Phaneropora galatheae Zezina, 1981

Bitner, Maria Aleksandra & Logan, Alan, 2016, Recent Brachiopoda from the Mozambique-Madagascar area, western Indian Ocean, Zoosystema 38 (1), pp. 5-41 : 28

Phaneropora galatheae Zezina, 1981

( Fig. 15 ; Table 13)

Phaneropora galatheae Zezina, 1981a: 18-19 , pl. 4, figs 1-7; 1985: 205; 1987: 560. — Foster 1989: 298, fig. 14.29-14.30. — Laurin 1997: 449, 450, figs 36A-D, 37. — Bitner 2008: 444, fig. 15A- F.; 2009: 16, fig. 9A.

Leptothyrella cf. ignota – Hiller 1986: 137, 138, fig. 19A-D.

MATERIAL EXAMINED. — Mozambique Channel. MAINBAZA, stn CC 3152, 29 bivalved specimens. — Stn CC 3153, 4 bivalved specimens. — Stn CC 3154, 5 bivalved specimens.

South Madagascar. ATIMO VATAE, stn DW 3515, 1 bivalved specimen. — Stn CP 3585, 10 bivalved specimens. — Stn CP 3592, 22 bivalved specimens, 1 ventral valve, 1 dorsal valve. — Stn CP 3615, 5 bivalved specimens.

DEPTH RANGE. — 184- 636 m.

MEASUREMENTS. — See Table 13.

REMARKS

The subfamily Phaneroporinae is represented by two genera, the monospecific genus Phaneropora Zezina, 1981 and Leptothyrella Muir-Wood, 1959 having three species, L. ignota , L. incerta , and L. fijiensis . Both genera are very similar exter- nally but clearly differ internally. In Phaneropora there is a gap between the crura and septal pillar ( Zezina 1981a, 1987; Bitner 2008) whereas Leptothyrella has continuous descending branches attached to the septum (Muir-Wood 1959; Logan 1983, 1998; Álvarez & Emig 2005; Bitner 2008). Thus, the presence or absence of descending branches constitute the main criterion for separating those genera ( MacKinnon & Lee 2006b; see also discussion in Bitner 2008: 444).

Phaneropora galatheae has already been reported from the Madagascar region ( Hiller 1986; Zezina 1987). It is a small species, weakly biconvex with a smooth surface. Its foramen is large, margined by two, narrow deltidial plates; beak ridges are distinctly tuberculate ( Fig. 15F, H ). The teeth are supported by short dental plates ( Fig. 15I ). The flattened area at the extremity of each crura is interpreted as the rudiment of a descending branch ( Fig. 15L, M ).

Figures

FIG. 15. — Phaneropora galatheae Zezina, 1981, South Madagascar, South-West Point Barrow, ATIMO VATAE, stn CP 3592, 450-455 m: A-C, dorsal view (A) of immature complete specimen (MNHN IB-2013-84), and enlargement of the umbonal part to show details of the beak (B) and the dorsal protegular node (C); D, dorsal view of complete specimen (MNHN IB-2013-85); E, F, dorsal view of complete specimen (E) and enlargement of the umbonal part (F) (MNHN IB- 2013-86); G-I, inner view of ventral valve (MNHN IB-2013-87), and enlargement of posterior part (H), and tilted view to show dental plates (I); J-M, dorsal valve (MNHN IB-2013-88), inner and oblique views, and enlargement (L, M) to show details of brachidium and cardinalia. All SEMs. Scale bars: A, F, H, I, L, 500 µm; B, M, 200 µm; C, 50 µm; D, E, G, J, K, 1 mm.