Turbellarian taxonomic database
Aphanostoma rhomboides Notes
Jensen OS 1878 (citation)- describes new species, definition in Latin p 23-24. Lists
Aphanostoma griseum as synonym- Plate I- figures 1-3.
Graff L v 1882 (citation)- illustration and description.
Bohmig L 1895 (citation)- in list p 44.
Attems CG 1897 (citation)- noted vacuolation at posterior end- are they osmoregulatory?
Iuustration otolith and epithelium. From Helgoland. brief note.
Graff L v 1902 (citation)- description of this species - occurs in Puerto Rico, synonym
are Aphanostoma elegans and Mecynostomum agile. Occurence in Bergen.
Graff L v 1905 (citation)- illustration and long description of Aphanostoma rhomboides.
Lohner L 1911 (citation)- on vacuole in this species.
Wilhelmi J 1913 (citation)- mentions p 95.
Steinbock O 1931 (citation)- from Faroes.
Steinbock O 1933 (citation)- lists from Arctic- gives list of synonums- see these.
Southern R 1936 (citation)- reports in Ireland.
Steinbock O 1938 (citation)- reports from Iceland.
Westblad E 1945 (citation)- notes Proporus cyclops is synonym of this.
Westblad E 1946 (citation)- brief describption- illustration. "S" shaped copulatory organ.
Note it is a littoral species.
Marcus E 1948 (citation)- this = Mecynostomum agile p 112, 187- species by Graff is not
species by Jensen. says Mecynostomum agile Jensen = Mecynostomum agile Westblad;
Aphanostoma rhomboides Graff does not = Aphanostoma rhomboides Jensen; and
Aphanostoma rhomboides Jensen = Convoluta.
Marcus EDB-R 1948 (citation)- p 12 this = Mecynostomum agile.
Westblad E 1948 (citation)- moved to Mecynostomum, p 74.
Dorjes J 1968 (citation)- p 85 lists in this genus but on p 157 under Mechynostomum.
Antonius A 1968 (citation)- p 370, notes on Westblad's treatment of this species.
Tyler S 1976 (citation)- adhesive papillae in.
Steinbock O 1931 (citation)- Notes on p 3 that Proporus cyclops O. Schmidt is "probably identical with
Aphanostoma rhomboides.
Jensen OS 1878 (citation)- Translation from latin and danish using Google translate:
Body about 1 mm long, 0.27 mm wide at both ends, broader in the anterior part, gradually narrower towards
the posterior. Color in the middle of the back from yellow to brownish. Otherwise body colorless.
Seminal vesicle oval. Penis soft, cylindrical, curved towards the male genital opening. Organs of
uncertain function protruding papilliformly around the male genital opening, arranged more or less
distinctly in rhomboidal lines.
In Orsted's diagnosis of Aphanostoma griseum, which is mentioned above as possibly synonymous with the
present species, only the body shape common to several Aphanostomum species and the color, which is
different, either grayish or yellowish, are mentioned. It is reasonable that Orsted has confused two
separate species in his A. griseum; for the color does not vary so easily in the rhabdocoel. Since I
have come across several different species that agree with the yellow form in both body
shape and color, it is impossible to decide whether A. rhomboides is identical with it or not.
Since, furthermore, Orsted's species name, which only applies to the gray-colored form (or species),
does not fit the present species, which is always of a yellow-brown color, I have found it best to give
it a new name.
When the animal's body is extended to its full length, it becomes almost even. On the surface. In the
anterior part of the body, there are spider glands (see page 13). For the otolith, see page 1"). Along
the back, there are embedded the peculiar bodies (Fig. 1, b), the histological nature of which is
discussed on page 10. In the mouth open fine-grained glandular threads, which converge all around
from salivary glands; they are not very numerous. The oval transversely placed spermatic cord (
Fig. 2, b) bears on its posterior side the penis (Fig. 2, c) in the form of a duct or tube, which
with its basal part turns backwards and then bends forwards under the seminal vesicle in the direction
of the genital opening.*) The walls of the penis are formed by two distinctly separated layers, an
inner very thin and an outer thicker, both clear and hyaline. The male genital opening
(Fig. 2, d. Fig. 3, a) lies just behind the female (Fig. 2, e, Fig. 3, b); it is a separate opening;
of this I have convinced myself by my observations; but often the animal extends the genital openings
towards each other, so that they flow together, and the cilia that surround the genital openings form
a single long ciliary rim around a common depression where both openings open.In the region behind and
on the sides of the male genital opening, there are remarkable papillary bodies protruding above the
surface of the body, forming a more or less distinct lattice-shaped network (Fig. 3). The lattices lie
in the direction of the genital opening (Fig. 3, a) and extend straight towards it. These papillary
bodies are also found in front of and to the sides of the male genital opening; but here only irregularly
and sparsely. The papillae* (Fig. 3*) are elongated, tapering towards their free end, which is not
quite pointed; their part located in the body also tapers and this more and more, until it disappears
from the eye. The bodies thus formed are strongly refractive with a dark field along the middle,
certainly the expression of an internal cavity that opens at the ends. They bend easily and serve the
senses well, but their essential function is undoubtedly another, which I have not yet discovered.
From the female genital opening, which is large, considerably larger than the male, a very short
passage leads into a large round sac with powerful walls, formed of fine circular fibres (Fig. 2, f).
The inner space of the sac, which is round, corresponding to the shape of a sac, contains a quantity of
small and a few larger vacuoles, separated by thin partitions. The sac is probably a bursa copulatrix.
I have never seen accessory grain substances in it, nor sperm, which is explained by the presence of a
Receptaculum seminis, into which the sperm immediately migrates, and which is also always seen filled
with sperm. This Receptaculum seminis (Fig. 2, g) is formed by a double bladder, situated laterally to
the side of the bursa copulatrix and connected with it by a passage, which issues from the upper side of the bursa;
the passage has at its origin the same width as the inner wall of the bursa; then it gradually tapers as
it approaches the receptacle; its walls are thick and show longitudinal ridges. I have found A. rhomboides
in numerous specimens in the Alværstrommen (2 miles north of Bergen), some a few feet below the water table
on kelp and fucus in June and September. All the individuals found in these months were sexually mature.
The foot consists of diatoms and small entomostraces; I have seen shells of these in their interior.
Notes from synonyms
Notes for Aphanostoma griseum
Oersted AS 1845 (citation)-
Diesing KM 1862 (citation)- describes and references.
Jensen OS 1878 (citation)- lists this species as synonym in part of his new species
Aphanostoma rhomboides.
Marcus E 1948 (citation)- says this one of original species of Aphanostoma but cannot be recognized
p 112, 187.
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