Acryptolaria longitheca ( 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 : 252-254

Acryptolaria longitheca ( Allman, 1877)

( Figures 9 , 16A , 18B ; Table IX)

Cryptolaria longitheca Allman 1877, p 18 , 19, 20, Plate 13, Figures 4 , 5 ; Clarke 1879, p 240, 244, Plate 2 Figures 7–13 .

Material examined

Holotype: MCZ 45714, off Double-Headed Shot Key, 315 fathoms (567 m), numerous small fragments up to 15 mm long.

Description

‘‘Hydrocaulus attaining a height of about two inches [50.8 mm], pinnately but not profusely branched’’ ( Allman 1877, p 19). Presently, type material consisting of numerous small fragments up to 15 mm in length. Fragment 15 mm long belonging to basal part of stem, completely polysiphonic, slightly geniculate and with a basally flat hydrorhiza probably indicating attachment to hard substratum.

Hydrothecae alternately arranged almost in one plane, forming an obtuse angle. Hydrotheca tubular, cylindrical in the free portion, then diameter slightly decreasing to basal part. Hydrotheca strongly curved abcaulinarly; approximately half of adcauline wall adnate to internode. Free portion of adcauline wall practically straight, adnate part slightly convex. Abcauline wall concave. Hydrothecal aperture circular, directed upwards, forming an angle of ca 60 ° with longitudinal axis of branch. Rim even, sometimes with few short renovations.

Coppinia not observed.

Remarks

All material studied by us and assigned to A. longitheca seems to belong to the same colony that corresponds to the holotype of the species. The jar in which the type material of A. longitheca is preserved included a small, unlabelled vial with colonies of A. abies .

Allman (1877, p 19) indicated that ‘‘ Cryptolaria longitheca is a far less profusely branched species than C. conferta and from this species it further differs in the pinnate disposition of its branches and in being a stronger form with larger hydrothecae. The hydrothecae, moreover, … are cylindrical throughout, presenting no diminution of their diameter towards the base as in C. conferta . They appear also to pass continuously into the tubes of the hydrocaulus, no distinct floor being apparent in the hydrothecae of any part of the specimen’’.

Calder and Vervoort (1998) examined type material of A. longitheca and A. crassicaulis . They found nothing to warrant their separation and, consequently, considered A. crassicaulis conspecific with A. longitheca . Although we recognize similarities between the two species, we regard them as valid (see below). The material studied by these authors is similar to A. crassicaulis , because of the shape of the hydrothecae, softly curved abcaulinarly, and the much larger adnate proportion of the adcauline wall. In A. longitheca the hydrotheca is strongly curved abcaulinarly and approximately half of the adcauline wall is adnate to the internode. Unfortunately, no information concerning the cnidome of the material studied by those authors is available, and it is not possible, at present, to evaluate their identifications based on nematocyst characters.

Acryptolaria longitheca belongs to a group of Acryptolaria species characterized by large hydrothecae with a long free portion of the adcauline wall, and includes A. corniformis , A. crassicaulis , and A. operculata (cf. Table XV). However, it is clearly distinguishable from these species. Acryptolaria operculata has much larger general dimensions (the differences between them will be discussed below, when dealing with that species). Acryptolaria corniformis is also a larger species with hydrothecae slightly bent abcaulinarly, forming an angle of ca 35 ° with the long axis of branch, the free portion of the adcauline wall is distinctly larger (680–930 Mm), and the larger size-group nematocysts are distinctly smaller (10–15X3–5 Mm). Acryptolaria longitheca has strong affinities with A. crassicaulis , though it has slightly larger hydrothecae, with a larger proportion of the adcauline wall adnate to the internode and with distinctly smaller larger nematocysts (14–16.5X4.5–5.5 Mm).

Clarke (1879) recorded Cryptolaria longitheca from off Tortugas. We considered Clarke’s record as valid, because it completely agrees with Allman’s species in shape and size of the hydrothecae, and in the free proportion of the adcauline wall. Clarke found coppinia and described them as ‘‘clustered upon the upper portions of the stem of one of the finest specimens were a number of peculiar bodies … They are polygonal in form, largest at the distal end, tapering to the base, crowded so closely together that the walls of adjoining bodies are in contact throughout their length, and are provided with a small tubular orifice arising from the centre of the distal end; at the base they are connected by branching stolons’’.

Distribution

Off Double-Headed Shot Key, 567 m ( Allman 1877) and off Tortugas (25 ° 339 N, 84 ° 219 W) , 181.8 m ( Clarke 1879), Florida, USA .

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 5. Acryptolaria corniformis Naumov and Stepanjants, 1962. (A) Branch fragment showing hydrothecal arrangement; (B, C) hydrothecae. All drawings from the holotype. Scale bar: 1 mm (A); 400 Mm (B, C).

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 11. Acryptolaria minuta Watson, 2003. (A–C) Branch fragments showing shape and arrangement of hydrothecae. All drawings from the holotype. Scale bar: 400 Mm.

Figure 12. Acryptolaria operculata Stepanjants, 1979. (A, B) Branch fragments showing shape and arrangement of hydrothecae. All drawings from the paratype. Scale bar: 1 mm.

Figure 13. Acryptolaria pulchella (Allman, 1888). (A) Branch fragment showing hydrothecal arrangement; (B–E) hydrothecae; (F) coppinia fragment (dorsal view); (G) gonotheca (lateral view). All drawings from the holotype. Scale bar: 1 mm (A); 400 Mm (B–G).

Figure 16. Hydrothecal arrangement in Acryptolaria (continued). (A) A. longitheca; (B) A. minima; (C) A. minuta; (D) A. operculata; (E) A. pulchella; (F) A. tortugasensis. Scale bar: 500 Mm (A, D); 250 Mm (B, C, E, F).

Figure 18. Shape of hydrotheca in Acryptolaria (continued). (A) A. gracilis; (B) A. longitheca; (C) A. minima; (D) A. operculata; (E) A. pulchella; (F) A. tortugasensis. Scale bar: 100 Mm (A, C, F); 250 Mm (B, D, E).