CHAPTER V
BIVALVIA CHAPTER V
BIVALVIA
INTRODUCTION
This chapter deals with the marine bivalves, which are quite abundant when compared to the gastropods in the marine Quaternary ueposits of Raigad District, Maharashtra.
The marine mollusc~, i.e. bivalves and gastropods
of the ~est Coast of India were studied in the early days by Melvill and Abercrombe (1893) and Melvill and Standen (1901). And after a long gap of time that the marine pelecypods of Bombay Coasts were studied by Subrahmanyam, Karandikar and Murti (1949), describing several genera and species. From the Karwar Coast, Patil (1952, 1954) described the mollusca including both bivalvia and gastropods and gave an exhausting list. Similarly, from the Krusadai Island, Gulf of Manner, Palk Strait, Coromandal Coast the marine mollusca were studied by Chricton (1941) and Gravely (1942). Later in 1956, Satyamurthy described in detail, the bivalves from these places.
SYSTEMATIC DESCRIPTION Phyllum Mollusca - r' Class Bivalvia Linn, 1758 (Buonanni, 1681) Subclass Palacotaxodonta Korobkov, 1954 Order Nuculoida Dall, 1889 - 64 -
S u pe r-f ami 1 y Nuculanacea H Adams & A. Adams, 1858
Family Nucu lan id as Adam & Adam Genus Portlandia March 1857 Subgenus .£:. ( Po r t lan d i a ) March, 1857
£. ( Portlandia) Sp. indet (Pl. XI, Fig. 7)
Material : Single broken specimen
No. MACS G 2391
Measurements Length Height Thickness L/H L/Th
No. MACS G 2391 2.0 em 0.9 em 0.4 em 2.2 5
De scription Shell thin, small, elongated and sub- triangular; umbone amphidetic, ligament thin; ventral margin straight, smooth, ante.rior margin broken, posterior margin gently rounded; ornamentation of faint concentric lines; hinge straight, taxodont; internal margin smooth, Pallial line not seen.
Remarks .0 I Present specimen can be assigned to the genus Portlandia (Portlandia) March on the basis of outline and indistinct posterior furrow. (Cox~ 21. 1969, P.N 23 g, Fig. A 9, 4) the hinge character is similar to Yoldia aretica Gray but the posterior is truncate, (which is not so in the present case (Zittel, 1937, P. 441, Fig. 657). So in view of - 65 - insufficient material thespecmen is placed under the genus Portlandia. But better and more material may need change in generic position.
Occurrence Limestone of Dive Agar Formation at ShekhadJ. •
Sub-class Pteriomorpha Beurlen, 1944 Order Arcoida Stoliezka, 1871 Super-family Arcacea Lamarck, 1BD9
~amily Arcidae Lamarck, 1809 Sub-family Arcinae Lamark, 1809 Genus Barbatia Gray, 1842
Sub-genus ~.(Barbatia) · Gray, 1842
~· (Barbatia) bistrigata (Dunker) (Pl.X, Fig. 3)
1949 Area bistrigate Okr. Subrahmanyam et ~, p. 59, Fig. 9 1951 Dkr. Hornell & Tomlin, p. 90
Material Several specimens Plesiotype No. MACS G 2411 - 2413
Measurements Height Length Thickness L/H L/Th MACS G 2411 2.3 em 3.7 em. 1.1 em. 1.60 3.36
Description Shells thick, mediuw.-sized, elongate, equivalved, inaquilaterla; umbo prosogyrate, about l / 3rd from anterior, ligament duplivincular, amphidetic, cardinal - 66 -
area low; margins round, ventral margin slightly protruding out; ornamentation of numerous fine radial ribs bifuncating concentric growth lines weak; hinge long, straight bearing small, numerous teeth, convergent terminally; internal margin smooth.
Remarks The present material agrees with B. bistrigata (Dank.) from Penang in the collection of Z.S.I, having
Reg. No. 4487.
Occurrence Shell limestone of Dive Agar Formation at Kashid and Velas.
Barbatia (Barbatia) sp.
(Pl. X, Fig. 10,13)
Material :
No. MACS G 2414 - 2416
Measurements : Height Length Thickness L/H L/Th No. 2414 2.1 3.9 1.3 1.9 3
Description Shell thick, medium-sized, Quadrate, posterior obliquely truocated, ligament amphide tic, umbo prosogyrate; ornament on anterior half of closely-spaced biturcating ribs with narrow intervening spaces, posterior half with primary ribs divided into close-spaced size rib-lets, primary ribs separated by narrow, dee p intervening grooves, internal margin thick with short and long radial
striations. - 67 -
Remarks : Present specimen differs from Balbatia (Barbatia)
bistrigata (Dunker) (Vide supra) and~ (B.) barbata (Linne) (Cox et 1!!..z. 1969, P.N 252, Fig. C2, 63; Dance, 1977 p. 224 with fig ) in having different ornament pattern on anterior and posterior sides. Area fusca Bruguiere and Area complanta
Chemnitz (Satyamurthy, 1956, p. 21-22, Pl. II, Figs. 3 a-b,
4 a-b) are nothing but Barbatia fu~ca and ~· complanta. They also differ from the present specimen on ornamentation.
Occurrence : Shell limestone of Dive Agar Formation at Akshi.
Sub-family Anadarina Reinhart, 1935 Genus Anadara Gray, 1847 Sub-genus A. (Anadara) Gray, 1847
Anadara (Anadara) granosa (Lamarck (Pl. X, Fig. 8; Pl. XI, Fig. 14, 15) 1949 Area granosa Lam. : Subrahmanyam --et al, p. 59, Fig. 4 1951 Lamarck : Hornell & Tomlin, p. 90 1977 Anadara granosa (Linnaeus) : Dance, p. 224
Material Several specimens
Plesiotype No. MACS G 2392 - 2394
Measurements Length Thickness Height L/H L/Th MACS G 2392 4.7 em 1.9 em 3.7 em 1.27 2.47
2393 3.7 em 1.6 em 3.1 em 1 .19 2.31 - 68 -
Description : Shell thick , sub-trapezoidal., thick, equivalved, inequilateral, umbo prosogyrate, ligament amphidetic, cardinal area broad, triangular; ventral margin broadly rounded; surface sculpture of strong scabrows, radial ribs counting 19-23 in number, separated by smooth interspaces; hinge straight bearing uniform taxodont teeth; internal margins strongly crenulated, depressions corresponding to the raised ribs on the surface.
Remarks : The present specimens agree well with Anadara (Anadara) granosa preserved in Z.S.I. museum No.
Occurrence : Shell limestone of Dive Agar Formation at Akshi and Korlai.
Genus Larkinca Reinhart
Larkinia fhombea (Bar~) (Pl. X, Fig. 1, 2)
1949 Area rhombea Born Subrahmanyam et ~' p. 59
1951 .• Born Hornell & Tomlin, p. 90
Material Several specimens Plesiotype No. MACS G 2395- 2397
Measurements Length Height Thickness L/H L/Th
MACS G 2395 5 o 7 em ~ 5 G2 em. 2 $8 em. l o09 2s03 em. 2396 2 e 1 em. 1.1 em. 1.23 2 o36 em. - 69 -
Description Shell big, thick, stout, sub-trapezoidal, equivalves, inequivalateral; almost same in height and length; umbo elevated, prosogyrate, ligament amphidetic, broad, triangular; ventral margin broadly rounded; posterior margin truncated; sur§ace, sculpture of strong, radiating, scabrons ribs intervened by furrows, beaded on anterior side, posterior side truncated and ribs closely spaced; hinge slightly curved, dentation typically taxodont; internal margins crenulated corresponding to the elevated ribs on the surface.
Remarks The present material agrees with Anadara rhombea in Z.S.I. museum from Andaman Islands bearing Reg. No. M. 3465/1 and M. 3421.
Occurrence : Shell limestone of Dive Agar Formation at Velas and Aravi.
Genus Scapharca Gray, 1847 Sub-Genus 2· (Scapharca), Gray, 1847
Scapharca (Scapharca) deyrollei Jousseaume (Pl. X, Fig. 11, 12)
Material Plesiotype : No. M.ACS G 2398 -2400 - 70 -
Measurements : Length Height Thickness L/H L/Th r~ACS G 2398 1 • 0 em. 0.7 em. 0. 4 em. 1.42 2.5
Description Shell relatively thin, slightly convex, equivalved, very inequilateral, trapezoidal; umbo proso- gyrate, ligament very narrow; margins round but.
p o s t e r i o r ma r gin e x p an de d , sur f ace o r n amen t at ion t h a t o f numerous, fine radiating ribs; hinge straight, taxodont, teeth converging to a point below the beak; internal margins crenulated.
Remarks : Present specimens compared with Scapharca (Scapharca) deyrollei preserved at z.s.r. museum are found to be identical with them.
Occurrence Shell limestone of the Dive Agar rormation at Aravi.
Scapharea (Scapharea) inaeguivalvis (Brunguiere) (Pl. X, Fig. 5, 6)
1941 : Area inaeguivalvis : Gravely, p. 32, Fig. 14 f.
