Paiaeobotanisl 49 (2000) : 225-237 0031-0174/20001225-237 $2.00
Study of plant megafossils from the Tura· Formation of Nangwalbibra, Garo Hills, Meghalaya, India
R.C. MEHROTRA
Sirbal Salmi Institute of Palaeobotany, 53 University Road, Lucknow 226007, India.
(Received 05 April 1999; revised version accepted 07 October 1999)
ABSTRACT
Mehrotra RC 2000. Study of plant megafossils from the Tura Formation of Nangwalbibra, Garo Hills, Meghalaya, India. Palaeobotanist 49(2) : 225-237.
Leaf-impressions collected from the Tura Formation (Upper Palaeocene) ofNangwalbibra. Garo Hills. Meghalaya belong to Grewia ofTiliaceae. Alalalllia of Rutaceae. Schleichera of Sapindaceae. Mallgifera of Anacardiaceae, Termillalia as well as Calycopleris of Combretaceae, Syzygiul11 of Myrtaceae and ChrysophyllulIl of Sapotaceae. In addition, a few palm leaves of uncertain affinities are also described. The modem comparable forms of the fossils indicate a tropical warm and humid climate in the area during the deposition of the beds.
Key-words-Leaf-impressions. Angiosperms. Tura Fonnation, Garo Hills, Upper Palaeocene.
~ ~ :ll~HP"l~~ ~ ~ ett1JTUqrfu- ~ %'1i4IcR'1~ j(C\qI~ql~tffqiT -3l&r1'1' m~T%~ mu~ ~ ~ (~qR1~1t111)~~'1~ ~ ~ ~ Q11<{lI~QW~ ~ Wt~,vn~ it;ftfcrqr, ~ it it "ffftim, it it eWiR741tzci/lidl'hNRfI,~ it A7$J{tf:;jlJlf nm ~ it #i1$vi'Jfi!;ITIlf B ~tm ~.~ ~ ~ or~ ~ ~ ~ ~ ~&1fUmrr{~. 01T~~ ~ ~ ~ ~ ~. 'fffiW it f1"mit ~ IiR if \jOUI iflkOl·tfrl, ~ tzci\3Wj <{iT m ~-quf~~'1,~, @ ~, miTqcffi~,~ qR141W1. INTRODUCTION bearing beds are located on the right bank of the Nangal stream within an area of3 km. The fossils are found in greyish-white HE rocks of the Tura Formation are well exposed near to buff coloured clay stones ranging 305-366 m in thickness. T Nangwalbibra (25°28' N, 90° 42' E), a town situated near The locality map (Fig. I) and litholog of the area are already Williamnagar, East Garo Hills District, Meghalaya. The plant gi ven by Bhattacharyya (1983) and Saxena el al. (1996). «:>Birbat Sahni Instilule of Palaeobotany. tndia 226 THE PALAEOBOTANIST Age Group Lithology 2S~ 40' Oligocene Simsang Formation WILLIAHNAGAR (100 m thick) JWEST KHASI Eocene-Palaeocene Jaintia Kopili Formation , HILLS (450 m to 500 m thick) '-~ KHERAPARA 2S' Siju Limestone ) 20' ' (100 m to 160 m thick) W[ST~ _ ASSAI1 ~' __ , --.,.." 1OCoAL.~.-.'- -).~r' v 5 ~HARA I ; PI [ G,k ';. LAY> 1:\ Tura Formation ~(;,MC",",.t.""tl&J.\ t "\. .~ . ~~) ./'-.--. r-"·-._.__~J._._. o~ 10 (180 m to 250 m thick) ....,. BAHGlAOESH' Upper Cretaceous Coarse grained sandstone Fig. 1- A map showing the fossiliferous locality near Williamnagar (after Saxena el ai., 1996). and conglomerate (60 m thick) however, the general stratigraphic sequence noticed in the area is given below in Fig. 2. As evident from this figure the Tura ------Unconform itY------Formation is considered as Upper Palaeocene in age (Saxena er at., 1996; Mehrotra ef at., 1998). Precambrian Coarse grained granite The average annual rainfall in the Garo Hills varies from ganodiorites, banded gneiss 250 cm to 320 cm. The climate is moderate during winter, but and quartzite gradually becomes warmer from middle of March. The monsoon sets in from mid-May and the area is covered with a Fig. 2-General slraligraphic sequence ofGaro Hills. Meghalaya (after Raja thick forest of mostly deciduous trees having a thick Rao, 1981). undergrowth of thorny bushes. The fossil flora of Nangwalbibra is not well known and SYSTEMATICS only a few plant fossils are described from the area. Lakhanpal (1964) first recorded a palm leaf from this area. Later, DICOTYLEDONS Bhatlacharyya (1983) described several forms, namely NeLumbo nagaLensis (Nymphaeaceae), Lirsea sp., Phoebe Family- TILIACEAE Bentham & Hooker f. subLanceoLara (Lauraceae), Arlocarpus garoensis (Moraceae), Genus-GREWIA Linnaeus Triumfetta rhomboideocarpa (Tiliaceae), Heteropwzax sp. (Araliaceae), Osmanthus eocenicus, Ligustrum turaense, Species-GREWIA SAHNII (Lakhanpal) comb. nov. AnthoLirhes oLeaceaeformis, A. campanuLatus (Oleaceae), PI. 1·1 Nipa sahnii (Palmae) and Poacites sp. A field excursion was undertaken to ascertain the NeoLitsea sahnii palaeofloral composition of the Garo Hills, Meghalaya and a 1954 Lakhanpal, p. 28, PI. I, figs 3, 4. large number of plant megafossils were collected from the Description-Leaf simple, more or less complete, Tura Formation of Nangwalbibra. Most of the fossils are in symmetrical, elliptic, about 9·0 x 4·0 cm in length and width the form of leaf-impressions, a few fruits and seeds were also respectively; apex slightly broken but appearing acute; base collected from the same locality. Some are complete and well asymmetrical, obtuse, normal; margin entire; texture appearing preserved while others are fragmentary in nature. chartaceous; petiole length and width about 1·3 x I'5 cm All the type specimens, negatives etc. of the fossils being respectively, normal; venation acrodromous, basal, imperfect; described in the paper are deposited in the repository of the primary veins (10) three in number, mid-rib stout, slightly Birbal Sahni Institute of Palaeobotany, Lucknow. curved near the apex, a pair of lateral primaries coming off at The terminology used in describing leaves is after Hickey base at an angle of25°-30° and running up to the middle of the (1973) and Dilcher (1974). The identification of leaves was leaf; secondary veins (20) arising from the mid-rib at about done by comparing them with the herbarium sheets at Forest one third of its length from