Leucosolenia australis Brøndsted, 1928

Azevedo, Fernanda, Hajdu, Eduardo, Willenz, Philippe & Klautau, Michelle, 2009, New records of Calcareous sponges (Porifera, Calcarea) from the Chilean coast, Zootaxa 2072, pp. 1-30 : 12-19

Leucosolenia australis Brøndsted, 1928

( Figs. 6 A–F, 9D; Table 6 )

Material examined. MNRJ 10320; in front of HSFS, Comau Fjord; collected by E.H. & Ph.W.; 9 October 2006; -8 to - 12 m.

Colour. Beige in life and in alcohol.

Description. Sponge delicate formed by erect asconoid tubes (6 mm in length and 2 mm in diameter) connected by a stolon ( Fig. 6 A). At the end of each tube there is an apical osculum without fringe. Surface is slightly hispid because of the presence of diactines. The microdiactines are disposed in parallel to the surface, while the diactines protrude through the surface. The skeleton is also composed of triactines and tetractines tangentially disposed on the surface ( Fig. 6 B). The apical actine of the tetractines is projected inside the lumen ( Fig. 6 C).

Spicules ( Table 6 ). Microdiactine [46.6 (±2.8) / 1.2 (±0.0) µm]: Fusiform and straight, with sharp tips. One of the tips has spines ( Fig. 6 D).

Diactine [198.4 (±73.3) / 6.7 (±1.1) µm]: Curved, with sharp tips. The tip projected outside the sponge sometimes has a lance shape. Near the other tip the spicule is thicker, and sometimes it has a bend, which is occasionally abrupt ( Fig. 6 E).

Triactine [paired actines 83.1 (±9.5) / 6.2 (±0.8) µm, unpaired actine 93.3 (±13.4) / 5.8 (±0.9) µm]: Sagittal. Actines are slightly conical and sharp. The unpaired actine is a little longer than the paired ones ( Fig. 6 F).

Tetractine [paired actines 85.3 (±7.1) / 6.6 (±0.6) µm, unpaired actine 95.0 (±13.3) / 6.3 (±0.6) µm, apical actine 34.0 (±6.9) / 4.1 (±0.7) µm]: Sagittal. Actines are slightly conical and sharp. The unpaired actine is a little longer than the paired ones. The apical actine is much shorter than the basal ones, smooth, sharp and curved in the direction of the paired actines ( Fig. 6 F).

Ecology. Collected specimens were attached to a gastropod shell (Mollusca). A Demospongiae was also attached to this shell.

Remarks. Five species of Leucosolenia have been described from the Southern region of South America (Table 7): L. australis Brøndsted, 1928 ; L. falklandica Breitfuss, 1898 ; L. feuerlandica Tanita, 1942 ; L. lucasi Dendy, 1891 and L. variabilis Haeckel, 1870 ( Breitfuss 1898, Tanita 1942). Comparing our specimen to the original description of these species, we found a great similarity with L. australis and L. lucasi . The first species was originally described from Kerguelen (Subantarctic) and was found later in the Magellanic region ( Tanita, 1942). The second species, L. lucasi , was originally described from Australia (Port Phillip Heads), and reported by Tanita (1942) from southern South America (Strait of Magellan). Both species have the same spicular composition (diactines, triactines, and tetractines) and their shape and size are very similar. However, comparing the illustrations provided in the original descriptions, they can be distinguished by the shape of the diactines. According to Brøndsted (1928), L. australis has fusiform and curved or straight diactines, while L. lucasi has diactines with one lance shaped tip and a bend tip. The collected Chilean specimen has both types of spicules, and also microdiactines. It is possible that Dendy and Brøndsted have not observed those spicules, however, as we had no access to the holotypes, we could not confirm this hypothesis. Besides, as we found both diactine types in our specimen, it is possible that they are also present in both species, and that they are in fact synonyms. As we cannot prove this at the moment, we decided to call the Chilean species L. australis until the holotypes are analysed.

The original measurements of spicules of L. australis and L. lucasi are given here. L. australis – diactine: 160/5 µm, triactine and tetractine: paired 70-5 µm, unpaired 100-5 µm. L. lucasi – diactine: 150–400/8–12 µm; triactine and tetractine: paired 75–110/6–10 µm, unpaired 80–120/6–10 µm, apical 25–80 µm long.

Known geographic distribution. Kerguelen ( Brøndsted, 1928); Strait of Magellan ( Tanita, 1942) Type material. IZUA-POR-0118 = MNRJ 8144 (holotype / alcohol). MNRJ 8147 (paratype / alcohol).