1949 Area inaeguivalvis Brug : Subrahmanyam ll ..§!l, p. 59 Fig. 8
1951 Brug : Hornell & Tomlin, p. 90
1956 ~ inaeguivalvis Bruguiere : Satyamurthy, p. 24, Pl. II, Fig. 7 a,b.
1969 Scapharca (Scapharca) inaeguivalvis (Brug)
Cox~~~ p. 256, Fig. C 5, 6 - 71 -
Material : Several specimens. Plesiotype : No. MACS G 2401 2402
Measurements Length Height Thickness L/H L/Th
MACS G 2401 4.7 em. 4.2cm. 2 .1 em. 1 • 11 2.23
2402 2. 8 em • 2. 5 em. 1.1 em. 1.12 2. 54
Description : Shell medium~sized, trapezoidal, equivalved, inequilateral, umbo prosogyrate, slightly flattened, ligament amphidetic, narrow, margins round, posterior than the anterior; ornamentation of strong, flattened radiating ribs with rectangular cross-section, hinge long,
teeth padded j~st below the hinge, converging below umbo; internal margins creunlated.
Remarks : Present material is compared with Scapharia (Scapharca) inaeguivalvis preserved at Z.S.I. museum and agrees with it.
Occurrence : Shell limestone of Dive Agar Formation at Vel as and Aravi. Scapharca (Scapharca) gubernaculum (Reeve) (Pl. X, Fig, 9)
1956 Area gubernaculum Reeve Satyamurthy, p. 25, Pl. II, Fig. 8 a-b - 72 -
Material : Several specimens Plesiotype No. MACS G 2403 - 2405
Me a su ramen t s Length Height Thickness L/H L/Th
MACS G 2403 3 .1 em. 1 .8 em. O.S em. 1 • 72 3.44
2404 3.7 em. 2 • 1 em • 1 • 0 em. 1. 76 3.7 " G 2405 Description Shell moderate, trigonal, elongated, equivalved, inequi1ater61, umbo small, prosogyrate, ligament amphidetic, narrow, margins rounded, ventral margin broader; surface ornamentation of strong, flattened radiating ribs with rectangular cross-section; separated by flattened interspaces, hinge slightly arched, taxodont; internal margins crenulated corresponding to the ribs on surface.
Remarks Present material ag~ees with Scapharca (Scapharca) gubernaculum from Penang, preserved at Z.S.I.
museum bearing No. 4527.
Occurrence Shell limestone of Dive Agar Formation exposed at Akshi, Dive Agar, Velas, and Boralai.
Scaphar ca .2.£. (Pl. X, Fig. 4, 7) Material : Single specimen
Plesiotype : No. MACS G 2406 - 73 -
Measurements Length Height Thickness L/H L/Th
MACS G 2406 4. 0 em. 2. 5 em. 1.3 em. 1 • 6 3.07
Description Shell thick, sub-trapezoidal, elongated inequilateral, umbo prosgyrato, flattened with narrow cardinal area; ligament duplivincular, amphidetic; margins rounded, posterior one slightly bigger; ornamentation of
flattened radiating ribs with rectangular c~oss-section and concentric growth lines; hinge long, straight, taxodont; internal margins crenulated.
Occurrence : ~hell limaston& of 0ivajAgar Fcrmation at
A rav i and Aakh i.
Genus Scapharca Gray
Sub-genus S. (Cunearca) Dall, 1898
Scapharca (Cunearca) clathrate (Reeve) (Pl. X, fig. 16, 17)
Material Several specimens
Plesiotype No. MACS G 2407- 2410
Measurements Length Height Thickness L/H L/lh
MACS G 2407 2.0 em. 1. 5 em. 0.7 em. 1.33 2.85
2408 1 • 9 em. 1.5 em. 0.7 em. 1.26 2.71
Description Shell small, sub-trapezoidal, equivalued, inequilateral; umbo prosogyrate, ligament narrow, am phi de t i c ; margins rounded, posterior margin slightly flared up, shell - 71~ -
sculpture of flatt~nad, radiating rib•, crossed by concentric striation•, hinga atraight, taxodont d~ntation, internal margin craunlatad.
Ramarks : Pra~gnt •pacimen~ are comparable with Scapb~L££
\Cunsarc_2) clathrata at z.~.l. mu~aum coming from Andaman
1aland bearing No. M. 3511/1. Though th~ posterior sid~ of
the pre•ant specimens is not as broad and extended but it can be kept under clathrata viewing the other characters.
Occurrence ~hall limestone of Dive Agar formation exposed at Uivs Agar, Aravi, Kashid, Shekhadi and Korlai. family Neotiidae Jteward, 1930
~ub-family Neotiinae Steward, 1930 Genus Noetra Gray, 1857.
.... ' .... uo-genus ~o lNoetia) Gray, 1857
\Pl. X, Figs. 18, 19) f o x l 9 6 9 ( Na e t i u ) f'l a r t in i i Re c 1 u z Cox .!D._, p. N 260 f'iate rial ::Javeral sp8cimens f.Jlesiot:x:12a No. MAC~ c 2417 - 2420
1'1easurement~ Length Haight Thickness L/H L/Th i•lAC~ G 2417 2.1 Cf•1 • 1.3 em. 0.6 em. 1.61 3.5
1'1 11C~ G 2418 3.1J em. 1.8 em. 0.8 em. 1.66 3.75 - 75 -
Description : Shell thick, heavy, subtrigonal, equivalved, inequilateral, umbo anteriorly placed, directed posteriorly - ophisthogyrate, ligament prosodetic, margins round, posterior margin produced ventrally; surface sculptured with unequal radiating ribs and a few concentric growth lines; hinge slightly curved bearing chevron teeth on margins, typical taxodont dentation; internal margins crenulated.
Remarks : Present specimens agree with z.s.I. museum
No. 4534 described as Area (~~ Martinii (Cox~~' 1969) where it appears as a separate family.
Occurrence : Mudstone of Nagaon Formation at Nagaon, and shell limestone of Dive Agar Formation at Kashid, Velas and Aravi.
Striarca avellana (Lamarck) (Pl. X, Fig. 14, 15)
1956 ~ avellana Lamarck Satyamurthy, p. 2D, Pl. II, Fig. 2 a-c
~laterial : Several specimens
Plesiotype No. MACS No. 2421 - 2423
Measurements Length Height Thickness L/H L/Th
MACS No. 2421 1.1 em. 0.9 em. 0.4 em. 1. 2 3 - 76 -
Description : Shell small, thick, quadrilateral, equivzlved, 0 sub-equilateral, umbo sub-median, prosgyrate, ligament amphidetic, anterior margin round, posterior margin broadly truncated; a strong posterior ridge extending from ~bones to ventral margin, ornament of fine radial ribs and concentric grooves; hinge slightly bent• taxodont dentation; internal margin smooth. Remarks Present specimens agree with -Area avellena Lamarck from Pamban and Krusadai Island (Satyamurthy, 1956).
Occurrence : Shell limestone oF Dive Agar Formation at Velas and Aravi.
Family Noetiidae Stewart
Sub-family Striarcinae MacNeil Genus Striarca Conrad
Striarca symmetrica (Reeve) (Pl. X, Fig. 14)
1949 Area Symmetrica Reeve Subrahmanyam ~ ~' p. 59, Fig. 7
1956 Reeve S atyamu rthy, p. 22, Pl. II, Fig. 5 a-b
Material Several specimens
Plesiotyps : No. MACS G 2424- 2426 - 77 -
Measurements Length Height Thickness L/H L/Th
MACS G 2424 1.2 em. 0.8 em. 0.4 em. 1 • 5 3
Description 5 he 11 s ma 11 , t hi c k , sub q u ad r i 1 ate r a 1 , equivalve, sub-equilateral; umbo sub-median, prosogyrate; ligament amphidetic, anterior margin round, posterior margin truncated, ornamentation of fine radial ribs crossed by concentric growth lines; hinge slightly curved, taxodont dentation; internal margin smooth.
Remarks : Present specimens agree with Arc a symmetric a Reeve from Bombay (Subrahmanyam et al, 1949) and from Pamban and Krusadai Island (Satyamurthy, 1956) which are now transferred to genus Striarca (Cox et ~. 1969, p. 263)
Occurrence : Shell limestone of Dive Agar Formation at Velo;t s and Aravi.
Striarca 2.,E.
Material : No. MACS G 242l - 2430
Measurements Length Height Thickness L/H L/Th
MACS G 2427 1.1 em. 0.35 em. 0.7 em. 1 • 57 1 • 57
Description : Shell small,thin, elongated, strongly inequilateral, umbo prosogyrate, l/5th from anterior; ligament narrow, amphidetic; margins round and smooth; ornamentation of fine, radial costal; hinge slightly - 78 -
curved, typically taxodont; internal margins smooth.
Remarks : Shell being very small and in a poor state of preservation, specific identification is not possible,
Occurrence Shell limestone of Dive Agar Formation at Akshi.
Genus Arcopsis Keonen, 1885 Sub-genus Arcopsis (Arcopsis) Koenen, 1885
Arcopsis (Arcopsis) ~apsis (Koenen)
(Pl. X Fig. 20-2l) .