the base, about 10 pairs visible, Research Institute (FRI), Dehradun; Central National alternate, 6-11 mm apart, angle of divergence moderately acute Herbarium (CNH), Howrah and Birbal Sahni Institute of to narrow acute (60°_40°), decreasing gradually towards the Palaeobotany (BSIP), Lucknow. apex, abruptly curved near the margin to form loops,joining MEHROTRA-STUDY OFPLANT MEGAFOSSILS FROM THETURA FORMATION OF NANGWALBIBRA 227 superadjacent secondaries at right angle to sometimes at acute and running up to the middle ofthe leaf; secondary veins arising angle, moderately thick; intramarginal vein absent; tertiary from the midrib at about one third of its length from the base, veins (30) fine, angle of origin usually RR, pattern percurrent, alternate, angle of divergence moderately acute 10 narrow simple, obliquely placed, predominantly alternate, close, some acute, decreasing gradually towards the apex, abruptly curved arising directly from mid-rib to join with the lateral veins; near the margin to form loops with the superadjacent higher order venation present; areoles well developed, secondaries; tertiary veins percurrent, simple, obliquely placed, oriented, usually quadrangular, medium to small, vein-lets not predominantly alternate, close, some arisingdirectly from the observed. mid-rib to join with the lateral veins. Holotype-Specimen no. BSIP 38086. Occurrellce- Tura Formation; Nangwalbibra near Species-GREWIA GAROENSIS (Lakhanpal) Williamnagar, East Garo Hills District, Meghalaya; Upper comb. nov. Palaeocene. PI. 1·2 Affillities- The important features of the fossi I leaf are: acrodromous basal imperfect venation, asymmetrical base, Trel1la garoensis entire margin, elliptic shape, secondary veins forming loops 1954 Lakhanpal, p. 27-28, PI. 1'1,2 and percurrent tertiary veins. These characters indicate its Description-Leaf more or less complete with slightly affinities with Grewia Linnaeus of Tiliaceae. Further broken apex, simple, symmetrical to slightly asymmetrical, identification of the fossil leaf up to specific level is very narrow ovate; preserved length (including petiole) ll·5 cm, difficult as there are lot of variations in leaf structure among maximum width 4-4 cm; apex appearing acute; base different species ofGrewia. The base varies from asymmetrical symmetrical; margin serrate, acute, apical side concave to to symmetrical (Grewia laevigala Yahl, Herbarium Sheet Nos straight, basal side straight; sinuses angular, spacing more or FRI 2362, 62203), while the margin varies from serrate to less regular, simple on complete margin; texture seemingly partially serrate to entire (G. calophylla Kurz, Herbarium Sheet chartaceous; attachment with petiole normal; petiole 2·5 cm Nos CNH 80761,1924). in length and 2 mm in thickness; venation acrodromous, Though fossil woods (Bande & Srivastava, 1995) and imperfect; primary veins three, one straight and moderately fruit (Paradkar & Dixit, 1984) of Grewia are of common thick called mid-rib, two laterals coming off at the base at an occurrence in the Deccan lntertrappean beds of India, its only angle of 40° and running half way of the lamina length; leaf, G. foxii Lakhanpal (1954), is known from the Eocene of secondary veins 7 pairs visible, arising slightly above the base, Damalgiri, Tura District, Meghalaya.lt differs from the present alternate, 0·8-1·6 cm apart, angle of divergence narrow to fossil in having serrate-crenate margin, ovate shape, smaller moderately acute (30°-50°), upper pairs more acute than lower, size and twisted petiole. A few years back Srivastava et al. moderately thick, uniformly curved, sometimes joining (1992) also described a fossil leaf of Grewia riliaefolia Yahl superadjacent secondaries; intersecondary veins not present; from the Pleistocene beds of Mahuadanr, Palamu District, intramarginal veins absent; tertiary veins percurrent, angle of Bihar. It also differs from the present fossil in having toothed origin RR-AR, unbranched, obliquely placed, predominantly margin. alternate, close; higher order venation of4lh order; areoles well Lakhanpal (1954) also described a fossil leaf, Neolirsea developed, oriented, quadrangular. safllzii Lakhanpal, resembling Neolitsea zeylallica of Holotype-Specimen no. BSlP 38087. Lauraceae from the Damalgiri beds. The venation pattern of Occurrence- Tura Formation; Nangwalbibra near this fossil leaf (Lakhanpal, 1954, p. 28, pI. I, figs 3, 4) appears Williamnagar, East Garo Hills District, Meghalaya; Upper to be basal acrodromous, while it is suprabasal acrodromous Palaeocene. in case of Neolitsea ?eylallica (Herbarium Sheet Nos BSIP Affillities- The diagnostic features of the fossil, viz., 2664,2665). Therefore, it cannot be the fossil leafofNeolirsea. serrate margin, asymmetrical base, narrow ovate shape and As the present fossil is identical to N. sahllii, it has been merged acrodromous venation indicate its affinities with that of Grewia with it and both are named as Grewia sahllii (Lakhanpal) comb. Linnaeus, especially G. laevigata YahI. (Herbarium Sheet No. nov., the revised specific diagnosis of which is given below: CNH 62203) ofTiliaceae. Grewiafoxii Lakhanpal (1954) is the only leaf of Grewia Specific diagnosis known in the fossil state. The present fossil differs from it in GREWIA SAHNII (Lakhanpal) comb. nov. size and angle of divergence of lateral primaries. Lakhanpal (1954) described another fossil leaf, Trema Leaf simple, symmetrical, elliptic; apex acute; base garoellsis Lakhanpal resembling Trema