Acryptolaria abies ( 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 : 233-235

Acryptolaria abies ( Allman, 1877)

( Figures 1 , 15A , 17A ; Table I)

Cryptolaria abies Allman 1877, p 20 , 21, Plate 13 Figures 1 , 2 .

Material examined

Lectotype: MCZ 9063 , Atlantic Ocean, Gulf Stream Expedition, several fragments up to 20 mm long . Paralectotype: MCZ 9077 , Atlantic Ocean, Gulf Stream Expedition, four fragments up to 18 mm long and one incipient stem ca 5 mm high . Other material: MCZ 45714, off Double-Headed Shot Key (23 ° 579300 S, 80 ° 299150 W), 315 fathoms (567 m), a vial with four fragments up to 9 mm included in the type material of Acryptolaria longitheca .

Description

‘‘Hydrocaulus attaining a height of about two inches [50.8 mm], irregularly branched, with a pinnate disposition of the ultimate ramuli’’ ( Allman 1877, p 20). Presently, lectotype material composed of several fragments up to 20 mm in length. Most fragments belonging to the strongly polysiphonic basal part of stem. Stem hydrothecae barely visible. Stem straight, giving rise to lateral branches at right angles, probably following an alternate pattern. Branches straight.

Hydrothecae alternately arranged in approximately one plane. Hydrotheca almost cylindrical; diameter sharply decreasing at basal part and, sometimes, slightly from the middle to the distal part. Hydrotheca gently curved abcaulinarly; adcauline wall approximately two-thirds adnate to internode. Adcauline wall convex; abcauline wall practically straight at basal half, concave at distal half. Hydrothecal aperture circular, parallel to longitudinal axis of branch or slightly directed upwards or downwards. Sometimes adcauline wall longer than abcauline one and, consequently, hydrothecal aperture oblique. Rim even, sometimes with few short renovations.

Coppinia not observed.

Remarks

The material described by Allman (1877) is presently divided into two lots, both held in the Museum of Comparative Zoology at Harvard University and, therefore, should be considered as syntypes of the species. We chose the material MCZ 9063 as the lectotype and MCZ 9077 as paralectotype of A. abies ( International Commission on Zoological Nomenclature 1999, Article 74).

Allman (1877, p 20) already noticed that ‘‘the hydrothecae of this species [ A. abies ] are considerably smaller than those of either C. conferta or C. longitheca . They can be seen … to be of a very different shape from those of the two former species, being here of an elongated flask-shape, tumid below and gradually narrowing towards its orifice’’.

Allman (1877, p 20) also pointed out that ‘‘Here [ A. abies ] also they [the hydrothecae] are plainly provided with a distinct floor, and in all respects resemble a typical sertularian hydrotheca’’, and figured (Plate 13 Figure 2 ) the hydrothecae completely closed at their base. Nevertheless, the examination of type material leaves no doubt that the hydrotheca is devoid of a floor or diaphragm, as shown in Figure 1 . The sharp decrease in diameter of the hydrothecae at the hydrothecal base could account for Allman’s (1877) mistake.

In the examined type material of A. longitheca ( MCZ 45714), there was a small vial with four fragments up to 9 mm long which clearly belong to A. abies . In these fragments the branching is alternate in one plane and the angle between stem and branches is ca 45 °. The shape and size of the hydrotheca is in complete agreement with the type material of A. abies .

Distribution

According to Allman (1877), the label belonging to the type material of A. abies was effaced, it not being possible to ascertain the exact locality and depth from which the specimen came. The material of A. longitheca here assigned to A. abies was collected at a depth of 567 m off Double-Headed Shot Key (23 ° 579300 S, 80 ° 299150 W), Florida.

Figures

Figure 1. Acryptolaria abies (Allman, 1877). (A) Part of branch showing hydrothecal arrangement; (B–F) hydrothecae. (A–C, E) From the paralectotype; (D) from the lectotype; (F) from MCZ 45714. Scale bar: 1 mm (A); 400 Mm (B–F).

Figure 2. Acryptolaria angulata (Bale, 1914). (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.