Geology Series Carboniferous pteridosperm frond Neuropteris heterophylla; Tertiary Ostracoda from Tanzania VOLUME 46 NUMBER 2 31 JANUARY 1991 The Bulletin of the British Museum (Natural History ), instituted in 1949, is issued in four scientific series, Botany, Entomology, Geology (incorporating Mineralogy) and Zoology, and an Historical series. The Geology Series is edited in the Museum’s Department of Palaeontology Keeper of Palaeontology: DrL.R.M. Cocks Editor of the Bulletin: Dr M. K. Howarth Assistant Editor: Mr D. L. F. Sealy Papers in the Bulletin are primarily the results of research carried out on the unique and ever- growing collections of the Museum, both by the scientific staff and by specialists from elsewhere who make use of the Museum’s resources. Many of the papers are works of reference that will remain indispensable for years to come. A volume contains about 400 pages, made up by two numbers: published Spring and Autumn. Subscriptions may be placed for one or more of the series on an Annual basis. Individual numbers and back numbers can be purchased and a Bulletin catalogue, by series, is available. Orders and enquiries should be sent to: Sales Department, Natural History Museum Publications, British Museum (Natural History), Cromwell Road, London SW7 5BD Telephone: 071-938 9386 Fax: 071-938 8709 World List abbreviation: Bull. Br. Mus. nat. Hist. (Geol.) © British Museum (Natural History), 1991 ISBN 0 565 07028 2 Geology Series ISSN 0007-1471 Vol 46 No 2 pp 153-270 British Museum (Natural History) Cromwell Road London SW7 5BD Issued 31 January 1991 Bull. Br. Mus. nat. Hist. (Geol.) 46 (2): 153-174 Issued 31 January 1991 EM f The Carboniferous pteridosperm frond sion | Neuropteris heterophylla (Brongniart) “OFEBIII | PRESENTED Sternberg CHRISTOPHER J. CLEAL Department of Botany, National Museum of Wales, Cardiff CF1 3NP CEDRIC H. SHUTE Department of Palaeontology, The Natural History Museum, Cromwell Road, London SW7 5BD CONTENTS SVMODSISteeei yeti erode any re Lot ated che trs role custewey attra sae taka Aiae a Mosldwa ddelien cn nl wia desneaa whales 153 ATCO MUCHO Rewer ra cre we etc eet cts es Sede eee Plating ee asa hetdlaeron dia, done Qua ui sagaentin djatiins | aaieeaye arernalaa Go's ag 153 INT tetas pbreretesen-tarctecsene stents cece sleyahcienmnaven renee edctasailala gateneneaha Pxeusuanirslle lor goad csr ie ala eebopianG aia bauglh- dao: chaigie lous’, ele ete eee 154 Wie th od sii greens si ioe ap dace ctete sate eeasis peace ae TWN cs eliayaveliens (s,Q BRAGS alee ne) deat 208 eee de dudes bctNsidthanevayhlgre orioe, a7Ri glee ak fag 154 ID CSCEIP LIONS see ee ise er operant paper ence eae te este c tntraes ccleaner ts tol yeracodvecilert ia Mig, Geoud shale elaine atdne-b rage arataye waa bee « 154 TOM iar chitectures ape vers cct spades wih tye, cost tices octet ayes Sum aeele t,t Ainge oeiiial eter a Blas 44 iG lala le wid drat aE sew dule Sul't eg 154 Binnulemorphologyay. seein tisk aeustery tis seh aa nt oda cited wie bape omnd dragons ie lelensidg lacarw ene TE oe 160 (CTT IS he A ict aa cas eT TE Cc eC TN Cc RP et a 162 PXSSOCIALE CIOS POLES teva eee iets tee Seana aus etre cal lsl ee eaitanatin ole whtavn Gland) « Ruansig vdesile dia ergile a cea ia ta aire nye ahs Rebseiace 164 PD ISCUSSIO Mtr ene ree iatastee spegpste eaten ves arrucracay lias mien als brates tcnepiel cicns! coke seajfadalsthva:.s.etat alive Beans 4 otha sles! akeliel bile le deetiel a hue Gs. 166 Reconstructtonottrondsencntartewastacccecais so cea aon bac keh aaiooniode eee MaMa Le dew at oo ew Mealy s 166 Significance of epidermal Structures: .). 032 sadjke ae eels oh ats Oe hy eh epee led eda ee nee a weeps bee eee 172 "LURED Coy AYO) CN er ae ee ty chats coe ry Per ex OSPR CSE ern 172 CompanisomwithiotherSpeciesy cietire ssama.stiess Ones Bie a widia, ois Garage e Nadw eighard a suo begla dR gies eyes oG ard gage avec etlt 173 PNCKMOWIER PMEMtES eet cme ete archer coc teh cece can Thaw e iad chet diet eh sibccacalcesttonn Suesdlbsmuw apm inte wig Sebi bons siteeaidh wide aha aed’ 173 IRELETENICES Reyer R pe Taree TP TNL TET seer eD oc eon aNol ne eee oes tak AE ek anh oe cod Bune R ale Mahe due Sve BPD Oe abe Bre 173 SYNOPSIS. New evidence on the frond architecture of Neuropteris heterophylla (Brongniart) Sternberg is presented, based on well-preserved adpressions from Clay Cross, Derbyshire. Their cuticles provide the first reported evidence of epidermal structure for this species, including remains of trichomes apparently with in situ exudate. The new evidence indicates that this species is more closely related to Neuropteris ovata Hoffmann and Neuropteris flexuosa Sternberg, rather than to Laveineopteris loshii (Brongniart) Cleal et al. and Laveineopteris tenuifolia (Sternberg) PALAEONTOLOGY LIBRARY Cleal et al., as argued by some previous authors. INTRODUCTION Neuropteris (Brongniart) Sternberg is one of the most widely reported macrofossil form-genera from the Westphalian of Europe and North America. It represents foliage of an extinct group of gymnospermous plants known as the Trigonocarpales Meyen 1987 (Medullosales auctt.), which probably grew on levee banks and other raised areas within the equatorial delta plains of the time (Zodrow & Cleal 1988). Recently, our understanding of the form-genus has significantly improved, particularly as a result of frond architecture and cuticle studies (Barthel 1961, 1962, 1976; Reichel & Barthel 1964; Laveine 1966a, 1966b, 1967, 1987; Laveine & Brousmiche 1982; Zodrow & Cleal 1988; Cleal & Zodrow 1989), and it has become evident that the form-genus is far from homo- geneous. As a result, some species have been transferred to other form-genera (e.g. Paripteris Gothan, Neuralethopteris Cremer ex Laveine — see Laveine, 1967) but, until recently, most have been retained in Neuropteris. This was partly because the frond of the type-species (N. heterophylla (Brongniart) Sternberg, 1825) had not been fully recon- structed, nor was anything known of its epidermal structure. Consequently, it was not possible to say which of the groups recognizable on, say, epidermal structure represented real Neuropteris, and which needed to be transferred to other form-genera. The type species was first published as Filicites (Nevropteris) heterophyllus by Brongniart (1822), and was later changed to Neuropteris heterophylla (Brongniart) by Sternberg (1825). (Few subsequent authors have recognized the validity of Sternberg’s initial publication of this combination, which is often attributed incorrectly to Brongniart (1828) — e.g. Crookall 1959, Laveine 1967). The small holotype was illus- trated diagrammatically only (Brongniart 1822: pl. 2, figs 6a, b) and is now reported lost (Laveine 1967). Many authors have regarded it as conspecific with Laveineopteris loshit (Brongniart) Cleal et al. 1990 (e.g. Stockmans 1933, Havlena 1953, Crookall 1959), a common species distributed widely through the Westphalian A—-C of Europe. Laveine (1967) has irgued that this is unlikely, however, basing his contention mainly on a rather larger specimen of N. heterophylla figured by Brongniart (1831: pl. 71). This latter specimen is clearly guite different from Laveineopteris loshii, and hence many traditional conceptions about N. heterophylla (and con- sequently of the form-genus Neuropteris itself) would appear to be ill-founded. N. heterophylla as interpreted by Laveine (1967) is in fact an uncommon species; his synonymy refers to only ten undoubted specimens illustrated in the literature, and he figured another three. The present paper documents some large and excellently preserved specimens in the palaeontological collections of the British Museum (Natural History), from which we have been able to provide a detailed reconstruction of the frond. Some of these specimens also yielded cuticles. The only previous record of N. heterophylla cuticles is by Wills (1914), based on specimens from North Wales. As we will argue later, however, Wills’ material is almost certainly misidentified, and our specimens provide the first unequivocal evidence of the epidermal structure of this species. The results presented here have important consequences for the generic classification of neuropterid foliage, and have been the basis of the revised classification published by Cleal et al. (1990). MATERIALS This study is based largely on eight hand-specimens stored in the Department of Palaeontology, British Museum (Natural History) (Accession Numbers V.1797, V.1867, V.1868, V.1871, V.1872, V.2727, V.63152, V.63153). They are all labelled as originating from the ‘Coal Measures, Clay Cross, Derbyshire’. No further stratigraphical details are given, but they probably came from the Westphalian B. Cuticles were prepared from four of these specimens: V.1867, V.1868, V.2727 and V.63152. METHODS The hand-specimens were photographed using crossed-polar filters. Because of limited page size, we cannot reproduce photographically all the specimens at the same scale; tracings from the photographs are therefore reproduced here at a uniform scale of x % (Figs 26-28). Cuticles were prepared using the method outlined by Barthel (1962). Pieces of fossil were removed from the hand- specimens with a small chisel, and then placed in 40% hydrofluoric acid to remove the rock matrix (pre-treatment with hydrochloric acid was found to be unnecessary). The carbonaceous phytoleims (sensu Krystofovich 1944) were next oxidized in Schultze’s Solution for 1—2 hours, and then treated with a 5% solution of ammonium hydroxide to remove the soluble oxidation products. The resulting cuticles were washed thoroughly in distilled water. Most of the cuticles were mounted in glycerine jelly con- taining safranin dye. They were examined with a Leitz Ortholux II microscope, using differential interference phas¢ contrast (Normarski contrast) at high magnifications. In addi- CLEAL & SHUTE tion, some cuticles were mounted on stubs, thinly coated with gold, and examined at 15 kV with an Hitachi S-800 field emission scanning electron microscope. DESCRIPTIONS Frond architecture In their gross morphology, the specimens dealt with in this paper basically fall into two groups: wide tripinnate pinnae with broad primary racheis; and distally tapered, tripinnate pinnae. These are interpreted as proximal and distal frag- ments of the frond, respectively, and are most conveniently described separately. Proximal frond fragments (Figs 1, 2, 26 and 27a). The most proximal part of the frond preserved in these specimens (Fig. 1) shows a primary rachis, 2-5 cm wide, that extends for 1-5 cm before branching dichotomously. The resulting branches lie at 90° to each other near the fork, but then gradually curve inwards towards each other. This curvature is achieved, at least in part, by a series of kinks occurring at about the points of attachment of each secondary pinna on the outward-facing side of the primary rachis (Fig. 2). The primary racheis above the dichotomy are 1-2-1-5 cm wide, tapering to c. 0-5 cm wide in the most distal part of the specimens (Figs 1, 2). The overall shape of the two primary pinnae produced by the dichotomous primary rachis is not shown in these speci- mens, but they appear to taper proximally, at least on their inward-facing side. Each primary pinna is markedly asymmetrical, although they are essentially symmetrical to each other about the long axis of the frond (Fig. 1). On the outward-facing side of the primary rachis branches, robust secondary pinnae with racheis 0-5)-6 cm wide are attached at 60°-70°, at intervals of 8-10 cm. Very little of these secondary pinnae is preserved, the longest fragment being only 15 cm long and clearly very incomplete, but they appear to be bipinnate (Fig. 1). Their shape cannot be determined from the fragments preserved. In between these large bi- pinnate secondary pinnae are much shorter (34 cm long) monopinnate intercalated pinnae spaced at 2-3 cm ‘intervals (Fig. 2). They are tapered and terminated by a single rhom- boidal apical pinnuie. On the inward-facing side of each primary rachis branch, secondary pinnae are inserted at intervals of 3-5 cm, usually at an angle of 70°-90°. They are 3 cm long and monopinnate near the base of the primary rachis branch (Fig. 1), becoming 30 cm long and bipinnate in the more distal parts (Fig. 2). Adjacent secondary pinnae overlap slightly in the middle of the frond. They appear tapered for much of their length, except in the longer ones which are parallel-sided in their proximal part, and are terminated by a single rhomboidal apical pinnule. There is little evidence of marked differentia- tion in development of the secondary pinnae, such as is seen on the outward-facing side of the primary racheis, but when they start to become bipinnate (some 20 cm from the base of the specimen), alternate secondary pinnae become shorter and less divided. Another specimen with an apparently curved primary rachis is shown in Figs 3 and 27b. The primary rachis is c. 1-5 cm wide, tapering distally to 1-0 cm wide. Bipinnate THE CARBONIFEROUS PTERIDOSPERM FROND NEUROPTERIS HETEROPHYLLA (BRONGNIART) STERNBERG 155 Fig. 1 Neuropteris heterophylla. Basal part of frond, showing dichotomy of primary rachis, photographed with crossed-polar filters. V.1797, x Vs. See also Fig. 26. secondary pinnae are attached at 60°—70° at c. 6 cm intervals on the right side of the specimen, but there is little evidence of secondary pinnae on the other side except for one short stump of secondary rachis. Short monopinnate pinnae are intercalated between the secondary pinnae, spaced at inter- vals of 1-5—2-:0 cm. (In the middle of the specimen is a detached pinna of Neuropteris semireticulata Josten, uncon- nected with the N. heterophylla frond fragment.) If this was 56 CLEAL & SHUTE Fig. 2 Neuropteris heterophylla, photographed with crossed-polar filters. Fig. 2a, primary rachis immediately above the dichotomy near base of frond. (The pinna fragment shown at the top is of the fern Senftenbergia plumosa (Artis) Zeiller.) V.1872, x 7. Figs 2b-d, details of Fig. 2a showing range of form of lateral pinnules, x 1. See also Fig. 27a. wal ~ THE CARBONIFEROUS PTERIDOSPERM FROND NEUROPTERIS HETEROPHYLLA (BRONGNIART) STERNBERG Vs Fig. 3 Neuropteris heterophylla. Primary rachis probably just above dichotomy near base of frond, together with a detached fragment of a N. semireticulata Josten pinna, photographed with crossed-polar filters. V.63152, X %. See also Fig. 27b CLEAL & SHUTE Figs 4, 5 Neuropteris heterophylla, photographed with crossed-polar filters. Fig. 4, distal part of primary pinna branch. V.1867, x 7%. See also Fig. 28c. Fig. 5, two bipinnate pinnae. V.1871, x 7. See also Fig. 28e. part of a primary rachis from just above the main dichotomy, the greater width of the rachis and spacing of the