orielltalis Blume of asymmetrical, obtuse, normal; margin entire; venation Ulmaceae from the Damalgiri beds near Tura (Lakhanpal, acrodromous. basal, imperfect; primary veins three in number, 1954, p. 27-28, pI. I, figs 1,2). This fossil leaf is exactly mid-rib stout, a pair of lateral primaries coming off at base similar with the present fossil leaf of Grewia . In order to :, . ',. I {i II I .. MEHROTRA-STUDY OFPLANT MEGAFOSSILS FROM THETURA FORMATION OF NANGWALBII3RA 229 confirm the identification herbarium sheets of Trema orienJalis Williamnagar, East Garo Hills District, Meghalaya; Upper (Herbarium Sheet Nos BSIP 11829-11831) were critically Palaeocene. examined and it was observed that secondary veins in T Affinilies- The diagnostic features of the fossil are small orienla/is are mostly straight and are not forming loops size, narrow ovate shape, entire margin. membranaceous whereas in T garoellSis the secondary veins are uniformly texture, brochidodromous venation, closely placed secondaries curved forming loops. It does not appear to be the leaf of with moderately acute angle of divergence, frequent Trema. As the present fossil leaf of Crewia is identical to T intersecondaries and random reticulate tertiaries. These garoellSis Lakhanpal, it has been merged with it and both are characters indicate its close resemblance with Ata/(/Illia Correa named as Crewia gamel/sis (Lakhanpal) comb. nov., the of Rutaceae. Among its various species the fossil shows revised specific diagnosis of which is given below: maximum resemblance with A. l1lolloplzylLa (Roxburgh) Decandolle (Herbarium Sheet No. FRI 21320). Specific diagnosis This is the first record of a fossil leaf of Alalalllia though GREWIA CAROENSIS (Lakhanpal) comb. nov. the fossil woods resembling Alalalllia are known from the Deccan Intertrappean beds of Mandla District, Madhya Leaf simple, symmetrical to slightly asymmetrical, narrow Pradesh (Lakhanpal el al., 1978). The present fossil leaf is ovate to oblong; apex acute; base symmetrical to asymmetrical; being named as Alalalliia palaeomonoplzylla, the specific margin sen'ate; venation acrodromous. imperfect; primary epithet indicating its resemblance with A. lIlonophylLa. veins three. one straight called mid-rib. two laterals coming The genus Alalal1lia consists of20 species of which only off at the base and running half way of the lamina length; five are found in India. They are usually evergreen shrubs. A. secondary veins arising slightly above the base, alternate, angle l1lonophyLia with which the present fossil shows maximum of divergence narrow to moderately acute, upper pairs more similarities, is found inSouth India (Santapau & Henry. 1973). acute than lower, moderately thick. uniformly curved. sometimes joining superadjacent secondaries to form loops; Specific diagnosis tertiary veins percurrent, close. ATALANTIA PALAEOMONOPHYLLA sp. nov. Family-RUTACEAE Bentham & Hooker f Leaf narrow ovate, symmetrical; base obtuse, normal; margin entire; texture membranaceous; venation brochido Genus-ATALANTIA Correa dromous; primary vein stout. straight; secondary veins Species-ATALANTIA PALAEOMONOPHYLLA alternate. angle of divergence moderately acute, uniform, sp. nov. abruptly curved to form loops, moderately thick; inter secondaries frequently present, simple to composite; tertiary PI. 1'3,5 veins random reticulate. Descriplion-Leaf nalTOWovate, symmetrical, preserved lamina length 4 cm, max;mum width 1·6 em; apex broken; Family-5APINDACEAE Bentham & Hooker f. base obtuse. normal; margin entire; texture membranaceous; Genus-SCHLEICHERA Wil!d. venation brochidodromous; primary vein stout. more or less straight; secondary veins more than 10 pairs visible, alternate. Species-SCHLEICHERA PALAEOTRIjUGA sp. nov. 1-3 mm apart, angle ofdivergence moderately acute (50°-60°), PI. 1·7 uniform, abruptly curved to form loops. moderately thick; intersecondaries frequently present, simple to composite; Descriplion-Lamina well preserved, elliptic. symmet tertiary veins fine, random reticulate; areoles well developed. rical; preserved length 8·6 cm, maximum width 5 em; apex Etylllology-From AlaLanlia lllOnophyila. slightly broken but appearing acute; base seemingly obtuse. Holotype-Specimen no. BSIP 38088. normal; margin entire; texture chartaceous; venation eucampto Occurrence- Tura Formation; Nangwalbibra near dromous; primary vein moderate, straight; secondary veins 9 / PLATE 1 "'" (All ligures are in nalUral size unless otherwise menlioned) I. A fossil leaf of Grewia .Iallllii (Lakhanpai) comb. nov. showing shape. and venation patlern. size and venation paltem: Specimen no. BSIP 380R6. 5. A portion or Ara/alllia pa/aeoll/l/llophylla sp. nov. enlarged 10 show 2. A fossil leaf of Grewia garoel1.lis (Lakhanpal) comb. nov. showing details of venation: Specimen no. BSIP 38088. x 3. shape. size and venation paltern: Specimen no BSIP 38087. 6 A fossil leaf or S,.ltIeichera pa/acolrijuga sp. nov. showing shape. 3. A fossil leaf of Alalalllia pa/aco/l/(II/ophylla sp. nov. showing shape size and venation pattern: Specimen no. BSIP 38089. and size: Specimen no. BSIP 38088. 