Overview

Brief Summary

Living Material

This small orange-red flatworm is characterized by one or more filamentous tails between its two caudal lobes. It was formerly common on Ulva in Little Harbor at Woods Hole, and on the mud flats of Hadley Harbor (Mark, 1892). It disappeared from the Woods Hole region with the eel grass, but has since been found near the breakwater at Provincetown. A close relative, Polychoerus carmelensis, has been found in enormous numbers at Carmel Bay, on the coast of California (D. P. Costello and H. M. Costello, 1938).

  • Bresslau, E., 1933. Turbellaria. Kükenthal-Krumbach Handbuch der Zoologie, Bd. 2.
  • Costello, D. P., 1937. The early cleavage of Polychoerus carmelensis. Anat. Rec., 70: Suppl.1, 108-109.
  • Costello, D. P., 1946. The giant cleavage spindle of the egg of Polychoerus carmelensis Anat. Rec., 96: 561.
  • Costello, D. P., 1948. Spiral cleavage. Biol. Bull., 95: 265. (See, also, Erratum, Biol. Bull., 95: 361.).
  • Costello, D. P., and H. M. Costello, 1938. A new species of Polychoerus from the Pacific Coast. Ann. and Mag. Nat. Hist., ser. 11, 1: 148-155.
  • Costello, H. M., and D. P. Costello, 1938. Copulation in the acoelous turbellarian Polychoerus carmelensis. Biol. Bull., 75: 85-98.
  • Costello, H. M., and D. P. Costello, 1939. Egg laying in the acoelous turbellarian Polychoerus carmelensis. Biol. Bull., 76: 80-89.
  • Gardiner, E. G., 1895. Early development of Polychoerus caudatus, Mark. J. Morph., 11: 155-176.
  • Gardiner, E. G., 1898. The growth of the ovum, formation of the polar bodies, and the fertilization in Polychoerus caudatus. J. Morph., 15: 73-110.
  • Löhner L., 1910. Untersuchungen über Polychoerus caudatus Mark. Zeikchr. f. w1ss. Zool., 95: 451-506.
  • Mark, E. L., 1892. Polychoerus caudatus, nov. gen. et nov. spec. Festschr. z. 70. Geburtstage R. Leuckarts. Leipzig. S. 298-309.
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Source: Egg Characteristics and Breeding Season for Woods Hole Species

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Distribution

Range covers both subprovinces of Acadian and Virginian.
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Source: World Register of Marine Species

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Woods Hole,Cape Cod, Massachusetts, USA
Collection date: between May and Aug 1907
Comments: numerous in the Ulven (Ulva) of Little Harbor, and the sea grass on the hotel breakwater.

Center (Centre, Hog) Island, New York, USA
Collection date: between May and Aug 1907
Comments: underside of mussel shells and smooth rocks.

Cold Spring Harbor, New York, USA
Collection date: between May and Aug 1907
Comments: underside of mussel shells and smooth rocks.

Woods Hole,Cape Cod, Massachusetts, USA
Collection date: 1965 or earlier
Comments: common in the Woods Hole region and regulary taken both in dredgings and on Ulva from piling and rocks. Bush notes in 1965 that it had not been reported recently.

inside Lockwoods Folly Inlet, Oak Island, North Carolina, USA
Collection date: Oct 2002
Depth: shallow subtidal
Substrate: medium grained sand

"Gutter" between Buzzards (Buzzard's) Bay and Hadley Harbor, near Woods Hole, Massachusetts, USA
Collection date: summer 1889
Kind: default type
Comments: collected "Gutter" which connects Buzzard's Bay with Hadley Harbor.
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© National Science Foundation - Turbellarian Taxonomic Database

Source: Turbellarian Taxonomic Database

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Ecology

Habitat

coastal, also on algae
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Source: World Register of Marine Species

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Depth range based on 3 specimens in 1 taxon.

Environmental ranges
  Depth range (m): 0 - 0
 
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.

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Life History and Behavior

Life Cycle

Later Stages of Development

Polychoerus has a direct development, and the embryo, when hatched from the egg mass, is a small worm with eyespots, and with typical caudal lobes.

