Recent Brachiopoda from the Mozambique-Madagascar area, western Indian Ocean Author Bitner, Maria Aleksandra Institute of Paleobiology, Polish Academy of Sciences, ul. Twarda 51 / 55, 00 - 818 Warszaw (Poland) bitner @ twarda. pan. pl bitner@twarda.pan.pl Author Logan, Alan Centre for Coastal Studies, University of New Brunswick, Saint John, N. B., E 2 L 4 L 5 (Canada) logan @ unbsj. ca Published on 25 March 2016 logan@unbsj.ca text Zoosystema 2016 2016-03-31 38 1 5 41 http://dx.doi.org/10.5252/z2016n1a1 journal article 10.5252/z2016n1a1 1638-9387 4578148 urn:lsid:zoobank.org:pub:96BFE594-1B39-4541-9441-181617BD4CF9 Eucalathis malgachensis n. sp. ( Fig. 11 ; Table 10 ) TYPE MATERIAL . — South Madagascar . ATIMO VATAE , stn CP 3614, holotype ( MNHN IB-2013-64 ; Fig. 11 F-I). — Same locality, stn DW 3552, CP 3614, CP 3615, four paratypes ( MNHN IB-2013- 66 - 69 : Fig. 11 B-E, J-L) . TYPE LOCALITY . — South Madagascar , South Cap Sainte Marie, ATIMO VATAE , stn CP 3614, 26°14’S , 45°09’E , 250- 300 m . FIG. 8. — Terebratulina meridionalis Jackson,1952 ; A -E , dorsal views of complete specimens,and enlargements ( C , E ) of umbonal part to show details of the beak (MNHN IB-2013-50-52), South Madagascar, north of Sainte Luce, ATIMO VATAE, stn DW 3530, 80-86 m; F -H , interior of dorsal valve (MNHN IB-2013-53), inner ( F ) and oblique ( G ) views, and enlargement ( H ) of posterior part to show details of loop and cardinalia, South Madagascar, north of Sainte Luce, ATIMO VATAE, stn DW 3532,86-87 m; I , dorsal view of complete specimen (MNHN IB-2013-54), Mozambique Channel, Maputo transect, MAINBAZA, stn CC 3175,155-165 m. All SEMs. Scale bars: A, B, D, F, G, I, 2 mm; C, E, H, 1 mm. ETYMOLOGY. — Referring to the Malgache, the French name of the ethnic group that forms nearly the entire population of Madagascar . DIAGNOSIS. — Eucalathis with fascicostate surface, primary ribs strong, triangular in cross-section, 7 to 9 in number, loop angular at the anterior. MATERIAL EXAMINED. — South Madagascar . ATIMO VATAE , stn DW 3515, 1 bivalved specimen. — Stn DW 3522, 7 bivalved specimens. — Stn DW 3523, 13 bivalved specimens. — Stn DW 3524, 37 bivalved specimens. — Stn DW 3528, 6 bivalved specimens.— Stn DW 3534, 5 bivalved specimens. — Stn DW 3552, 54 bivalved specimens, 1 ventral valve, 2 dorsal valves. — Stn DW 3553, 76 bivalved specimens, 4 ventral valves, 4 dorsal valves. — Stn DW 3557, 14 bivalved specimens. — Stn DW 3564, 1 bivalved specimen. — Stn CP 3595, 2 bivalved specimens. — Stn DW 3599, 2 bivalved specimens. — Stn CP 3613, 11 bivalved specimens, 1 ventral valve, 1 dorsal valve. — Stn CP 3614, 4 bivalved specimens. — Stn CP 3615, 64 bivalved specimens, 3 ventral valves, 4 dorsal valves. DEPTH RANGE . — 122- 910 m . MEASUREMENTS. — See Table 10. DESCRIPTION Shell small (maximum length 6.3 mm), strongly biconvex, triangular in outline with greatest width near anterior. Shell surface fascicostate with the dominance of strong, triangular in cross-section, primary ribs 7 to 9 in number; secondary ribs delicate, indistinct. Growth lines distinct. Anterior commissure rectimarginate to incipiently broadly unisulcate. Hinge margin short, straight to slightly curved. Beak suberect to erect