secondary racheis suggest that it must have originated from a signifi- cantly larger frond than the specimens in Figs 1 and 2. Distal frond fragments (Figs 4, 6-8, 28). These are distal segments of tripinnate pinnae, which are markedly asym- metrical about the primary rachis. The secondary pinnae on one side of the primary rachis are both longer and more pinnately divided than on the other. It is probable that the longer and more divided secondary pinnae were facing out- wards from the frond, in which case Figs 4, 6 and 7 show left- hand primary pinna branches, and Fig. 8 a right-hand primary pinna branch. The primary rachis in most of the specimens is more or less straight, except that in Fig. 8, where curvature is accompanied by apparent distortion of the secondary pinnae, and may thus be a taphonomic effect. The widest primary racheis in these distal primary pinna fragments are 6 mm wide (Figs 6-7), and thus overlap with the width of the most distal preserved part of the primary pinnae in Fig. 1. THE CARBONIFEROUS PTERIDOSPERM FROND NEUROPTERIS HETEROPHYLLA (BRONGNIART) STERNBERG 159 Fig. 6 Neuropteris heterophylla. Near distal part of primary pinna, photographed with crossed-polar filters. V.1868, x 74. See also Fig. 28b. Secondary pinnae are attached at 60°—90° (most usually c. 70°) on either side of the primary rachis. They are parallel- sided for much of their length, but are gently tapered in their distal part and terminated by a small, rhomboidal apical pinnule, c. 1 cm long. The secondary racheis are 0-5-3 mm wide. In the distal part of the frond the secondary pinnae are monopinnate and oppositely arranged at intervals of 1-3 cm; lower in the frond they become bipinnate and alternately arranged at intervals of up to 5 cm. Where the secondary pinnae are bipinnate, one or two short, monopinnate pinnae are intercalated on the primary rachis between them. They are up to 2 cm long with a rhomboidal apical pinnule, and are spaced at intervals of c. 1 cm. Tertiary pinnae are attached to the secondary racheis at 80°-90°, except near the secondary pinna apex where they are more oblique (c. 60°). They are spaced at intervals of 0-4 cm for the shorter pinnae, increasing to 0-8 cm in the longest preserved pinnae, and are oppositely or sub-oppositely CLEAL & SHUTE Se Gee a, Sens oy Sa ee 8 SAE Te Se Fig. 7 Neuropteris heterophylla. Distal part of primary pinna, photographed with crossed-polar filters. V.2727, x 7. See also Fig. 28a. arranged. They are parallel-sided for most of their length, round to oval, about as broad as long; but the larger ones are and terminated by a single, rhomboidal apical pinnule, more elongate, parallel-sided to linguaeform with a round c. 1 cm long. apex. The longest pinnules are sometimes subtriangular with a bluntly acuminate apex. An acroscopic and sometimes a basiscopic swelling occurs near the base of the larger pin- nules. In the largest pinnules the former becomes more Typical pinnules are shown in Figs 2b-d. They vary from 3 to prominent, until it eventually develops into a discrete, sub- 15 mm long and are 3-6 mm wide. The smallest pinnules are sidiary order pinnule. Except near the pinna apex, the Pinnule morphology THE CARBONIFEROUS PTERIDOSPERM FROND NEUROPTERIS HETEROPHYLLA (BRONGNIART) STERNBERG 161 Fig. 8 Neuropteris heterophylla. Distal part of primary pinna, photographed with crossed-polar filters. V.63153, x %4. See also Fig. 28d. pinnules are at least partially constricted at the base. The degree of constriction is often more pronounced on the acroscopic side, with the pinnule being partially fused to the rachis on the basiscopic side. Only the largest pinnules tend to be equally constricted on both acroscopic and _ basiscopic sides. The angle of attachment of the pinnules to the rachis is usually 70°-80°. High in the pinna it sometimes appears to be as low as 60°, but this may be due to taphonomic distortion. In the smallest pinnules there is little or no evidence of a midvein. In most pinnules, however, a thin midvein arises from the rachis at a low angle on the basiscopic side of the pinnule. It then curves and lies along the long axis of the pinnule. In most pinnules, the midvein is restricted to the CLEAL & SHUTE Fig. 9 Neuropteris heterophylla. Cuticle from adaxial surface of pinnule showing differentiation of cells in costal and intercostal fields, photographed using bright field illumination. V.2727$1, x 125. lower half of the pinnule, but in the largest forms it may extend for up to two-thirds of the pinnule length. This decurrent midvein is never very pronounced, being only slightly wider than the lateral veins. Lateral veins occur alternately on either side of the mid- vein, attached at intervals of 0-S—1-0 mm. They initially lie at a low angle to the midvein, extend for a short distance in an approximately straight line, and then arch to meet the pinnule margin at 80°-90°. They may branch up to four times, depending on the width of the pinnule. The angle of branch- ing is usually 20°-30°, which often gives the veining a some- what flexuous appearance. The vein density along the pinnule margin may vary from 40 to 55 per cm, but is usually between 48 and 52 per cm. Cuticles The adaxial cuticles from the pinnules appear robust, but have weakly developed intercellular flanges (Fig. 9). There is some differentiation in cell structure in the costal and inter- costal fields. In the costal fields, the cells are elongate and subrhomboidal, up to 150 um long x 20 pm wide (Fig. 17). Their long axes are aligned approximately parallel to the veins. In the intercostal fields the intercellular flanges are very weak, but there is a faint impression of shorter and more irregularly polygonal cells, up to 50 pm long x 20 um wide (Fig. 18). Again, their long axes are aligned more or less parallel to the veins. The abaxial cuticles are significantly thinner, and only small fragments could be prepared. Intercellular flanges, although not prominently developed, are clearly visible. Costal cells are elongate, parallel-sided and approximately 15 um wide. It was impossible to determine their length. The intercostal cells are irregularly polygonal, 40-60 um long and 12-18 pm wide, with their long axes aligned parallel to the nervation (Figs 10 and 20). Stomata are restricted to the intercostal fields of the abaxial surface (Figs 10-11 and 19-22). They are anomocytic, with their polar axes approximately parallel to the veins. Their guard cells are 20-25 um long and 5 um wide. They do not seem to be significantly sunken. Papillae occur in the costal fields of the abaxial epidermis (Fig. 10). They are 30-40 pm wide at their base and 25-35 pm high. Smaller papillae, 15-25 ym wide at their base and 10-20 pm high, also occur in the intercostal fields of the abaxial epidermis (Figs 19-20). They are less densely distri- buted than in the costal fields, and are mainly on the stomatal neighbour cells, where they appear to over-arch the guard cells (Figs 10-11 and 21-22). Multicellular trichomes are also restricted to the abaxial epidermis, occurring mainly in the intercostal fields (Figs 12— 14 and 23). They are 25-30 wm in diameter at their base, tapering to 20 um. They consist of a uniseriate string of cells 25-35 pm long, and there is a slight constriction of the trichome at the junction of each cell (Fig. 12). The longest preserved fragment is 130 um long, but is clearly incomplete (Fig. 12). Other examples are only 100 pm long, but seem to be entire and terminated by a swollen cell 35 um in diameter, resembling a glandular structure (Figs 13-14). When viewed by SEM, these terminal structures appear to have ruptured, and situated on and near the apex of the trichome is an amorphous mass (Fig. 23; see also Fig. 13 for a view using light microscopy). Similar amorphous masses observed on these cuticles using light microscopy could be seen to have taken the safranin dye, and are almost certainly organic in origin. Being consistently associated with the trichome apices, they are, in our view, probably the remains of exudate produced by the trichomes. However, the volume of this THE CARBONIFEROUS PTERIDOSPERM FROND NEUROPTERIS HETEROPHYLLA (BRONGNIART) STERNBERG 163 Figs 10-16 Neuropteris heterophylla. Cuticles photographed using Normarski contrast (except Fig. 15). Figs 10-11, cuticles from abaxial surface of pinnule, showing papillate stomata, x 500. Fig. 10, V.1867$2. Fig. 11, V.1867$1. Figs 12-14, multicellular trichomes from abaxial surface of pinnule, x 500. Figs 12-13, V.63152$2. Fig. 14, V.2727$8. Fig. 15, cuticle from rachis, using bright field illumination. V.2727$8, x 125. Fig. 16, cuticle from rachis. V.2727$9, x 500. 164 CLEAL & SHUTE Figs 17-22 Neuropteris heterophylla. Cuticles photographed using Normarski contrast. Fig. 17, cuticle from costal field on adaxial surface of pinnule. V.2727$1, x 250. Fig. 18, cuticle from intercostal field on adaxial surface of pinnule. V.1867$1, x 250. Figs 19-20, cuticles from abaxial surface of pinnule, showing parallel alignment of stomatal polar axes. V.1867$1, x 250. Figs. 21-22, details of papillate stomata. V.1867$1, x 500. exudate often seems larger than could be contained in just the apical cell (e.g. Fig. 23d). This suggests that either the entire trichome functioned as a gland, in which case the transverse cell walls must have broken down when the trichome had become fully developed; or the exudate originated from a superficial cell within the body of the pinnule, and was channelled through the trichome to its apex. Associated miospores Attached to many of the cuticles prepared during this study were numerous miospores, mostly c. 25 um in diameter (Figs 24-25). Dr B. Owens has kindly examined SEM photographs of some of them and concluded that they are a mixed assemblage, dominated by ?Lycospora, ?Densosporites and ?Granulatisporites. These trilete form-genera are believed to have been mostly produced by lycophytes and ferns (Smith & Butterworth 1967) and are quite different from the monolete prepollen produced by most medullosans (Stidd 1981). The only possible medullosan male reproductive organ to produce trilete prepollen is Potoniea (Halle 1933, Florin 1937), which Millay & Taylor (1979) have interpreted as an early offshoot from the main medullosan stock (see also Stidd 1978, 1981). In THE CARBONIFEROUS PTERIDOSPERM FROND NEUROPTERIS HETEROPHYLLA (BRONGNIART) STERNBERG 165 1% fea | | Fig. 23. Neuropteris heterophylla. Scanning electron micrographs of multicellular trichomes showing glandular tips with in situ exudate. V.2727$11. Figs 23a and 23e, x 2000. Figs 23b-d, x 500. Tele) CLEAL & SHUTE Fig. 24 Neuropteris heterophylla. Cuticle from abaxial surface of pinnule, photographed using bright field illumination, showing numerous spores attached. V.2727$2, x 250. any case Potoniea prepollen is significantly larger (40-90 pm in diameter), has a less prominent tetrad mark than the miospores attached to our cuticles, and displays a distal sulcus. In our view, therefore, the miospores are unlikely to have anything to do with the plant which produced the N. heterophylla fronds. They probably only reflect the general spore/pollen rain in these lycophyte-dominated forests. DISCUSSION Reconstruction of frond Based mainly on the specimens from Clay Cross described in this paper, we propose a reconstruction of the N. heterophylla frond, shown in Fig. 29. For convenience, the specimens have been reproduced at a unified scale as drawings (Figs 26-28), and the following discussion will refer to these rather than the photographs illustrated earlier in the paper. The recon- structed frond shows the following key features. Dichotomy of primary rachis. This is particularly well seen in Fig. 26. The dichotomy is wide-angled and the resulting branches curve distally towards one another. It is also shown by the specimen figured by Brongniart (1831: pl. 71). Brongniart’s drawing of this specimen suggests that the fork was a lateral branch, but Laveine’s (1967: pl. A) photograph clearly shows that the right-hand side of the frond fragment is distorted. Taking this distortion into account, Brongniart’s specimen shows the same pattern of branching as our Fig. 26, and differs only in having a narrower primary rachis and closer-spaced secondary pinnae (see comments below on estimated frond sizes). Another, but less complete specimen figured by Laveine (1967: pl. M, fig. 1), part of which is also figured by Zeiller (1886: pl. 44), shows part of the frond just above the dichotomy. The two primary pinna branches lie at c. 80° to each other, although the dichotomy itself is not preserved. Architecture below dichotomy. The specimen in Fig. 26 shows little of the frond below the dichotomy, but some evidence about this part of the frond is supplied by the specimen figured by Brongniart (1831: pl. 71). A 4-cm length of the main rachis below the dichotomy is preserved, and has monopinnate pinnae attached on either side. The only other specimen which probably shows this part of the frond is that illustrated by Crookall (1959: pl. 33, fig. 2), which has a rachis 0-9 cm wide, bearing short monopinnate pinnae. It compares favourably with the structure and dimensions of that part of the Brongniart (1831) specimen lying below the dichotomy, and it is difficult to see where else it could have occurred in the frond. The Crookall specimen is 13 cm long, and this is thus the minimum distance below the dichotomy that these monopinnate pinnae could have been attached. There is no evidence of orbiculoid cyclopterid pinnules being attached to the primary rachis near the dichotomy, as in Laveineopteris loshii (Brongniart) Cleal et al. (von Roehl, THE CARBONIFEROUS PTERIDOSPERM FROND NEUROPTERIS HETEROPHYLLA (BRONGNIART) STERNBERG 167 Fig. 25 Neuropteris heterophylla. Scanning electron micrographs of spores attached to cuticle from abaxial surface of pinnule, V.2727$11. Fig. 25a, cluster of spores near base of multicellular trichome, x 500. Fig. 25b, unidentified azonate spore with equatorial ornamentation. Fig. 25c, ?Densosporites sp. Fig. 25d, ?Granulatisporites sp. Figs 25b-d, x 2000. 