7. A fossil leaf of Tenllillalia pa/ae(}/'arappa Awaslhi and Mehrolra show 4. A modern leaf of Ala/alliia 1I1O/lOpllvlla showing similar shape. size ing shape. size and venation pattern: Specimen no. I3SIP 38091. N oW 11111111 IlmIT\ \\~U \\\\\\\\\~ \\\\\\\\,\; \\\\\\\~~ \\ \\II\~ ~\ \\\\\\~ MEHROTRA-STUDY OF PLANT MEGAFOSSILS FROM THE TURA FORMATION OF NANGWALBIBRA 231 pairs visible, each 8-12 mm apart, alternate, angle of Description-Leaf incomplete without apex, symmet divergence moderately acute (45°-50°), upper pairs more acute rical, lorate, preserved length 16·5 cm, maximum width 3·5 than lower, moderately thick, uniformly curved; intersecondary cm; apex broken; base symmetrical, appearing obtuse.; margin veins observed near apex; intramarginal veins absent; tertiary entire; texture chartaceous; venation eucamptodromous; veins percurrent, fine, simple to forked, sometimes recurved primary vein stout, straight; secondary veins about 14 pairs also, oblique, close, predominantly alternate; further details visible, alternate, 5- 10 mm apart, angle of di vergence acute not visible. (70°-85°), uniformly curved, moderately thick; intersecondary Etymology-From Schleicllera trijuga. veins present; tertiary veins percurrent forked, sometimes Holotype-Specimen no. BSIP 38089. recurved also; areoles well developed; intra-marginal veins Occurrence- Tura Formation; Nangwalbibra near absent. Williamnagar, East Garo Hills District, Meghalaya; Upper Figured Specill/en-Specimen no. BSIP 38090. Palaeocene. Occurrence- Tura Formation; Nangwalbibra near Affinities-The important features of the fossil, viz., Witliamnagar, East Garo Hills District, Meghalaya; Upper elliptic shape, entire margin, eucamptodromous venation, Pal aeocene. moderately acute angle of divergence of secondary veins, Affinities-The important characters of the fossil, viz., presence of intersecondary veins and percurrent tertiaries bigger size, lorate shape, entire margin, eucamptodromous indicate its affinities with Schleiclzera trijuga Willd. of venation, stout primary vein, presence of intersecondaries, Sapi ndaceae. wide acute angle of divergence of secondary veins and There is no previous report of the fossil leaf of percurrent tertiaries with well developed areoles indicate its Sclzleiclzera from India though its woods are known from affinities with Mangijera Linnaeus especially M. indica Kankawati Series of Gujarat (Awasthi et al.. 1982). Therefore, Linnaeus (Herbarium Sheet No. CNH 10564) of it is being described here as a new species of Sclileicliera, S. Anacardiaceae. palaeotrijuga sp. nov. Most of the Indian fossil leaves resembling Mangifera Schleichera trijuga is a tree found in dry forests of North are described as Mangijera sOlileslzwarica Lakhanpal and west Himalayas, throughout Central and Northern India, Awasthi (1984). Another leaf resembling Mangijera was Myanmar and Sri Lanka. recently described as EOII/angifempizyilulll dall/algiriensis Mehrotra et a/. (1998). After a detailed comparison it was Specific diagnosis found that the present fossil is similar to the former and SCHLEICHERA PALAEOTRIJUGA sp. nov. therefore, has been placed under the same. The genus Mangijera presently consists of about 40 Lamina elliptic, symmetrical; apex acute; base obtuse, species distributed in South east Asia and Indo Malayan region normal; margin entire; texture chartaceous; venation (Willis, 1973). Out of them only four are found in India. M. eucamptodromous; primary vein moderate, straight; secondary indica, with which the fossil shows maximum resemblance, is veins alternate, angle of Jivergence moderately acute, upper found in all the forests of the plains of India and in Sub pairs more acute than lower, moderately thick, uniformly Himalayan tracts. It is also found in Bangladesh, Myanmar, curved; intersecondary veins preseilt; tertiary veins percurrent, Thailand, Vietnam and Malaya Peninsula (Gamble, 1972). fine, simple to forked, sometimes recurved also, oblique, closely placed. Family-COMBRETACEAE Bentham & Hooker f. Genus- TERMINALIA Linnaeus Family-ANACARDIACEAE Bentham & Hooker f. Species-TERMINALIA PALAEOCATAPPA Awasthi & Genus-MANGIFERA Linnaeus Mehrotra,1995 Species-MANGIFERA SOMESHWARICA Lakhanpal PI. 1·6 & Awasthi, 1984 PI. 2·3 /" " PLATE 2 (All ligures are in natural size unless otherwise mentioned) I. A fossilleafofChrvsopll\,lll/IlIlerliomlll sp. nov. showing shape. size 4. A fossi I leaf of Cal."mpleril palol'(!f!oriiJllllda sp. nov. showing shape. and venation pallern: Specimen no IlSIP 38094. size and venation pattern: Specimen no. BSII' 38092. 2. A modern leaf of Cilr\'sophyill/lll ('(lillito showing similar shape. size 5. A fossi I leaf of 5v:."gi/l1ll lIallglt'aliJibrensis sp. nov. showing shape, and venation pattern. sizc and venation pallern: Specimen no. BSIP 38093. 3. A fossilleafof MOllgifem .IOIIIl'.I!lIl'ari('(l Llkhanpal and Awasthi show 6. A portion of 5v:ygil/lll lIallgll'Oibibrl'll.li.1 sp. nov. enlarged 10 show ing shape, size and venation pallern: Specimen no. IlSll' 38090. inlramarginal vein: Spccimcn no BSIP 38093. x 2 232 THE PALAEOBOTANIST Description-Leaf incomplete, symmetrical, narrow OCCllrrence- Tura Formation; Nangwalbibra near obovate, preserved lamina length 8 cm, maximum width 65 Williamnagar, East Garo Hills District, Meghalaya; Upper cm; apex broken; base broken; margin entire; texture Palaeocene. chartaceous; venation eucamptodromous; primary vein stout, Affinities-The identifying characters of the fossi I leaf straight; secondary veins 6 pairs visible, alternate, 8-16 mm are narrow elliptic shape, entire margin, brochidodromous to apart, uniformly curved but upturned near the margin, angle eucamptodromous venation, narrow to moderately acute angle of divergence moderately acute to wide acute (45°-80°), lower ofdivergence ofsecondary veins and percun'ent tertiary veins. pairs more