVE BIOLOGY

In males, the genital pore is located in the boundary between epidermal rings 15 and 16; in females, in ring 14. The male and female may bring their genital pores together long enough for sperm transfer to be effected.

CONSERVATION STATUS Not listed by the IUCN.

SIGNIFICANCE TO HUMANS None known. ♦

No common name

Intoshia linei

FAMILY

Rhopaluridae

TAXONOMY

Intoshia linei Giard, 1877, Wimereux, France.

OTHER COMMON NAMES

None known.

PHYSICAL CHARACTERISTICS

Body length up to 0.006 in (160 pm); usually 24 rings of epidermal cells. In males, the body of the largest individual is not over 0.0016 in (41 pm) in length. In this genus, more than half the rings of epidermal cells are completely ciliated; the rest lack cilia. Sexual dimorphism usually occurs. Males are much smaller than females, are ovoid, and have two genital pores. Males have no crystalline inclusions in epidermal cells compa

I Intoshia linei I Rhoparula ophiocomae I Ciliocincta sabellariae rable to those in male Rhopalura. In females, the oocytes fill most of the axial mass, and are packed together so they seem to form two or three rows.

DISTRIBUTION

The hosts are the nemerteans Lineus viridus, L. sanguineus, and L. rubber, which occur on the English Channel coast of France at Wimereux and Roscoff.

HABITAT

Tissues of a parasitized nemertean. BEHAVIOR

Generally swims in a spiraling motion.

FEEDING ECOLOGY AND DIET

May absorb nutrients in the host cytoplasm.

REPRODUCTIVE BIOLOGY

In males, there are two genital pores, located in epidural rings 8 and 16; in females, in ring 12. The male and female may bring their genital pores together long enough for sperm transfer to be effected.

CONSERVATION STATUS Not listed by the IUCN.

SIGNIFICANCE TO HUMANS None known. ♦

Resources Books

Kozloff, Eugene N. "Phyla Placozoa, Dicyemida, and Orthonectida." In Invertebrates. Philadelphia: Saunders College Publishing, 1990.

Periodical

Kozloff, Eugene N. "The Genera of the Phylum Orthonectida." Cahiers de Biologie Marine 33 (1992): 377-406.

Pawlowski, J., J. Montoya-Burgos, J. F. Fahrni, J. Wuest, and L. Zaninetti. "Origin of the Mesozoa Inferred from 18S rRNA Gene Sequences." Molecular Biology and Evolution 13 (1996): 1128-1132.

Hidetaka Furuya, PhD

Phylum Cnidaria Class Anthozoa Number of families 130

Thumbnail description

Exclusively polypoid cnidarians. Tubular body with hollow tentacles around the mouth; has a pharynx that opens into a digestive cavity subdivided by infoldings of the gut wall. May be solitary or colonial, with or without an internal or external skeleton.

Photo: Jeweled anenome (Corynactis californica) (©Shedd Aquarium. Photo by Patrice Ceisel. Reproduced by permission.)

Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

Get My Free Ebook


Post a comment