1969 . Arcopsis (Arcopsis) limopsis (Koenen) : Cox~ i!J., p. 264, Fig. 10,6
Material : Several small specimens
Plesiotype : No. MACS G 2431 - 2433
Measurements : Length Height Thickness L/H L/Th
MACS G 2431 1.2 em. 0.6 em. 0. 5 em. 2.0 2.4
Description : Shell small, thick, sub-quadrilateral, equivalve, sub-equilateral; umbo sub-median, prosogyrate, ligament amphidetic anterior margin round, posterior margin broadly truncated, surface with a ridge. On the posterior side, triangular resilifer prominently seen below beak; surface ornament of fine radial ribs and concentric growth lines; hinge straight with taxodont dentation, internal mar gin smooth. - 79 -
Remarks : Present specimen agree with Arcopsis (Arcopsis) limopsis (Koenen) by Cox tl .2J., in the treatise.
Occurrence : Mudstone of Nagaon Formation at Nagaon.
Order Pterioida Ne we 11 , 19 6 5 Sub-order Pteriina Newell, 1965 Super family Pectin <-l cea Rafinesque, 1815 Family Pectinidae Rafinesque, 1815 Ganus Pecten Muller, 1776 Sub-genus _!:dPecten) Muller, 1776
P. (Pect&n) senatorius Gmelin (Pl. XII, Fig. 2, 3) l: 951 Chlamys sanatorium Gmelin Hornell & Tomlin, p.91
1977 Gmelin 0 an c e , p • 2 3 4 , F i g •
Material Plesiotype ~o. MACS G 2434 - 2435
Measurements Length Height Thickness L/H L/Th
MACS G 2434 3. 9 em. 3.5 em. 0.6 em. 1.11 6.5
Description Shell fairly thick, moderately big, pectiniform, Nentral and labara sides rounded, byssal notc h large, surface ornamentation of strong, flattened radial ribs with almost equal spaced grooves fine concentric striations seen on the shell, outer margin round, crenulated, the grooves on the margin corresponding to the ribs on the surface, inner surface with weak riblets; - 80 -
cardinal crura on one side fully d~veloped, the other side denticulations are seon.
Flernarks Although the present speci~en is comparable with Pecten (Pecten) senatorium collected from trincomalin by L.~.l. ba~ring Regd. No. M 3310 1, However, Oance 1977 p. 234, placing it under the genus Chlamys.
Occurrence Mudstone of Nagaon Formation at Nagaon.
:Jup&r farnily Anomiacea Rafinesque, 1815 Family Anomiidae RafinEsque, 1815
Genus ~ nomia Linr.~, 1758
..JUb-genus .B..· \11nnmi::~)
E_. ~Anomia_) ~phippium Linnaeus
l~l. XIII, Fig. 11,1 ; ,13,14)
1969 Anomia \Hnomia) ephiQQium Linne, Cox et al,
P. N 383 Fiy C 10:3 1 4 1977 ephippium Linnaeus, Dance p. 238
Plesiotype No. MAC~ G 2436 - 2438 l'leasu rements Length Height Thickness L/H L/Th
1 1lAC S L.; 2436 4.4 em. 3.9 c Ill. 0.9 CHI • 1 • 12 4.9
2437 3.2 ern. 2.8 em. 0.6 em. 1 • 1 6 5.4
Uescri~tion :ihells thin, fra gile, irregularly circular, only one valve ~left) preserved; central ligament supported by crura, hinge lacking tssth, muscle scars three, - 81 - sub-equal; shell surface ornamented by unequal radiating striations, inner margin smooth but irregular, and nacreous.
Remarks : The present sp~cimens agree in all respect with 8_. (Anomia) ephippium Linne (Cox~ .§.1, 1969) in having a thin fragile shell with three sub-equal musclo marks. The Z.S.I. museum specimens of this species bear the register No. 15481/1.
Occurrence : Mudstone of Nagaon Formation at Nagaon and limestone of Dive Agar Formation at Dive Agar, Adgaon and Ve las.
Family Spondyliadae Gray, 1826
Genus Spondylus Linne, 1758 Sub-genus 2· (Spondylus) Linne. 1758
i· (Spondylus) layardi Reeve (Pl. XII, Fig. 4,5,6,7)
1956 Spondylus layardi Reeve, Satyamurthy, p. 62-63, Pl. IX, Fig. 4 a-b
Material : Plesiotype : No. MACS G 2439-2440
Measurements Length Height Thickness L/H L/Th
MACS G 2439 5.3 em. 5.9 em. 1 • 7 em. 0.89 3.11
2440 1.6 em. 1.5 em. 0.4 em. 1.06 4.0 - 82 -
Description : Shell large, thick, irregularly ovate, cardinal area amphidetic, ligament alivincular, hinge isodont, with two small, stout processes on either side; monomyarian, scar big, sub circular, posteriorly placed, surface ornamented by stout radial ribs bearing flat, spinose processes, intervened by very thin radial striations, internal margin crenulated.
Remarks : The present species resembles .2_. layardi Reeve as described by Satyamurthy (1956) from Krusadai Islands.
It differs from .2_. (2) truncatus (Lamarck) Cox et ~ (1969) from where in lacking big spines on the surface and not being well inflated.
Occurrence Mudstone of Nagaon Formation at Nadgaon.
Sub-class Heterodonta Neumayr, 1884
0 rder Veneroida H. Adams & A. Adams, 1856
Super family Lucinacea Fleming, 1828
Family Lucinidae Fleming, 1828
Sub-family Lucininae Fleming, 1828
Genus Codakia Scopoli, 1777
Sub-genus f. (Codakia) Scopoli, 1777
Codakia (Codakia) ~ivergens (Philippi) (Pl. XV, Fig. 9, 10) 1956 Codakia divergens (Philippi) : Satyamurthy, p. 80, Pl. XII, Figs.? a-b - 83 -
Material : Plesiotype No. f~ACS G 2441
Measurements Length Height Thickness L/H L/Th
~1ACS G 2441 1.0 em. 0.9 em. 0.3 em. 1 • 1 3.33
Description Shell small, sub-circular to oval, outline slightly inequilateral, umbo prosogyrate, dorsal margin in front of the umbo gently depressed, other margins round; hinge teeth well developed, cardinal teeth stronger than the laterals, surface ornament of predominant, diverging radial ribs and concentric growth lines; inner margins smooth.
Remarks The present specimens agrees with f. divergenus (Philippi) as described from Krusadai Island by Satyamurthy
(1956) in general characters. But the present material is a juvenile form. It is alsd compared with Z.S.I. museum specimens collected from Gujarat and found to agree in general,
Occurrence Shell limestone of Dive Agar Formation at Velas.
Super family Cardiacea Lamarck, 1809
Family Cardiidae Lamarck, 1809
Sub-family Cardiinae Lamarck, 1809
Genus Cardium Linne, 1758
Sub-genus.£. (Cardium) Linne, 1758 - 84 -
Cardium (Cardium) coronatum Spengler (Pl. XI, Fig. 10, 11)
1949 :; Cardium coronatum Spang : Subrahmanyam et al, p.64
Material Plesiotype No. MACS G 2442 - 2444 Measurements Length Height Thickness L/H L/Th
MACS G 2442 3.2 em. 3.4 em. 1 • 5 em. 0.94 2.13 2443 2.8 em. 2.8 em. 1 • 4 em. 1.0 2.0
Description Shell moderately big, roughly quadrangular, ligament parivincular, external, very short, umbo prosogyrate; hinge more or less straight, long, bearing two conical cardinal teeth, of which anterior tooth of LV very long, lateral teeth well separated from the cardinal, one anterior and one posterior in LV, two anterior and one posterior in RV, posterior lateral well elevated and small, ornament of strong, flat-topped, radiating ribs with equal furrows in between them; margins round, posterior margin cantata, other margins crenulated; pallial line entire, muscle scars almost equal.
Remarks The present species differs from f. (f) testatum Linne in ornamentation and shape of lateral teeth.
It is compared with f_~_Edium (fardium) coronatum at Z.S.I. museum bearing No. 14464/2 and is found to agree with it. - 85 -
Occurrence Shell limestone of Dive Agar Formation exposed at Dive Agar, Velas and Kashid.·
Super family Mactracea Lamarck, 1809 Family Mactridae Lamarck, 1809
Genus Spisula Gray~ 1837 Sub-genus ,2. ( Stand e 11 a) Gray , 18 53
Spisula (Standella) pellucida (Gmelin) (Pl. XVI, Fig. 4,7,13,1!)
1949 Stanuella pellucida Gmelin Subrahmanyam et ~' p. 69, Fig. 52
Material : Plesiotype : No. MACS G 2445 - 2448
Measurements Length Height Thickness L/H L/Th
~lACS G 2445 4. 5 em • 3 • 1 em. 1 • 1 em. -1 .45 4.09
2446 3. 6 em • 2. 5 em. 0.9 em. 1.44 4.0
De scription Shells thin, inflated, trigonal, sub- equilateral, lunule and escutcheon delimited, resilium well developed; hinge well developed two cardinals in each valve in the form of inverted 'V', laterals long, smooth; ornamentation of concentric striations; Pallial sinus large and deep posterior margin truncated, anterior and ventral margins round, internal margins smooth.
Remarks : Present material resembles Spisula (Standella) pellucida from Bombay coast, at Z.S.I. museum, specimen
No. M 3604. - 86 -
Occurrence : Mudstone of Nagaon Formation at Nagaon, and shell limestone of Dive Agar Formation at Akshi and Nandgaon.