1868: pl. 17), Laveineopteris rarinervis (Bunbury) Cleal et al. (Carpentier, 1930: pl. 8; Gothan, 1953: text-fig. 8; Laveine, 1967: pl. 41, fig. 3; pl. 45, fig. 3; pl. O, fig. 1). The specimen identified as N. heterophylla with possible cyclopterids attached (Gothan, 1953: text-fig. 6) has been re-identified as L. loshii by Laveine (1967). The architecture seen in N. heterophylla is nearer to that of N. obliqua (Gothan, 1953: text-fig. 7) and N. ovata Hoffmann (Zodrow & Cleal 1988). Neither V.1797 nor the specimen figured by Brongniart (1831: pl. 71) show any evidence of the type of enlarged pinnules present in the lower part of the N. ovata and N. obliqua fronds (sometimes referred to as forma impar pinnules). However, the specimen of N. heterophylla illus- trated by Laveine (1967: pls 11-12), which is probably part of a left-hand primary pinna just above the basal dichotomy, seems to have large, subtriangular pinnules, similar in shape to the forma impar pinnules from the base of the N. obliqua fronds. Primary pinna branches immediately above dichotomy. A distinctive feature of N. heterophylla is the way that the primary pinna branches compensate for the reduced space available on their inward-facing side, due to the curvature of the primary rachis. It is achieved by the secondary pinnae being alternately long and short along that part of the primary rachis showing maximum curvature. It has not been demon- strated in any other neuropteroid species, nor in related fronds such as Odontopteris (Zeiller 1906) or Callipteridium (Wendel 1980). It can be clearly seen in Figs 26 and 27a. Primary pinna terminals. These are well shown in Figs 28a—d. Another example was figured by Zeiller (1879: pl. 164, fig. 1; refigured by Zeiller, 1886: pl. 43, fig. 1). They become tripinnate at only a short distance from the pinna apex, and are normally distinctly asymmetrical about the primary rachis. This asymmetry is almost certainly a continuation of the asymmetry of the lower part of the primary pinna, with the side with the longer secondary pinnae facing outwards from the frond. The small specimen shown in Fig. 28e may also have come from near a primary pinna terminal. However, bipinnate pinnae are also known attached to the inward-facing side of the primary pinna, lower in the frond (e.g. c. 40 cm above the dichotomy in Fig. 26). Since only two pinnae are shown in 10cm CLEAL & SHUTE Fig. 26 Neuropteris heterophylla. Drawing of specimen shown in Fig. 1, showing dichotomy of primary rachis near the base of the frond. V.1797, x 0.3. Fig. 28e, it is impossible to determine whether they are alternating long and short, as is characteristic of the lower part of the frond. This demonstrates the difficulty of position- ing such small specimens within so complex a structure as the N. heterophylla frond. Size and degree of pinnation of secondary pinnae. No com- plete secondary pinnae have been found attached to the outward-facing sides of the primary pinnae in the basal part of the frond. The longest known examples are 13 cm long (Fig. 26; see also Laveine, 1967: pl. 11, fig. 1), but are clearly very incomplete. The longest detached example is probably that shown in Crookall (1959: pl. 25, figs 1-2). It is a 17-cm long near terminal fragment of a bipinnate pinna. It is more or less symmetrical about the penultimate rachis, and is thus quite different from the asymmetrical terminals of the primary pinnae (discussed above). In nearly all of the known speci- mens, these outward-facing secondary pinnae are bipinnate. Just one (Laveine, 1967: pls 11-12) shows a tendency to become tripinnate. Size of frond. None of the specimens described in this study, or documented in the literature, are complete enough to give a very reliable estimate of the overall size of the frond. However, using the largest available specimen (Fig. 26) it is possible to assess the approximate distance from the dichotomy to the frond apex (hereafter referred to as the DAD). Assuming that the two primary pinna branches, which curve distally in towards one another, did not overlap significantly at the frond apex, then the DAD in this frond was about 1 m. Using this as a base-line, it is possible to estimate the DAD of fronds in other, less complete speci- mens, using the assumption that frond size is broadly cor- related with primary rachis width (PRW) and the spacing THE CARBONIFEROUS PTERIDOSPERM FROND NEUROPTERIS HETEROPHYLLA (BRONGNIART) STERNBERG 169 ae Fig. 27 Neuropteris heterophylla. Drawings of specimens shown in Figs 2-3, showing parts of primary rachis near the main dichotomy of the frond. Fig. 27a, V.1872. Fig. 27b, V.63152. Both x 0.3. between secondary racheis (SRS) in comparable parts of the frond. a. The smaller fragment shown in Fig. 27a has PRW and SRS dimensions comparable to a position about 35 cm above the dichotomy in Fig. 26. Consequently, it is also probably from a frond with a DAD of c. 1 m. b. The specimen figured by Zeiller (1886: pl. 44) and Laveine (1967: pl. M, fig. 1) also has PRW and SAS dimensions similar to that in our Fig. 26. Its DAD is therefore again estimated to be c. 1 m. c. The specimen figured by Brongniart (1831: pl. 71) has a PRW immediately below the dichotomy of 1-4 cm, and a SAS on the outward-facing side of the frond just above the dichotomy of 4-5 cm. These dimensions are about half those in Fig. 26, and so the DAD is estimated as c. 0-5 m. d. Fig. 27b shows a curved primary rachis with a PRW 1-5—1-0 cm and a SAS of c. 6 cm. If this was the proximal part of a primary pinna branch, then the PRW is approxi- mately twice that in Fig. 26, and consequently the DAD would be c. 2 m. It is true that Fig. 27b does not show the alternating long and short secondary pinnae normally characterizing the proximal part of the frond, but this may simply be because the secondary pinnae were more widely spaced, reducing the competition for space in this part of the frond. The only alternative position for such a specimen would be below the dichotomy, but the marked tapering of the primary rachis, and the presence of bipinnate secon- dary pinnae (only monopinnate secondaries have been otherwise found in this part of the frond) tend to argue against this. From the above evidence, it appears that the DAD of the fronds was normally 0-5-1-0 metres, possibly sometimes reaching 2-0 metres. To translate this into an estimate of the total length of the foliage-bearing part of the frond, it would be necessary to know how far the foliage extended below the dichotomy. There is little unequivocal evidence on this. The specimen figured by Brongniart (1831: pl. 71) shows 4 cm of frond below the dichotomy. However, if the specimen figured by Crookall (1959: pl. 33, fig. 2) has been correctly inter- preted as part of a primary rachis below the dichotomy (see p. 166), then there was at least 13 cm of foliage below the dichotomy in a small frond. This suggests that there may have been at least 30 cm of foliage below the dichotomy in one of the fronds with a DAD of 1 metre, and perhaps 60 cm or more in the largest fronds. Combining this evidence, we suggest that the overall length of the foliage-bearing part of the frond may have varied from 0-7 m to 2-6 m, the most commonly found probably being about 1-3 m long. There is no evidence available as to the length of the petioles, and so it is impossible to estimate the complete length of the frond, from its point of attachment to the stem to the apex. No complete outward-facing secondary pinnae are pre- served, so the width of the frond cannot be determined. Fig. 26 shows a width of 0-6 m, but the secondary pinnae are clearly very incomplete, and the total frond width may have been 1-0 m or more. If this estimate is correct, then that part of the frond lying above the primary pinna dichotomy must have been as wide as it was long. General comments on frond architecture. The type of bi- partite frond reconstructed in Fig. 29 broadly reflects the CLEAL & SHUTE Ne? iy THE CARBONIFEROUS PTERIDOSPERM FROND NEUROPTERIS HETEROPHYLLA (BRONGNIART) STERNBERG 171 LO is Fig. 29 Neuropteris heterophylla. Proposed reconstruction of average-sized frond. About one seventh natural size. 797 Fig. 28 Neuropteris heterophylla. Drawings of specimens shown in Figs 4-8, showing near terminal parts of primary pinnae. Fig. 28a, V.272 Fig. 28b, V.1868. Fig. 28c, V.1867. Fig. 28d, V.63153. Fig. 28e, V.1871. All x 0.3. qa) structure envisaged by Gothan (1941) for Neuropteris (syn. /mparipteris), except for the absence of orbicular cyclopterid pinnules at the base. Although varying in detail, such a bipar- tite structure is extremely common in Palaeozoic pteridosperm fronds, occurring in the Calamopityales, Callistophytales and | yginopteridales, as, well as the Trigonocarpales (Daber 1980, Gastaldo 1988); only the Peltaspermales fronds are normally characterized by exclusively pinnate branching (Kerp 1986). It thus occurs in both classes of Palaeozoic pteridosperms (the Ginkgoopsida and Cycadopsida sensu Meyen, 1987), which are believed to have evolved indepen- dently from the progymnosperms. Consequently, the bipar- tite frond structure also probably developed independently in the two classes. Its function is at present unclear, but may have maximized the width of each frond without developing excessively long racheis, particularly those of the second order. For structural reasons, the longer a rachis becomes, the wider it must be, particularly in its proximal part. Since the racheis probably had no photosynthetic function (they show no evidence of stomata), minimizing the rachis:lamina bulk ratio would help increase the efficiency of the frond as a whole. Significance of epidermal structures Based mainly on cuticle evidence, Cleal & Zodrow (1989) divided Neuropteris into four main groups. Elucidating the epidermal structure of N. heterophylla has had important consequences for the nomenclature of this group of foliage, since it has allowed the four groups to be made the basis of a formal taxonomy. Full details of the revised nomenclature are presented by Cleal et al. (1990), but the results may be summarized as follows. Group 1 = Laveineopteris Cleal, Shute & Zodrow 1990 Group 2 = Neuropteris (Brongniart) Sternberg emend. Cleal, Shute & Zodrow 1990 Group 3 = Macroneuropteris Cleal, Shute & Zodrow 1990 Group 4 = Neurocallipteris Sterzel emend. Cleal, Shute & Zodrow 1990 From the preconceptions of earlier authors (e.g. Bertrand, 1930) N. heterophylla might be expected to fall into Group 1 of this classification (i.e. with ‘N.’ loshii, ‘N.’ tenuifolia and ‘N.’ rarinervis). However, the epidermal characters found in the present study place it clearly in Group 2 (i.e. with N. ovata and N. flexuosa). These are: the cell structure in the costal and intercostal fields are clearly differentiated on the adaxial surface; the stomata are anomocyftic; cell structure is clearly visible on the abaxial cuticle; and there are both papillae and multicellular trichomes on the abaxial cuticle. Although multicellular trichomes are present in other neuropteroid species (Barthel 1961, 1962, Cleal & Zodrow 1989), this is the only one reported to have glandular-tipped hairs. In some of the specimens, what appear to be the remains of the exudate produced by the glands are preserved. To the best of our knowledge, this is the oldest evidence of in situ exudate preserved in the fossil record. It seems to have been a sticky, resinous substance, which also covered at least part of the abaxial surface of the frond, causing numerous miospores to adhere to it. Whether this condition was the result of taphonomic breakdown of the glandular tips, causing the exudate to become spread over the frond surface, or whether the exudate covered the frond surface in life, is not clear. Its function is also not certain, although a protective role against herbivorous insect attack would seem possible. It CLEAL & SHUTE has been noted elsewhere that there is little direct evidence of insect attack in medullosan foliage and that they must have had some defence against it (Cleal & Laveine 1988, Cleal & Zodrow 1989). The sticky exudate produced by the hairs of N. heterophylla could well have been a deterrent to such attack, although it seems strange that this is the only neuro- pterid known to adopt such a strategy. On the other hand, Beerbower et al. (1987) argued that herbivory was not a significant feeding mode for Carboniferous arthropods, in which case the exudate may have had an alternative, perhaps excretory function. Taxonomy Laveine (1967) has reported that the type specimen of N. heterophylla figured by Brongniart (1822) is lost. He there- fore nominated a specimen figured by Brongniart (1831: pl. 71) as neotype, and illustrated a photograph of it. In the absence of direct evidence of reproductive organs or stem/rachis anatomy, the taxonomic position of N. hetero- phylla can only be determined from circumstantial evidence. We have provisionally placed it in the pteridosperm order Trigonocarpales Meyen based on its similarity, in both frond architecture and epidermal structure, to Neuropieris ovata, which Beeler (1983) has reported attached to Medullosa noei Steidtmann stems. As with most species of trigonocarpalean foliage, the identification of N. heterophylla has traditionally depended on the shape and nervation of the pinnules, and we have been able to add little to the description of these features given by Laveine (1967). We have, however, been able to add details of its epidermal structure, which require the diagnosis to be enlarged. The taxonomy may be summar- ized as follows. Division PINOPHYTA Meyen, 1987 Order TRIGONOCARPALES Meyen, 1987 Form-genus NEUROPTERIS (Brongniart) Sternberg emend. Cleal et al. 1990 Neuropteris heterophylla (Brongniart) Sternberg 1822 Filicites (Nevropteris) heterophyllus Brongniart: 239; pl. 2, fig. 6. 1825 Neuropteris heterophylla (Brongniart) Sternberg: xvi. 1967 Neuropteris heterophylla (Brongniart) Sternberg; Laveine: 140; pl. A; pl. B, fig. 1; pls 11-13 (q.v. for synonymy). 