obtuse, moderately thick; intersecondaries not These features indicate its affinity with Calycopterisfloribullda observed; intramarginal veins absent; tertiary veins indistinct, Lam. (Herbarium Sheet No. CNH 81122) of Combretaceae. appearing percurrent. Prasad (1990) described Calycopteris floribulldoides Figured Specimen-Specimen no. BSIP 38091. Prasad, the only known fossil leaf of Calycopteris from the Occurrence- Tura Formation; Nangwalbibra near Siwalik sediments of Koilabas, Nepal. It differs from the Williamnagar, East Garo Hills District, Meghalaya; Upper present fossil in having narrow ovate shape. smaller size, Palaeocene. craspedodromous venation and closely placed secondaries. Affinities-The identifying characters of the fossil are In the light ofthe above facts the present fossil leaf is described narrow obovate symmetrical leaf, entire margin, eucampto here as Calycopteris palaeofloribunda sp. nov., the specific dromous venation, stout primary vein, moderate acute to wide name signifies its resemblance with that of C. floribullda. acute angle ofdivergence ofsecondaries and percurrent tertiary Calycopteris is a monotypic genus represented by C. veins. These features indicate its affinities with Terminalia jloribunda which is a large scandant shrub growing in Linnaeus in general and T. catappa Linnaeus (Herbarium Sheet deciduous forests of Western Peninsula, Assam, Chittagong Nos CNH 66, 16334) in particular. and Lower Myanmar (Brandis, 1971). Among the various fossil species of TerJllinalia known so far (Awasthi & Mehrotra, 1995) the present fossil is almost Specific diagnosis identical to T palaeocatappa Awasthi and Mehrotra (1995) CALYCOPTERIS PALAEOFLORIJ3UNDA sp. nov. and therefore, has been placed under the same species. As this species was described from the Oligocene sediments of Leaf symmetrical, narrow, elliptic: base symmetrical, Makum Coalfield, its occurrence in Nangwalbibra traces its normal acute; margin entire; texture chartaceous: attachment antiquity up to Upper Palaeocene. with petiole normal; venation brochidodromous to eucampto T catappa is a tall tree found in the beach forests of dromous: primary vein moderate, straight; secondary veins Andamans and the Malayan Peninsula. It is a widespread alternate. angle of divergence narrow to moderately acute, littoral species within the tropics (Brandis, 1971). moderately thick, uniformly curved and running parallel to the margin, some of them forming loops with superadjacent Genus-CALYCOPTERIS Lamarck secondaries; intersecondaries present; tertiary veins percurrent, fine, close. Species-CALYCOPTERIS PALAEOFLORIBUNDA sp. nov. Family-MYRTACEAE Bentham & Hooker f. PI. 2-4 Genus-SYZYGIUM Gaertner Description-Leaf symmetrical, narrow elliptic, Species-SYZYGIUM NANGWALBIBRENSIS sp. nov. preserved lamina length 9 em, maximum width about 3 em, PI. 2'5, 6 apex broken; base symmetrical. normal acute; margin entire; texture chartaceous; attachment with petiole normal, petiole Descriptif'll-Leaf incomplete without base, symmet size 5 x I mm; venation brochidodromous to eucampto rical, preserved lamina length 7·7 em, maximum width 3·2 dromous; primary vein moderate, straight; secondary veins 6 em, appearing narrow elliptic to narrow oblong; apex pairs visible, alternate, 1-1'8 em apart, angle of divergence acuminate; base broken; margin entire; texture chartaceous; 400-500, more or less uniform, moderately thick, uniformly venation eucamptodromous; jJri,nary vein stout, straight to curved and running parallel to the margin, someofthemjoining curved near the apex; secondary veins alternate, 4-7 mm apart, superadjacent secondaries at right angles to form loops; angle of divergence 40°-50°, uniformly curved forming an intersecondaries observed; tertiary veins indistinct, percurrent, intramarginal vein, intersecondary veins commonly present, angle of origin RR, fine, close. simple; tertiary veins fine. random reticulate. Etymology-From Calycopteris floribullda . Etymology-From Nangwalbibra. Holotype-Specimen no. BSIP 38092. Holot)pe-Specimen no. BSIP 38093. MEHROTRA-STUDY OF PLANT MEGAFOSSILS FROM THE TURA FORMATION OF NANGWALBIBRA 233 PLATE 3 (All figures are in natural size unless olhcrwise mentioned> I. A leaf of AllleSOlletlrfJl/ lak/IOI/palii sp. nov. showing shape and size: shape and size: Specimen no. BSIP 38096. Specimen no. BSIP 38095. 3. An enlarged portion of Alllcsol/cUlYI1/ lakhallpa/ii sp. nov.; Specimen 2. A leaf of AlllesolletllYlll deccal/ellsis Guleria and Mehrolra showing no. BSIP 380')5. x 2. Occurrcllcc- Tura Formation; Nangwalbibra near America to extant genera of Myrtaceae. However. they Williamnagar, East Garo Hills District, Meghalaya; Upper (probably unknowingly) have not made any reference of the Palaeocene. already known fossil leaves of Syzygiul11 from India. Their Affinitics- The characteristic features of the fossil, viz., new combination Syzygioidcs Manchester et al. is similar to presence of intramarginal vein, narrow elliptic shape, entire some extant with the species of SYZygi1ll11in leaf architecture margin, presence of intersecondary veins and random reticulate but differs in fruit morphology. So far only 4 species of tertiary veins indicate its close resemblance with SyzygiulIl Sy::.ygiul1lare known from various Tertiary sediments ofIndia. Gaertner ofMyrtaceae. Its further identification is very difficult These are S. kacllchhcnse Lakhanpal and Guleria (1981) from due to homogenity in leaf structure observed among various the Eocene of