Spisula (Standella) nicobarica) (Gmelin) (Pl. XV, Fig. 7, 8)
1956 Standella nicobarica (Gmelin) Satyamurthy, p. 142, Pl. XXIII, Fig. 1 a-b.
Material : Plesiotype : No. MACS G 2449 - 2450
Measurements Length Height Thickness L/H L/Th
MACS G 2449 2.6 em. 2.0 em. 0. 7 em. 1 • 3 3.71
Description Shell small, ovate, inflated, sub- equilateral, ligament small, hinge well developed with a big resilium, small and smooth cardinals and laterals; shell surface sculptured by concentric striations; posterior margin truncated, anterior margin round, internal margin smooth; pallial sinus deep.
Remarks : Small, ovate, inflat9d shell and small, smooth cardinal and lateral teeth help in differentiating it from Spisula (Standella) pellucida (vide supra).
Occurrence Shell limestone of Dive Agar Formation at Aravi. - 87 -
Spisula(Standella)nameguensis Carrington & Kensley (Pl. XVI, Fig. 1,2,16,17)
1969 Spisula namaguensis Carr. & Ken.:Carrington & Kensley, p. 210, Pl. 26 Fig. 5
Material : Plesiotype : No. MACS G 2451
Me asu ramen ts Length Height Thickness L/H L/Th
~1 ACS G 2451 3.7 em. 2.8 em. 1.0 em. 1 • 32 3.7
2452 3.8 em. 2.8 em. 1.1 em. 1 .3 5 3.45
Description Shell somewhat thick, inflated, broadly trigonal, sub-equilateral; linule and escutcheon very thin, resilium developed; hinge bearing two small cardinals placed slightly posteriorly, laterals smooth; sculpture of concentric striations; posterior margin broadly truncated, anterior and ventral margins round, internal margins smooth, pallial sinus oval and deep.
Remarks Present material differs from Spisula (Standella) _pellucida (vi@ supra) in having somewhat thick, inflated shell, lateral teeth smooth but not very long and broadly truncated posterior margin.
Occurrence : Mudstone of Nagaon Formation at Nagaon and limestone of Dive Agar Formation at Dive Agar. - 88 -
Family Donacidae Fleming, 1828 Genus Donox Linne.
Sub-genus Q.(Latona) Schumacher, 1817
Donax (Latona) semisulcatus Hanley (Pl. XIII, Fig. 3, 4)
Material : Plesiotype No. MACS G 2453 - 2454
Measurements Length Height Thickness L/H L/Th MACS G 2453 1.4 em. 1.0 em. 0.5cm. 1.4 2.8 2454 1.0 em. 0.8 em. 0.4 em. 1.25 2.5
Description : Shells thin, small, trigonal, equivalve, inequilateral umbones ophisthogyrate, lunule, very thin, hinge well developed bearing both cardinals and laterals, surface with a posterior carina, radial ribs very thin, but much stronger on posterior side, posterior margin truncated owing to the carina, anterior margin goes round, internal margin dentate, pallial sinus well developed.
Remarks : Present specimens are equable with Z.S.I. museum specimens bearing No. 4820 collected from Ceylon. It differs from Donax rogersi Hanghton (Carrington & Kensley,
1969, p. 213, Pl. 27b, d) from Namaqualand coast in having radial ribs on surface, though it resembles in having a surface carina and concentric striations. - 89 -
Occurrence : Shell limestone of Diva Agar Formation at Aravi and Nandagaon.
Donax (Latona) lubrica Hanley
(Pl. XIII, Fig. 15, 16)
1956 Oonax Lubrica Hanley, Satyamurthy, p. 148, Pl. XXII• Fig. 5
!Y.aterial Plesiotype No. MACS G 2455 - 2457
Me asuremants Length Haight Thickness L/H L/Th
MACS G 2455 1 • 8 em • 1 • 3 em • 0. 5 em. 1.38 3.6
2456 1 • 4 em • 1 • 0 em • 0. 4 em. 1 • 4 3.5
Description : Shells small, strong, trigonally elongated, equivalve, inequilateral, umbons ophisthog~rat~ . ligament aaternal, lunule not wall defined , hinge bearing both cardinals and laterals, small but wall defined, surface with a posterior keel, concentric striations more prominent towards the keel anterior and posterior margins rounded, internal margin finely dentate; adductor muscle scars joined by pallial sinus.
Remarks : Agree with Donax lubrica Hanley (Satyamurthy,
1956, p. 148) from Krusadai Islands in having a prominent surface keel and concentric striations, round margins and internal margin centate and also with Z.S.I. museum specimen collected from Arkan coast. - 90 -
Occurrence : Shell limestone of Dive Agar Formation at Velas and Aravi.
Donax (Latona) incarnatus Chemitz (Pl. XIII, Fig. 9, 10)
1951. Donax incarnatus Gmelin Hornell & Tomlin, p. 92 1956 Chemnitz Satyamurthy, p. 148, Pl. 22, Fig. 6 a-b.
Material : Plesiotype : No. MACS G 2458 - 2460
Measurements : Length Height Thickness L/H L/Th
MACS G 2458 1.8 em. 1.5 em. 0. 4 em. 1.2 4.5
2459 2.0 em. 1.6 em. 0. 5 em. 1.25 4.0
Description : Shells small, solid, trigonal, equivalve, inequilatera1 umbo ophisthogyrate, lunule external, thin, hinge bearing thin, small cardinals and laterals; ornamentation of concentric striations and fine radial ribs seen only towards posterior side near the well defined ridge; anterior side expanded, margins rounded, internal margin finely dentate; Pallial sinus deep.
Remarks : Present specimen.·is compared with Donax (Latona) incarnatus at Z.S.I. museum bearing No. M 13467/2 collected from Bombay and is identical with it. It differs from Oonax haughtoni Carrington & Kensley (1969, p. 213, Pl. 27a, c) from Namaqualand coast in having radial ribs on the surface alongwith concentric striations all over the surface. - 91 -
Occurrence : Mudstone of Nagaon Formation at Nagaon, and limestone of Dive Agar Formation at Velas, Kashid and Agar Danda.
Donax (Latona) faba Cmelin (Pl. XVI, Fig. 5)
1956 Oonax faba Gmelin, Satyamurthy, p. 147, p. 147, Pl. XXII, Figs. 4 a-c
Material : Plesiotype : No. 2461
Measurements Length Height Thickness L/H L/Th
MACS G 2461 2.6 em. 1.9 em. 0.7 em. 1.36 3.71
Description Shell thick, moderate in size, trigonally ovate, inequilateral, lunule not well defined, very narrow, elongate, umbo ophisthogyrate, hinge gently bent, bearing
both cardinals and laterals~ surface ornamented by fine concentric striations, a keel on the posterior side is faintly seen, anterior margin long, rounded, posterior margin bluntly truncated, ventral margin bears an indentation towards the posterior side; pallial sinus deep, slightly inclined upwards.
Remarks : The present specimen agrees with D. faba Gmelin in ornamentation shape of the shell and shape of pallial sinus as described by Satyamurthy (1956) from Pamban, Krusadai and Shingle Islands. It is also agrees with z.s.I. museum specimen No. 4824 collected from Bombay coast. - 92 -
Occurrence Shell Limestone of Dive Agar Formation at Velas.
Super Family Tellinacea de Blainville, 1814 Family Tellinidae de Blainville, 1814 Sub-family Macominae Olsson, 1961 Genus Gastrana Schumacher, 1817
Gastrana po1ygona (Gmelin) (Pl. XU, Fig. 17, 18)
1941 : Tellina polygona Gmelin : Gravely, p. 101 1949 Gastrana polygona Gmelin : Sugrahmanyam et al, p. 71, Fig. 68
Mate rial : Plesiotype : No. MACS G 2462
Me as uremen ts Length Height Thickness L/H L/Th
MACS G 2462 4.4 em. 3.3 em. 1 • 1 em • 1.3 4.0
Description : Shell medium in size, inflated, obliquely ovate, inequilateral, ligament external, thick, umbo
0 prosgyrate, hinge bearing cardinals, 3b bifed, later . ~ls absent; surface sculptured by irregular concentric limellae and radial elevations, anterior margin rounded, posterior margin sinuate, internal margins smooth, ~allial sinus deep, rounded, not confluent. - 93 -
Remarks : Present material agrees with Gastrana polygona collected from ~1adras, Arakan and preserved at Z.S.I. museum. It differs from Gastrana rostrata Carrington &
K en s 1 e y ( 1 9 6 9 , p • 2 1 8 , P 1 • 2 9 , F i g • 1 0 ) from Nam a q u a 1 and coast in surface ornament and the nature of pallial sinus.
Occurrence Shell limestone of Dive Agar Formation at Velas.