1990 Neuropteris heterophylla (Brongniart) Sternberg; Cleal et al.: 487. DIAGNOSIS. Ultimate pinnae oval and imparipinnate. Pin- nules oval, sometimes somewhat triangular, generally with round apex. Pinnule base cordiform in proximal part of pinna; towards pinna apex becoming attached to rachis by up to half of its catadromic side. Apical pinnules usually broad with round apex, and length:breadth ratio 1-2; on short pinnae, more elongate with an obtuse apex. Nervation dense. Midvein visible for about half of the pinnule length and rather strong at base. Thick, somewhat flexuous lateral veins arise from midvein at acute angles, dichotomize two to four times, and reach pinnule margin at oblique angles. Adaxial cuticle thicker than abaxial. Adaxial epidermal cells sub- thomboidal, more elongate in costal fields. Papillae and THE CARBONIFEROUS PTERIDOSPERM FROND NEUROPTERIS HETEROPHYLLA (BRONGNIART) STERNBERG 173 glandular multi-cellular trichomes abundant on abaxial epidermis. Stomata anomocytic, only on intercostal fields of abaxial epidermis; polar axes more or less parallel to veins. Comparison with other species Neuropteris heterophylla is most similar to N. obliqua (Brongniart) Zeiller and isolated fragments are easily con- fused. However, the former has rounder lateral pinnules, attached more narrowly to the rachis; and broader, more deltoid apical pinnules with a rounder apex. Also, it does not have the large subtriangular pinnules (known as forma impar) that characterize the basal part of the N. obliqua frond. The epidermal features of N. obliqua are at present unknown (cuticles identified as this species by Barthel, 1962, in fact belong to Laveineopteris loshii (Brongniart) Cleal et al. — see Laveine, 1967). Also very similar is the holotype of Neuropteris grangeri Brongniart, which originated from the Pennsylvanian of Ohio, USA (Laveine 1967: pl. H, fig. 2). The American specimen has pinnules with a more obtuse apex than is typical for N. heterophylla, and lateral veins that meet the pinnule margin at a less oblique angle. However, not enough material has been described from the type area of N. grangeri to determine the range of its morphological variation, and so a full comparison with N. heterophylla is impossible. Many of the European records of N. grangeri were trans- ferred to Neuropteris ghayei Stockmans & Williére by Stockmans & Williére (in Pastiels & Williére, 1954). N. ghayei is very similar to N. heterophylla, but has rather larger, rounder, thicker-limbed pinnules. Furthermore, the midvein of N. ghayei is only well developed near the base of the pinnule and the lateral veins are more flexuous, sometimes pseudoanastomosed. It also tends to have more tapered ultimate pinnae. The epidermal structure of N. ghayei is unknown. It can be difficult to distinguish the smaller pinnules of N. heterophylla and Laveineopteris loshii (Brongniart) Cleal et al., which are more or less oval in both species. However, the larger pinnules of the latter are more linguae- form and have a more prominent midvein extending for at least % of the pinnule length. Also, L. loshii has more broadly arched lateral veins, which meet the pinnule margin at a less oblique angle and are never flexuous. There is also a signifi- cant difference in the cuticles. The adaxial epidermal cells of L. loshii do not differ significantly between the costal and intercostal fields; the abaxial cuticle shows little evidence of cell structure, other than the stomatal guard cells, and there are neither papillae nor the glandular hairs as found in N. heterophylla. Laveineopteris tenuifolia (Sternberg) Cleal et al. could be confused with the larger pinnules of N. heterophylla, but are generally more linguaeform, have a more prominent midvein extending for up to % of the pinnule length, and non-flexuous lateral veins. The epidermal structure of L. tenuifolia, which is essentially identical to that of L. loshii, also serves to distinguish it from N. heterophylla (see previous paragraph). The specimens described by Wills (1914) as N. heterophylla are difficult to assess. Only one figured specimen shows features of the gross morphology, and this is a single, small pinnule, probably from a near-terminal position in a pinna. It shows none of the characters necessary to place it in a particular species. The cuticles figured by Wills are quite different from those of N. heterophylla, lacking the promi- nent papillae on the abaxial surface, and having cyclocytic stomata with a ring of significantly thickened subsidiary cells. Based on the epidermal characters, Wills’ specimens are closest to Macroneuropteris scheuchzeri (Hoffmann) Cleal ef al., but it would be difficult to reconcile such an identification with the small size of the pinnules. ACKNOWLEDGEMENTS. ‘Thanks go to Dr C. R. Hill (Natural History Museum) for reading the manuscript and making many constructive suggestions. We are also grateful to Dr Bernard Owens (British Geological Survey) for advice on the spores attached to the cuticles prepared during this study. The macro-photographs in this paper were taken by Mr Harry Taylor (Photographic Studio, Natural History Museum). REFERENCES Barthel, M. 1961. Der Epidermisbau einiger oberkarbonischer Pteridospermen. Geologie, Berlin, 10: 828-849. —— 1962. Epidermisuntersuchungen an einigen inkohlten Pteridospermen- blattern des Oberkarbons und Perms. Geologie, Berlin, 11: 1-140. —— 1976. Die Rotliegendflora Sachsens. Abhandlungen des Staatlichen Museums fiir Mineralogie und Geologie zu Dresden, 24: 1-190. Beeler, H. E. 1983. Anatomy and frond architecture of Neuropteris ovata Hoffmann and N. scheuchzeri Hoffmann from the Upper Pennsylvanian of the Appalachian Basin. Canadian Journal of Botany, Ottawa, 61: 2352-2368. Beerbower, R., Scheckler, S. E. & Valkenburgh, B. van 1987. An entangled bank — The Smithsonian Conference on the Evolution of the Terrestrial Ecosystem. Palaios, Tulsa, 2: 526-527. Bertrand, P. 1930. Bassin Houiller de la Sarre et de la Lorraine. I. Flore Fossile. 1. Neuroptéridées. Etudes des Gites Minéraux de la France, Paris. 58 pp., 30 pls. Brongniart, A. 1822. Sur la classification et la distribution des végétaux fossiles en général, et sur ceux des terrains de sédiment supérieur en particulier. Mémoires du Muséum d’ Histoire Naturelle, Paris, 8: 203-240. —— 1828. Prodrome d’une histoire des végétaux fossiles. viii + 223 pp. Paris. — 1831. Histoire des végétaux fossiles. 1 (5): 209-248, pls 61-74 + 61 bis. Paris. Carpentier, A. 1930. Notes paléophytologiques. Annales de la Société Géologique du Nord, Lille, 54: 186-189. Cleal, C. J. & Laveine, J.-P. 1988. The juvenile frond of the Middle Carboniferous pteridosperm Paripteris Gothan. Géobios, Lyon, 21: 245-250. ——,, Shute, C. H. & Zodrow, E. L. 1990. A revised taxonomy for Palaeozoic neuropterid foliage. Taxon, Berlin, 39: 486-492. — & Zodrow, E. L. 1989. Epidermal structure of some medullosan Neuropteris foliage from the middle and upper Carboniferous of Canada and Germany. Palaeontology, London, 32: 837-882. Crookall, R. 1959. Fossil plants of the Carboniferous rocks of Great Britain. Part 2. Memoirs of the Geological Survey of Great Britain, Palaeontology, London, 4: 85-216. Daber, R. 1980. Zum Problem der Gabelwedelformen des Karbons und Perms ~ eine Ubersicht. Schriftenreihe ftir Geologische Wissenschaften, Berlin, 16: 1548. Florin, R. 1937. On the morphology of the pollen-grains in some Palaeozoic pteridosperms. Svensk Botanisk Tidskrift, Stockholm, 31: 307-338. Gastaldo, R. A. 1988. The frond architecture of Sphenopteris pottsvillea (White) Gastaldo and Boersma. Journal of Paleontology, Tulsa, 62: 982-988 Gothan, W. 1941. Palaobotanische Mitteilungen. 5. Die Unterteilung der karbonischen Neuropteriden. Paldontologische Zeitschrift, Berlin, 22: 421-428. 1953. Die Steinkohlenformation der westlichen paralischen Steinkohlen- reviere Deutschlands. Lief. 5. Beihefte zum Geologischen Jahrbuch, Hannover, 10: 1-83. Halle, T. G. 1933. Observations sur la structure de quelques échantillons carbonisés de Potoniea du terrain houiller de la Lorraine. Annales de la Société Géologique du Nord, Lille, $8: 193-206. Havlena, V. 1953. Neuropteridy Ceského karbonu a permu Ustfedniho Ustavu Geologického, Prague, 16: 1-168. Kerp, J. H. F. [1986]. On Callipteris Brongniart from the European Rotliegend basins. PhD thesis, Rijksuniversiteit te Utrecht (unpubl.). Kryshtofovich, A. 1944. The mode of preservation of plant fossils and its Rozpravy bearing on the problem of coal. American Journal of Science, New Haven, 242: 57-73 Laveine, J.-P. 19662. Remarques sur quelques frondes ptéridospermophytiques paléozoiques. Compte Rendu Hebdomadaire des Séances de |’ Académie des Sciences, Paris, (D) 262: 1625-1628. —— 1966b. A propos de la classification des Neuroptéridées. Compte Rendu Hebdomadaire des Séances de |l’Académie des Sciences, Paris, (D) 262: 1680-1683. 1967. Les Neuroptéridées du Nord de la France. Etudes Géologiques pour l’Atlas de Topographie Souterraine, Lille, 1 (5): 1-344, pls A—P, 1-84. —— 1987. Importance of understanding of the architecture of frond for systematics of Neuropteridae and Callipteridiaceae and its stratigraphic implications. Acta Palaeontologica Sinica, Beijing, 26: 71-79. —— & Brousmiche, C. 1982. Documents pour servir a la reconstitution de la fronde chez certaines Neuroptéridées. Géobios, Lyon, 15: 243-247. Meyen, S. V. 1987. Fundamentals of palaeobotany. 432 pp. London. Millay, M. A. & Taylor, T. N. 1979. Paleozoic seed fern pollen organs. Botanical Review, Lancaster, Pa, 45: 301-375. Pastiels, A. & Williére, Y. 1954. Etude géologique du Bassin houiller de Charleroi. La concession Trieu-Kaisin. Publication, Association pour I’ Etude de la Paléontologie et de la Stratigraphie Houilléres, Brussels, 20: 1-196. Reichel, W. & Barthel, M. 1964. Das ‘Schweinsdorfer Fl6z’ des Dohlener Beckens. Neue Flézaufschlusse und Florenfunde. Jahrbuch des Staatliches Museum ftir Mineralogie und Geologie, Dresden, 1964: 203-247. Roehl, E. von 1868. Fossile Flora der Steinkohlenformation Westphalens, einschliesslich Piesberg bei Osnabriick. Palaeontographica, Stuttgart, 18: 1-191. CLEAL & SHUTE Smith, A. H. V. & Butterworth, M. A. 1967. Miospores in the coal seams of the Carboniferous of Great Britain. Special Papers in Palaeontology, London, 1: 1-324. Sternberg, K. von 1825. Versuch einer Geognostisch-botanischen Darstellung der Flora der Vorwelt, Leipzig, 4. xlii + (8) + 48 pp., pls 40-59, A-E. Stidd, B. M. 1978. An anatomically preserved Potoniea with in situ spores from the Pennsylvanian of Illinois. American Journal of Botany, Lancaster, Pa, 65: 677-683. —— 1981. The current status of the medullosan seed ferns. Review of Palaeobotany and Palynology, Amsterdam, 32: 63-101. Stockmans, F. 1933. Les Neuroptéridées des bassins houillers belges. Mémoires du Musée Royal d'Histoire Naturelle de Belgique, Brussels, 57: 1-61. Wendel, R. 1980. Callipteridium pteridium (Schlotheim) Zeiller im Typusgebiet des Saaletrogs. Schriftenreihe fiir Geologische Wissenschaften, Berlin, 16: 107-169 (incl. 18 pls). Wills, L. 1914. Plant cuticles from the Coal Measures of Britain. Geological Magazine, London, (6) 1: 385-390, pls 30-31. Zeiller, R. 1879. Végétaux fossiles du terrain houiller de la France. Explication de la Carte géologique de la France, Paris, 4 (2): 1-185, atlas pls 159- 176. —— 1886. Bassin houiller de Valenciennes, description de la flore fossile. Etudes des Gites Minéraux de la France, Paris. Atlas of 94 pls. : —— 1906. Bassin Houiller et Permien de Blanzy et du Creusot. Fasc. II. Flore fossile. Etudes des Gites Minéraux de la France, Paris. 265 pp., 51 pls. Zodrow, E. L. & Cleal, C. J. 1988. The structure of the Carboniferous pterido- sperm frond Neuropteris ovata Hoffmann. Palaeontographica, Stuttgart, (B) 208: 105-124. Bull. Br. Mus. Nat. Hist. (Geol.) 46 (2): 175-270 Issued 31 January 1991 Tertiary Ostracoda from the Lindi area, | Tanzania MANZOOR AHMAD Customs Co-operation Council, Rue de I’Industrie 26-38, B-1040 Brussels, Belgium (on secondment from the Central Board of Revenue, Islamabad, Pakistan). JOHN W. NEALE Department of Geology, The University, Hull, England, HU6 7RX QADEER A. SIDDIQUI Department of Geology, St Mary’s University, Halifax, Nova Scotia, Canada, B3H 3C3 CONTENTS IMtrOcdUCHOM ar Saeco t teen h elo D eta, tina ann aveie sn af dtiine ’ Sue Bissau gage oD behead eee earth dibyaie ah aha Sree 178 Strath Ora pl Visagesetrtavccte atte cnet le fen Sai stay exmence a/cnuccsthh manne, Wavtene nich Siar aidds ocane dada seagate Grud pues ade waa Gee 179 Previous work on Tanzanian Osttac0ds)..2. oe. Fae ek ee ee ln eee alae e nee ne ee ene etre eee eee 179 Systematic descriptions: Subclass Ostracoda Latreille, Order Podocopida Muller .....................00005. 179 Suborder PlatycopaSars e258) cit ctewteapke arin ye nasa agate g aaa thal danas a eitslane de TS Hal eek ee eee me eg 179 Ramily;CytherellidaeiS af$):...iidariae san cad tiene aa ed eMedia ee See eee da wantaweste eee seo 179 Genusi@ytherellagl ones): ccc acs. Seisngh eee Tala o.3-4 pale aiaanctiem 2Mo dagueda Ol wales wieneph yale fe iee etna 179 Eyrtherellailindiensis SP eNOVe sie sis% soho bintsieleal ayiernle hide rlieenecaseneie cceuacg 4 4 boda pled alaied Dare cqee se te 179 Gytherélla'mediocalva sp. DOV. siies ap isjsice eis ete 8 one cette ear evento nen wee wane gy alinla eye aden 182 Génus'Gytherelloidea Alexander 2.x caei ici ce ncd ae ene as aa ein eS pols ewe hee eee ee eee 184 GCytherelloidea gemellata sp MOV 6.5084 4G)s av ccoe sind sue opens ews eae ee Ew ae RE Oe ba Eee Ge tle ee 184 Cytherelloidea patagidta'sp. MOV. 60... 20 stn ee ee cds eee eee veda ache sane ee eee ee nas 184 Gytherelloideasp YA a. Pree ietscaviinys tat the S sa naralet inate namibia sig nae ackaGalt ean’ aca eaten % 187 Gy enelloideaiSp yp Bis, cor sethe hominis Gage Ok aus Weak Dea OL Simoes lays yateleva apa, snake Subset ardleonala a duagalera & 187 Suborder: PodocopaSarsiat/een.ctocstyecnk wart itty ees Sent anne eae hap ene a eld weg Teg een ge Bele nS ales 187 Superfamily, BaindiaceaSarsicinccics. Gidea waveihete sist ansectase das ovata SAG Hwee ee Ee ORE Eee Cb EeS 187 Family Bairdiidae: Sars: <2). c.ciscyiaie dbegsuttieatiosiod Cae Sonoma ca vee VEE MONE Te aad Pee aed ewe eae 187 GenUs!B air diGIMSGOyies, Baden: Soest aeteuceutna cit oracaepene singentheig CMU S ight arse WbManenal ants Bienes gas Gs oS aye, dra. cyn ich ese 187 Bairdia amygdaloides (Brady) oblongata van den Bold ..........0000 20000 c eee eee ees 187 BQU ia Ch GitENUAtASBEAGY, sec fenice ce eh doo, a-siinls SBAG,S Ah A Seva Go SURTLTE 38 Spleens BEE, dies gua dun cbini gw wellness 188 Bairdiact-schulzi (Hartmann) soak anck dene ot eee geld Osada ee Paine ewe bE eels 188 GenusiParanesided: Maddocks ai. iviheccistaths et Gaedsataie eacons aoa ayers sree Aveo Hererd Na 8 See Bgie Nee 188 Paranesidea fracticorallicola Maddocks .... 00... 0.0. eee ees 188 Paranesidea nigrescens (RUGSICTI) ces tcc cuets ase ses Rendon le Man thas eee aaa ene a 188 Paranesideaich. fortificata (Brady) ives teint can stent aes oid ots aleindedale tants wns wg Sete es 188 PG ANCSIAC ASP AAG ret on Sect eatin anenany Wat actrees gtrt enort-trentaaeewaner ote MPSA N IO ea TeMee cowe 05.0 = 19] Genus iiriebelinavanidemBol dig tcc: cne cs acraneeeto snare sone Rtsnnd Vandal aera hotel tba and wneneie, Danes Ane eae 191 diriebelinainowetl(StepnensOn)) srev.etoosee lavaue nein 's Guthanare ave Taconic otsuge suet ab Be eenelinere wierancro sod tre cra 191 Supertamily;@ytherace are and sess se easeate dist av ere rest wuypsuoneneaiiouss clisern Hiela: sesso tatelare’ evade Wiel shone ela bage arenesdte ac¥s aie ars 191 Family CythenridaesB airdtr seman ccer esac otnt tye come tego etbnartes OE wanin we rngrew due nie eee pels oodkeha sea! gy geue sales ees 191 Subfamily Cytherinae Baird, Tribe Paijenborchellini Deroo .. 2.0.00... 0.0 ee eee 191 Genus'RaijenborchellaiKan gma ce sces.cic uate fides daa eases eieeicens See ete elersisc teem wens ee NGS eee es 191 Subgenus#Paijenborchella Kin gma: oxs css.cseswttue yaiavs sad al eteenslh QU Mand sade ol soocePe Ree Meteo el sees 191 Paijenborchella (Paijenborchella) cf. iocosa Kingma ... 0... 