Pyura gangelion ( Savigny, 1816 )

Monniot, Françoise, 2018, Ascidians collected during the Madibenthos expedition in Martinique 3. Stolidobranchia, Pyuridae and Molgulidae, Zootaxa 4459 (3), pp. 401-430: 413-414

publication ID

https://doi.org/10.11646/zootaxa.4459.3.1

publication LSID

lsid:zoobank.org:pub:5C5A86AC-6FA4-46AD-9A89-068E9119DD28

persistent identifier

http://treatment.plazi.org/id/039187CA-B956-3C0A-FF6B-506FBA903AFD

treatment provided by

Plazi

scientific name

Pyura gangelion ( Savigny, 1816 )
status

 

Pyura gangelion ( Savigny, 1816) 

Figs 12 View Figure , 13 View Figure , 14 View Figure , 15 View Figure

Cynthia gangelion Savigny, 1816 

Pyura gangelion: Monniot C. 1973  , Elat, Fig. 3B View Figure ; Monniot F. & C. 2001, Indonesia, Fig. 106; Kott 2004 (synonymy excluded).? Pyura sansibarica: Millar 1956  Mozambique

Pyura torpida: Monniot C. 1983  (Martinique)

? Pyura albanyensis: Monniot F. & C. 1996  , Micronesia, Fig 58

Stations: AR 87, AR 100. AB 199. (MNHN S2 PYU 501)

The specimens are fixed by their ventral side ( Fig. 12A,B View Figure ). The tunic is wrinkled, more or less covered with epibionts. In formalin the tunic is beige on the body and brown near the siphons. The siphon apertures are surrounded by protuberances and they have dense spinules. The internal tunic lining at both siphon apertures is brown and thick with spinules of different sizes as long as 0.25mm with a more or less inflated centre ( Figs 12E,F View Figure ; 15B View Figure ). This internal tunic is prolonged more interiorly in a thinner bulbous membrane without spinules but with chalk-white round inclusions ( Fig.12C View Figure ). This deep part of the siphonal lining is tightly applied on the thin internal velum and is divided into 4 wide lobes only at the atrial siphon ( Figs 12C View Figure , 15A View Figure ). This atrial lobed membrane is also present in specimens from Eilat and Djibouti ( MNHNAbout MNHN collection) ( Fig.15A View Figure ). The body wall is thin, except on the red and much contracted siphons. The musculature issued from each siphon forms well separated bundles regularly crossed on both body sides ( Fig. 13A View Figure ). There are about 18 large oral tentacles with short pinnules and smaller tentacles intercalated at the base of the velum. The prepharyngeal band, in a deep dorsal V, encloses a dorsal tubercle with horns variably rolled ( Fig. 13B View Figure ). The dorsal lamina has numerous long thin papillae erect along the rim of an imperforated band. The 6 high branchial folds on each body side end by papillae at the oesophagus entrance ( Fig.14A View Figure ). The longitudinal vessels are equally spaced over and between the folds and it is difficult to know when they belong to a fold or to the interspace. There is an average of 5 stigmata in a mesh between the folds and 4 stigmata on the sides of the folds. There are parastigmatic vessels and the main transverse vessels are particularly wide. A branchial formula on the right side in a specimen 5cm large is: E- 8 (30) 7 (34) 6 (34) 6 (35) 6 (32) 6 (22) 5-DL.

The gut loop widely opened extends far anteriorly occupying a large part of the left body side ( Figs 13A View Figure ; 14B View Figure ). It is totally attached to the body wall. The stomach is slightly enlarged at the cardia and wears few digitate hepatic lobes; on the pyloric part there is a hepatic massive pedunculate gland in shape of cauliflower with dark green papillae in a convoluted design ( Figs 13A View Figure ; 14B View Figure ). The intestine is narrow and isodiametric with the wall of the descending limb wrinkled in transverse ridges. Foliated endocarps are numerous on the gut along the exterior side of the loop from the oesophagus to the anus. The anus in a funnel has a slim rim in few low lobes ( Fig. 13C View Figure ). There is one curved gonad on each side with 15 to 20 lobes on the left gonad and up to 25 lobes on the right one ( Figs 13A View Figure ; 14B View Figure ). The left gonad is totally included inside the gut loop and all lobes wear endocarps. The right gonad is parallel to the endostyle and curves posteriorly. The short gonoducts open near to the atrial siphon ( Fig. 13A View Figure ). In the space between the right gonad and the endostyle is a long and inflated vessel wearing aligned endocarps ( Fig. 13A View Figure ; 14C View Figure ). There are no endocarps on the body wall.

Remarks: Specimens described under the name Pyura torpida  by Monniot (1983) from Martinique have been re-examined and have the same anatomy as the Madibenthos samples. The characters described above also well correspond to re-examined specimens of P.gangelion  from Eilat redescribed by Monniot C. (1973) and specimens from Djibouti ( Fig. 15 View Figure ). In the same publication

Monniot (1973) suggested a possible synonymy between P. gangelion  and P. sansibarica Michaelsen 1908  ; this is emphasised by precisions given by Millar (1956) for a specimen identified as P. sansibarica  from Mozambique (he noted “white spherical bodies” different from spicules). The Indo-Pacific material named P.albanyensis  ( Monniot F. & C. 1996 Fig. 58 and 2001 Fig. 106) and P. gangelion: Kott (2004)  have the same organisation but the tunic is thicker and the 4- lobed atrial membrane of the siphon is not mentioned or not present.

P. gangelion  by its external aspect, the spinules, the branchial sac, the gonads and the absence of endocarps on the body wall, can be confused with P. vittata  . Both species are variable but they differ by the diameter of the rectum, the internal tunic lining of the siphons, dark brown in P. vittata  and with a 4-lobed atrial membrane and chalky inclusions in P. gangelion  . The spinules have a similar shape in both species but are more iridescent in P. vittata  .

MNHN

Museum National d'Histoire Naturelle

Kingdom

Animalia

Phylum

Chordata

Class

Ascidiacea

Order

Stolidobranchia

Family

Pyuridae

Genus

Pyura

Loc

Pyura gangelion ( Savigny, 1816 )

Monniot, Françoise 2018

2018
Loc

Pyura albanyensis:

Monniot F. 1996

1996
Loc

Pyura torpida:

Monniot C. 1983

1983
Loc

Pyura gangelion:

Monniot C. 1973

1973
Loc

Pyura sansibarica:

Millar 1956

1956
Loc

Cynthia gangelion

Savigny 1816

1816