Super family Tellinicea de 8lainville, 1814
Family Tellinidae
Sub-family Macominae Olsson, 1961
Genus Macoma Leach, 1819
Sub-genus ~ (Masoma) Leach 1819
Macoma bruguieri Hanl~y
( P 1. XVI , Fig • 3 , 6)
1941 Te 11 in a b rug u i e r i Han ley : Grave 1 y , p • 1 0 1
1949 Macoma bruguieri · Hanley : Subrahmanyam et al, p. 72, Fig. 69
1951 Hanley : Hornell & Tomlin, p. 92 r 1956 Tellina bruguieri Hanley : Satyamurthy, p. 156 Pl. XXIII, Fig. 4 a-b
Mate rial Plesiotype : No. MACS G 2463 - 94 -
Me a sure men ts . Length Height Thickness L/H L/Th
~1 AC S G 2463 2.6 em. 2.4 em. 0. 6 em. 1.08 4.3
Description Shell small thin, inflated, ovate or trigonal, inequilateral, ligament external, thin, hinge curved, cardinals small, slightly elevated, laterals not clearly seen; shell surface ornamented by thin concentric lines, anterior margin round, posterior margin slightly twisted and truncated, internal margins smooth, pallial sinus deep.
Remarks ! The present material agrees with the specimens collected from Bombay, Ceylon, Singapore, Andaman and preserved at Z.S.I.
0 ccu rrence Shell limestone of Dive Agar formation at Velas. family Psammobiidae fleming, 1828
Sub-family Psammobiinae Fleming, 1828
Genus Asaphis Modeer, 1793
Sub-genus .fl. (Asaphis) Modeer, 1793
Asaphis (Asaphis) deflorata (Linne)
( ; Pl. XIV, Fig. 1,2,7,8)
1951 Asaphis deflorata Linn. : Hornell & Tomlin, p. 93
1969 (Asaphis) deflorata (Linne) : Cox~ al, p. 633, Fig. 116, 3 - 95 -
Material : Plesiotyp~ No. MACS G 2464 - 2465
Measurements : Length Height Thickness L/H L/Ih
MACS G 2464 7.4 em. 5.4 em. 2. 2 em. 1.37 3.36
2465 4.1 em. 2.7 em. 1 • 1 em • 1 • 51 3. 72
Description Shell big, solid, trapezoidal to roughly elliptical in outline, inequilateral, lunule external, elongated, umbo ophisthogyrate; hinge plate medium-sized, bearing inclined cardinals and long lateral teeth; surface sculpture that of numerous radiating ribs, rounded in cross-section, reticulated by concentric growth lines; posterior margin bluntly truncated, anterior margin round, internal margin smooth; pallial alnus deep and round.
Remarks : Although the present material matches well with Asaphis (Asaphis) defldrata (Cox £1 ~' p. 63, Fig. 116, 3) in having medium hinge plate with inclined cardinals, posterior truncated margin and surface ornament. It also agrees with z.s.I. museum specimen bearing No. M 15385/2 from Andaman Islands.
Occurrence Shell limestone of Dive Agar Formation at Velas.
Family Semelidae Stollezka, 1870 Genus Semele Schumacher, 1817 - 96 -
Semele cordiformis (Sowerby)
(Pl. XIV, Fig. 5,6)
1949 Semele cardiformis Sow. Subrahmanyam et ~' p.71,Fig.66 1951 Saw. Hornell & Tomlin, p.92
Material : Plesiotype : No. MACS G 2466 - 2468
Measurements : Length Height Thickness L/H L/Th
~lACS G 2466 3.2 em. 2.9 em. 0.8 em. 1.10 4.0
2467 2.5 em. 2.2 em. 0 .6 em. 1.13 4.16
Description Shells thin, big, round almost equilateral, ligament extending inside, narrow, umbo prosogyrate, hinge bearing a resilium in triangular shape, two sub-equal cardinals and laterals, ornamentation of concentric ribs separated by very fine x·adial· striations; anterior margin round, posterior margin slightly short and roughly truncated, internal margin smooth; pallial sinus ascending obliquely.
Remarks : Present material matches well with the Z.S.I.
museum specimens bearing ~a.M. 14455/2.
Occurrence : Shell limestone of Dive Agar Formation at
Ve 1 as and Ar a vi •
Super family Veneracea Rafinesque, 1815 Family Veneridae Rafinesque, 1815 - 97 -
Sub-family Circinae Dall, 1896
Genus Grafrarium Roding, 1798
Grafrarium pectinatum (Linne) {Pl. XV, Fig. 15,16)
1956 Grafrarium pee tina tum (Linne) : Satyamurthy, p. 108, Pl. XV, Figs 4 a-b
1969 (Linne) Cox ~ 2.1, PL .N .672, Fig. E 142, 6
1977 (Linnaeus),Dance, p. 264, Fig.
Material : Plesiotype : No. MACS G 2469- 2471
Me asu ramen ts Length Height Thickness L/H L/Th
MACS G 2469 3.1 em. 2.9 em. 6.9 em. 1.06 3.44
2470 2.9 em. 2.8 em. 0.8 em. 1.03 3.62
Description Shells thick, solid, ovate-oblong, equivalved, sub-equilateral, somewhat compressed; ligament and escutcheon well developed, umbo prosgyrate, placed at about anterior one third on dorsal margin, hinge well defined with three inclined cardinals in each valve, anterior lateral well marked; ornament of fine, radial ribs crossed by concentric striations on ventral side; anterior margin very finely crenulated; pallial fine little sinnate. - 98 -.
Remarks : It agrees with Gafrarium pectinatum (Satyamurthy, 1956, p. 108, Cox tl al, 1969, p. 672) in having fine, diverging radial ribs crossed by concentric striations and in having fine crenulations on internal margin, and also with Z.S.I. specimens bearing No. M. 20981/4 collected from Tu ticor in.
Occurrence : Mudstone of Nagaon Formation at Nagaon, and Shell limestone of Dive Agar Formation at Kashid, Velas, Dive Agar, Kurlai, Aravi, Nandgaon, Adgaon and Agar Danda.
Sub-family Sunettinae Stoliezka, 1870 Genus Sunetta Link, 1807 Sub-genus 2_. (Sunetta) Link, 1807
Sunetta (Sunetta) solanderii Gray (Pl. XVII, Fig. ·8)
1949 Sunetta solandri Gray Subrahmanyam ~ ~' p.66, Fig. 37 1951 Gray . Hornell & Tomlin, p • 93
Material Plesiotype No. 2472 - 2474
Measurements Length Height Thickness L/H L/Th MACS G 2472 4.9 em. 4.2 em. 1 • 5 em. 1 .16 3.26
2473 4.4 em. 3.5 em. 1.4 em. 1 .2 5 3.14
Description Shells, solid, thick, elongated-oval, equivalve; sub-equilateral, ligament ophisthodetic, placed - 99 -
in a deep escutcheon, lunule well developed, umbo prosogyrate, hinge long, bearing cardinals and laterals, ornamentation of faint concentric striations, anterior and posterior mnrgins round, internal margin finely dentate, pallial sinus big and round.
Remarks The present material agrees with Sunetta solanderii in the Z.S.I. collection from Goa bearing No.
M 21061/4. It is reported by Subrahmanyam tl al (1949) from Bombay.
Occurrence : Shell limestone of Dive Agar Formation at Velas, Aravi and Kashid.
Sub-family Meretricinae Gray, 1847
Genus Meretrix Lamarck, 1799
Meretria meretrix (Linne)
(Pl. XV, Fig. 1,2)
1949 Meretrix meretrix Linn Subrahmanyam at al, p. 66, Fig. 38
1951 Linn. : Hornell & Tomlin, p. 91
1969 (Linne), Cox et tl• p.N 673, F'ig. E 143.1
Material : Plesiotype : No. 2475- 2477
Measurements Length Height Thickness L/H L/Th
MACS G 2475 4. 9 em. 4.4 em. 1.9 em. 1.11 2.57
2476 2.8 em. 2.3 em. 0. 9 em. 1.21 3.11 - 100 -
Description : Shell thick, big elongate-ovate, equivalve, sub-equilateral lunule and escutcheon weak, thin umbo prosPgyrate; hinge bearing large cardinal and lateral teeth, cardinals tending to radiate; ornamentation wanting and dnly concentric growth lines seen, anterior and posterior margins broadly truncated, internal margin smooth, pallial sinus broad. Th · 701-f I Remarks Present material is identical with Meretrix meretrix preserved at Z.S.I. museum collected from Ernakulam,
Kerala with No. M 21452/4.
Occurrence Shell limestone of Dive Agar Formation at Dive Agar, Aravi, Akshi, Adgaon, Nandgaon and Agar Danda.
Meretria casta (Gmelin) (Pl. XVII, Fig. 4, 5)
1 956 Meretrix casta (Chemnitz) Satyamurthy, p. 111, Pl. XVI, Fig. 2 a-b
Material . Plesio type . No~ MACS G 2478 - 2480
Measurements Length Height Thickness L/H L/Th
MACS G 2478 5.2 em. 4.7 em. 1 • 9 em. 1 .10 2. 73
2479 4.4 em. 4.0 em. 1.6 em. 1 • 1 2.75
Description Shell solid, thick, elongate-ovate, sub-equilateral, lunule thin, undefined; umbo prosogyra te; hinge thick, bearing three radiating cardinal teeth,
Th-?OLJ 1 - 101 - anterior lateral on LV very strong and stout, posterior lateral bears fine crenulations on the top, surface sculpture of very faint concentric striations, anterior margin round, posterior margin truncated; internal margin smooth; Pallial sinus broad.