Type locality. Comau Fjord, X th Region, Chile.

Material examined. (IZUA-POR-0118 = MNRJ 8144, MNRJ 12372, MNRJ 12373, MNRJ 12374, MNRJ 12384); in front of HSFS, Comau Fjord; collected by E.H. & Ph.W.; 22 April 2004; - 6.5 m. MNRJ 8147, MNRJ 12375, MNRJ 12376, MNRJ 12377, MNRJ 12378, MNRJ 12379, MNRJ 12380, MNRJ 12381, MNRJ 12382, MNRJ 12383; Punta Llonco, Comau Fjord; collected by V. Häussermann & G.F.; 12 February 2004; - 10 m.

Colour. Beige in life and in alcohol.

Etymology. Named after the Fundación San Ignácio del Huinay (HSFS).

Description. Sponge tubular, very hispid ( Fig. 9 E). The holotype is 16 mm long and 6 mm wide ( Fig. 7A ). The osculum is apical surrounded by a delicate fringe of trichoxeas supported by an organised skeleton of sagittal triactines disposed parallel to each other with the unpaired actine directed towards the basal region ( Fig. 7B ). A suboscular region is present between the base of the crown and the first choanocyte chambers. At this region, there are diactines protruding through the surface. The atrium is central and the wall is 1 mm thick. The radial tubes are fully coalescent ( Fig. 7C ) and have trichoxeas and 2 kinds of diactines protruding through the distal cones ( Fig. 7D ). These diactines are similar to those of the suboscular region. The proximal side of the diactines occasionally crosses the atrial skeleton. The cones are supported by triactines with thicker actines than those of the tubar skeleton. Their unpaired actine crosses the distal part of the cones. The inhalant canals are closed by a thin membrane supported by actines of the spicules of the distal cones. The tubar skeleton is articulated, composed of rows of triactines that point their unpaired actine, which is a little longer than the paired ones, to the surface ( Fig. 7E ). The subatrial skeleton is composed of sagittal triactines (and rare tetractines) that point their unpaired actine, which is longer than the paired ones, towards the distal cones. The atrial skeleton is composed of triactines and tetractines tangentially disposed. The apical actine of the tetractines is shorter than the basal ones and as thick as the basal ones. They are projected into the atrium ( Fig. 7F ). Trichoxeas are also present in the atrium, where they lay tangentially. The holotype shows reproductive structures (amphiblastula larvae).

Spicules ( Table 8). Trichoxeas of the perioscular crown (>1,668 / 4.9 µm) and of the distal cones (>117 / 2.4 µm): As they were frequently broken, it was difficult to measure them.

Diactines I of the suboscular region and of the distal cones [343.0 (±59.2) / 7.6 (±1.3) µm]: These spicules are cylindrical and straight. Both tips are sharp but one tip is thicker than the other ( Fig. 7G ).

Diactines II of the suboscular region and of the distal cones [673.1 (±390.2) / 14.2 (±4.8) µm]: Large, slightly curved, undulated and fusiform. Both tips are sharp, but one of them is lanceolate ( Fig. 7H ). They have very variable size and the smaller spicules are more abundant. Each cone has at least 3 of these diactines.

Triactines of the distal cones [unpaired actine 70.6 (±12.6) / 6.2 (±0.7) µm, paired actines 95.0 (±9.4) / 6.2 (±0.7) µm]: Sagittal. Actines are conical and sharp. Paired actines are frequently curved, accompanying the shape of the distal cones. They are longer than the unpaired actine, which points to the surface ( Fig. 7I ).

Tubar triactines [unpaired actine 135.1 (±30.6) / 6.8 (±0.5) µm, paired actines 84.6 (±9.6) / 6.2 (±0.7) µm]: Sagittal. Actines are conical, undulated and sharp. Paired actines are curved and shorter than the unpaired one, which points to the surface. Frequently one of the paired actines is shorter than the other ( Fig. 7J ).

Subatrial triactines and tetractines [triactines - unpaired actine 127.5 (±18.3) / 6.8 (±1.0) µm, paired actines 80.8 (±12.4) / 5.5 (±0.6) µm]: Sagittal to subregular, with curved paired actines. Actines are conical and sharp. The unpaired actine is longer than the paired ones, and points to the surface ( Fig. 7K ). The rare tetractines are very similar to the triactines, but they show a thin apical actine shorter than the basal ones. It is curved, smooth, conical and sharp.