Kachchh, S. lIliocCl/iCUIIlPrasad and Prakash species of SyzygiulIl. (1984) from the Siwalik beds of Koilabas, Nepal, Recently Manchester ct al. (1998) have questioned the S. palaeobractcatwll Awasthi and Lakhanpal (1990) from the identi fication of isolated fossil leaves known from North Siwalik sediments of Bhikhnathoree, Bihar and 234 THE PALAEOBOTANIST S. palaeocuminii Prasad and Awasthi (1996) from the Siwalik Etymology-From Tertiary. of Surai Khola, Nepal. The first one though resembling the Holotype-Specimen no. BSIP 38094. above fossil very closely differs from it in having asymmetrical Occurrence- Tura Formation; Nangwalbibra near leaf. S. miocenicum is different due to oblanceolate shape and Williamnagar, East Garo Hills District, Meghalaya; Upper closely placed secondary veins while S. palaeobracteatum Palaeocene. differs in having hyphodromous venation and smaller size. Affinities-The diagnostic characters of the fossil are: The last one S. palaeocuminii possesses acute apex and closely elliptic shape, rounded base, entire margin, eucamptodromous placed secondary veins and is thus also different from the venation, moderate to wide acute angle of divergence of present fossil leaf where apex is acum inate and secondary veins secondary veins, stout primary vein and presence of are comparatively distantly placed. As the present fossil is intersecondary veins. These features indicate the affinities of distinct from all the species known so far from India, it is the fossil leaf with that of Chrysophyllum Linnaeus of being described here as S. nangwalbibrellSis sp. nov., the Sapotaceae. Its identification up to specific level is not possible specific name is after its locality Nangwalbibra. due to absence of well preserved tertiaries in the present fossi I Syzygium is represented by about 500 species of trees, leaf. However. the only species available for comparison, C. shrubs or rarely climbers (Willis, 1973). Brandis (1971) has cainilO, shows close resemblance with the fossil. listed 79 species of it from India of which atleast 76 are As this is the first record of a fossil leafof Chrysophyllwll, indigenous. Most of the species are water loving and occur it is being described here as CllIysophyllwn tertiarum sp. nov. along the banks of rivers. They are found in all the types of The genus Chrysophylluill is a tree, consisting of about tropical forests (Champion & Seth, 1968). ISO species of which only 2 are found in India. C. roxbllrghii is found in Assam and Meghalaya while C. lal1ceolalulll occurs Specific diagnosis in West Coast (Hooker, 1872-1897; Santapau & Henry, 1973). SYZYGIUM NANGWALBIBRENSIS sp. nov. Specific diagnosis Leaf symmetrical, narrow elliptic to narrow oblong; apex CHRYSOPHYLLUM TERTIA RUM sp. nov. acuminate; margin entire; texture chartaceous; venation eucamptodromous; primary vein stout, straight to curved near Leaf symmetrical, elliptic; base rounded; margin entire; the apex; secondary veins alternate, angle of divergence narrow texture chartaceous; attachment with petiole normal to inflated; to moderately acute, uniformly curved forming an intra venation eucamptodromous; primary vein stout, straight; marginal vein, intersecondary veins commonly present, simple; secondary veins alternate, angle of divergence moderately tertiary veins fine. random reticulate. acute to wide acute, upper pairs more acute than lower. moderately thick, usually uniformly curved but showing abrupt Family-SAPOTACEAE Bentham & Hooker f. curving near the margin; intersecondary veins present; tertiary veins fine. percurrent. Genus-CHRYSOPHYLLUM Linnaeus Species-CHRYSOPHYLLUM TERTIARUM sp. nov. MONOCOTYLEDONS PI. 2'1 Family-PALMAE Bentham & Hooker f. Description-Leaf basal 3/4111part preserved, symmet Genus-AMESONEURON (Goeppert) Read & Hickey, rical, preserved lamina length (including petiole) 6 em, 1972 maximum width about 4 em, elliptic; apex broken; base rounded; margin entire; texture chartaceous; attachment with Species-AMESONEURON LAKHANPALII sp. nov. petiole normal to inflated; petiole length and width about 7 PI. 3'1, 3 mm and 2 mm respectively; venation eucamptodromous; primary vein stout, straight; secondary veins more than 10 Specific diagllosis-Leaf incomplete without base and pairs visible, alternate, 5-6 mm apart, angle of divergence apex; preserved lamina length 8 cm, width about 5 cm; margin moderately acute to wide acute (5SO-700),upper pairs more entire; texture coriaceous; venation parallelodromous; primary acute than lower, moderately thick, usually uniformly curved vein stout. straight; secondary veins numerous, fine. very but showin~abrupt curving near the margin; intersecondary closely placed (maximum 0·5 mm apart), running parallel to veins pn!sent; intramarginal vein not observed; tertiary veins each other, cross bars or commissures indistinct; further details ill preserved, fine, appearing percurrent. not visible. ./-.... Fig. 3 - Present day distribution of the modem comparable taxa of the fossils known from the Tura Formation of Nallgwalbibra and nearby areas. MEHROTRA-STLJDY OF PLANT MEGAFOSSILS FROM THE TLJRA FORMATION OF NANGWALBIBRA 235 Name of the fossil taxa Modern comparable form Present day distribution References Nymphaeaceae Nell/mbo naga/ensis Neillmbo IIl1cifera An erect large perennial water herb distributed Bhattacharyya. 