Remar~s Present material agrees well with Meretria c as t a Sat y am u r thy , 1 9 56 , p • 1 11 , P1 • XV I , Fig s • 2 a-b ) in having pros~gyrate umbo, surface sculpture and posterior margin truncated. It is also identifiable with Z.S.I. museum specimens be aring No. M 21234/4.
Occurrence : Shell limestone of Dive Agar Formation at Akshi and Velas.
Sub-family Dosiniinae Deshayes, 1853 Genus Dosinia Scopoli, 1777 Sub-genus Q. (Dosina) Scopoli, 1777
Dosinia (Dosinia) excisa (Schroter) (Pl. XV, fig. 3,4,11,13; Pl. XVII, Fig. 9)
1949 Dosinia excisa Gml : Subrahmanyam et ~. p. 67, Fig. 40
Material : Plesiotype : No. MACS G 2481 - 2485
Measurements Length Height Thickness L/H L/Th MACS G 2481 2 .1 em. 2 .1 em. 0. 7 em. 1 • 0 3.0 2482 1 • 9 em. 1 • 9 em. 0.6 em. 1 • 0 3.16 - 102 -
Description : Shells moderately thin, ovate, equivalve, slightly inequilateral, umbone~ high, prrnsogyrate, lunule heart-shaped, escutcheon well developed; surface ornaments- tion of concentric striations; anterior margin broadly angulated; posterior margin rounded, inner margins smooth; hinge long bearing both cardinals and laterals, pallial sinus broad and round.
Remarks : Present material matches well with Oosinia (Dosinia) excise preserved at z.s.I. museum collected from East Coast (Tranquabars) having Regd. No. M 21401/4.
Occurrence : Shell limestone of Dive Agar Formation at Vales, Aravi and Agar Danda •
.Q.. (Doeinia) pubescens (Philippi) (Pl. XVII, Fig. 7, 10)
1949 . Dosinia pubscens Phil. Subrahmanyam !! ~. p. 67, Fig. 41
1951 : Phil. : Hornell & Tomlin, p. 91
Material Plesiotype : No. MACS G 2486 - 2488
Measurements : Length Height Thickness L/H L/lh MACS G 2484 1. 3 em. 1 .2 em. 0.5 em. 1.08 2.6
Description : Shell small, ovate-elongate, inequilateral, umbo high, prosogyrate, lunule and escutcheon deep, hinge long bearing cardinals and laterals; shell surface - 103 - sculptured by weak, smooth concentric lines; anterior margin round, posterior margin truncated, ventral margin broadly round and smooth internally, pallial sinus deep.
Remarks Present material agrees with Dosinia (Dosinia) pubescens collected from Visakhapatnam and preserved at z.s.r. museum.
Occurrence : Shell limestone of Dive Agar Formation exposed at Velas.
Sub-family Tepetinae Adams and Adams, 1857
Genus Tapes Meger le von "'uhlfe ld, 1 a 11 Sub-genus l· (Ruditapes) Chiamenti, 1900
Tapes (Ruditape) bruguieri (Hanley)
(Pl. XVI, Fig. 10, 11)
Material : Plesiotype No. MACS G 2489
Me as uremen ts Length Height Thickness L/H L/Th
MACS G 2489 1.8 em. 1.3 em. 0. 5 em. 1.38 3.6
Description Shell moderate, quite thick, inequilateral, elongate; ligament external, well developed, urr:bo prosogyrate, hinge plate narrow, bearing three cardinals and one posterior lateral, anterior laterals wanting; ornamentation that of Fine decussate anteriorly and coarse posteriorly; anterior margin round, posterior margin truncated, internal
margin smooth; pallial sinus present. - 104 -
Remarks : Present material is compared and found to agree with Tapes (Ruditapes) bruguieri from 8hatkal coast preserved at Z.S.I. museum with Regd. No. M 21456/4.
Occurrence Shell limestone of Dive Agar Formation at Aravi.
Ge n u s Ma r c i a Ad am s & Ad am s , 18 57
Sub-genus .!:!.• (Maricia) Adams & Adams, 1857
.!:!.• (Marcia) recens (Chemnitz) (Pl. XVII, Fig. 6)
Material : Plesiotype : No. MACS G 2490 - 2492
Measurements Length Height Thic kn es s L/H L/Th
MACS G 2490 3.5 em. 2.4 em. 0.8 em. 1.45 4.37 2 491 2.4 em. 1.6 em. 0.6 em. 1.5 4.0
Description Shells moderately big, thick, elongate, ine qui lateral, ligament well developed, umbones prosogyrate, hinge well defined bearing cardinals, anterior laterals wanting; ornamentation of slightly irregular, concentric ribs; anterior and posterior margins round, internal margin smooth, pallial sinus deep and rounded.
Remarks : Present material agrees well with Marcia (Marcia) receNS preserved at z.s.I. museum collected from Karwar coast bearing No. M 21399/4. - 105 -
Occurrence : Shell limestone of Dive Agar Formation at Ak shi and Ve las.
Marcia (Marcia) pinguis (Gmelin) (Pl. XVI, Fig. 8, 9)
1969 Venus pinguis Gmelin : Cox et ~. p. N. 684
Material Plesioty pe No. MACS G 2493 - 2495
Measurements : Length Height Thickness L/H L/Th
MACS G 2493 2.9 em. 2. 5 em. 1. 0 em. 1 .16 2.9 2494 2. 5 em. 2. 0 em. o.e em. 1 .2 5 3.1
Description : Shells moderately thick, ovate-elongate, inequilateral, ligament well defined, escutcheon lenticular placed in a depression, umbo prosogyrate,
hinge bearing cardinals, lat~rals wanting, 3b tending to be oifid; ornamentation of irregular,concentric striations; anterior and posterior margins rounded, internal margin smooth, pallial sinus deep, oval and horizontal.
Remarks Present material agrees well with Marcia (Marcia) Ringuis preserved at Z.S.I. museum collected from Madras coast, bearing No. M 21357/4.
Occurrence Mudstone of Nagaon Formation at Nagaon and Agar Danoa and limestone of Dive Agar Formation at Velas. - 106 -
Sub-family Chioninae Frizzell, 1936 Genus Chione Megerle von Muhlfeld Sub-genus£. (Chione) Megerle von Muhlfeld
C. (Chaine) scabra) (Hanley) (Pl. XV, Fig. 12, 14)
1956 Chiona acabra (Hanley), Satyamurthy, p. 124, Pl. XIX, Fig. 1 a and lb
Material : Plesiotype : No. MACS G 2496 - 2504
Measurements Length Height Thickness L/H L/Th
MACS G 2496 1.4 em. 1.3 em. 0.5 em. 1.07 2.8
2498 1.0 em. 0.9 em. 0.4 em. 1.11 2.5
Description Shells small, moderately thin~ ovate trigonal, slightly longer than high, inequilateral, ligament thin, narrow, umbo ·prosogyrate, hinge small, bearing tiny thick cardinals and laterals; surface traversed by thick, close set, nodular radial costae and fine concentric ridges crossing them, anterior margin rounded, posterior margin truncated and drawn out, internal margin crenulated corresponding to surface ornament; pallial sinus small and angular.
Remarks The present specimens agree with£. scabra (Hanley) in all essential characters as described by
Satyamurthy (1956) from Krusadai Island and also with z.s.I. museum specimens. - 107 -
Occurrence : Mudstone of Nagaon, Formation at ~Ja-tjaon, and shell limestone of Dive Agar Formation at Velas, Akshi, Adgaon, Nandgaon and Agar Danda.
Order Myoida Stoliezka, 1870
Sub-order Myina Stoliczka, 1870
Super family Myacea Lamarck, 1809
Family Corbulidae Lamarck, 1818
Sub-family Corbulinae Gray, 1823
Genus Corbula Bruguiere, 1797
Sub-genus.£. (Corbula) Bruguiere, 1797
Corbula (Corbula) subguadrata Melvill
Material : Plesiotype No. 2505
Measurements Length Height Thickness L/H L/Tn
~lACS G 2505 0. 5 em. 0.35 em. 0.1 em. 1.42 5.0
Description Shell very small, thick, tiny, inequilateral, ligament thin, narrow, umbo prosogyrate, hinge bearing a chondrophore in RV and posterior lateral; surface ornament of strong, concentric ribs, raised, round with sufficient gaps in between; anterior margin smooth, posterior margin truncated and ro~trate, internal margin smooth; pallial sinus small. - 108 -
Re ma r k s : Pre sen t s pe c i men s a r e i d e n t i f i a b 1 e to Co r b u 1 a (Corbula) subguadrata from Bombay preserved at Z.S.I. museum bearing No. M 13517/2.
Occurrence : Mudstone of Nagaon Formation at Nagaon.
DISCUSSION
The accompanying Table No. IV shows the distribution and affinities of bivalve species studied
here. Total 42 species have been described, w~ich are
shared by 14 families. The most dominant element of the fauna is Arcidae being represented by 14 species. Family
~eneridae is the next dominant family having 10 species followed by Donacidae with 4 species. Rest of the families are represented by a single ·or a couple of species. In addition to these species, shells of extent species and they include Oysters have been picked up from the different beaches of the area under study. These extent species have not been so far recovered from the shell limestone and hence only illustrations have been given, avoiding
descriptions.