  • Bresslau, E., 1933. Turbellaria. Kükenthal-Krumbach Handbuch der Zoologie, Bd. 2.
  • Costello, D. P., 1937. The early cleavage of Polychoerus carmelensis. Anat. Rec., 70: Suppl.1, 108-109.
  • Costello, D. P., 1946. The giant cleavage spindle of the egg of Polychoerus carmelensis Anat. Rec., 96: 561.
  • Costello, D. P., 1948. Spiral cleavage. Biol. Bull., 95: 265. (See, also, Erratum, Biol. Bull., 95: 361.).
  • Costello, D. P., and H. M. Costello, 1938. A new species of Polychoerus from the Pacific Coast. Ann. and Mag. Nat. Hist., ser. 11, 1: 148-155.
  • Costello, H. M., and D. P. Costello, 1938. Copulation in the acoelous turbellarian Polychoerus carmelensis. Biol. Bull., 75: 85-98.
  • Costello, H. M., and D. P. Costello, 1939. Egg laying in the acoelous turbellarian Polychoerus carmelensis. Biol. Bull., 76: 80-89.
  • Gardiner, E. G., 1895. Early development of Polychoerus caudatus, Mark. J. Morph., 11: 155-176.
  • Gardiner, E. G., 1898. The growth of the ovum, formation of the polar bodies, and the fertilization in Polychoerus caudatus. J. Morph., 15: 73-110.
  • Löhner L., 1910. Untersuchungen über Polychoerus caudatus Mark. Zeikchr. f. w1ss. Zool., 95: 451-506.
  • Mark, E. L., 1892. Polychoerus caudatus, nov. gen. et nov. spec. Festschr. z. 70. Geburtstage R. Leuckarts. Leipzig. S. 298-309.
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Source: Egg Characteristics and Breeding Season for Woods Hole Species

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Egg Characteristics

The eggs originate in the eilager, which is situated just behind the statocyst. Two divergent streams of developing ova extend posteriorly toward the bursa. The full-grown oocytes are found at the level of the bursa.

The egg is in the germinal vesicle stage when it is penetrated by a spermatozoon. This stimulus causes the egg to undergo its maturation division and to proceed to the metaphase of the first cleavage division, preceding egg-laying. The large "polar suns" of the first cleavage spindle may sometimes be seen through the body wall of a flattened animal.

After the eggs are laid, the polar bodies are not visible at the egg surface and there is no marker for the animal pole. These unextruded polar bodies remain submerged in the egg cytoplasm, where they eventually degenerate.

The fixed eggs of Polychoerus carmelensis measure about 220 microns in diameter. Those of Polychoerus caudatus are probably about the same size, although Gardiner (1895) states that they measure 40 by 60 microns. The eggs lack a fertilization membrane, and contain flecks of red-yellow pigment. In the freshly laid egg, these pigment granules extend throughout the cytoplasm except in the region of the amphiaster, which is thus outlined as an enormous dumb-bell. The pigment granules move along the cleavage furrows during division.

  • Bresslau, E., 1933. Turbellaria. Kükenthal-Krumbach Handbuch der Zoologie, Bd. 2.
  • Costello, D. P., 1937. The early cleavage of Polychoerus carmelensis. Anat. Rec., 70: Suppl.1, 108-109.
  • Costello, D. P., 1946. The giant cleavage spindle of the egg of Polychoerus carmelensis Anat. Rec., 96: 561.
  • Costello, D. P., 1948. Spiral cleavage. Biol. Bull., 95: 265. (See, also, Erratum, Biol. Bull., 95: 361.).
  • Costello, D. P., and H. M. Costello, 1938. A new species of Polychoerus from the Pacific Coast. Ann. and Mag. Nat. Hist., ser. 11, 1: 148-155.
  • Costello, H. M., and D. P. Costello, 1938. Copulation in the acoelous turbellarian Polychoerus carmelensis. Biol. Bull., 75: 85-98.
  • Costello, H. M., and D. P. Costello, 1939. Egg laying in the acoelous turbellarian Polychoerus carmelensis. Biol. Bull., 76: 80-89.
  • Gardiner, E. G., 1895. Early development of Polychoerus caudatus, Mark. J. Morph., 11: 155-176.
  • Gardiner, E. G., 1898. The growth of the ovum, formation of the polar bodies, and the fertilization in Polychoerus caudatus. J. Morph., 15: 73-110.
  • Löhner L., 1910. Untersuchungen über Polychoerus caudatus Mark. Zeikchr. f. w1ss. Zool., 95: 451-506.
  • Mark, E. L., 1892. Polychoerus caudatus, nov. gen. et nov. spec. Festschr. z. 70. Geburtstage R. Leuckarts. Leipzig. S. 298-309.
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© Donald P. Costello and Catherine Henley