20. ee eee 191 Subgenus/Mopaijenborchella Reij soc, ce,spevicyvars aye the Biv se woe elayors oolginSiove) a alas avasnia: aie gpeislereie sila wierers 192 Paijenborchella (Eopaijenborchella) quasimalaiensis Sp. MOV... 0.600 es 192 Paijenborchella (Eopaijenborchella) quasimalaiensis dilata subsp. nov. ............---+5555 192 Paijenborchella (Eopaijenborchella) disadunca sp. NOV. 6... ee ees 194 MOphotypestA SD ri rcpare aiccrecneccansiolssoreicieselcbele. cle dNetarsiah cuaraudstabarayste xtesst legis kes eiahauale ere emyers a 194 Ranilysveptocytheridaeiblan aliens: isc, ayseceyctcvovsvensydaiorevayeretie wie eis aie {ishonenehcicre iret etahelalere fe lgy a a.eigia'e aeele isie.8 eis 194 Genuspeptocythere Sars irc eee crete och wetness sero sheave Noga ve eens ohev ek elu enekayesene viele ovstaietele ous o/s cen 6 194 SeDtOCy thereiaMOeNaiSP MOV) ve varssereseicesieasicts tai sherenel ee he ee area Ae ate BiaNeE helenae DiaNe Mansi S wee sole ws 194 TSCPlOCYINCTeI AST PALA'SP OMOW stray se sere) uci slecae vans sz alanevalohaeanaiesele WeVece oroles Ponatelinerelals s ateiees a c NRNE Sele os 196 GENUS, CGIliStOCyINEreIRUG CISTI Ge siensccsetch. dered ate a cketere lee icles cfd talacosetare suale shores byatiavs! tera eile wens Giareere 2-196 GEallistocyiherejUgOsarsp MONA tever este se ars ys oust nave vere erevehe oi ousts shave Mare eletene Uieiere: Mere e oka see ears Se 98 176 AHMAD, NEALE & SIDDIQUI Genus Tanéelia Kin@Ma cds casino boweade nap steas trae cation duane mar tae oat enema aaag 198 Tanella sp. Av a iisac dsc udens cana aoe seas oeeesivc avle Peale qemu vad oe aes wae oaae 198 TANnEMASP UB sw Shade: chilean sods. ab dare Oued tree eH aad dalla ss des oe OU aig GdlewsaaG SoD oes 198 Family Cytherideidaé Sars: dita. 2 oink abo Wisnersiasnsiers aye etn Gt avec: gah arepseineratealeure Gla sani auto Gentied einem ges 201 Subfamily Cytherideinae Sars: 3.0024. x fe eie a ax Ake dhs Lua anes Shug wtieei ease ititea ahead g antletiralgdere a rane adored 240 201 Genus Clithrocytheridea Stephenson i...9 2. scc064. cc conte ee eeeee Dheweebeesde can/eleneeebieees 201 Clithrocytheridea? semiluna Sp.NOV: «sce se ois Galena vss eee ted cae bee eee ea ee eee Ee Cees 201 Genus Rostrocytheridea Dingle 44..adec. 08 faced tre need Misa a de ee OSB ae eda ae Rae 201 Rosirocyiheridéa? Sp. « vsiiaaie oe nls Gece dene ceeds The ed Deed daunda eRe enee eed wee aidaend 201 Family Krithidae Brady 8 RobertsOmies.s. 005 sc. es ee rand ee caaig OE. vided Se adie’ es HE ates ed 201 Subfamily:-Krithinae:Mandelstam) 32's. .s2h5¢.a: pheahGensiiacebsen caging oa gaie haeees dtanctetes 201 Genus Krithe Brady,.Crosskey & Robertson 4 oasis chee vee aaee pe eevee eee se Ded bee winee nd 201 Krithe burdigaliad sp; NOV. i. i..ccsc0e segcaeae de he eed et anes tan cewnatnpebates eeb ane tales 201 Krithé lebaur sp: NOV: wisas a2 Qnadenend Qrta ions bases he ee dewas sara ens tae kate oda soi teas 202 Krithe medioelata Sp. MOVs iv s8 auesais 2 So sinie Pain Abad Woes Rae One eRe oii daw dallReS Se oF atertete 205 Genus:Onmimatolcrithe: ANIMA. 3. $6. c5 2.22.0 id anejdeaiete eGi8, seu. bot sk & tb angls See: c0e. dP bela w aise Geek nag lp 205 Onimatokrithe prolata AMMAG cscs ond ce pace eee Rents bathe nd Fenn Sele we dege aa sitet es 205 Genus. Parakrithe van den Bold’... 0.0 0000eds tancctaen eae cee bees sg ehwawe ns wloes Peewee 205 Parakrithe cicatricosa’Sp.. NOV.) 2-0 cas daa ccanawee te cei pag ewe eves bee badeaw 2°) Diddle wena el’ 205 Family Trachyleberididae Sylvester-Bradley .......... 0.0... c cee ccc eee eee eens 206 Subfamily Trachyleberidinae, Tribe Trachyleberidini Sylvester-Bradley .................00222-.00. 206 Genus: Trachyléberis Brady i52és0e0300.55.0d eed edie esha oe veils Seas oapheeeeanbes gla eaeae es 206 Trachyleberis duplex spoMOV. 2.02.52 0050 ncscee on ce cea eee odes oe ee Ce ee a Teen eee neem ee ERS 206 Genus Gujaraiella Khosla... seca cme cdacie xe gieGwiitn howe wane ecw ss weloa ha ieee ooo ee 206 Gujaratella? tanZQniensis SP. NOV: 2..03..08 saree habia Me Ga eae Fo Ke Caves ae Te eee d 206 Genus Haughtonilebéeris Dimple... i. f0'65, 22.0 Seiad. s Se. d sais des agales BeOe-hew sabe sues Feeble 209 Haughtonileberis radiata Dingle. es6:.6 65 sees ee oes ae ele eee Rees 5 SEO RG be Hebe Bo Leese 209 Haughtonileberis rastapuriensis SP. NOV... 6. tee tenet teens 209 Genus Acanthocythereis HOWE: sie vada hed dace cade aached 4a 1 gh gadan eRe eee a wae pe eud Pande 209 Acanthocythereis postcornis (Siddiqui)... . 2.0.0.6. .eeceeeeeeeeee 211 Genus Falsocythere RUST 2:4 saiscdacevde ss 500 lala seeks auerece es cepyistas netted Megat 2 cades 211 Falsocythere maccagnoi (Ciamp0) ......0. 025. eee tne bet nee ee eee eg eee 211 Tribe: Costaini Hartman: & Purt.s.2gc.ci08 inewileiaen tower canned iam eante nee ah odes Seka 211 Genus Carinocythereis RUSPIEM ...cF seed. taegliaes wees Fh Sets trdien aes dees oeba heaeg tan canes 211 COLINOCVINCFEIS'SP)s «22 oe 6. 4 save acces dnd oe Goa 5 ey eimais eel eesase tne ah eres vase, cna ata ited Gna: erage 211 Génus Costa NEViAaNl 20h ceca d iow ey iw ne boats edd viele cede hwo Rania ES o Oe cea Ra Mem ees 211 Costa? hullinasp. NOVs -ncs5 soe sn te gee deeded Raed ee deen Tob ete dw eo betian ee noes 211 Costa triidis ANMad 6.02605 5 Sache obs HA hd estates aioe EE Grom or ar ee eee Coee eae oS 212 Genus Trachyleberidea BOW6M oi .i-eaces eden ghia aie Maal Gos Gans ieee ainda S Baste Hew Ee eee Beas 212 Trachyleberidéa? cirrata Sp. MOVs 02.054.i0¢ {4 te naga sd die ya he waded tees iaae Shas ai ae wards oes 212 Genus Stigmatocythere Siddiqui... .+........ 00s eect eee ne een been beset eeeees 215 Stigmatocythere bornhardli sp. NOV... 22.260 seen desag see bead se Pek kab awenesm eee ee ades 215 Stigmatocythere intexta SP. NOV. coca eeeiss ba edie ewe La dds soba Ce eag eas eae bate 215 ‘Tribe Pterysocythereidint: Puts: 6 cos cewcin gated see tig is. 6. op wake ace. o ictitn den ano,o- Wig wie gplegen arash Sigua detent 217 Genus Incongrucllina: RUSSIEH -2. 0 otc h0ds Heads Ge owt Raves ba ed Pan ened Tea ee See eee eas 217 Incongruellina tonsa: sp. NOV. 2.220002 eee cce ee cea ge We baa eee bea eee eee ea ele dels 217 Tribe Echinocythereidint Hazel o.oo) c5 ene pasiebincn dee dbas sa vasios Poh bees sea pean’ ees wie 217 Genus: Henryhawella Pua s...30 e064 becwieek waooy ee Heceas Mo ure wakes Meee hee ias Die Bowe Roe ae wee 217 Henryhowella sentosa Sp. NOV: « .cc44 ce cede cnn abv e teen eta cante cede ea caley ees ewes 217 Subfamily Buntoniinae Apostolescu «2.22.02 0000nr se ene bodRa ean ame Ata Maia File way eee a 217 Genus: Buntonia Howe & Chambers «00.25. os aegis Bete te see csdibats heres Hales Ghaalepe gto oka eas 217 BURLONIG SPs wise tet xce 6 nS AS ee oats yes ew ack SWRA anew a AE vedanta Dae Rane wa aie are ae 217 Genus: Ambocythere van den Bold «.....0.. c005 cece ere n end tiene eee gee dade debe dh Deevebe te aehes 218 AMDOCYtheré SPs 5. sc.c-9 nse ee ded Years Ra SP Aad sins, wee Daten Aba bie b bataebada an moe Ae ates 218 Genus Occultocytherets HOWE .oic. 2.5.2 cise ke Gis, sina’ dae Paaloan Gag dae odau aul e reas Gime eeaeie ee 218 Occiltocythereis africana Spo ThOV:, esis osteo 50 4 Hac PH oe els Wedge aad Nia 4 DUET age ame eee 218 Genus Jdiocythere THEE. ..si6.9.2,c008 oes wd vp 1s FSO IO MOI acy 8 do aire BOOT ey EE ER 220 FiO yther€ SP Be 2 aia de Pisse nd diane Reds Hae Rb Hate eA RES RCE ARG TS claire S 6, BEDS ATS change rdeeeybee 220 Subfamily Campylocytherinae Puri, Tribe Leguminocytherini Howe ..................00 0002220005 220 Genus Leguminocythereis Howe (in Howe & Law) .........000 000 eects 220 Leguminocythereis dinglet Sp. OV si. s-sicaticdgre Maen ek ot ste sg Was Tate R sa wth denser s eee 220 Genus RUG gIeria Kelp sivecscc-sisccics bdcqpaipdiad 6 nna arowRcaRIee Oe HPMEGA ital DELI Reend PRS Powe 220 Subgenus. Ruggierid Ket 3 .saye.ccore Sey donde aides cine alate Stems gnsets BL CONSE REM TENE ME 220 Rigegieria (Ruggieria) furcilla:sp: MOVs. «sci eeeic.cteshcs 9:5 wel toccacatoy seine eda Sagas lei sunble:s auatataae ele dane 222 Pamily Hemicytherdae: Pures ...5-00.a.2 4.2,5atoirs erasers, 2 clete oe arse eee Pay aes os eee A lle bal op etsa boats aS Gieateeti ses 222 Subfamily Hemicytherinae Puri, Tribe Aurilini Purt’ s,s. .:00cc0edied town ge eee neasn oy wade agiocees 222 Genus Aurila POkOIny: $cc ca sistas oco.8. asians axdiehas ee Sea cormseld cs isa aed Aateiar wine tpa Ate ain ta0 weaiope epee Roars 222 TERTIARY OSTRACODA FROM THE LINDI AREA, TANZANIA PAT ILA CONCENIFICA SP UNOV sctecsvsrsaisvnavs ous wietrs +: son Gags Oa dH MMU Sage a dies TEAST EOE waa oe 8 222 MorphotypeSsAqBiiic i came-nsnanto icmegas he Acie waaay Raa Delain nee sa eas ds.e%, a0 224 GENUS!PLOCYINErels:‘SKOPSDELG = Ssca.are qaygiad ao ne dtia vem aaa gid anew wierd availa gab hibdlae Ha doo BR We Bee 6 ae 224 POC IETels ALL BETA: SPs MOV 335 at, seats S055, Sauer oa a: even Sata ai lande $8) Seaialene love: a diavaue aw atade Widue! pide ead as 224 PV OCYERETEIS FAGIAIGISD!, MOV ern ayas ss spesanetacesciauslind 3 itaya ce 4 4 Bow ayes ele els band ad andyaies See abr 8 Re dre, asap gedhe nee DOA Subfamily Thaerocytherinae Hazel, Tribe Thaerocytherini Hazel ...........0000 0.000000 c eee ee eee 225 GENUS Herriamiles RUT a 55 ce: s ies sucksie yesh auacsusy stove so eyapdrSgonsaay sista alta orl 0h aos pbb Sig en Riad 600 t.t.nia's eee 2 oe EO FLerManites CAnCheSium SP: NOV... balers discs ss ered sceeinacacsnie ead diane Hebe dle due bab suae dae @aewaedee ees 225 FICFIMANILES: TONZOENSIS' SP. MOV. vieiccvecdiica savacesivesece.e vos rhe salle ab gan deme a end da baa de eee eee 225 Morphotypés:A=B: Si..ticicclitate Sac mesine be os asble ee ben degen n ede trp natn see wed gees 227 Hermanites percultus:Sp. NOVs..< .o8s 0s coin nba i onese rece ct tip awed ved sep bRGG wee baled wo 4 227 ‘Tribe Bradle Vin BENSON a sioaps eRe cys ced wave ceo pais dk-and wee od mea a ales eae tava caied se dda daw s waleeed » 229 GenusBradleya HOmibrook: osis65 se navatevecins soe Wek ede sais Soh eben oe hal he Gg Gude sale Ging emer wees 229 BY AAIC VAIS SAN Gres erate lon ac oran Mevansranche Bhs sonestd apaiatie exerei gy aloeia or Siva rduase wuss) grate ate teu aus & eae sees 229 Bradleya? sp .iBe soec als waes cite wn eternigtye Geis dain clas teeteahehiele tense 506 4 bb gelark aware aan’ 229 Genus Quadracythere Hornibrook 2.0.2.0... 0c bebe beeen tenes 231 Quadracythere arcana (Lubimova & Guha) ........ 00660 e en ees 231 Quadracythere arcana cornigera SubSP. NOV... 6... eee eee 231 Ouadracyihere HaCuia: Sp MOVs, .cieccpte sysee an eyes ated Wa Na Qa ORU A ana ene eda dea da Gee areca eae 231 Quadracy there distenta-sp .NOV + sccesicis fis sis ice Ose veces Gdn 4A oa oa BAA be dat Ba Weleda ded gene 231 (QUAATACY theres Keritt’ SP. MOVs 6 ieieisahe sievacavaira oo: aside & wl esd aa 13 a0: Vow hin asels bela te ae, 0: dhellg aualerbyasncd eee 233 Quadracythere subquadra Siddiqui... 2.6... eee eee eens 233 Ouadracy there trijUgiS FAGIGED «isc oc Fcio es Busse cos 4 ate oincin dard, Reale on Bw ESA DECOM MINE Be Owe Bal 233 Quadracythere Vanga' sp: NOV. 6 sina ce vties wn aiiel ee t's vee ie nee see e ed ea eed change ee eaea aie 233 Quadracyihere sp Ae tote ace nto deen Ne ee hye jos 2abei on sheds Kaan s begs a ek nga dee ewe hee 235 GenlsiGrenaleyamovigs. ahs caved siesG ekendiaay nae kaos baigeted Mee we edalets G08 Fale dee a Teieg Oe 235 CrenaleyatUbertssSps OV: o.5,4.5:i0s) scare Fahtaleiec a: ciate als e(apose eae Gd # aueahacidte ei aia) eishand ea) dlais eaters ai algetons 237 GCrenaleyaspeAirscke ten selec eens ae ele NO eek ocr Hasse ee Honea ey ae Reese ea Sale es 237 EFENALEYAUSD a. Hoyt tcks oe OF Se eed Ho OES bee sree le Siecle UiGUs gpepae, org A 4.m lee > ee eo a eles ae 237 Genus: Wrocyihereis;RUSSIEN. facia tea annem nen tai 6 dg had nwa bao daa ed dee tees wala « 237 Urocytheréis:salebrosd’'sp: NOV» .0c0 56 cate ewe eee beet ng bade end de aae Dede eee a 237 Urocytherets:apolegma sp sMOVe vast cccrcaes bead hee Mente ea mde news vee tteathieed ebeas 238 Subfamily. OnOnmMIN ae UMy 54 cesses aeayeacts vorsauicuaiatarele wvecdvacd octad ye Glens h RWtacer esac acB.G-4) oS a Qin @ o Readndle WS 238 Genus Anterocythere McKenzie & Swain... 2.2... eee tect eee eee 238 Anterocythere sp. B of Swain & Gilby... 2.0.0.0... 2. cee cette teen ee ee 238 GenusiCaudites Coryell Fields:. foie. ik eae HERA Mae ey page a eevee giealede eet ede weil 240 CGUAILESISP Ser ements ete Screen Gy brgntreete Tae ET isis bay SEG aIaPDA LA ohaNe BEN aigual Ravens ue 240 Caudites chsrosalicnsis Swain s acccectte vetesais cite ete Fe ras prs Sines daa Be OE EAE DEY te aver le alee 240 HamilyMzoxoconchidae:Sats® ss ieics or, exenpaeiteucnn acest elosve ae teless-g olod 89, So Sea ecslt win une ented he cuales 240 SubfamilyroxoconchindeSarso.. 8.8 ote fh set oclec ted ase be Dace da Stee dean oes Hani demlate Bee wees 240 Genus!ZOXOGONChA'S ars! tFith ok ARG sce eRe pecde nee ep lav ayers apt ele RP REA towed sa en ome 240 Subgenus oxoconcha Sars? wake rs cctees diet hws Shoes Mee wan eee ees MOG Cee aehes 240 Loxoconcha (Loxoconcha) mbanjaensis sp. NOV. 0.0... 00 cece eens 240 Subgenus Loxocorniculum Benson & Coleman .........0.0.0000000 0 eect eee eee 243 Loxoconcha (Loxocorniculum) postnodosa Sp. NOV. «0... 6.62 eee ee eee 243 MorphotypesA=B irae ca hac goede «pn henaidmwaneee see tiee Rie te hoe sales wcdeae24o Loxoconcha (Loxocorniculum) tricornis sp. NOV. 2... 60. eee eee 243 Loxoconcha (Loxocorniculum) cf. longispina Keij......0 0000 ccc eee eee 245 SUDPENUS MY ren asNeale ss hs prgscscvese leit i6.5, 08%) cisaarwraneuaie dia’ afeoye ig) d che Bysnane onl oleyasafatMlews Mie. Salsa Cusayaierg 3 245 Loxoconcha (Myrena) loculus sp. MOVs wis: -. js s'sveaian ccc etc ee bas nanele ee Sashes vein o Sieioe ese 245 Subgenus Palmoconcha Swain & Gilby ©2000... 6.00 cc ete eees 246 Loxoconcha (Palmoconcha) pinguis Sp. NOV. 2... cee eee 246 GenussBhlyctocy here vMen yer. tase ts aes co ares iaiaicnsvarcisl vitae dud os paravene ao ouds Hasenousts aaa Nese a USIGLO Peusials s Crepeseia S 246 Phiyctocytherereniformis Sp: NOV. 202. s.cchc ead thes 25.24 Role ee SHAS oR Ota Vase oer ewane gases 253 Cytheropteron cf. nipeensis van den Bold ............0 0.0 ccc cee teen eens 253 Cytheropteron Spc A: 3 iliac cn ten oes Sumbiadn ce 8ies aborees caaugaedad sentenced wee neaae'n! 253 Genus Kangarina:Coryell’S Fields: 2 ecciae cee cawed wie eea sien teeben aoe Meaew ae sw daedsaar ieee aa6 253 KON ZAring SD a iale a ledrcciks cia. Gis eo Randle eb aba G's AE d ayeiaag SAN a BUNA Goa) Faw acon drake, crete WNES Raut aed 253 Family Xestoleberididae: Sars: je o.5 cid: oes Hare: Gediedeaced bad baie Os wematteed d/eaielelaw ' a5 Gh be Suse ome « 255 Genus Uroleberis Vriebel. o.3 03.50 cine ee oan dae dante bos oes Make ae meee oe SEE Oe ee pee ee 255 Uroleberis: Kya sp. NOV. 44s scsen ete ae Hee bela ba ees Sead eee Oe Oboes Fe Redon ds 255 UrOleDeris SPs aa tice beached a oand mein inats diode mete dead oases hae eta o ee Aad eat 255 Family Bythocytheridae Sars ........ 