Saccostrea cuculata is the most common Oyster found attached to the rocks including shell limestone in intertidal zone and even beyond. It is rather difficult - 109 - to determine whether these oysters are constituents of the shell limestone or only using shell limestone as a enlistrate for attachment, hence they have not been considered here.
The maximum size of the shells obtained from the shell limestone is 7.4 em. shown by the species Asaphis
(Asaphis) deflorata (Linn.). Otherwise, most of the species are medium to small sized.
Out of 42 species described here, 8 species are common to both Nagaon and Dive Agar formation, while 2 species, viz. Corbula subguadrata and Spondylus layardii occur only in Nagaon Formation. As many as 32 species are exclusive to Dive Agar Formation.
Species common to both Nagaon and Dive Agar Formation are Noetia __ (Noetia) martini!, Anomia (Anomia) ephippium, Spisula (Standella) pellucida, Spisula (Standella) hamaquensis, Donax (Latona) incarnatus, Gafrarium pectinatum, Marcia pingens and Chione scabra.
The entire bivalve fauna is still extent in present waters but many of the species so far have not been reported along the Uest Coast of India. From the Table No. IV it is evident that as many as 22 species do not occur in present day marine waters of our area. Of these species, 11 species occur on the East Coast - 110-
(Satyamurthy 1956). The remaining 11 species do not occur on Indian Coasts.
Consequently, two significant points have to be answered satisfactorily. a) All these 22 species may be present along the West Coast but have not so far been discovered and an assiduous search may prove their existance. b) Even after sufficient efforts, if we fail to
record these species in that event it would mean
that these spe~ies had left the West Coast and hence they are now present only in the shell limestone and mudstone of the Raigad Group.
A possible reason for. their retreat will have to be established by interpreting ecological conditions during the Holocene period when these rocks were deposited. As would be detailed in the general discussion (Chapter IX), ecological conditions during the Holocene and Recent have not been so different as to cau~e a retreat of as many as 22 species in ao short a span of time. And hence, it is likely that the argument in (a) may stand true.
finally, the affinities shown by this bivalve fauna is Indo-Pacific, with a few stray elements from Europe, North and South America, Carribbean and Africa as listed
in Table No. IV. TABLE IV SHOWING DISTRIBUTION OF BIVALVE SPECIES IN RAIGAD GROUP AND THEIR AFFINITIES
Nagaon Oi ve Agar Sr.No. Name of the Species Affinities Fa rma Formation tion
1. Port1andia ( Portlandia) sp. X Cosmopolitan
2 • Anadara (A.) grana sa (Linne.) X II
3. Larkiria rhombea (Born) X E • Pacific , Carribean
4. Sc apharc a (2.•) deyro1lei Jou. X Cosmopolitan 5. s.(s.) inaeguiva1vis -- (Brug.) X - II -
6 • S. (S.) gubernaculum II - (Reeve) X
7 • Scapharca sp. X II
8 • S. (Cuneorca) clathrata (Reeve) X II
9. Barbatia (Barbatia) bistrigota (Dunker) X II
II 10. 8. s p. X 11. Noetia (Neotia) E • Pacific, martinii Reduz. X X Carribean
12. Striarca avellana Lam. X N. Amercia, Europe and Australia
II 13. S. s ymme tr i c a (Reeve ) X 14. s. sp. X "
15. Arcopsis (Arcopsis) X lndo-Pacific 1 Europe and N. America
16. Pecten (P.) sanatorium Gmelin X Co ·_.rnop.olitan N agaon 0 i ve Agar Sr.No. Name of the Species Affinities Forma Formation tion
17. Anomia ephippium Linn. X X Europe, Africa, Asia lB. Spondylus layardi Reave X W. Pacific, Indo-Pacific, Medit.
1 9 • Cod ak i a diverge us Europe, (Philippi) X ~J • Am e r i c a , Asia, Pacific
20. Cardium (Cardium) France, coronatum Spengler X w. Africa
21. Spisula (Standella) East S. Americc: pellucida (Gmelin) X X W. Afx:ica
2 2 • S • ( S • ) n i cob ar i c a '[Gmelin) X " 23. _2. (.§..) namaquensis Co rr. & Ken. X X " 24. Donax (Latona) semisulcatus Hanley X E. Indies
2 5 • Q. ( .h • ) 1 u b r i c u s Han 1 e y X II
26. D. (,h.) incarnatus Chemn i tz X X E. Indies (abundant in Bombay)
2 7. Q. (,h.) f aba Gmelin X "
28. Gastrna polygona (Gmelin) X Europe, w. Africa
29. Macoma bruguieri (Hanley) X Cosmopolitan
3 0. ~phis def lo-ra ta (Linne) X Carr i be an Indo-Pacific
31. Semele cardiformis (Sow.) X N. America, 5. America, Europe and Pacific
32. Gayrarium 2ectinatum Indo-Pacific, {Linne) X X Japonic common Nagaon Dive Agar Sr.No~ Name of the Species Affinities Forma- Formation tion
33. Sunetta solandrii X W. Pacific, Grey Europe (found in Bombay)
34. Marcia receus ( X Africa, (Chemni tz) East Indies
3 5. M• pinguis X X " 36. Chione scabra East & West (Hanley) X X N • America
37. Mere tri~ meretrix X America, (Linne) East Indies (found in Bombay)
38. M. casta (Gmelin) X "
39. Dosinia excisa X New Zealand Schrotor) (found in Bombay)
40. Q. pubescens X - II - (Philippi)
4 1 • Tapes (Ruditapes) X Europe, bruguieri (Hanley) w. Pacific
42. Corbula subguadrata X . w~ Africa, Melvill Europe, Asia, Indo-Paci fie, c • America, N • & s. America TABLE V LIST OF'--Bl.UAlll£ SRECIE 5 FOliNO ON THE SHORE..S.
Sr.No. Name of the species Pl. Fig. No. Occurrenc.
1. Barbatia (Barbatia) MACS Nagaon obliguata (Gray) XI 12,13 G2566- 2568
2. Scapharca (Cunearca) sp. MACS N agaon, Ve G2509- & Ara vi 2510
3. Perna (Perna) vir id is XI 1 ,2 MACS (Linnaens) G2 511- Nagaon 2512
4. Modiolus Modi61us) XII 12,13 MACS striatulus Hanley) G2513- Nagaon & 2514 Akshi
5. Cardium (Bucardium) XI 5,6 MACS Nagaon, Vel latum Born G2515- K ashid and 2517 Dive Agar
6. Mactra (Eomattra) XII 1 MACS Nandgaon, luzonica Deshnyes G2518- Velas, & 2520 Dive Agar
7. Tellina (Tellinoides) X VI 12,15 MACS Nagaon sinuata Spengler G2521- 2525
8 • Apolymetis edentula XIV 3,4 MACS Nagaon, (Spengler) G2526- Velas 2529
9. Donax (Hecuba) scortum XIII 5,6 MACS Nagaon, ( Linnaeus) G2530- Ve las 2532 Nandgaon Dive Agar
10. San juinolaria (Soletellina) XV 5,6 ~lACS Dive Agar violacea Reeve G2533
Con td. Sr.No. Name of the species Pl. Fig. No. OccurrencE
1 1 • Trapezium (Neotrayezium) XI 3,4 r1ACS Nagaon & vellicatum (Reeve G2535- Velas 2536
12 • Paphia (Paphia) XVII 1 '2 f·l AC 5 Nagaon, malabarica Chemmtz. G2532- Akshi, Vela:: 2 539 & Nandgaon 13. £. (f.) marmarata Lamarck XVII 3 MACS Nagaon,Akst G2540- Velas, 2542 Nand gaon, Adgaon, & Agar Danda
14, Pho las (Mono thyra) XII 10,11 MACS Nagaon & orientalis Gunelin G2543- Agar Danda 2545
15. Barnea (B.) candida XII 8,9 MACS Nagaon & ( Linnaeus) G2546- Agar Danda 2547 Fig. 1 5. Striaq~a ave llana Lam. p. 75
P lesio type No. MACS G 2421 X 2
Fig. 1 6 t ScaghaJea c~uo~ai:~g) clathrata p. 73 1 7. (Reeve 16. Plesiotype Nci. f'1A C S G 2407 X 1
17. External view of the same. fig. 18, Noetia _(Noetia) martinii \7{ec luz p. 74 1 9. 18. Plesiotype ~Jo • MACS G 2417 X 2 19. External view of the same
Fig. 20, Areo psis (Arcoesis) limo psis p. 78 21 • (Koenen)
20. Plesiotype No. f~ ACS G 2431 X 2 21 • Internal view of the same. PLATE X
Fig. 1, 2. Larkinia rhombea (Born) p. 68
1 • Plesiot:tt2e No. MACS G 2395 X 1 2 • Same specimen, internal view
Fig. 3. Barbatia (Barbatia) bistrigata 1Dunker) p. 65
Plesiotype No. ~lACS G 2 411 X 1
Fig. 4,7. ScaE!harea (ScaE!harea) sp. p. 72
4. Internal view r~o. r1A c s G 2406 X 1 7. External view, same specimen
Fig. 5 '6. p. 70
5. PlesiotyE!e No. G 2 401 X 1 6 • Ple sio type No. rr1 ACS G 2 402 X 1
Fig. 8. Anadara (An ad ar a) granos a (Lam • ) p. 67
PlesiotyE!e No. MACS G 2392 X 1
Fig. 9. Sca£barea (Scapharea) p. 71 Q__lJbernaculurr. (Reeve1
PlesiotyE!e No. MACS G 2403 X 1
Fig. 10, Barbatia (Barbatia) s p. p. 66 13. 1 0 • Internal view, No. MACS G2414 X 1 1 3 • External view, No. filA CS G2415 X 1
Fig. 11, Scapharea (Scaeharea) p. 69 12. de yrollei Jous.