1983 Bhattacharyya throughout India Tiliaceae Crewia sahnii (Lakhanpal) Crewia Hotter regions of the world especially in tropical comb. nov. moist deciduous forests C. garOellsis C. laevigara In moist deciduous forests of eastern and (Lakhanpal) comb. nov. southern India, Meghalaya. Sikkim, Manaban and Nepal hil/mJerla rhomboideocarpa Triul1lJerra rhOl1lboidea Throughout tropical and sub-tropical India and Sri Bhaltacharyya. 1983 Bhaltacharyya Lanka ascending up to 4,000 ft in the Himalaya Ruta~eae Aralanria Ara/anria l1lonophylla In tropical deciduous and thorn forests of south palaeomonophylla sp. nov. India, Sylhet. Meghalaya and Sri Lanka Sapindaceae Schleichera palaeorrijl/ga Schleichera rrijuga In almost all the types of tropical forests from north sp. nov. west Himalayas from Sinnor to throughout central and southern India. Myanmar and Sri Lanka Anacardiaceae Mangifera sOllleshwarica Mangifera indica An evergreen tree of all the forests of plains of Lakhanpal & Lakhanpal & Awasthi India Awasthi, 1984; Present paper Combretaceae Tennina/ia palaeocarappa Terl1lina/ia Beach forests of Andamans and Malayan Awasthi & Mehrotra, Awasthi & Mehrotra carappa Peninsula 1995; Present Paper Ca/ycopreris Calycopreris jloribunda In tropical moist deciduous forests of Western pa/aeoj7oribl/nda sp. nov. Peninsula, Assam. Chittagong and Lower Myanmar Myrtaceae Syzygillm nangwa/bibrellSis sp. nov. SYZygi1l11l Water loving plants found throughout India Araliaceae Hereropanax sp. Hereropanax jragrans In subtropical Himalayas. Assam, Bengal, Bhaltacharyya, 1983 Andamans. Myanmar, Java and China Sapotaceae CllIysophyllum rerriarul1l sp. nov. Chrysophylllll1l West Coast, Assam. Meghalaya. Sylhet and Malacca Oleaceae Ligusrrllm ruraense LigusrrUIIl Temperate Himalayas at 1200-2200 m in height Bhallacharyya, 1983 Bhattacharyya Osmanrlllls eocenicus Osmanrlws sua vis Evergreen shrub of sub-alpine Himalayas, Bhattacharyya. 1983 Bhattacharyya Sikkim, East Nepal and Bhutan Alllholirhes oleaceaeJormis Osmanrhlls suavis Evergreen shrub of sub-alpine Himalayas, Bhattacharyya. 1983 Bhaltacharyya Sikkim, East Nepal and Bhutan A. campanll/arlls Bhattacharyya. 1983 Bhattacharyya Lauraceae Phoebe sublanceo/ara Phoebe lanceo/ara In swampy and semi-evergreen forests of Bhattacharyya. 1983 Bhaltacharyya Meghalaya. South Deccan. subtropical Himalayas from Shimla eastwards and Myanmar Lirsea sp. Lirsea salicifolia In evergreen bush or small tree of northern and Bhattacharyya, 1983 eastern India. Assam. Bangladesh and Pegu Moraceae Arrocarpus garoensis Arrocarpus chap/asa Tropical evergreen forests of transgangetic India, Bhattacharyya, 1983 Bhattacharyya from Bengal. Sikkim and Assam to Myanmar and Andaman Islands Palmae Nipa sahnii Nipa jrllilicans Sunderbans southwards to Kanyakumari and the Lakhanpal, 1952; Lakhanpal Andamans in estuarine or swampy water Bhaltacharyya. 1983 Amesonellron lakhanpalii sp. nov. A. deccanensis Guleria & Mehrotra, Guleria & Mehrotra 1999; Present paper 236 THE PALAEOBOTANIST Etymology-After a well known Indian Palaeobotanist Palaeocene. The occurrence of Terminalia catappa and Nipa Dr R.N. Lakhanpal. jruiticans, the typical beach forest elements, suggests the Holotype-Specimen no. BSIP 38095. presence of estuarine conditions with large amount of swampy Occurrence-Tura Formation; Nangwalbibra near vegetation in the area during the period. This shows that the Williamnagar, East Garo Hills District, Meghalaya; Upper climate was warm and humid with much higher rainfall than Palaeocene. today. This view is also supported by palynological studies Affinities-The coriaceous texture and typical parallelo (Saxena et al., 1996). The occurrence of Nelwnbo nucijera dromous venation of the fossil leaf suggest its affinities with indicates the existence of ponds around Nangwalbibra duri ng Palmae (Read & Hickey. 1972). However, due to the absence the deposition of beds. However, certain forms for e.g., of base and apex its further comparison is not possible. LigllStrtllll nepalcnse and Osmantlllls suavis which occur in Read and Hickey (1972) have given a key for the temperate or subalpine Himalayas, are against the general identification of palm-like leaves. Accordingly the above nature of the flora which is defi nitely tropical as evidenced by specimen has been placed under the form genus Alllesonellron the other forms. Therefore, these taxa need critical re (Goeppert) Read and Hickey. Recently. Guleria and Mehrotra investigation as their affinities appear to be doubtful in the (1999) have given a detailed list of the fossil palm and palm light of the above facts. like leaves known so far from the Tertiary sedi ments of India. AcknowLedgements-The author is thank/III to N. Awasthi/or his After a detailed comparison with all of them it was concluded great help during the collectioll of the material. He is also thankful that the present fossil leaf is different from them. Therefore. it to the Head. Botony!Jranch, Forest Research Institute, Dehra DIl/I is being described here as a new species of Amesonellroll, A. and Dj: Director, Cell/ral National HerbariUIJl. Howrah for allolV lakhanpalii sp. nov. The specific name is in the honour of Dr ing him to consult their Herbarium. Lastly, the author is also grale R.N. LakhanpaL a well known Indian Palaeobolanisl. ful to Prof Anshu K Sinha, Director, Birbal Sahni Institute of Pal aeobotany, Lucknowfor necessaryfacilities and' 'rmission to pub lish this work. Species-AMESONEURON DECCANENSIS Guleria & Mehrotra, 1999 REFERENCES PI. 3·2 Description-Leaf incomplete without apex and base; Awasthi N. Guleria JS & Lakhanpal RN 1982. Two new fossil woods of Sapindaccae from the