Atrial triactines and tetractines [triactines—unpaired actine 127.3 (±27.5) / 6.8 (±0.8) µm, paired actines 86.1 (±18.3) / 5.6 (±0.7) µm; tetractines—unpaired actine 160.4 (±28.7) / 7.6 (±0.5) µm, paired actines 106.0 (±30.4) / 6.8 (±0.9) µm, apical actine 40.5 (±5.4) / 7.5 (±0.0) µm]: Sagittal to subregular, with curved paired actines. They are tangentially disposed. Actines are conical and sharp. The unpaired actine is longer than the paired ones. The tetractines are less abundant than the triactines. Their apical actine is shorter than the basal ones, conical, smooth and sharp and penetrates the atrium ( Fig. 7L and 7 M ).

Ecology. Specimens are found on vertical hard substrate, associated to mussels ( Mytilus chilensis ) and exposed to sunlight. Its relatively shallow occurrence denotes resistance to reduced salinity levels found in the upper layers of the fjord.

Remarks. Five species of Sycon have been previously documented off the Chilean coast (Table 9): S. raphanus var. proboscidea Haeckel, 1870 , reported by Breitfuss (1898); S. coronatum var. commutata Haeckel, 1872 , reported by Breitfuss (1898); S. incrustans Breitfuss, 1898 , originally described from Chile; S. coronatum ( Ellis & Solander, 1786) , reported by Tanita (1942); and S. ornatum Kirk, 1897 , cited by Tanita (1942). S. coronatum was synonymised to S. ciliatum ( Fabricius, 1780) by Burton (1963) and this synonymy was subsequently accepted by Borojevic (1967). The same happened to S. commutatum as it was a variety of S. coronatum , however, we decided not to consider this synonym until a revision of the genus is done.

As the Chilean specimens of S. coronatum var. commutata , S. raphanus var. proboscidea and S. coronatum were not formally described by Breitfuss (1898) and Tanita (1942), we could not confirm their identifications. Therefore, we compared S. huinayense sp. nov. to the original descriptions of these species instead, pending a re-examination of Breitfuss’ and Tanita’s materials.

The presence of a suboscular region in S. huinayense sp. nov. differentiate it from all other Sycon spp. cited for Chile, but further differences were also found.

S. huinayense sp. nov. can be also differentiated from S. coronatum by the size of the apical actine of the atrial tetractines, which is as long as the basal actines in S. coronatum and much shorter than the basal actines in our species. This distinctive feature is also present in the former variety of S. coronatum , viz. S. commutatum . S. proboscideum can also be differentiated by the size of the diactines, which is much larger in this species (e.g. 1000 to 3000 µm long and 30 to 40 µm thick) and organised differently, with a single largest diactine in the centre of each tuft of diactines of the cone. Besides, Haeckel (1872) mentioned that the apical actine of the atrial tetractines was a little shorter than the basal actines, while in S. huinayense sp. nov. the apical actine is much shorter. In relation to S. incrustans , the atrial skeleton is composed only of triactines and rare tetractines with vestigial apical actine. In S. huinayense sp. nov. atrial tetractines are abundant (although less abundant than the triactines) and their apical actines are not vestigial. Finally, S. ornatum , a species from the Cook Strait, can be differentiated by the thickness of all actines (thinner in the new species) and by the absence of triactines in the atrial skeleton of S. ornatum .

(MNRJ 8147, MNRJ 12372).

Spicule Length (µm) Width (µm) n min mean s max mean s

IZUA-POR-0118 Diactine I 241.5 343.0 59.2 493.5 7.6 1.3 30 Diactine II 315.0 673.1 390.2 1,449.0 14.2 4.8 30 Triactine from the Unpaired 49.5 70.6 12.6 92.4 6.2 0.7 30 cones Paired 72.6 95.0 9.4 115.5 6.2 0.7 30 Tubar triactine Unpaired 89.1 135.1 30.6 217.8 6.8 0.5 30 Paired 69.3 84.6 9.6 112.2 6.2 0.7 30 Subatrial triactine Unpaired 93.6 127.5 18.3 150.8 6.8 1.0 30 Paired 44.2 80.8 12.4 109.2 5.5 0.6 30 Atrial triactine Unpaired 81.6 127.3 27.5 195.0 6.8 0.8 30 Paired 59.8 86.1 18.3 124.8 5.6 0.7 30 Atrial tetractine Unpaired 91.0 160.4 28.7 208.0 7.6 0.5 20 Paired 57.2 106.0 30.4 150.8 6.8 0.9 20 Apical 30 40.5 5.4 50.0 7.5 0.0 20