1 1 • Ple sio ty12e No. MACS G 2398 X 2
12. Plesio t~ No. MACS G 2399 X 2
Fig. 14. Striarca syrr.metrica (Reeve) p. 76 ...., P le sio ty 12e No. ~1ACS G 2424 X L PLATE X
13 12
11
14 15 PLATE XI
Fig. 1,2. Pe rn a ( Pe rn a ) vir i d i s (Linn • ) 1. Plesiotype No. MACS G 2511 X 1 2. External view of the same. fig. 3,4. Trapezium ve llicatum (Reo ve) 3. Plesiotype No. MACS G 2535 X 2 4. Internal view of the same with serpulid tubes. fig. 5,6. Cardium (Bucardium) latum Born 5. Plesiotype No. MACS G 2515 X 1 .2 6. Internal view of the same.
Fig. 7. Portlandia (Portlandia) sp. p. 64 No. MACS G 2391 X 3. 5 fig. 8,9. Striarea (Striarea) sp. B. External view, No. MACS G 2548 X 2 • 5 9. Internal view, No. MAC S . G 2549 X 2 .5 fig. 10, Cardium (Cardium) coronatum p. 84 1 1 • ·Spengler
10. Plesiotype No. MACS G 2442 X 1 .2 11. Internal view of the same.
Fig. 12,13. Barbatia (Barbatia) obliquata (Gray) 12. Plesiotype No. MACS G 2566 X 1 13. External view of the same.
Fig. 14,15. Anadara (Anadara) granosa (Lam.) p. 67 14. Plesiotype No. MACS G 2393 x 1 15. Plesiotype No, MACS G 2394 x 1 PLATE XI
1 PLATE XII
Fig. 1 • Mac tr a luzonica Oeshnyes
P le siotype No. MACS G 2518 X 2.5
Fig. 2,3. Pecten sanatorium Gmelin p. 79
2 • Plesiotype No. ~1A CS G 2434 X 1
3 • P!e sio type No. MACS G 2435 X 2. 5
Fig. 4,5, Spondylus (Spondl:lus} la;tondii p. 81 6 '7. Reeve 4 • Plesiotype No. MACS G 2439 X 3 5. External view of the same. 6 • Plesiotz:pe No. MACS G 2440 X 1 7 • External view of the same.
Fig. 8,9. Barnea (Barnea) candida (Linn.) 8. Plasio tl: pe No. MACS G 2546 X 1 9. In tern al view of the same.
Fig. 10, Pholas (Mono thyra} orientalis Gmelin 1 1 • 1 0. Ples io type No. MACS G 2543 X 1 1 1 • External view of the s arne.
Fig. 1 2 , Modiolus (Modiolus) striatulus 13. ~Hanley)
12. Ple sio type No. MACS G 2513 X 2.5 1 3 • Internal view of the same. PLAIE XII PLATE XIII
fig. 1,2.; Sanguinolaria (Soletellina) sp.A. 1 • Extern a 1 view , No • MAC S G 2550 X 1 2. Internal view, same specimen fig. 3,4. Donax (Latona) semisulcatus Hanley p. 88 3. Plesiotype No. MACS G 2453 X 2.2
4. External view of the ~arne
Fig. 5,6. Donax (Hecuba) scortum (Linn.) 5 ·. Plesiotype No. MACS G 2 530 x 1 6. Internal view of the same.
Fig. 7,8. f~eretrix sp. 7. Internal view No. MACS G 2551 X 2.5 8. External view, No. MACS G 2552 X 2.5 fig. 9,10. Donax (Latona) incarnatus p. 90 9. Plesiotype No. MACS G 2458 X 2 10. Internal view of the same fig. 11,12, Anomia (Anomia) eplippium (Linn.) p. 80 13 14 • • 11. Plesiotype No. MACS G 2436 X 1 12. lnternal view of the same.
13. Plesiotype No. MACS G 2437 X 1 14. Internal view of the same. fig. 15,16. Donax (Latona) lubrica Hanley p. 8 9
15. Plesiotype No. MACS G 2455 X 2 16. Internal view of the same . PLATE XIII
3
1 2
4
5 G
7
9 10
8
11 12 15 PLATE XIV
fig. 1,2,7,8. Asaehis (Asaehis) p. 94 E_eflorata (Linn.)
1 • p 1 e s i 0 t :i ee No. MACS G 2464 X 1. 5 2 • External view of the s arne
7. Ple sic t:t ee No. ~lAC 5 G 2465 X 2 8 • External view of the same.
fig. 3,4. Aeol~metis edentula (Spengler) 3, Ple sio tz: ee No. MACS G 2526 X 1 4. Internal view of the same.
fig. 5,6. Seme 1 a cordiformis (Sow.) p. 95 5. Plesiotz:ee No. MACS G 2466 X 1·. 5
6. External view of the same X 2
PLATE XV
fig. 1, 2 Meretrix meretrix (Linn.) p . 99
1 • Plesiot~ee No. ~lACS G 2475 X 1.2 2. External view of the same.
Fig. 3, 4. Dosinia (Dosinia) excise p . 1 01 11,13. (Schroter
3 • Ple sio type No. ~1A CS G 2481: X 2
4. External view of the same. 11. External viet.J, No. MACS G 2482 X 2 13. Internal view, No. MACS G 2483 X 2
Fig. 12, Chione (Chione) scabra~ p . 106 1 4. 1 Hanley) 1 2 • Ple sio type No. r~ ACS G 2496 X 2 14. Plesiot;t EB No . MACS G 2498 X 2
Fig. 1 5 , Gafrarium pee tin a tum (Linn .) p . 97 1 6 • 1 5. Plesiot~ee No . MACS G 2469 X 1
16. Internal view of the same
Fig. 17, Gastran a polygona (Gmelin) p. 92 1 8 • 1 7 • Plesiotype No. MACS G 2462 X .75 1 8 • Internal view of the s arn e • PLATE XV
8 10
14 11 12 13
17 PLATE XVI
Fig. 1 '2 ' Spisula (Standella) p. 87 16,17. n amaguen sis
1 • P 1 e s i o t :t Ee No. MACS G 2451 X .75 2 • In tern a1 view of the same
16. P1esiot;tEe No. MACS G 2452 X .75 17. E xterna1 view of the same.
Fig. 3,6. ~1 a com a bruguieri Hanley p. 93
3 • . Plesiot;tee No. MACS G 2463 X 1 • 5 6. Internal view of the same.
Fig. 4,7, Seisula (Stand e 11 a) ,Ee1lucida p. 85 13,14. (Gme1in)
4. Plesiot;tee No. MACS G 2445 X 1 7. Internal view of the same.
13. P1e sio t:L ee No. MACS G 2446 X 1 14. External view of the same.
Fig. 5. Don ax (Latona) faba Gme1in ~. 91
Pl esiot;t ee No. MACS'G 2461 X 1 • 5
Fig. 8,9. Marcia (Marcia) einguis (Gmelin) p. 105
8 • Ple siotn~e No. MACS G 2493 X 2 9 • External view of the s arne.
fig. 10,11. ~ (Ruditaees) bruguieri p. 103 8 y)
1 0. P1esiot:Lee No. MACS G 2489 X 2 11 • Internal view of the same.
Fig. 12 t Tel lin a (Tellinoides) 1 5 • sinnata Spengler.
12. Ple sio t:L ee No. MACS G 252 5 X 1 1 5. Internal view of the same. PLATE XVI
1 2
10 8
12
13 14 PLATE XVII
Fig. 1,2. Paphia malabarica Chemnitz 1. Plesiotype No. MACS G 2532 X 1 • 5 2. Internal view of the same.
Fig. 3. Paphia marmarata Lam. Plesiotype No. MACS G 2540 rig. 4,5. Meretrix casta (Chemnitz) p. 100
4. Plesiotype No. MACS G 2478 X 1 • 5 5. In te rna! view of the s arne.
Fig. 6. Marcia (Marcia) recen s ( Chemn i tz) p . 104
Plesiotype No. MACS G 2490 X • 2
Fig.7,10. Dosinia (Dosinia) pubescens p. 102 {Philippi) 7. Plesiotype No. MACS G 2486 X 4 10. Internal view of the same.
Fig. a. Sune tta (Sunetta) sol an de rii Gray p. 98
Plesiotype No. MAGS G 2472 X 1.5
Fig. 9. Dosinia (Dosinia) excisa p . 101 (Schrotei Plesiotype No. MACS G 2484 X 2 PLATE XVII