Source: Egg Characteristics and Breeding Season for Woods Hole Species

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Reproduction

Cleavage and Gastrulation

Cleavage is total and, after the two-cell stage, unequal. According to Costello (1937, 1948) the cleavage is best described as spiral cleavage by duets, instead of by quartets. It was described earlier as bilateral. Gastrulation occurs by a curious pivoting type of epiboly. See the papers by Bresslau (1933) and Gardiner (1898) for figures of cleavage stages.

  • Bresslau, E., 1933. Turbellaria. Kükenthal-Krumbach Handbuch der Zoologie, Bd. 2.
  • Costello, D. P., 1937. The early cleavage of Polychoerus carmelensis. Anat. Rec., 70: Suppl.1, 108-109.
  • Costello, D. P., 1946. The giant cleavage spindle of the egg of Polychoerus carmelensis Anat. Rec., 96: 561.
  • Costello, D. P., 1948. Spiral cleavage. Biol. Bull., 95: 265. (See, also, Erratum, Biol. Bull., 95: 361.).
  • Costello, D. P., and H. M. Costello, 1938. A new species of Polychoerus from the Pacific Coast. Ann. and Mag. Nat. Hist., ser. 11, 1: 148-155.
  • Costello, H. M., and D. P. Costello, 1938. Copulation in the acoelous turbellarian Polychoerus carmelensis. Biol. Bull., 75: 85-98.
  • Costello, H. M., and D. P. Costello, 1939. Egg laying in the acoelous turbellarian Polychoerus carmelensis. Biol. Bull., 76: 80-89.
  • Gardiner, E. G., 1895. Early development of Polychoerus caudatus, Mark. J. Morph., 11: 155-176.
  • Gardiner, E. G., 1898. The growth of the ovum, formation of the polar bodies, and the fertilization in Polychoerus caudatus. J. Morph., 15: 73-110.
  • Löhner L., 1910. Untersuchungen über Polychoerus caudatus Mark. Zeikchr. f. w1ss. Zool., 95: 451-506.
  • Mark, E. L., 1892. Polychoerus caudatus, nov. gen. et nov. spec. Festschr. z. 70. Geburtstage R. Leuckarts. Leipzig. S. 298-309.
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© Donald P. Costello and Catherine Henley

Source: Egg Characteristics and Breeding Season for Woods Hole Species

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Relevance to Humans and Ecosystems

Benefits

Procuring Embryos

The following account is based on data for Polychoerus carmelensis, but probably applies equally well to P. caudatus.

The adults are hermaphroditic, and usually mate during the early morning hours (H. M. Costello and D. P. Costello, 1938). The sperm presumably pass from the anterior pocket of the vagina through the bursa, and fertilize the eggs while the latter are in the parenchyma. Egg-laying occurs by extrusion involving a disruption of the ventral body wall.

Deposition of the egg-masses usually occurs at sundown. These egg-masses are small gelatinous bodies containing from five to twenty eggs. They are fastened to the glass sides of the aquarium, or attached to Ulva. To collect egg-masses, it is convenient to remove 20 or 30 adults to fingerbowls of standing sea water on the sea water table. This sea water may be changed once or twice a day. Egg capsules are usually deposited on the side of the dish away from the light.

It is possible to dissect the fertilized eggs from the body, since they can be seen readily through the body wall, but their viability is not known. Past investigators have depended upon being present at the time of egg-laying to obtain the earliest developmental stages. The embryos are easily dissected from the gelatinous masses, but do not develop well after removal.

