Acryptolaria rectangularis ( Jarvis, 1922 ),

Peña Cantero, Alvaro L., Marques, Antonio C. & Migotto, Alvaro E., 2007, Revision of the genus Acryptolaria Norman, 1875 (Cnidaria, Hydrozoa, Lafoeidae), Journal of Natural History 41 (5 - 8), pp. 229-291: 263-265

publication ID

http://doi.org/ 10.1080/00222930701228132

persistent identifier

http://treatment.plazi.org/id/AC456037-6034-6269-FE2B-FBE78FDC68A3

treatment provided by

Carolina

scientific name

Acryptolaria rectangularis ( Jarvis, 1922 )
status

 

Acryptolaria rectangularis ( Jarvis, 1922) 

Cryptolaria rectangularis Jarvis 1922, p 335  , Plate 24 Figure 3View Figure 3.

Acryptolaria rectangularis: Millard 1967, p 174  , Figure 2BView Figure 2 (in part).

Acryptolaria angulata: Vervoort 1966, p 117  , Figure 17View Figure 17.

Description

‘‘The material consists of a part of a colony 0.7 cm high and lacking both basal and distal portions. Fascicling tubes are few and limited to the proximal end of the stem. Branches are irregular, or perhaps opposite, and polysiphonic for a short distance beyond their origin. The hydrothecae are alternate, long and tubular, the proximal halves erect and adnate, the distal diverging at a right angle. The margin is smooth with several reduplications and circular aperture. A well-marked fold occurs in the lower wall of the hydrotheca at the point of divergence. Gonosomes absent’’ ( Jarvis 1922, p 335–336).

Remarks

Unfortunately, it has not been possible to examine type material of this species. According to Vervoort and Watson (2003), the location of the type material of Jarvis’ species is unknown.

The branches represented in Jarvis’ (1922) figures have a zigzag arrangement. According to Vervoort (1966, as A. angulata  ) ‘‘The stems are erect and largely monosiphonic; there are some accessory tubes at the basal parts of some of the hydrocauli and some short hydrorhizal fibres’’.

As already noted, the species A. angulata  , A. bulbosa  , and A. rectangularis  share similar hydrothecal morphology and may be phylogenetically closely related species. In fact, Acryptolaria rectangularis  has been considered conspecific with A. angulata  by several authors (e.g. Hirohito 1995; Vervoort and Watson 2003). Vervoort and Watson (2003, p 41), for example, indicated that they studied ‘‘great amount of material of this species [ A. angulata  ] from all over its large area of distribution … has convinced us that Cryptolaria angulata Bale, 1914  and Cryptolaria rectangularis Jarvis, 1922  are inseparable’’.

We found, however, that the three species are different, although sharing similar hydrothecae. Acryptolaria angulata  is characterized by the presence of the adcauline boss projecting into the hydrothecal cavity. Jarvis (1922) made it clear that A. rectangularis  differs from A. angulata  in the straightness of the upper wall of the hydrotheca, in its divergent portion, and in the absence of an internal thickening opposite the fold. Gravier- Bonnet (1979, p 18) followed the opinion of Jarvis (1922) and Millard (1967, 1968, 1975) that this species is clearly distinguishable from Bale’s species by the absence of the adcauline thickening of the hydrothecae. Schuchert (2003, p 155) also considered A. rectangularis  and A. angulata  as ‘‘separate species because both morphotypes were found not very far apart’’; but he acknowledges, however, ‘‘the possibility that both could be only forms belonging to the same species’’.

The presence of the adcauline boss projecting into the hydrothecal cavity is clearly a distinct character of A. angulata  . On the other hand, the absence of this boss makes A. bulbosa  and A. rectangularis  morphologically similar. However, the shape of the hydrotheca of these two species seems to be slightly different. Stechow (1932) indicated that A. bulbosa  differs from A. rectangularis  mainly in the stronger bend of the hydrotheca, the smaller diameter of the hydrothecal aperture and the shorter free portion of the hydrotheca (cf. Table XV). These differences, though small, prevent us from considering the two species to be conspecific. In addition, the hydrotheca of A. bulbosa  is similar to that of A. angulata  , it distinctly bends upwards after the adcauline wall becomes free. By contrast, A. rectangularis  has the free portion of the adcauline wall straight, the diameter of the hydrothecal aperture larger, and the free portion of the hydrothecal wall longer than in the other two species.

Possible misidentifications of A. rectangularis  , especially by Millard (1967, 1968, 1980), Gravier-Bonnet (1979), and Schuchert (2003), are listed under the discussion of A. bulbosa  . On the other hand, Vervoort (1966) assigned to A. angulata  material belonging to Jarvis’ species. The material shares with A. rectangularis  the shape and size of the hydrothecae and the absence of the adcauline notch so characteristic for Bale’s species.

Distribution

Acryptolaria rectangularis  seems to be a bathyal species, having been found from depths between 225 ( Jarvis 1922) and 495 m ( Vervoort 1966). It is certainly known from the

western Indian Ocean, off Providence Islands ( Seychelles) and off Durban, east coast of South Africa ( Vervoort 1966; Millard 1967).

Kingdom

Animalia

Phylum

Cnidaria

Class

Hydrozoa

Order

Leptothecata

Family

Lafoeidae

Genus

Acryptolaria

Loc

Acryptolaria rectangularis ( Jarvis, 1922 )

Peña Cantero, Alvaro L., Marques, Antonio C. & Migotto, Alvaro E. 2007
2007
Loc

Acryptolaria rectangularis

: Millard 1967: 174
1967
Loc

Acryptolaria rectangularis

: Millard 1967
1967
Loc

Acryptolaria angulata

: Vervoort 1966: 117
1966
Loc

Cryptolaria rectangularis

Jarvis 1922: 335
1922