0... cc cee ccc cette eee ene e tenn ee eens eens scenes teteesees 255 Genus Byihoceratina HOmMibrook 0). ue a eek cea bade ey neenbene baked bade taede aaa ced 255 BYINOCEFAUNGT ASIETIG Sp NON ee seca ts 6t0 ana: af, o-% a. acandy Settee aghane ete Rlears HOE AG edlakx OMAR eg we oe 255 BYthOcerann@ Spo . ccosicwee ccbadins.e need wee. Carngared b4 OeeEE GO EES Gag ekouin ded Dies 257 Superfamily Cypridacea Baird)... sacha wn csas awd hese ow na barees ao hiawedenns Pode @raee imbaese aan es 257 Family Macrocyprididaé MUNEr jis.5.5c5:25cica cts otaen sede gobo eam pele ee alad eeccanes bq iain Wass o coalas 257 Genus MaCcrocypris Brady. vases ecahie8s ecdcrng beens ane fe be eg nnd be Ree Realy pad Dade ae eae ane weE 257 MaCrOCYPHISTSP OA: si G2aw ag iosh ind chose hk ee Pe ORE RE EEE LG Dee ved UykE bene s Ou led 257 Macrocypris Spe B: os wictierger tebe de anh bread of peas Goes ede ble sor Chee Rela haa Pew 257 INCertae SedIS: c..i:..c concen @uavmoda atc datien Garces stn Ae sad 6k hphmeucr ae pega ie big Bie aneaceeTe ack 258 GENUS ASP sa.ieinig ised boa tekeeuedeaaeee Reena ee dbase ee oed macaw oats deeaee ee antie 258 ens BSPt Yineca Seno ees beatecentiiass sachs 26s aire nee ese ee eeu el Sapa eee ors atte 258 GENUS 'C SPs) ood ahogen tine cache tanya teacadaa ae bodae 1a ae Doug aac ana seers meatedahee as 258 PalacoecOlogy’ c..0aa dion dootag be debdrdiaanarsan Sek wedadepbnvein banned Reba deed nasa onreedaaemee 259 Patinal assemblages ss. i504 sscies Sie tieniGige ea didhseadasd doe didaaGed dae tsladedeuard aaiteee Obie yadd aeen cits 259 Ostracod 'bioZOneS vic 2 sig ckadigs Sead okie dea nd abe eal clbhin eeaGe 24d Sneha benine doen pate hak ageless as 263 CONnCIUISIONS® » s5 cuits oon tess aoe he dle ee awgedae Recetas Wud RaMetaaes oe ebet kale meue ee Rae eta ed ae 263 FCRM sample data... c.icis2ae25400cioia ded ped ethe He dines oa ge Coed aslna eyed peated soy adtant eens 264 ACKNOWILEREMENIS jajinc sd arate tae eter deie Gud b4 6 aN oF Abieewla ste a ea nee Ding walielow Wem Ow Ma SEES onde tees 265 FRELELEMCES: ssc. 5 fos asecah ie hs gnns Sp deeisca che arcu Alas oacSeet daghcibed a imteag eta Aiset en gUtay Bish Sguceh ars Gan evan nh ie lbated hentia neioses Geena 265 INEX: 6.53 adores sobs dendesselegnressrncgeree aun Seueeetathechld ae Abbe deena de otteasd G00 begets s 268 SYNOPSIS. Ostracods from the Upper Eocene—Lower Miocene of the Lindi area of Tanzania, East Africa, are described. 114 species and 2 subspecies are recognized, of which 51 species and 2 subspecies are new. A new genus, Crenaleya, is proposed. The stratigraphical distribution of the ostracod faunas indicates a close relationship with regional geological events, the faunas becoming less diverse during the Oligocene regression and more diverse during the Miocene transgression. The sedimentation rate deduced from valve/carapace ratios shows a higher rate of sedimentation for the Upper Eocene and Lower Miocene than for the Oligocene. The faunas, in general, are indicative of warm shallow shelf-seas with nearby reefs, with temperatures varying between 10°—25° C and water depths of about 50 m. Three ostracod biozones are recognized; the presence of a deep water fauna in the Lower Miocene of the South Mtwero region is also recorded. The Tanzanian ostracods show affinities with those of India, Pakistan and South Africa; there are a few species in common with the Mediterranean, Caribbean and Indo-Pacific regions. INTRODUCTION The fossil ostracods described in this paper come from the Lindi area, which lies in the Southern Province of Tanzania and is bounded by latitudes 9° 50’ S and 10° 05’ S, and longitudes 39° 40’ E and 39° 45’ E. The position of the area relative to the remainder of coastal East Africa is shown in Fig. 1. Cretaceous to Pliocene marine sediments are known from the area, but the present study is concerned only with those ranging from Upper Eocene to Lower Miocene. These Palacogene beds are in continuity with, or sometimes rest with slight unconformity on, the Upper Cretaceous rocks and have been laid down continuously from late Eocene times into the overlying Oligocene. A small break in deposition during the Chattian was followed by transgression, resulting in widespread deposition of Lower Miocene beds, a wide occurrence recognized by Eames & Kent (1955). The Pliocene is not well known in this area though farther north in the synclinal areas and seaward of the Dar-es-Salaam embay- ment, post-Miocene sediments amount to thousands of feet in thickness. The whole succession dips gently to the ENE, the dip not exceeding 10°. According to Eames et al. (1962), the late Eocene to early Miocene was a time of low tectonic activity and the region seems to have undergone gentle overall subsidence with no apparent violent movement; the whole sequence of Cretaceous—Tertiary sedimentation seems to have been associated with the various cycles of broad gentle warping. Kent (in Burk & Drake 1974) mentions a period of peneplanation, occupying most of the Cretaceous and TERTIARY OSTRACODA FROM THE LINDI AREA, TANZANIA ~ i UGANDA} ¢ He U INDIAN OCEAN TANZANIA Fig. 1 Map of East Africa, showing the position of Lindi. Palaeocene, which was disturbed by activation of the Lindi fault system during Oligocene and early Miocene times. STRATIGRAPHY The marine Cretaceous succession in the Lindi area consists in general of clay with subordinate sandstones and lime- stones. There was no break in deposition between the Cretaceous and the Palaeocene but there was a change in environment. (a) Palaeocene. Outcrops of Palaeocene deposits are numerous but small and frequently disturbed. At the base lies brown sandy detrital limestone followed by a chain of reef- knolls, the lithology of which varies considerably. Formation of reef-knolls was followed by a series of silts, clays and impersistent thin limestones. (b) Upper Eocene. Sandy reef limestones with interbedded layers of soft marly clays lie at the base and are overlain by sandy reef limestones in a series of interbedded buff-grey clays, buff siltstones and thin, hard, sometimes siliceous, foraminiferal limestones. The thickness is estimated to be almost 70 m. (c) Oligocene. Distribution of Oligocene deposits is limited, representing a further stage in the early Tertiary regression. The rocks are generally impersistent, being rubbly and silty limestones, soft marly limestones, buff-grey marly clays and buff silts. The estimated thickness is about 80 m. (d) Lower Miocene. The early Lower Miocene is 179 represented by about 5 m of soft buff silty sandstones, which become increasingly calcareous upwards and contain some lenses of gypsiferous clay. In the area immediately to the east of Lindi Town (Kitunda Cliff) the silty sandstones pass upwards into massive reef limestones, but north of Lindi Bay clays and silts appear to replace part of the limestones. BP-Shell surveys have shown that Lower Miocene beds are brought in on the downthrow side of the Lindi Fault in Lindi Bay, showing evidence of large-scale contemporaneous movement of the fault. At Ras Tapuri a breccia of very large blocks of Miocene limestone is developed 400 m from the easternmost Eocene limestones. PREVIOUS WORK ON TANZANIAN OSTRACODS The earliest description of ostracods from Tanzania was given by Sars (1910), who described 29 Recent species belonging to seven genera, all from the fresh-water Lake Tanganyika. Rome (1962) monographed the Lake Tanganyika fauna, establishing two new genera, one new subgenus and 47 new species. Short papers by Vavra, Klie, Lowndes and others also deal with the Recent ostracods of this general area. Ramsay (1968) described three late Cretaceous species of Cytherelloidea from the Mikaramu Stream, Tanzania. A year later, Bate (in Bate & Bayliss 1969) described 22 new species from Cretaceous sediments and later Bate (1975) described 52 species of which 24 were new, and four new genera, from the Middle Jurassic sediments of Tanzania. The first Tertiary species described from the Lindi area (sample FCRM 1648, Upper Eocene) was Phalcocythere cf. spinosa Siddiqui, com- pared with P. spinosa Siddiqui 1971 from the Upper Eocene of Pakistan. The only other Tertiary ostracod described from Tanzania, the Triebelina cf. howei (Stephenson, 1946) of Keij (1976), is from the mid-Oligocene sample FCRM 1576 and is here regarded as identical with 7. howei from the Caribbean region: see p. 191. SYSTEMATIC DESCRIPTIONS All type and figured specimens mentioned in this paper are deposited in the collections of the Palaeontology Department of the British Museum (Natural History); register number prefix OS. Reference is made to other material held at the BP Research Centre, Sunbury-on-Thames. Subclass OSTRACODA Latreille, 1806 Order PODOCOPIDA Miller, 1894 Suborder PLATYCOPA Sars, 1866 Family CYTHERELLIDAE Sars, 1866 Genus CYTHERELLA Jones, 1849 TYPE SPECIES. Cytherina ovata Roemer, 1840. Cytherella lindiensis sp. nov. Pl. 1, figs 4-9 NAME. After the Lindi area, the type locality in Tanzania. SO [| Mikindani Pliocene HER Marine Pl Lower Miocene Oligocene = Upper Eocene Paleocene & HMI Middle Eo Undifferentiated AHMAD, NEALE & SIDDIQUI Ras Mongo “Ras Tapuri t LINDI BAY Beds. “Db, lol, : ra. Estate iocene i cene 4 Palaeogene —] HLT] Cretaceous “>, Stratigraphic ‘_~ Boundary we or Fault 39°35’ Fig. 2 Geological map of the Lindi area, Tanzania (after Kent et al., 1971). TERTIARY OSTRACODA FROM THE LINDI AREA, TANZANIA 181 aua2d0BI10 1745-46 ® @ 737-38 INDIAN OCEAN e 1574-78 LIND! BA Lower Miocene b e 9 2045-46 5 miles Fig. 3. Sample location map, Lindi, Tanzania. #approx. position only. FCRM 1963 lies off the south-east corner of the map. 182 DIAGNOSIS. A species of Cytherella with females egg-shaped and males subovate in lateral view. Surface completely smooth. Sexual dimorphism pronounced. Ho.orype. A female right valve, OS 8025. Ten paratypes, OS 8026-35. Sample FCRM 2033, Lindi Creek, east shore; Upper Eocene. OTHER MATERIAL. 50 specimens, from FCRM 1711, 2033, 2034, 2045. DESCRIPTION. Carapace medium-sized with greatest width just behind the mid-length and greatest height in the anterior half of the valve. Sexual dimorphism pronounced; presumed females more egg-shaped, males more elongate. Dorsal margin convex, ventral margin slightly concave. Anterior margin broadly rounded, posterior comparatively narrowly rounded. Right valve overlaps left. External lateral surface smooth. Internally, central muscle scars form a pinnate impression with 14 elongate scars in the anterior row and 10 in the posterior; the axis slopes from dorsal to posteroventral in females and is almost perpendicular to the length in males. The scars are at approximately mid-length in males, posterior to mid-length in females. AHMAD, NEALE & SIDDIQUI DIMENSIONS (pm). L H W Holotype, female right valve OS 8025. = 550 +370 170 Paratype, male carapace OS 8027 710 415 275 Paratype, male right valve OS 8026 690 410 170 REMARKS. C. ovata (Roemer, 1840) and C. tumidosa Alexander, 1934 are the closest in shape to C. lindiensis. C. ovata differs in having the anterior and posterior margins more arched; C. tumidosa is larger than C. lindiensis, and has the greatest height posterior to the mid-length. Cytherella mediocalva sp. nov. Pl. 1, figs 1-3 NAME. Latin medio, middle + calvus, bald; with reference to the smooth central area of the valves. DIAGNOsIs. Elongate, subquadrate in lateral view. Dorsal margin gently arched, ventral almost straight. Anterior symmetrically rounded, posterior rather narrowly rounded. Carapace strongly pitted except for an inverted T-shaped smooth central area. HoLotyPe. A carapace, OS 7994. 10 paratypes, OS 7995— 8004. Sample FCRM 1745, Mbanja River; Lower Miocene. OTHER MATERIAL. 28 specimens, from FCRM 1566 (e.g. Raised reef limestone Rubbly sandy coral limestone (Mtanda Hill) Sands and mottled clays with Oyster Bed at base (Mikindani Beds) Massive mostly sandy reef limestone Grey-buff clay with silty limestone and siltstone increasing upwards. Grey-buff clay. Rubbly silty limestones, calcareous siltstones and some clay. Thin hard limestones, clay and silt. Sandy reef limestone. Limestone often laterally impersistent, silt and silty marl. FEET METRES O O Quaternary [en Ga Sa Unconformity Pliocene ca.100ft. ( Unconformity 100 Lower Miocene (500 ft.at west Mtwero but increases rapidly to east) 500 200 Unconformity ~~ —"== a SS Be 6S Ge ss | —— — — | = a Oe ee Oligocene (290ft) ie Ee Se 300 | —_ 1000 a Upper Eocene aa Middle Eocene and Paleocene ea ft.) 1500 Fig. 4 Stratigraphical succession in the Lindi area (from unpublished BP-Shell report, 1957). TERTIARY OSTRACODA FROM THE LINDI AREA, TANZANIA 37° 100 Km 80M Palaeocene Shoreline Oligocene Shoreline Msanga ° 7 INDIAN @ OCEAN 8° Present-day limit of Marine Miocene —— Possible former extent Marine Pliocene Outcrop WOES end-Jurassic peneplain end-Miocene end-Cretaceous peneplain ae penep LAND AREAS Pliocene Regressive gocene/ ransgressive Paleocene Transgressive Faulting Late Cretaceous Trans- Oligocene Regressive gressive Miocene Late Oli Turonian Regressive Albian /Cenomanian Transgressive Faulting - lain uplift erosion Aptian Regressive and often non marine Fig. 5 Tanzania, coastal region. a, positions of early Tertiary shorelines. b, distribution of Neogene rocks. c, geological history of the area. (a, b from Kent et al., 1971; c from Kent, in Burke & Drake 1974.) OS 8005-17), 1746 (e.g. OS 8076-83), 1989 (e.g. OS 8024), 2010 (e.g. OS 8018-24). DESCRIPTION. Shell medium to thick; shape elongate, sub- quadrate to subovate, with greatest height in the middle and widest just behind the mid-length. Sexual dimorphism present, presumed males being more elongate than females. Anterior margin symmetrically rounded, posterior compara- tively narrower but the carapace is thicker here than at the anterior margin. Dorsal margin arched, passing smoothly into anterior and posterior margins; ventral margin almost straight. Right valve larger than left and overlaps it all round. Surface ornamentation consists of circular pits con- centrated in anterior and posterior portions and along ventral 184 KENTS ESTIMATE |VALVE/CARAPACE URATION | nes RATE RATIO AR 5 | 6 YEARS PERIOD | cm/102 YEARS |Valves Carpaces |} 2 4 6 8 100-100 | _ rir aa a i a | 50 PLIO-— PLEISTOCENE MIDDLE MIOCENE Fig. 6 A comparison of the valve/carapace ratio with the sedimentation rate. (Estimated by Kent et al., 1971.) margin. There is a smooth central area in the form of an inverted T. DIMENSIONS (ym). Ie H WwW Holotype, male carapace OS 7994 835 S15 360 REMARKS. C. mediocalva differs from C. cretensis Sissingh 1972 in its