Vasichona
Vasichona Jankowski, 1972 (ref. ID; 7260)
Subclass Chonotrichia: Order Exogemmida; Family Chilodochonidae (ref. ID; 7260)
[ref. ID; 7260]
Remarks; These chonotrich ciliates belong to the order Exogemmida, based on the kind of budding observed, and can be placed in the family Chilodochonidae, based on the ovoid body shape, the absence of a distinct "neck", and their presence of the mouthparts of a decapod (Jankowski 1973; Small and Lynn 1985). There are presently three published genera in this family Chilodochona, Cryptochona, and Vasichona (Corliss 1979; Jankowski 1973). Corliss (1979) mentioned a fourth genus, Mystichona, as an unpublished one attributed to Jankowski. Chilodochona differs from the first two genera in having an enlarged oral area with two relatively broad surfaces (Grain and Batisse 1974; Jankowski 1973). Cryptochona and Vasichona have a petal-like projection or oral flap extending from the "right" lip of the oral cavity. Jankowski (1973) considered this flap to be dorsal. However, given that it is adjacent to what was the right field of kineties of the bud, we prefer to consider it to be on the right, consistent with the interpretation of the morphology presented by Grain and Batisse (1974). According to Jankowski (1973), the flap does not cover the oral cavity opening of Vasichona, a while it does cover the oral cavity opening of Vasichona, while it does cover the oral cavity opening in Cryptochona. Cryptochona also has a constriction in the neck region of the body. However, it is our view that these features are not substantial enough to warrant a generic distinction. Jankowski (1972) established Vasichona and then subsequently established Cryptochona (Jankowski 1973). We conclude that Cryptochona is a junior synonym of Vasichona and transfer the single species in this genus to Vasichona as Vasichona tumida (Jankowski, 1973) n. comb. (ref. ID; 7260)
- Vasichona opiliophia Taylor, Lynn, and Gransden, 1995 (ref. ID; 7260 original paper)
- Vasichona paguri Jankowski, 1972 (ref. ID; 7260)
- Vasichona tumida (Jankowski, 1973) Taylor, Lynn, and Gransden, 1995 (ref. ID; 7260 redescribed paper)
Vasichona opiliophia Taylor, Lynn, and Gransden, 1995 (ref. ID; 7260 original paper)
Diagnosis
Elongate ovoid body, when fixed 56-102 um long x 31-57 um wide and when live 47-119 um long x 31-58 um wide, narrowing slightly to a "collar" anteriorly. Small oral flap, closing over an oral cavity, 9-28 um in diameter. Oral ciliature divided into two fields: a right field that covers one side of the oral cavity and extends onto the opposite side to abut against the left field of oral ciliature. Body sitting atop a stalk, when fixed 27-84 um long x 2.7-6.4 um wide and when live 36-114 um long x 2-7 um wide, interrupted by a cone disk 6-25 um wide x 3-7 um high. Macronucleus 18-37 um long x 5-25 um wide. Found on setae of the basal endites of maxillae of Chionoecetes opilio. (ref. ID; 7260)
Descriptions
These chonotrichs had an elongate ovoid body that tapered slightly at the anterior end, forming a slight "collar." The anterior oral cavity was capped by a flap that was observed either lifted up or closed over the oral cavity opening. The flaps of individuals with the oral cavity closed and open were measured to determine if there were significant differences in flap size: in closed individuals the flap length was ~6.5-11 um and the flap width was ~7-9 um; in open individuals the flap length was ~6.5-9 um and the flap width was ~7-10 um. The ciliature of the oral cavity is divided into two fields: a right field whose kineties parallel the anterior border of the oral cavity, extending unbroken across this wall of the cavity and extending onto the opposite side, and a left field whose kineties are obliquely orientated with respect to the anterior border of the oral cavity. The body sits atop a thick stalk that originates in an inpocketing of the body and broadens just after it leaves the body into a cone disk. The stalk attaches most individuals to a seta of the second maxilla. Some individuals are found attached to the maxillary cuticle.
Division occurs by exogemmous budding, with the bud forming near the anterior end of the body. The buds has two fields of somatic kineties. A "right" field extends from an anterior suture posteriorly in a curve lining the right side of a ventral groove in which the ciliature resides. The field is continuous over the dorsal portion of the groove with its kineties extending anteriorly-posteriorly to insert posterior to and to the left of the cytostome. The kineties of the "left" field arise almost perpendicularly to the anterior suture and extend along the dorsal anterior part of the groove and ventrally along the anterior left portion of the ventral groove. At the posterior, the lateral kineties of the "right" field curve slightly left to partially encircle the rosette from which the stalk is secreted. (ref. ID; 7260)
Host
Most chonotrichs were attached to the basal portions of the setae of the maxillae. However, a few individuals were attached to the cuticle itself, near the bases of setae. (ref. ID; 7260)
Habitats
This species found on C. oilio, in the North Atlantic Ocean, and at great depths, >150 m. (ref. ID; 7260)
Habitats
This species found of littoral and sublittoral Pagurus pubescens in the Barents Sea, Murmansk, and the Zelen Sea. (ref. ID; 7260)
Vasichona tumida (Jankowski, 1973) Taylor, Lynn, and Gransden, 1995 (ref. ID; 7260 redescribed paper)
Remarks
V. tumida differs from V. paguri and V. opiliophila n. sp. in having a constriction in the neck region of the body, while V. paguri has a longer body (117-125 vs. 56-103 um) and a generally longer (74-117 vs. 29-84 um) and wider (8 vs. 2.7-6.4 um) stalk than V. opiliophila n. sp. (ref. ID; 7260)
Habitats
This species found on Crangon dalli in the Ochotsk Sea. (ref. ID; 7260)