Acryptolaria crassicaulis ( Allman, 1888 )

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 : 245-247

Acryptolaria crassicaulis ( Allman, 1888)

( Figures 6 , 15D , 17E ; Table VI)

Cryptolaria crassicaulis Allman 1888 , p lvii, lxvii, lxviii, 41, Plate 19, Figures 3, 3a .

Material examined

Holotype: BMNH 1888.11 .13.29, Challenger expedition, Sta. 344, off Ascension Island, 07 ° 549200 N, 14 ° 289200 W, 420 fathoms (756 m), volcanic sand. One colony consisting of several stems up to 65 mm long.

Description

‘‘Colony attaining a height of four inches [101.6 mm], profusely and very irregularly branched main stem’’ ( Allman 1888, p 41). Colony apparently composed of several stems growing tight together on a coral fragment. Longest stem ca 65 mm high.

Stem strongly polysiphonic; only distalmost branches monosiphonic. Stems branched more or less irregularly in one plane. Some basal branches becoming lower-order stems; branches up to five-order, sometimes anastomosing.

Hydrothecae alternately arranged in approximately one plane. Hydrotheca tubular, cylindrical in the free part; diameter softly decreasing towards basal part. Hydrotheca curved abcaulinarly, especially at distal part; ca two-thirds of adcauline wall adnate to internode. Free part of adcauline wall distinctly convex; adnate part only slightly convex. Abcauline wall straight basally, but clearly concave at distal third. Hydrothecal aperture circular, directed upwards. Rim even, sometimes with few short renovations.

Coppinia not observed.

Remarks

Allman (1888, p 41) characterized this species by the ‘‘profuseness and irregularity of its ramification, and for the great thickness of its stem and principal branches. The ultimate branches on the other hand are slender and flaccid. The hydrothecae are stout, and the exserted portion rather long. Here and there, and at uncertain intervals, slight constrictions may be noticed in the branches’’.

As indicated above, Acryptolaria crassicaulis has been regarded by some authors as conspecific with A. corniformis . Nevertheless, we consider that both species are valid. Acryptolaria corniformis has distinctly larger hydrothecae (cf. Table XV) and the hydrothecae are not so bent abcaulinarly as in A. crassicaulis , in which they are strongly abcaulinarly directed at distal third.

A variety of the species, Acryptolaria crassicaulis var. dimorpha , was described for the genus Cryptolaria by Ritchie (1911) from Australian waters, based on the presence of single hydrothecae. The subspecies was subsequently recorded by Jarvis (1922) for Solomon Islands. Millard (1967, p 174) properly stated that ‘‘as the ability to produce solitary hydrothecae is a feature common to many, and possibly all, Lafoeidae , it is not necessary to retain Ritchie’s variety dimorpha ’’, a position adopted by Gravier-Bonnet (1979, p 20).

Distribution

Off Ascension Island, 07 ° 549200 N, 14 ° 289200 W, 756 m, volcanic sand ( Allman 1888).

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.

Figure 6. Acryptolaria crassicaulis (Allman, 1888). (A–C) Hydrothecae. All drawings from the holotype. Scale bar: 400 Mm.

Figure 15. Hydrothecal arrangement in Acryptolaria. (A) A. abies; (B) A. conferta; (C) A. corniformis; (D) A. crassicaulis; (E) A. flabellum; (F) A. gracilis. Scale bar: 500 Mm (A, B, D, E); 250 Mm (C); 100 Mm (F).

Figure 17. Shape of hydrotheca in Acryptolaria. (A) A. abies; (B) A. angulata; (C) A. conferta; (D) A. corniformis; (E) A. crassicaulis; (F) A. flabellum. Scale bar: 250 Mm.