  • Bresslau, E., 1933. Turbellaria. Kükenthal-Krumbach Handbuch der Zoologie, Bd. 2.
  • Costello, D. P., 1937. The early cleavage of Polychoerus carmelensis. Anat. Rec., 70: Suppl.1, 108-109.
  • Costello, D. P., 1946. The giant cleavage spindle of the egg of Polychoerus carmelensis Anat. Rec., 96: 561.
  • Costello, D. P., 1948. Spiral cleavage. Biol. Bull., 95: 265. (See, also, Erratum, Biol. Bull., 95: 361.).
  • Costello, D. P., and H. M. Costello, 1938. A new species of Polychoerus from the Pacific Coast. Ann. and Mag. Nat. Hist., ser. 11, 1: 148-155.
  • Costello, H. M., and D. P. Costello, 1938. Copulation in the acoelous turbellarian Polychoerus carmelensis. Biol. Bull., 75: 85-98.
  • Costello, H. M., and D. P. Costello, 1939. Egg laying in the acoelous turbellarian Polychoerus carmelensis. Biol. Bull., 76: 80-89.
  • Gardiner, E. G., 1895. Early development of Polychoerus caudatus, Mark. J. Morph., 11: 155-176.
  • Gardiner, E. G., 1898. The growth of the ovum, formation of the polar bodies, and the fertilization in Polychoerus caudatus. J. Morph., 15: 73-110.
  • Löhner L., 1910. Untersuchungen über Polychoerus caudatus Mark. Zeikchr. f. w1ss. Zool., 95: 451-506.
  • Mark, E. L., 1892. Polychoerus caudatus, nov. gen. et nov. spec. Festschr. z. 70. Geburtstage R. Leuckarts. Leipzig. S. 298-309.
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Source: Egg Characteristics and Breeding Season for Woods Hole Species

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Care of Adults

After collection, the adults are placed in an aquarium through which sea water is gently flowing. The animals crawl about on the glass sides, or on Ulva placed in the water. Under these conditions, the adults may live for some weeks, but usually produce gametes only during the early part of this period.

  • Bresslau, E., 1933. Turbellaria. Kükenthal-Krumbach Handbuch der Zoologie, Bd. 2.
  • Costello, D. P., 1937. The early cleavage of Polychoerus carmelensis. Anat. Rec., 70: Suppl.1, 108-109.
  • Costello, D. P., 1946. The giant cleavage spindle of the egg of Polychoerus carmelensis Anat. Rec., 96: 561.
  • Costello, D. P., 1948. Spiral cleavage. Biol. Bull., 95: 265. (See, also, Erratum, Biol. Bull., 95: 361.).
  • Costello, D. P., and H. M. Costello, 1938. A new species of Polychoerus from the Pacific Coast. Ann. and Mag. Nat. Hist., ser. 11, 1: 148-155.
  • Costello, H. M., and D. P. Costello, 1938. Copulation in the acoelous turbellarian Polychoerus carmelensis. Biol. Bull., 75: 85-98.
  • Costello, H. M., and D. P. Costello, 1939. Egg laying in the acoelous turbellarian Polychoerus carmelensis. Biol. Bull., 76: 80-89.
  • Gardiner, E. G., 1895. Early development of Polychoerus caudatus, Mark. J. Morph., 11: 155-176.
  • Gardiner, E. G., 1898. The growth of the ovum, formation of the polar bodies, and the fertilization in Polychoerus caudatus. J. Morph., 15: 73-110.
  • Löhner L., 1910. Untersuchungen über Polychoerus caudatus Mark. Zeikchr. f. w1ss. Zool., 95: 451-506.
  • Mark, E. L., 1892. Polychoerus caudatus, nov. gen. et nov. spec. Festschr. z. 70. Geburtstage R. Leuckarts. Leipzig. S. 298-309.
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Source: Egg Characteristics and Breeding Season for Woods Hole Species