dorsal view and in not being pitted over its entire lateral surface. Also, the anterior margin of C. cretensis is more conspicuously raised. C. vandenboldi Sissingh is more quadrate than C. mediocalva and the slope of its postero- dorsal margin is different. Genus CYTHERELLOIDEA Alexander, 1929 TYPE SPECIES. Cythere williamsoniana Jones, 1849. Cytherelloidea gemellata sp. nov. Pl. 2, figs 9-10 NAME. ‘Paired’ or ‘double’, with reference to the pair of longitudinal ridges on the lateral surface. DIAGNOSIS. A species of Cytherelloidea characterized by a strong marginal ridge and two longitudinal ridges running parallel to the dorsal and ventral margins, from the posterior margin to just behind the anterior margin. HOLOTYPE. A carapace, OS 8088. A right valve, OS 8089, is a paratype. No other material. Sample FCRM 2033, Lindi Creek, east shore; Upper Eocene. DESCRIPTION. Carapace medium-sized, subrectangular, with greatest height behind anterior margin and greatest width in PLATE 1 AHMAD, NEALE & SIDDIQUI posterior half. Anterior margin symmetrically rounded, pos- terior not so symmetrical, being obliquely inclined towards the ventral margin. Dorsal margin straight in anterior half, then sloping down posteriorly. Ventral margin slightly con- cave. Right valve overlaps left, the overlap being conspicuous along mid-dorsal and mid-ventral borders. Externally a strong ridge runs along all margins. Two longitudinal ridges, parallel to the dorsal and ventral margins, run from the posterior margin to just before the anterior end. Entire surface finely reticulate. DIMENSIONS (um). L H WwW Holotype, carapace OS 8088 500 280 160 Paratype, right valve OS 8089 540 300 105 REMARKS. The two lateral ridges in C. gemellata are longer than in any other Tanzanian Cytherelloidea species. How- ever, the present species resembles Cytherelloidea sp. B, and it is possible that C. gemellata is the male and Cytherelloidea sp. B the female dimorph of the same species. C. gemellata also resembles C. andersoni and C. wayensis, both described by Sexton (1951); however, the upper ridge in C. andersoni bends at an obtuse angle just before the mid-length, and that of C. wayensis is concave, while the upper ridge of C. gemellata is comparatively straight. Cytherelloidea patagiata sp. nov. Pl. 2, figs 1-4 NAME. ‘Ornamented with a border’. DIAGNOsIS. A species of Cytherelioidea with an almost entire marginal ridge. Two short ridges run from the posterior end towards the middle. Two more short ridges originate from the dorsal margin; the anterior one runs more or less parallel to the anterior margin and the median one runs obliquely towards the middle of the anterior margin. Left valve with a distinct hinge tooth. HootyPe. A male left valve, OS 8085. Two female left valves, OS 8086-7, are paratypes. Sample FCRM 2033, Lindi Creek, east shore; Upper Eocene. No other material. DESCRIPTION. Left valve elongate, subrectangular with great- est height at anterior cardinal angle and greatest width near posterior end. Sexual dimorphism is extremely pronounced, presumed females being swollen ventrolaterally, and males being comparatively slender. Anterior margin symmetrically rounded; posterior rounded in the upper half but obliquely inclined towards ventral border in the lower half. Dorsal margin concave anteriorly but uniformly convex from mid- length to posterior end; ventral margin convex. There are five external ridges; the longest, a strong marginal ridge, runs subperipherally along the anterior margin, becomes peripheral ventrally, is inflated posteriorly and is reduced along the dorsal margin. A short median ridge originates from the inflated posterior end, runs for about one-third of Figs 1-3. Cytherella mediocalva sp. nov. Holotype, male carapace, OS 7994; 1, lateral view from left, 54; 2, lateral view from right, x54; 3, dorsal view, X56. Figs 4-9 Cytherella lindiensis sp. nov. Figs 4-6, holotype, female right valve, OS 8025; 4, muscle scars, X350; 5, external lateral view, x72; 6, internal lateral view, 69. Fig.7, paratype, male carapace, OS 8027, X66. Figs 8, 9, paratype, male right valve, OS 8026; 8, external lateral view, X62; 9, internal lateral view, x64. Figs 10-12 internal lateral view, * 140; 12, internal lateral view, X59. Paranesidea fracticorallicola Maddocks, 1969. Right valve, OS 8114; 10, external lateral view, x57; 11, muscle scar pattern, 185 TERTIARY OSTRACODA FROM THE LINDI AREA, TANZANIA AHMAD, NEALE & SIDDIQUI TERTIARY OSTRACODA FROM THE LINDI AREA, TANZANIA the length and disappears into the ventral swelling. Above this, a slightly longer ridge runs parallel to the dorsal margin, and ends just above the muscle scars. Starting slightly behind mid-length, another ridge runs obliquely from the dorsal margin to slightly in front of the muscle scar pit. The fifth ridge runs along the anterior part of the dorsal margin for a short distance, then bends almost at a right angle ventrally, where it disappears about the middle of the valve. Entire surface reticulate, most of the fossae being secondarily pitted. Fossae more elongate and larger along the free margins than in the central and dorsal areas. Muscle scars visible externally in a depressed area. Line of concrescence, inner margin and marginal zone cannot be differentiated. Muscle scars raised, forming two rows with a central axis between them, in a feather-shaped pattern. There are five scars anterior to the axis, one at the tip, four posterior to the axis and one at the bottom. Hinge adont as in other Cytherelloidea but the selvage of the left valve grows out just behind the anterior end to form a distinct tooth. Keij (1953), van Morkhoven (1963) and Al-Sheikhly (personal discussion) have observed a similar tooth in some Tertiary—Recent species. DIMENSIONS (jum). L H WwW Holotype, male left valve OS 8085 450 260 085 Paratype, female left valve OS 8086 425 250 085 REMARKS. Cytherelloidea patagiata is very similar to C. beck- manni Barbieto-Gonzales (1971: 262; pl. 2, figs 1c, 2c, 3c; pl. 45, figs 14, 15) first reported from Naxos (Cyclades) and later by Sissingh (1972) from Crete (Calabrian age), the differences between the two being in the degree of develop- ment of the ridges. The anterior marginal ridge is stronger in the Tanzanian species, while the lower posterolateral ridge is shorter in C. patagiata than in C. beckmanni. The outline of the posterior margin also differs slightly. Cytherelloidea sp. A Pl. 2, figs 5-8 FIGURED SPECIMEN. A carapace, OS 8084. The only specimen, which is not well preserved. Sample FCRM 2034, Lindi Creek, east shore; Upper Eocene. DESCRIPTION. A Cytherelloidea with a strong rim along the anterior and posterior margins; the entire lateral surface is weakly reticulate. Carapace rectangular, compressed, with greatest width just in front of mid-length. Anterior and posterior margins symmetrically rounded, dorsal margin straight to slightly concave, ventral margin convex. A strong marginal ridge occurs along the anterior and posterior margins; another strong short ridge occurs just in front of the posterior end and parallel to it. No interior details could be seen because there were no single valves. PLATE 2 187 DIMENSIONS (1m). L H W Carapace OS 8084 730 370 170 REMARKS. The present species differs from all other Tanzanian Cytherelloidea in not having any lateral ridges. Cytherelloidea sp. B Pl. 2, figs 11-12; PI. 3, fig. 1 FIGURED SPECIMEN. A carapace, OS 8090. Sample FCRM 2033, Lindi Creek, east shore; Upper Eocene. The only specimen. DESCRIPTION. A species of Cytherelloidea with a compara- tively inflated posterior end, and having a strongly developed marginal rim along the anterior and dorsal margins. Two short parallel ridges run from the posterior to about one- quarter the length; another ridge runs along the mid-dorsal border. Carapace elongate, subrectangular, with greatest height near anterior margin and greatest width near posterior end. Anterior margin symmetrically rounded, with about thirty denticles along the edge; posterior margin inflated. Dorsal margin wavy because of the strong marginal rim, ventral margin straight to very slightly convex. Left valve overlaps right. Surface ornamentation consists of a rounded sub-peripheral ridge running along anterior and dorsal mar- gins. Two short parallel ridges run forward from the inflated posterior margin for about a quarter of the length; another lateral ridge runs along the middle third of the carapace. Entire surface reticulate. DIMENSIONS (1m). L H W Carapace OS 8090 540 270 190 REMARKS. In general shape, Cytherelloidea sp. B resembles Sexton’s (1951) two species C. wayensis and C. andersoni, from the Miocene and Mid-Oligocene of North America. The only difference is that Cytherelloidea sp. B has shorter lateral ridges, which run for only about a third of the length; in fact this feature differentiates this species from all other Cytherelloidea. For more discussion see remarks on C. gemellata, p. 184. Suborder PODOCOPA Sars, 1866 Superfamily BAIRDIACEA Sars, 1888 Family BAIRDIIDAE Sars, 1888 Genus BAIRDIA M‘Coy, 1844 TYPE SPECIES. Bairdia curta M‘Coy, 1844. Bairdia amygdaloides (Brady) oblongata van den Bold, 1946 Pl. 3, fig. 12; Pl. 4, figs 1-3 1946 Bairdia amygdaloides (Brady) var. oblongata van den Bold: 70; pl. 1, fig. 5. Figs 1-4 Cytherelloidea patagiata sp. nov. Figs 1, 2, holotype, male left valve, OS 8085; 1, external lateral view, X 108; 2, internal lateral view, X 105. Figs 3, 4, paratype, female left valve, OS 8086; 3, external lateral view, x 102; 4, muscle scar pattern, external lateral view, <670. Figs 5-8 Cytherelloidea sp. A. Carapace, OS 8084; 5, lateral view from left, <62; 6, details of surface ornamentation, x 700; 7, dorsal view, X62; 8, lateral view from right, x62. Figs 9,10 Cytherelloidea gemellata sp. nov. Holotype, carapace, OS 8088; 9, dorsal view, X93; 10, lateral view from left, x92. Figs 11,12 Cytherelloidea sp. B. Carapace, OS 8090; 11, lateral view from right, X82; 12, dorsal view, X86. See also Pl. 3, fig 1. 188 FIGURED SPECIMENS. A carapace, OS 7925 (FCRM 1578); a right valve, OS 7927 (FCRM 2033). LOCALITIES AND HORIZONS. Sample FCRM 1578, 1628, 1711, 2033; Palaeocene to Middle Oligocene. REMARKS. This species, originally described from the Miocene of Cuba and Guatemala, is widespread in Tanzania. The Tanzanian specimens have a slightly more upturned posterior margin than van den Bold’s material but are otherwise very similar. They also resemble some specimens (BM(NH) In.37118) from the Palaeocene of the Salt Range, Pakistan, named by Latham (1938: text-fig. 1) as Bairdia subdeltoidea (Munster). DIMENSIONS (im). L H WwW Carapace OS 7925. 1045 690 520 Right valve OS 7927. 1050 610 350 Bairdia cf. attenuata Brady, 1880 Pl. 3, fig. 10 cf. 1880 Bairdia attenuata Brady: 59; pl. 11, fig. 3a—c. FIGURED SPECIMEN. A carapace, OS 7934. Sample FCRM 1989, Likonga bridge; Lower Miocene. No other material. REMARKS. The original locality is given as dredgings at depths of 40 fathoms off the reefs at Honolulu, Hawaii, and 155 fathoms at lat. 11° 35’ S, long. 144° 3’ E, in Torres Strait, between Australia and Papua. The Tanzanian specimens have a more acuminate posterior end and are slightly smoother. In this respect they are closer to Bairdoppilata planolata Holden, 1976, but Holden’s species has a more upturned and produced posterior margin. DIMENSIONS (1m). L H WwW Carapace OS 7934. 760 490 370 Bairdia cf. schulzi (Hartmann, 1964) Pl. 4, figs 4, 5 cf. 1964 Triebelina schulzi Hartmann: 44; pls 4, 5, figs 14-22. cf. 1966 Species BA of Maddocks: 47, fig. 2. cf. 1969 Neonesidea schulzi (Hartmann) Maddocks: 20-22. cf. 1976 Neonesidea schulzi (Hartmann); Holden: 12; pl. 7, figs 9-11. FIGURED SPECIMEN. A carapace, OS 7933. Sample FCRM 1989, Likonga bridge; Lower Miocene. OTHER MATERIAL. 14 carapaces, including juveniles, from samples FCRM 2033 (Upper Eocene) and FCRM 1746, 1792, 1989, 2015 (Lower Miocene). REMARKS. The Tanzanian specimens are much smaller, but otherwise compare well with Triebelina schulzi Hartmann from El Salvador, and sp. BA of Maddocks, 1966, from PLATE 3 Fig. 1 Figs 2, 3 Figs 4, 5, 9, 11 AHMAD, NEALE & SIDDIQUI Madagascar. Holden has described the species from the Lower and Upper Miocene of the Midway area, Hawaiian Islands. DIMENSIONS (1m). L H WwW Carapace OS 7933. 590 370 «(315 Genus PARANESIDEA Maddocks 1969 TYPE SPECIES. Paranesidea fracticorallicola Maddocks, 1969. Paranesidea fracticorallicola Maddocks, 1969 Pl. 1, figs 10-12 1969 Paranesidea fracticorallicola Maddocks: 43; pl. 1, figs 5, 6; text-figs 16-18. FIGURED SPECIMEN. A right vaive, OS 8114. Sample FCRM 2033, Lindi Creek, east shore; Upper Eocene. There is one other specimen from the same sample. REMARKS. Maddocks’ species, from the Recent of Nossi-Bé, Madagascar, is larger than the Tanzanian specimens but they are otherwise identical. DIMENSIONS (1m). Ly H WwW Right valve OS 8114 795 430 285 Paranesidea nigrescens (Ruggieri, 1962) __ PI. 3, figs 6-7 1962 Bairdia nigrescens Ruggieri: 11; text-figs 4, 4a; pl. 1, figs 7,8. 1972 Neonesidea nigrescens (Ruggieri) Sissingh: 77; pl. 2, fig. 14. FIGURED SPECIMEN. A carapace, OS 7923. Sample FCRM 2033, Lindi Creek, east shore; Upper Eocene. The only specimen. DIMENSIONS (1m). L H WwW Carapace OS 7923 840 500 480 REMARKS. Ruggieri (1962), who described this species from the Miocene (Tortonian) of central Sicily, placed it in Bairdia. Based on his material from the Early Tortonian Tefeli Formation of central Crete, Sissingh (1972) transferred it to Neonesidea. As the species is coarsely punctate, rotund, and has a tight spiral muscle scar pattern (as illustrated by Ruggieri), it is here transferred to Paranesidea. Paranesidea cf. fortificata (Brady, 1880) Pl. 3, figs 4,5, 9, 11 cf. 1880 Bairdia fortificata Brady: SO. FIGURED SPECIMENS. A left valve, OS 7953, and a carapace, OS 7951; both from FCRM 1989. Cytherelloidea sp. B. Carapace, OS 8090; lateral view from left, x82. See also Pl. 2, figs 11-12. Triebelina howei (Stephenson, 1946). Left valve, OS 7968; 2, external lateral view, X72; 3, internal lateral view, x75. Paranesidea cf. fortificata (Brady, 1880). Figs 4, 5, left valve, OS 7953; 4, external lateral view, x58; 5, internal lateral view, «58. Figs 9, 11, carapace, OS 7951; 9, lateral view from right, 79; 11, dorsal view, x76. Figs 6,7 Paranesidea nigrescens (Ruggieri, 1962). Carapace, OS 7923; 6, lateral view from left, x54; 7, lateral view from right, x55. Fig. 8 Paranesidea sp. A. Carapace, OS 7924; lateral view from right, x60. Fig. 10 Bairdia cf. attenuata Brady, 1880. Carapace, OS 7934; lateral view from right, x58. Fig. 12 Bairdia amygdaloides (Brady) oblongata van den Bold, 1946. Carapace, OS 7925; lateral view from right, x39. See also PI. 4, fig. 1. TERTIARY OSTRACODA FROM THE LINDI AREA, TANZANIA 189 190 AHMAD, NEALE & SIDDIQUI TERTIARY OSTRACODA FROM THE LINDI AREA, TANZANIA OTHER MATERIAL. Eight specimens from samples FCRM 1989 (e.g. OS 7951, 7953); 2033, 2046 (e.g. OS 7952); Upper Eocene to Lower Miocene. DIMENSIONS (1m). L H WwW Left valve OS 7953 690 450 190 Carapace OS 7951 590 350 = 240 REMARKS. The Tanzanian specimens are identical in shape with Brady’s from the Recent of Booby Island, south of New Guinea, but are only slightly more than half the size. Paranesidea sp. A Pl. 3, fig. 8 FIGURED SPECIMEN. A carapace, OS 7924. Sample FCRM 1711, east flank of Kitulo Hill; probably Palaeocene. The only specimen. DESCRIPTION. Carapace subovoid, with the greatest height slightly more than two-thirds of the greatest length. The greatest height lies almost at mid-length whilst the greatest length is subventral. Dorsal margin strongly arched, sloping steeply towards both anterior and posterior margins; ventral margin concave in the middle with convex anteroventral and posteroventral ends. Left valve larger than right and overlaps it all round. Lateral surface finely punctate in the centre to almost smooth along the margins. DIMENSIONS (tm). L H WwW Carapace OS 7924 620 460 360 REMARKS. The Tanzanian specimen strongly resembles Bairdia subdeltoidea (Minster) var. rotunda Alexander, 1927, but the anterior margin is higher and the posterior more produced in that species. Genus TRIEBELINA van den Bold, 1946 TYPE SPECIES. Triebelina indopacifica van den Bold, 1946. Triebelina howei (Stephenson, 1946) Pl. 3, figs 2, 3 1946 Glyptobairdia howei Stephenson: 347; pl. 42, figs 5—6; text-figs 1-2. 