Acryptolaria conferta ( Allman, 1877 )

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 : 240-243

Acryptolaria conferta ( Allman, 1877)

( Figures 4 , 15B , 17C , 19A ; Table IV)

Cryptolaria conferta Allman 1877, p 17 , 19, 20, Plate 12 Figures 6–10 .

Material examined

Holotype: MCZ 45715, off Cojima , Cuba, 450 fathoms (810 m).

Description

‘‘Hydrocaulus attaining a height of about two inches [50.8 mm], much and irregularly or subdichotomously branched, fascicled except towards the terminations of the branches’’ ( Allman 1877, p 17).

Branches in distinct zigzag pattern. Hydrothecae alternate, more or less in one plane. Hydrotheca tubular, almost cylindrical in the free part; diameter softly decreasing towards basal part. Hydrotheca gently curved abcaulinarly; approximately two-thirds of adcauline wall adnate to internode. Adcauline wall convex, except the straight basal third. Abcauline wall concave, though practically straight at basal third. Sometimes, a ring of nodules visible at the base of the hydrothecae. Hydrothecal aperture circular, slightly directed upwards. Rim even, sometimes with short renovations.

According to Allman (1877, p 18), the fusiform coppinia consists of a mass of closely set, flask-shaped gonothecae provided with a distal neck ending in an even circular orifice. Each gonotheca gives rise to a single ovum, subsequently lodged in an acrocyst. The coppinia lacks defensive tubes.

Remarks

According to Allman (1877, p 17–18) the hydrotheca has a distinct floor, which possibly disappears with age, being completely absent in the older hydrothecae immersed in the fascicled stem. The examination of type material has left no doubt that the hydrotheca lacks any floor, as shown in Figures 4 , 17C . However, as indicated above, a ring of nodules is sometimes visible at the base of the hydrothecae.

Ritchie (1911) proposed Cryptolaria conferta var. australis , differing from the nominotypical variety mainly in the growth-form and slightly smaller hydrothecae. Totton (1930) and Ralph (1958) considered the overlapping hydrothecae and the absence of any slight convexity at the base of the abcauline wall as the main diagnostic characters of the variety. Millard (1968) found those characters variable within a colony and, therefore, held that it was not justifiable to retain Ritchie’s form as a separate variety or subspecies. Vervoort and Watson (2003, p 43) considered the subspecies A. c. australis and the nominotypical subspecies as conspecific.

Ramil and Vervoort (1992) described a new subspecies, Acryptolaria conferta minor , as it had smaller hydrothecae than the material referred to A. conferta in their collection and did not intergrade with it ( Ramil and Vervoort 1992, p 46–48). Under the synonymy of this subspecies, Ramil and Vervoort (1992, p 43) included the records of Acryptolaria gracilis by Billard (1906b, 1906c) and Patriti (1970), but not Acryptolaria gracilis by Totton (1930) and Ralph (1958), that would be synonyms of the valid species Acryptolaria gracilis ( Allman, 1888) (see below). We believe that, without further information on cnidome and a broader revision of the species records, the description of a new subspecies is premature.

The material assigned to A. conferta by Hirohito (1995) has several coppiniae, either with or without protective hydrothecae, branched in rare occasions. It is likely that Hirohito’s material embraces more than one species. In fact, his material probably includes a new species of Acryptolaria , since the known species described so far, with the exception of A. bulbosa and A. rectangularis , lack defensive modified hydrothecae in the coppinia, and in these species the structure of the coppinia, with the modified hydrothecae forming a canopy, and the shape of the hydrothecae are completely different.

Although Acryptolaria conferta is the most frequently recorded species of the genus, most of the records refer to sterile material and none gives information on the cnidome. Because the species has no clearly distinguishing features, we considered only the original record as representative of its geographical distribution.

Distribution

Off Cojima, Cuba, 810 m ( Allman 1877).

Figures

Figure 4. Acryptolaria conferta (Allman, 1877). (A, B) Branch fragments showing hydrothecal arrangement; (C–F) hydrothecae; (G) gonothecae. All drawings from the holotype. Scale bar: 1 mm (A, B); 400 Mm (C–G).

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

Figure 7. Acryptolaria flabellum (Allman, 1888). (A, B) Branch fragments showing hydrothecal arrangement; (C, D) hydrothecae. All drawings from the holotype. Scale bar: 1 mm (A, B); 400 Mm (C, D).

Figure 8. Acryptolaria gracilis (Allman, 1888). (A) Branch fragment showing hydrothecal arrangement; (B–F) hydrothecae. All drawings from the ‘‘cotype’’. Scale bar: 1 mm (A); 400 Mm (B–F).

Figure 9. Acryptolaria longitheca (Allman, 1877). (A) Branch fragment showing hydrothecal arrangement; (B–D) hydrothecae. All drawings from the holotype. Scale bar: 1 mm (A); 400 Mm (B–D).

Figure 10. Acryptolaria minima Totton, 1930. (A) Branch fragment showing hydrothecal arrangement; (B–E) hydrothecae; (F) gonothecae. All drawings from the holotype. Scale bar: 1 mm (A); 400 Mm (B–F).

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.

Figure 19. Shape of gonothecae: (A) Acryptolaria conferta; (B) A. minima. Detail of different structures: (C) bottleneck-shaped basal part of hydrotheca in A. gracilis; (D) opercular structure in A. minima; (E) opercular structure in A. operculata; (F) longitudinal striae in hydrotheca of A. flabellum; (G) intrathecal cusp of A. tortugasensis. Scale bar: 100 Mm (A, B, D, F, G); 50 Mm (C); 250 Mm (E).