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Names and Taxonomy

Taxonomy

Mark EL 1892 (citation)- original description. p 298-309., pl 31, fig 1-22. describes genus   and species. Long description with beautiful illustrations.    Buchanan F 1892- Zoological Record 29:72. Zoological Record chapter misspells Polychoerus   as Polychaerus referring to Mark EL 1892 (citation) citation. Buchanan is chapter editor.    Verrill AE 1893 (citation)- "Caudal cirri one to five. In adult examples there are generally   1-3 slender, pale, translucent caudal cirri--sometimes, in large specimens, another   samller pair is developed external to the latteer, on the posterior lobes" etc. etc.   extended description and figures. Plate 41, 11 and 11a and plate 43, 6-10.     Length 3-4 mm, breadth 1.5 to 2 mm.   Common from Great Egg Harbor, NJ to Casco Bay, ME- taken in New Haven Harbor; Noank, Conn;   Newport, RI; Woods Hole, MA; and Quahog Bay, ME. Note eggs on shells and stones, etc.   possibly "eggs escape from mouth"?    Gardiner EG 1895 (citation)- anatomy, egg and p 155-174 plates 10 & 11 on embryology.  Bohmig L 1895 (citation)- mentions p 35 and lists p 44.  Gardiner EG 1898 (citation)-  Graff L v 1904 (citation)- "better diagnosis" of th genus - (he says).  Graff L v 1904-08 (citation)- in Bronn- p 1984 - def of genus. Depicts Polychoerus caudatus   plate I.15 and its embryology Plate IV, 20-31.    Stevens NM, Boring AM 1905 (citation)- on regeneration in.  Child CM 1907 (citation)- experiments on form regeneration.  Graff L v 1910 (citation)- notes from U.S.  Graff L v 1911 (citation)- says collected on ulven in Little Harbor and Hotel Breakwater.  Lohner L 1911 (citation)- looked for excretory canals in.  Luther A 1912 (citation)- brief mention of.  Lohner L 1913 (citation)- Compares with species of Amphiscolops  Wilhelmi J 1913 (citation)- outline with muscles p 23, anatomy with muscles p 85, also 24, 103, 113.  Allee WC 1923 (citation)- lists it as collected at Woods Hole.  Keil EM 1929 (citation)- used this in regeneration experiments at Woods Hole.  Bresslau E 1933 (citation)- p 55 gig 24.4- exterior view- from Nachon Island, Woods Hole.   length to 4 mm x 1.4mm- flattened- color red orange through yellow and purple pigment   granules, etc. p 204 fig 202- regeneration and ? in.    An der Lan H 1936 (citation)- mentions.  Westblad E 1946 (citation)- notes nozzles on bursa.  Westblad E 1948 (citation)- p 30 on presense of a germvitellarien in- not a real germvitellarien   but more like that of Hallangia - abortive eggs add to others to nourish them etc.    Hyman LH 1951 (citation) -vol 2, p 175 notes study of embryology of this by Gardner EG 1895 (citation)-   Discusses acoel embryology.    Ax P 1963 (citation)-discusses presence of tails in this non sand form, may be sensory.  Hadzi J 1963 (citation)- p 212- on embryology of - comment. p 222- on symbionts in.  Steinbock O 1963 (citation)- p 49 mentions work on cleavage of.    [Bush note: Collected by dredging at Woods Hole, Mass 6/23/64]  [Bush note: Collected from shelly sandy mud by Bob Smith from Sewage Beach, Virginia Key, Miami   Oct 1964; drawings and sectioned. is this caudatus?- did not have orange color of those   I saw in Woods Hole.]  [Bush note: collected from sand at ? November 1965.]  [Bush note: many specimens finally found July 1969 on Nantucket in Great Bay not far from   Wauwinet- near Swopes House- under scale of shells in intertidal zone.]    Dorjes J 1968 (citation)- lists.  Ax P, Doerjes J 1966 (citation)- note "brain" surrounds the statocyst.  Kato K 1968 (citation)- on development of purple eggs in.  Apelt G 1969 (citation)- p 268 notes Gardiner's observation of copulation in- is first for   acoels Gardiner EG 1898 (citation)-    Henley C 1974 (citation)- p 296- notes Mark EL 1892 (citation)- observations on sperm in bursa.   p 299 - on ultrastructure of sperm.  

 October 2003  MDH collected several specimens of what apppeared to be P. caudatus from subtidal sand at Oak Island, NC.  Sexually mature specimens were smaller than MA specimens (those described by Verill) - approx. 1.3 - 2.4 mm  long and 600 µm wide (MA specimens are approx. twice that size). NC specimens only had 2 bursal nozzles,  while MA specimens have many (up to 50). Histological sections of NC specimens revealed a cop organ that  could not be distinguished from MA specimens.
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Source: Turbellarian Taxonomic Database

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