with a large, subcircular, mesothyrid foramen; deltidial plates minute, triangular, disjunct. Ventral valve interior with a broad pedicle collar and small, hooked teeth ( Fig. 11E ). Dorsal valve interior with massive inner socket ridges extending beyond margin. Cardinal process prominent ( Fig. 11K, L ). Crura stout, crural processes short. Loop thin, angular at anterior, however, in some specimens it can be thickened ( Fig. 11M ). FIG. 9. — Chlidonophora chuni Blochmann,1900 ,Mozambique Channel,Bazaruto transect,MAINBAZA: A , B , dorsal view of complete specimen (MNHN IB-2013- 55), and enlargement of the umbonal part ( B ) to show details of the beak, stn CC 3158, 1220-1248 m; C , D , inner view of dorsal valve (MNHN IB-2013-56) with preserved subplectolophous lophophore, ( D ) enlargement of lophophore, stn CC 3157, 1410-1416 m; E , F , inner view of ventral valve (MNHN IB-2013-57) and enlargement of umbonal part ( F ), stn CC 3157; G -J , inner and oblique views of dorsal valve (MNHN IB-2013-58), enlargement ( I ) and tilted view ( J ) of posterior part to show cardinalia and loop, stn CC 3157; K , L , inner and tilted views of posterior part of dorsal valve (MNHN IB-2013-59), stn CC 3157. All SEMs. Scale bars: A, C, E, G, H, 2 mm; B, F, D, I-L, 1 mm. FIG. 10. — A -D , Eucalathis magna Cooper, 1981 , ventral, dorsal, lateral and anterior views of complete specimen (MNHN IB-2013-60), South Madagascar, sector of Manantenina, stn DW 3529, 402-407 m; E -O , Eucalathis daphneae n. sp. , North-West Madagascar, MIRIKY, SEM: E , inner view of ventral valve (MNHN IB- 2013-62), paratype, West of Cap d’Ambre, stn DW 3196, 238-249 m; F -J , dorsal view of complete specimen, enlargement of umbonal part ( G ) and anterior view to show rounded ribs ( H ), and inner view of dorsal valve ( I , J ) of the same specimen to show cardinalia and loop, holotype (MNHN IB-2013-61), West of Nosy Be, stn DW 3234, 187-247 m; K -O , inner view of dorsal valve (MNHN IB-2013-63), enlargement ( L ) and tilted ( M ) views of posterior part,and a fragment of incomplete transverse band ( O ), paratype, stn DW 3196, 238-249 m. Scale bars: A-D, 5 mm; E, F, H, I, K, 2 mm; G, J, L,1 mm; M, 500 µm; O, 200 µm. TABLE 11. — Measurements (in mm) of Macandrevia emigi n. sp. DIAGNOSIS. — Small Macandrevia with subtriangular outline and large, oval permesothyrid foramen. Loop and cardinalia typical of the genus.

Station No.	Length	Width	Thickness
CP 3139 (paratype)	12.3	11.5	6.2
CC 3170 (holotype)	12.6	12.0	6.3
CP 3589	7.3	6.4	3.4
CP 3589	7.6	6.0	3.2

DEPTH RANGE. — 132-1195 m. TABLE 12. — Measurements (in mm) of Frenulina sanguinolenta ( Gmelin, 1791 ) . MEASUREMENTS. — See Table 11.

Station No.	Length	Width	Thickness
DW 3230	5.7	5.1	2.8
TA01	7.2	6.5	4.1
TS09	5.5	4.7	2.4
DW 3519	7.7	6.9	4.4

REMARKS This species is the most common brachiopod in the studied material (more than 300 specimens ), occurring only in South Madagascar . It differs from hitherto described species of Eucalathis in the strong costation of its broad, triangular in cross-section ribs. A similar triangular ribbed shell is observed in Melvicalathis macroctena , however, ribs in the latter species have smooth ridges without tubercles ( Lee et al. 2008 ).