Acryptolaria bulbosa ( Stechow, 1932 )

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 : 237-240

Acryptolaria bulbosa ( Stechow, 1932)

( Figure 3 ; Table III)

Cryptolaria bulbosa Stechow 1932, p 87 .

Acryptolaria bulbosa: Yamada 1959, p 49 .

Acryptolaria angulata: Hirohito 1995, p 102 , Figure 29a, b, Plate 6 Figure B.

Material examined

Holotype: Sagami Bay , Japan, ‘‘ Doflein’ ’ Expedition 1904, on sponge, sterile specimen in two whole-mount preparations and in alcohol ( ZSM no number).

Description

Several fragments up to 25 mm long ( Stechow 1932, p 87). Polysiphonic almost throughout. Branches straight.

Hydrothecae alternately arranged, approximately in one plane. Hydrotheca mostly cylindrical; though diameter smaller at adnate portion and decreasing at basal part. Hydrotheca curved twice; strongly outwards at approximately half its length and later slightly upwards, clearly far from the point at which the adcauline wall becomes free. Adcauline wall slightly convex at basal part, extremely convex at approximately half its length and concave at distal third. Abcauline wall straight or slightly convex at basal and

Mean¡SD Range n

Hydrothecae

Length of abcauline wall 710.4¡31.2 680–760 5 Length of free adcauline wall 360.0¡57.7 280–440 5 Length of adnate adcauline wall 464.0¡53.7 400–520 5 Length of adcauline wall 824.0¡27.7 800–864 5 Ratio adnate/free adcauline wall 0.9–1.9

Diameter at aperture 155.2¡4.4 152–160 5 Diameter at base 78.4¡6.7 72–88 5 Nematocysts

Larger group 22.1¡0.6X6.4¡0.3 21–23X6–7 10 Smaller group 7.2¡0.3X3 7–7.5X3 3

distal third, but provided with a sharp invagination at approximately half its length, forming a sort of hump. Approximately half of adcauline wall adnate to internode, though hydrothecae with free part either longer or shorter than adnate one also present. Hydrothecal aperture circular, oblique, upwardly directed. Rim even, sometimes with up to four short renovations.

Coppinia not observed.

Additional information

Hirohito (1995, p 102) described the gonosome of this species (as A. angulata ), noting that the bottle-shaped gonothecae are aggregated into a coppinia, that the gonophores are in the form of fixed sporosacs, producing acrocysts, and that there are modified hydrothecae diverging and entangled with each other, forming a canopy.

Remarks

Acryptolaria bulbosa has been considered conspecific with A. angulata by several authors (e.g. Hirohito 1995; Vervoort and Watson 2003). Stechow (1932) considered that the species should be called Cryptolaria angulata var. bulbosa if transitions were found. Nevertheless, we consider both species as valid. Although the general appearance of the hydrothecae is similar, only A. angulata is characterized by the presence of the adcauline boss projecting into the hydrothecal cavity. Moreover, we have found clear differences in the size of the larger nematocysts in the cnidome of the type material of A. angulata and A. bulbosa (7.7–8.8X4.4–5.5 Mm and 21–23X6–7 Mm, respectively). There are also slight differences in the shape of the hydrotheca. In A. angulata the upward bending of the hydrotheca begins almost immediately after the adcauline wall becomes free, whereas in A. bulbosa it starts distinctly further, with a relatively long free portion of the adcauline wall forming an angle more or less perpendicular to the longitudinal axis of the branch. The abcauline side of the abcauline perisarc invagination is distinctly sharper in A. bulbosa , and the abcauline wall forms a much marked hump after it. Furthermore, the size of the hydrotheca in A. angulata seems to be larger, especially concerning the length of the hydrotheca (cf. Table XV).

The material from Sagami Bay described as Acryptolaria angulata by Hirohito (1995, p 102), who considered Cryptolaria angulata , C. rectangularis , and C. bulbosa conspecific, clearly does not belong to Bale’s species, as it lacks the adcauline invagination of the hydrothecal wall. The general shape of the hydrotheca conforms better with A. bulbosa .

The material described by Gravier-Bonnet (1979) as A. rectangularis is different from that described by Jarvis (1922) and Millard (1967, in part), and it is quite similar to A. bulbosa both in shape and size of the hydrotheca.

The material assigned to A. rectangularis by Millard (1967) apparently includes two species: A. rectangularis (ABD 15P) and A. bulbosa (AFR 1251D). Millard indicated that ‘‘the two samples have hydrothecae of very different sizes, though the proportions are similar’’. Moreover, it is possible to recognize both species in Millard’s (1967) figures. If these records can be confirmed, the southwestern Indian Ocean would be an area of sympatry of A. rectangularis and A. bulbosa .

The material assigned to Acryptolaria rectangularis by Millard (1968) conforms more to the concept of A. bulbosa adopted here, particularly in the shape and the size of the hydrothecae. In A. rectangularis the free portion of the adcauline wall is straight, whereas in A. bulbosa it is concave and distinctly bends upwards, as described by Millard. Therefore, the two coppiniae described by her would be, actually, the still undescribed coppiniae of A. bulbosa .

The same applies to Millard’s (1980) material of Acryptolaria rectangularis , which could belong to A. bulbosa . Although she provided neither figure nor measurements of the hydrothecae, she stressed that the ‘‘trophosome of these specimens agrees entirely with those previously described’’ ( Millard 1980, p 138). She provided a detailed description of the coppinia, this time based on well-preserved material ( Millard 1980, p 138–140). The structure of this coppinia is similar to that described by Hirohito (1995) in material assigned to A. angulata , and here considered conspecific with A. bulbosa .

Schuchert’s (2003) material assigned to A. rectangularis agrees with Stechow’s material of A. bulbosa here studied. The specimens are similar in the size of the hydrotheca, as well as in the size of the nematocysts (23X7 Mm and 5X3 Mm). However, Schuchert’s figures are similar to A. rectangularis in the shape of the hydrothecae and, therefore, no decision seems possible at the moment.

Distribution

Apart from the many possible records, the species is only known with certainty from Sagami Bay ( Stechow 1932; Hirohito 1995), where it was collected at 100 m ( Hirohito 1995).

Figures

Figure 3. Acryptolaria bulbosa (Stechow, 1932). (A) Part of branch showing hydrothecal arrangement; (B–D) hydrothecae. All drawings from the holotype. Scale bar: 400 Mm.