Gibbolucina zelee, Taylor & Glover, 2018

Taylor, John D. & Glover, Emily A., 2018, Hanging on - lucinid bivalve survivors from the Paleocene and Eocene in the western Indian Ocean (Bivalvia: Lucinidae), Zoosystema 40 (7), pp. 123-142: 127

publication ID

http://doi.org/ 10.5252/zoosystema2018v40a7

publication LSID

lsid:zoobank.org:pub:urn:lsid:zoobank.org:pub:7652DEC7-3C6C-414F-AF2C-7C396D78F6F6

DOI

http://doi.org/10.5281/zenodo.3811347

persistent identifier

http://treatment.plazi.org/id/03858788-FFC3-F17A-FED1-FA5E4B39F81D

treatment provided by

Felipe

scientific name

Gibbolucina zelee
status

n. sp.

Gibbolucina zelee   n. sp.

( Fig. 2A-S View FIG )

urn:lsid:zoobank.org:act:3994D94E-2522-4608-B837-513901FE615B

TYPE MATERIAL. — Holotype. Whole shell, L 15.3 mm, H 14.8 mm, T single valve 4.3 mm ( MNHN-IM- 2000-33710). Shell in 70% ethanol rehydrated from dried sample   .

Paratypes. From type locality, MNHN-IM- 2000-33711 figured 1 whole shell with body rehydrated ( Fig. 2 View FIG E-G) L 12.7 mm, H 12.5 mm   ; 1 dry shell L 17.7 mm, H 16.2 mm   ; 2 whole shells, L 10.5 mm, H 10.7 mm, L 9.2 mm, H 9.3 mm   ; unfigured 2 whole shells with bodies reconstituted, L 16.9 mm, H 17.4 mm, ( NHMUK paratype 20170401), L 13.7 mm, H 13.8 mm   ; unfigured 6 whole shells and 3 single valves   .

TYPE LOCALITY. — Mozambique Channel, Banc de la Zélée, Expédition BENTHEDI 1977 stn R110, 12°25’6”S, 46°16’2”E, 24 m, 10.IV.1977. Shallow, sandy bottom in the lagoon with dense seagrass beds of Thalassodendron ciliatum ( Thomassin et al. 2009)   GoogleMaps   .

ETYMOLOGY. — From French for zealous, named for Banc de la Zélée itself named after one of the ships of J. Dumont d’Urville’s Astrolabe Expedition (1837-1840).

OTHER MATERIAL EXAMINED. — Madagascar. Campagne MIRIKY, stn DW 3255, North of Cap Saint-André , 15°48.2’S, 44°43’E, 36 -39 m, 1 rv ( L 15.3 mm) ( MNHN). GoogleMaps   Campagne MIRIKY, stn CP3287, in front of Baie Narendry , 14°33.7’S, 47°27.9’E, 48 -54 m, 1 rv ( L 14.6 mm) ( MNHN). GoogleMaps   Toliara, Grand Récif de Tuléar, Andeteky area, outer reef slope, lower platform 24 m sand, Thomassin stn TUL 222, 2 lv (1 broken, and L 4.3 mm), 1 rv ( L 10.9 mm) ( MNHN). GoogleMaps   Beloza, Grand Récif de Tuléar lagoon, inner coral reef, coarse sand <1 m, Thomassin stn TUL 257, 1 lv ( L 11.1 mm) ( MNHN). GoogleMaps   South (2-3 mi) of Nosy Iranja, 31 mi (50 km) SW of Nossi Bé, 15-18 fthms (27-33 m), muddy sand, stn H, 12 v ( ANSP 263071 View Materials ). GoogleMaps   West (7 mi) of Angorombalo, SW Nossi Bé, 35 fthms (64 m), fine sand and mud, stn H 66, 12 v juveniles ( ANSP 261566 View Materials ). GoogleMaps   West (4 mi) of Nosy N’Tangam, SW Nossi Bé , 20 fthms (37 m), muddy sand, stn H 68, I rv, ( L 13.7 mm) ( ANSP 260083 View Materials ) GoogleMaps   .

DISTRIBUTION. — Mozambique Channel, Western Madagascar.

DESCRIPTION

Shell small, longer than high, L to 17.7 mm, H. to 16.0 mm, subtrigonal, anteriorly extended, umbones prominent. Thin, lightweight, glossy or waxy shell with thick periostracum; in a rehydrated specimen this is clear, flexible with pleated flaps ( Fig. 2E View FIG ). Ventral edge of periostracum extending beyond the shell margin ( Fig. 2G View FIG ). In dry specimens, periostracum thick and encrusting. Sculpture of irregular, widely spaced, low, commarginal lamellae. Shell often with growth distorsions ( Fig. 2H View FIG ). Protoconch: P1 + P2 = 210 µm, PI 189 µm, with PII a narrow rim with no growth increments ( Fig. 2S View FIG ). Lunule ovate, scooped, symmetrical. Ligament short, set on shallow resilifer. Hinge teeth: LV with two, small, cardinal teeth, RV with a single bifid cardinal. Lateral teeth absent. Anterior adductor muscle scar medium long, detached for ½ of length at an angle of 15°. Posterior scar small, elongate, ovoid. Pallial line entire.Ventral margin smooth, shell interior often thickened particularly across the posterior and around the anterior adductor scar.

Anatomy

Limited observations from a rehydrated body ( Fig. 2G View FIG ) show ctenidia with single thickened demibranchs occupying half of mantle cavity, a vermiform foot, simple posterior apertures lacking papillae and short ventral mantle fusion.

REMARKS

Gibbolucina zelee   n. sp. is similar in shape and hinge characters to Gibbolucina trigonula   from the Miocene of the Aquitaine Basin, France ( Fig. 1O, P View FIG ). The only other similar species in the Indian Ocean is Megaxinus arabicus Glover & Taylor, 1997   (holotype NMW. Z.1995.009) described from a depth of 58 m off southern Oman. Although this has the overall shape of Gibbolucina   species, the hinge has no defined teeth only some irregular folds and the anterior adductor scar is longer, both features similar to Megaxinus transversus (Bronn, 1831)   .

NHMUK

NHMUK

MNHN

France, Paris, Museum National d'Histoire Naturelle

ANSP

USA, Pennsylvania, Philadelphia, Academy of Natural Sciences

NHMUK

Natural History Museum, London

MNHN

Museum National d'Histoire Naturelle