Amphoriscus semoni Breitfuss, 1896

Van, Rob W. M. & De, Nicole J., 2018, Calcareous sponges of the Western Indian Ocean and Red Sea, Zootaxa 4426 (1), pp. 1-160: 130-132

publication ID

https://doi.org/10.11646/zootaxa.4426.1.1

publication LSID

lsid:zoobank.org:pub:18929E20-5296-4458-8A8A-4F5316A290FD

persistent identifier

http://treatment.plazi.org/id/386CC616-DCF3-A5B2-FF67-8C5CFC6DFA1C

treatment provided by

Plazi

scientific name

Amphoriscus semoni Breitfuss, 1896
status

 

Amphoriscus semoni Breitfuss, 1896 

Figs 80a–e View Figure , 81a–d View Figure

Amphorisus semoni Breitfuss, 1896: 435  ; Breitfuss 1898: 221; Van Soest & De Voogd 2015: 93, figs 68a–f.

Material examined. ZMAAbout ZMA Por. 10527, Seychelles, NE of Aride Island, 4.1667°S 55.7333°E, depth 55 m, Agassiz trawl, coll. R.W.M. van Soest, field nrGoogleMaps  . NIOP-E stat. 714/ 01, 19 December 1992.

Description. The sample consists of a dozen small thin tubes ( Fig. 80a View Figure ), which are mostly loose, but two tubes are attached together to a small stone. It is likely the tubes were in contact on the substratum. Live color reported as white, in alcohol they become beige. Size of individual tubes 1–3 cm high, 5–9 mm in diameter. Apical oscules naked. Consistency soft.

Aquiferous system. Syconoid.

Skeleton. ( Figs 80b–e View Figure ) Inarticulate ( Fig. 80b View Figure ). The cortical skeleton ( Figs 80c–d View Figure ) is formed by the unpaired and paired actines of giant tetractines. The apical actines of the ectosomal tetractines form the choanosomal skeleton together with the unpaired actines of subatrial sagittal triactines. The subatrial skeleton is formed by the paired actines of sagittal triactines and all actines of smaller triactines. The atrial skeleton ( Fig. 80e View Figure ) is formed by small tetractines, the apical actines of which protrude into the atrial lumen.

Spicules. ( Figs 81a–d View Figure ) Giant tetractines, triactines, small tetractines.

Giant tetractines ( Fig. 81a View Figure ), with straight or curved actines of rather variable length and thickness, unpaired actines 162– 264 –487 x 12 – 20.1 –31 µm, paired actines 210– 336 –552 x 12 – 21.1 –29 µm, apical actines 239– 425 –882 x 13 – 21.8 –31 µm.

Triactines ( Figs 81b–c View Figure ), divisible in overlapping larger and smaller spicules:

Large triactines ( Fig. 81b View Figure ), sagittal, usually with unpaired actines slighty shorter; unpaired actines 200– 266 –342 x 13 – 14.8 –18 µm, paired actines 279– 309 –336 ≈ 12– 13.3 –15 µm.

Small triactines ( Fig. 81c View Figure ), slightly sagittal, unpaired actines 48– 137 –180 x 7 – 9.4 –14 µm, paired actines 88– 178 –246 x 6 – 8.8 –11 µm.

Small tetractines ( Figs 81d View Figure ), sagittal, often with curved or wobbly paired actines; unpaired actines 81– 150 –241 x 7 – 9.4 –11 µm, paired actines 121– 214 –269 x 7 – 9.8 –12 µm, apical actines 15– 54 – 94 x 3 – 5.2 –7 µm.

Distribution and ecology. Indonesia, Seychelles, shallow-water down to 55 m.

Remarks. We assign this material to the Indonesian species A. semoni  because of overall similarity with recently described material (cf. Van Soest & De Voogd 2015). However, there are several discrepancies: the tubes of the Indonesian ZMAAbout ZMA Por. 0 8073 were described as green in life, and they also appeared slightly different in shape as their diameter gradually narrowed down towards the substratum, whereas our present specimens were white in life and and remain cylindrical over most of their length. The apical actines of the giant tetractines of the Indonesian specimens penetrated through the atrial wall, which we do not observe in the present specimens. We consider these differences as minor  and subject to variation.

The South African Amphoriscus kryptoraphis Urban, 1908  , from deeper water (155 m) differs from the above a.o. by the possession of trichoxeas. Unfortunately, our attempt to obtain partial 28S sequences failed.

ZMA

Universiteit van Amsterdam, Zoologisch Museum

Kingdom

Animalia

Phylum

Porifera

Class

Calcarea

Order

Leucosolenida

Family

Amphoriscidae

Genus

Amphoriscus

Loc

Amphoriscus semoni Breitfuss, 1896

Van, Rob W. M. & De, Nicole J. 2018

2018
Loc

semoni

: 435