Tertiary of India. PalaeobotaniSI 30 : preserved lamina length 13·5 cm, width about 3 em; strap 12-21. shaped: margin entire; texture coriaceous; venation Awasthi N& Lakhanpal RN 1990. Additions to the Neogene norule parallelodromous; primary vein moderately thick-walled. from near Bhikhnathorec. West Champaran District. Bihar. straight; secondary veins many, very closely placed. fine, Palaeobotanist 37 : 278-283. running parallel to each other, cross bars or commissures Awaslhi N & Mchrotra RC 1995. Oligocene nora from Makum absent: further details not visible. Coalfield, Assam. India. Palaeobotanisl 44: 157-188 Figured Specilllen-Specimen no. BSIP 38096. Bande MB & Srivastava R 1995. Crewia type of fossil woods from Occllrrence- Tura Formation; Nangwalbibra near the Deccan Intertrappcan beds of India. Geophytology 24: 131 Williamnagar, East Garo Hills District, Meghalaya; Upper 135. Palaeocene. Bhattacharyya B 1983. Fossi I plants from the Tura Formation (Eocene) in the Garo Hills. Meghalaya. Indian Journal or Earth Affinities-In having coriaceous texture. parallelo Sciences 10: 1-10. dromous venation and entire margin the fossil shows affinities Bonde SD 1986. AlIleSOlleUlvn borassoides a borassoid palm leaf with Amesoneuron (Goeppert) Read and Hickey (1972). Only from the Deccan Intertrappean bed at Mohgaonkalan. India. 3 species of the genus are known so far from India. These are Biovigyanam 12 : 89-91. Amesoneuron borassoides Bonde (1986), A. deccanensis Brandis D 1971. Indian Trees. Bishen Singh Mahendra Pal Singh, Guleria and Mehrotra (1999) (both from the Deccan Dchra Dun: 767. Intertrappean sediments) and A. lakhonpalii (Present paper). Champion HG & Seth SK 1968. A revised surveyor the foresllypes As the present fossil is identical to A. deccanensis in almost of India Manager of Publications. Delhi: 404. Dilchcr DL 1974. Approaches to the identitication of angiosperm all the morphological characters such as shape, size and leaf remains. Botanical Review 40: 1-157. venation, it has been placed under the same species. Gamble JS 1972. A Manual of Indian Timbers. Bishen Singh Mahendra Pal Singh, Dehradun : 856. DISCUSSION Guleria JS & Mehrotra RC 1999. On some plant remains from Deccan Inlertrappean localities of Seoni and Mandla districts of Madhya A perusal of the Fig. 3 indicates that most of the modern Pradesh, India. Palaeobotanist 47 : 68-87. comparable forms of the fossils were growing in tropical Hickey LJ 1973. Classification of the architecture of dicotyledonous evergreen to moist deciduous forests of India during Upper leaves. American Journal of Botany 60: 17-33. MEHROTRA-STUDY OF PLANT MEGAFOSSILS FROM THE TURA FORMATION OF NANGWALI3I1JRA 237 Hooker JD 1872-1897. The Flora of British India. 1-7. L. Reeve and Indian Geophytological Conference. Lucknow (1983). Special Company. Kent. Publication: 155-162. Lakhanpa\ RN 1952. Nipa sa/mii. a palm fruit in the Tertiary of Prasad M 1990. Fossil flora from the Siwalik sedimel1ls of ~oilabas. Assam. Palaeobotanist I: 289-294. Nepal. Geophytology 19 : 79-105. Lakhanpal RN 1954. Recognizable species of Tertiary plal1ls from Prasad M & Awasthi N 1996. Contribution to the Siwalik flora from Damalgiri in the Garo Hills. Assam. Palaeobotanist 3 : 27-31. Surai Khola sequence. Western Nepal and its palaeoecological Lakhanpal RN 1964. A new record of angiospelmic leaf impressions and phytogeographical implications. Palaeobotanist43 : 1-42. from the Garo Hills. Assam. Current Science 33 : 276. Prasad M & Prakash U 1984. Leaf impressions from the Lower Lakhanpal RN & Awasthi N 1984. A late Tertiary florule from near Siwalik bedsofKoilabas. Nepal./II: Proceedings of the V'''lndian Bhikhnathoree in West Champaran District. Bihar. /n: Proceedings Geophytological Conference. Lucknow (1983), Special of the Seminar on Evolutionary Botany and Biostraligraphy. Publication: 246-256. Calcutta (1979). Prof. A.K. Ghosh Commemoration Volume: Raja Rao CS 1981. Coalfields of north eastern India-I. Bulletin of 587-596. the Geological Survey of India 45 A: 1-76. Lakhanpal RN & Guleria JS 1981. Leaf impressions from the Eocene Read RW & Hickey LJ 1972. A revised classification of fossil palm of Kachchh. Western India. Palaeobotanist 28-29: 353-373. and palm-like leaves. Taxon 21: 129-137. Lakhanpal RN. Prakash U& Bande MB 1978. Fossil dicotyledonous Sal1lapau H & Henry AN 1973. A dictionary of the flowering plants woods from the Deccan Intenrappean beds of Mandla District in in India. Publication & Information Directorate. New Delhi: 198. Madhya Pradesh. Palaeobotanist 25 : 190-204. Saxena RK, Tripathi SKM & Prasad V 1996. Palynofloral Manchester SR, Dilcher DL & Wing SL 1998. Attached leaves and investigation of the Tura Formation (Palaeocene) in Nongwal fmits of myrtaceous affi nity from the Middle Eocene ofColorado. Bibra area. East Garo Hills. Meghalaya. Geophytology 26 : 19 Review of Palaeobotany and Palynology 102 : 153-163. 31. Mehrotra RC. Dilcher DL & Awasthi N 1998. A Palaeocene Srivastava GP. Mishra VP & Bande MB 1992. Further contribution Mangifera-like leaf fossil from India. Phytomorphology 48: 91 to the Late Cenozoic flora of Mahuadanr, Palamu District. Bihar. 100. Geophytology 22: 229-234. Paradkar SA & Dixit VP 1984. GreH/ia l11ohgaoensis-a new petrified Willis JC 1973. A dictionary of the flowering pIa illS and ferns. dicotyledonous fruit from the Deccan Intenrappean beds of Cambridge University Press. Cambridge: 1245. Mohgaonkalan, Madhya Pradesh. India. /n: Proceedings of V'"