MNRJ 8147 Diactine I 220.5 394.2 117.5 724.5 6.9 1.7 26 Diactine II 367.5 804.3 445.8 2,100.0 12.8 4.1 30 Triactine from the Unpaired 39.0 61.8 13.2 91.0 5.5 0.5 20 cones Paired 65.0 87.6 10.3 101.4 5.5 0.5 20 Tubar triactine Unpaired 91.0 115.8 21.8 156.0 6.0 0.8 20 Paired 70.2 88.9 11.0 106.6 5.7 0.7 20 Subatrial triactine Unpaired 104.0 149.8 16.7 176.8 6.6 1.2 20 Paired 57.2 81.4 11.7 104.0 5.5 0.6 20 Atrial triactine Unpaired 85.8 128.8 28.9 195.0 6.0 0.8 20 Paired 65.0 91.7 24.2 143.0 5.5 0.8 20 Atrial tetractine Unpaired 91.0 133.1 33.7 189.8 7.4 0.8 11 Paired 83.2 121.5 22.1 156.0 6.6 0.9 11 Apical 18.2 32.1 5.9 44.2 7.3 0.9 20

MNRJ 12372 Diactine I 315.0 386.9 58.7 525.0 6.9 1.4 20 Diactine II 294.0 646.8 371.4 1,365.0 13.2 4.3 30 Triactine from the Unpaired 46.8 70.7 11.6 96.2 7.3 0.8 20 cones Paired 57.2 84.0 15.9 114.4 6.6 0.7 20 Tubar triactine Unpaired 70.2 113.5 23.4 174.2 7.0 1.0 20 Paired 59.8 84.1 10.7 104.0 6.2 1.2 20 Subatrial triactine Unpaired 98.8 132.1 22.8 169.0 6.6 1.1 20 Paired 57.2 78.3 11.2 96.2 5.2 0.0 20 Atrial triactine Unpaired 70.2 150.2 47.5 236.6 8.3 0.9 20 Paired 49.4 95.7 27.0 158.6 7.2 1.0 20 Atrial tetractine Unpaired 122.2 140.0 20.1 166.4 7.8 0.0 6 Paired 65.0 110.5 34.8 156.0 6.5 1.4 6 Apical 31.2 37.1 6.2 52.0 7.7 0.9 20

All specimens Diactine I 220.5 374.7 27.7 724.5 7.1 0.4 - Diactine II 294.0 708.1 84.4 2,100.0 13.4 0.7 - Triactine from the Unpaired 39.0 67.7 5.1 96.2 6.3 0.9 - cones

Paired 57.2 88.9 5.6 115.5 6.1 0.6 - Tubar triactine Unpaired 70.2 121.5 11.9 217.8 6.6 0.5 - to be continued.

Figures

FIGURE 6. External and internal morphology of Leucosolenia australis; A—Fixed specimen; B—Tangential view of tube wall; C—Detail showing the apical actine of tetractines penetrating into the lumen; D—Microdiactine with detail of the two tips; E—Diactine; F—Triactine (black arrow) and tetractine (white arrow).

FIGURE 9. Specimens in situ: A— Clathrina fjordica sp. nov.; B— Guancha ramosa sp. nov.; C— Leucaltis nuda sp. nov.; D— Leucosolenia australis; E— Sycon huinayense sp. nov.; F— Sycettusa chilensis sp. nov.

FIGURE 7 A – I. External and internal morphology of Sycon huinayense sp. nov. A—Fixed specimen; B—Detail of the oscular skeleton; C—Transversal section; D—Detail of the distal cone; E—Detail of the tubar skeleton; F—Subatrial (arrow shows a subatrial triactine) and atrial skeletons (at: atrium); G— Diactine I; H—Diactine II; I – Triactine of the cone.

Tables

TABLE 6. Spicules measurements of the specimen of Leucosolenia australis (MNRJ 10320).

Spicule		Lenght (µm)			Width (µm)	n
		min mean	s	max	mean s
MNRJ 10320 Microdiactine		41.3 46.6	2.8	48.6	1.2 0.0	6
Diactine		62.7 198.4	73.3	346.5	6.7 1.1	30
Triactine	Paired Unpaired	66.0 83.1 69.3 93.3	9.5 13.4	105.6 122.1	6.2 0.8 5.8 0.9	30 30
Tetractine	Paired	69.3 85.3	7.1	99.0	6.6 0.6	30
	Unpaired	66.0 95.0	13.3	118.8	6.3 0.6	30
	Apical	26.7 34.0	6.9	41.3	4.1 0.7	5