1947 Triebelina howei (Stephenson) Stephenson: 578. 1974 Triebelina howei (Stephenson); Poag: 42; pl. 1, fig. 3. cf. 1976 Triebelina howei (Stephenson); Keij: 41-42; pl. 2, figs 8-9. FIGURED SPECIMEN. A left valve, OS 7968. Sample FCRM 1578, coastal cliff west of Ras Tapuri; Middle Oligocene. PLATE 4 19] OTHER MATERIAL. A specimen from sample FCRM 1576. DIMENSIONS (um). L, H W Left valve OS 7968 620 325 180 REMARKS. Keij (1976) also found six valves of this species in sample FCRM 1576, from approximately the same locality as 1578. While comparing his specimens with 7. howei, he remarked that the two are practically identical except that the East African specimens have a much weaker ornamentation. He mentions that, while the ornamentation of the right valves is very similar, there are major differences in the ornamenta- tion of the left valves. The semicircular dorsal carina of the nominal species is absent in his African specimens, except for weak indications of its ends; also, the ventrolateral carina with the flattened triangular area around its mid-length is barely indicated in the African specimens though well devel- oped in those from the Caribbean. He also noted that the length/height ratio was 1-75 for the Caribbean form and 2-0 for the East African. Our left valve does not show any of the differences mentioned by Keij; the ornamentation is as strongly devel- oped as in Caribbean specimens, and the length/height ratio is 1-93. Van den Bold’s figures (1974: pl. 1, figs 5-6) show the ratio of 1-75 for the left valve to 2-0 for the right valve, almost the same as we calculated from Keij’s figures (1976: 41). Keij’s suggestion that the African forms may be older than the American, and have weaker ornamentation because they are closer to the supposed ancestral genus Paranesidea, is therefore not supported. His other conclusion, that Tanzanian specimens demonstrate that Tertiary to Recent shallow-water tropical marine ostracods sometimes had, and have, a wide geographical distribution, remains valid. Superfamily CYTHERACEA Baird, 1850 Family CYTHERIDAE Baird, 1850 Subfamily CYTHERINAE Baird, 1850 Tribe PAIJENBORCHELLINI Deroo, 1966 Genus PALJENBORCHELLA Kingma, 1948 TYPE SPECIES. Paijenborchella iocosa Kingma, 1948. The genus comprises two subgenera, Paijenborchella s. str. and Eopaijenborchella Keij, 1966. Subgenus PALJENBORCHELLA Kingma, 1948 Paijenborchella (Paijenborchella) cf. iocosa Kingma, 1948 PI. 5, fig. 4 cf. 1948 Paijenborchella iocosa Kingma: 86; pl. 8, fig. 12. Figs 1-3 Bairdia amygdaloides oblongata van den Bold, 1946. Fig. 1, carapace, OS 7925; dorsal view, X43; see also PI. 3, fig. 12. Figs 2, 3, right valve, OS 7927; 2, external lateral view, x42; 3, internal lateral view, x43. Figs 4,5 Bairdia ct. schulzi (Hartmann, 1964). Carapace, OS 7933; 4, lateral view from right, x72; 5, lateral view from left, x72. Figs 6-10 = Paijenborchella (Eopaijenborchella) quasimalaiensis sp. noy. Figs 6, 7, paratype, male carapace, OS 7722; 6, lateral view from left, x83; 7, lateral view from right, X85. Figs 8-10, holotype, female carapace, OS 7721; 8, lateral view from left, X93; 9, lateral view from right, x95; 10, dorsal view, x 100. Figs 11,12 © Paijenborchella (Eopaijenborchella) quasimalaiensis dilata subsp. nov. Female? carapace, OS 7733 (specimen lost); 11, lateral view from left, x96; 12, lateral view from right, X97. See also PI. 5, figs 1, 3. 199 FIGURED SPECIMEN. A carapace, OS 7740. Sample FCRM 1566, Mongo Stream, Lindi; Lower Miocene. OTHER MATERIAL. Two specimens: samples FCRM 1738 (right valve, specimen lost); FCRM 1989 (left valve, OS 7739). DIMENSIONS (yum). L H W Carapace OS 7740 550 210 300 REMARKS. Except for the less developed alar spines, and especially the fact that the upper spine is missing, the Tanzanian specimens agree with P. iocosa Kingma. On the other hand, the ventrolateral spine and the lateral, upper, bridge-like ridge are better developed in the Tanzanian speci- mens than in P. solitaria Ruggieri. Probably the Tanzanian specimens represent a form intermediate between the Far Eastern P. iocosa and the Italian P. solitaria. Subgenus EOPAIJENBORCHELLA Keij, 1966 Type species. Paijenborchella lomata Triebel, 1949. Paijenborchella (Eopaijenborchella) quasimalaiensis sp. NOV. Pl. 4, figs 6-10 NAME. Like malaiensis Kingma, 1948. DIAGNOSIS. Species of subgenus Eopaijenborchella with three prominent ridges; the lower two lie in the ventral half, the upper one almost at mid-height of the valve. Median sulcus prominent. Ho.otyPe. A female carapace, OS 7721. Four other speci- mens, OS 7722-5, are paratypes. Sample FCRM 2034, Lindi Creek, east shore; Upper Eocene. OTHER MATERIAL. Three specimens from samples FCRM 2033 (2) and 2034 (OS 7720). DESCRIPTION. Carapace subovate to almost pear-shaped in lateral view. Anterior margin slightly modified by a flange, but otherwise rounded; posterior margin produced into a caudal process. Dorsal margin straight to slightly arched, except for a small constriction above the median sulcus. Ventral margin is strongly modified by the ventral ridges and appears convex in lateral view. Sexual dimorphism present, presumed males being more elongate and slightly less wide than females. The difference can be seen most clearly in dorsal view, when females look distinctly bulbous. Left valve PLATE 5 AHMAD, NEALE & SIDDIQUI overlaps right, the overlap being especially obvious along the dorsal margin. Surface ornament consists of three prominent longitudinal ridges, the most ventral of which is weakly developed and slightly longer than the others. Middle ridge well developed and ends in a short blunt spine; top ridge weakly developed and about the same length as the middle one. Median sulcus well developed, running from the middle ridge to the dorsal margin, with a triangular ridge behind it and a hook-shaped projection in front of it. Inner margin and line of concrescence coincide throughout and run parallel to the outer margin. Marginal pore canals straight, simple and almost equally spaced. Anterior marginal pore canals number about 12; only two could be seen passing through the caudal process. The hinge in the right valve consists of a bifid anterior tooth followed by a coarsely serrated groove termi- nated by a narrow posterior tooth. DIMENSIONS (1m). L H -W Holotype female carapace OS 7721 460 280 260 Paratype male carapace OS 7722 550 290 280 REMARKS. P. malaiensis Kingma, P. cymbula Ruggieri, 1951, and P. geoffreyi Anderson, 1964, are all closely related to this Tanzanian species. The most obvious differences are in the patterns of ornamentation, especially the outlines of the small ridges in the dorsal part; also, the caudal process is shorter in the Tanzanian species than in the others. P. quasimalaiensis differs from both P. cymbula and P. malaiensis in not having a well developed secondary ridge running along the median ridge from the sulcus towards the posterior. Unlike any other Paijenborchella species from Tanzania, this one has three lateral ridges almost equal in length. Paijenborchella (Eopaijenborchella) quasimalaiensis dilata subsp. nov. Pl. 4, figs 11-12; Pl. 5, figs 1-3 NAME. ‘Spread, expanded’, with reference to the two median ridges broadening out towards the posterior. HovotyPe. A male right valve, OS 7732. A female carapace, OS 7733, is a paratype (lost). Sample FCRM 2014, stream SW of Mtwero; Lower Miocene. OTHER MATERIAL. One specimen from sample FCRM 1745. DIMENSIONS (tm). |e H W Holotype, male right valve OS 7732 475 190 120 Female carapace OS 7733 (spec. lost) 465 220 230 REMARKS. The subspecies differs from the typical subspecies in having three subequal longitudinal ridges, the length decreasing from the ventral one to the dorsal. The small kink Figs 1-3 Paijenborchella ( Eopaijenborchella) quasimalaiensis dilata subsp. nov. Figs 1, 3, Female? carapace, OS 7733 (specimen lost); 1, dorsal view, X98; 3, ventral view, X96; see also Pl. 4, figs 11, 12. Fig. 2, holotype, male right valve, OS 7732, external lateral view, x95. Fig. 4 Paijenborchella ( Paijenborchella) cf. iocosa Kingma, 1948. Carapace, OS 7740, slightly oblique lateral view from left, x83. Figs 5-7 Paijenborchella (Eopaijenborchella) disadunca sp. nov. Figs 5, 6, holotype, male right valve, OS 7727; 5, external lateral view, x99; 6, internal lateral view, x 100. Fig. 7, paratype, female right valve, OS 7728, external lateral view, x 100. Figs 8,9 Paijenborchella (Eopaijenborchella) disadunca, Morphotype A. Right valve, OS 7726; 8, external lateral view, x 108; 9, internal lateral view, 110. Figs 10, 11 11, dorsal view, 114. Paijenborchella (Eopaijenborchella) disadunca, Morphotype D. Carapace (juvenile), OS 7731; 10, lateral view from right, x 105; Fig. 12 Paijenborchella (Eopaijenborchella) disadunca, Morphotype B. Carapace OS 7729, lateral view from left, x 114. See also PI. 6, fig. 1. TERTIARY OSTRACODA FROM THE LINDI AREA, TANZANIA 193 194 in the mid-dorsal margin of P. quasimalaiensis s.str. is not present in the subspecies. In dorsal view the males of the subspecies do not widen posteriorly. Paijenborchella (Eopaijenborchella) disadunca sp. nov. PI. 5, figs S—7 NAME. ‘Not hooked’, with reference to the absence of a hook- like ridge in front of the sulcus. DIAGNOSIS. Species of subgenus Eopaijenborchella having a comparatively sharp caudal process and no ridges above the upper longitudinal one. Ho.Loryee. A male right valve, OS 7727. A female right valve, OS 7728, is a paratype. Sample FCRM 1742, Mbanja River; Lower Miocene. OTHER MATERIAL. Five specimens, from samples FCRM 1742 and 1745. DESCRIPTION. Carapace subtriangular to subquadrate in lateral view. Anterior margin symmetrically rounded, posterior pro- duced into a sharp caudal process. Dorsal margin straight, ventral margin obscured by the ventral longitudinal ridge running parallel to it. Surface ornament consists of a sub- central sulcus and three longitudinal ridges. These ridges decrease in length from the ventral to the dorsal one. The upper ridge runs up towards the dorsal margin, the other two run parallel to the long axis. Intercostal areas pitted by numerous pores. DIMENSIONS (1m). L H W Holotype, male right valve OS 7727 455 210 130 Paratype, female right valve OS 7728 440 210 130 REMARKS. This species differs from P. quasimalaiensis only in not having ridges on the dorsolateral surface and in the caudal process being more acutely pointed. Some specimens differ slightly in the number and distribution of pores, and in the arrangement of the longitudinal ridges; these are grouped as four morphotypes. Morphotype A PI. 5, figs 8-9 FIGURED SPECIMEN. A right valve, OS 7726. Sample FCRM 1738, South Mtwero; Lower Miocene. The only specimen. DIMENSIONS (ym). L H WwW Right valve OS 7726 420 235 145 REMARKS. This differs from typical P. disadunca in having the dorsal ridge comparatively strongly developed, diverging away from the lower ridges and ending in a blunt knob. PLATE 6 Fig. 1 Figs 2, 3 3, Male left valve, OS 7736, external lateral view, X98. Figs 4-8 AHMAD, NEALE & SIDDIQUI Pl. 5, fig. 12; Pl. 6, fig. 1 FIGURED SPECIMEN. A carapace, OS 7719. Sample FCRM 1628, Kitunda; Middle Oligocene. The only specimen. Morphotype B DIMENSIONS (um). L H WwW Carapace OS 7719 395 200 185 REMARKS. The three lateral ridges are subparallel rather than divergent. Morphotype B is more densely punctate than any of the others. Morphotype C Pl. 6, figs 2-3 FIGURED SPECIMENS. A female carapace, OS 7730, and a male left valve, OS 7736. Sample FCRM 1742, Mbanja River; Lower Miocene. OTHER MATERIAL. Two specimens, from FCRM 1738 and FCRM 2016. DIMENSIONS (1m). L H W Female carapace OS 7730 415 230 220 Male left valve OS 7736 460 240 150 REMARKS. The upper lateral ridge is shorter and thicker, the median sulcus is deeper and the anterior margin is more symmetrically rounded than in P. disadunca s.str. The pores are concentrically arranged. Morphotype D Pl. 5, figs 10-11 FIGURED SPECIMEN. A juvenile carapace, OS 7731. Sample FCRM 2033, Lindi Creek, east shore; Upper Eocene. The only specimen. DIMENSIONS (1m). L H WwW Carapace OS 7731 395 220 215 REMARKS. The median ridge of morphotype B is not devel- oped in this form and the caudal process is set lower. Family LEPTOCYTHERIDAE Hanai, 1957a Genus LEPTOCYTHERE Sars, 1925 TYPE SPECIES. Cythere pellucida Baird, 1850. Pl. 7, figs 5—11 Leptocythere amoena sp. nov. NAME. ‘Delightful, lovely’, with reference to its beautiful ornamentation. Paijenborchella (Eopaijenborchella) disadunca, Morphotype B. Carapace, OS 7729, dorsal view, X118. See also PI. 5, fig. 12. Paijenborchella ( Eopaijenborchella) disadunca, Morphotype C. Fig. 2, Female carapace, OS 7730, lateral view from left, x 107. Fig. Leptocythere fastigata sp. nov. Fig. 4, holotype, left valve, OS 8132, external lateral view, x 124. Figs 5, 7, paratype, left valve, OS 8134; 5, internal lateral view, x 122; 7, external lateral view, X120. Fig. 6, paratype, right valve, OS 8133, external lateral view, x 110. Fig. 8, right valve, OS 8136, external lateral view, «129. Figs 9-12 Callistocythere jugosa sp. nov. Fig. 9, holotype, right valve, OS 8140, external lateral view, x 135. Figs 10, 11, paratype, left valve, OS 8141; 10, internal lateral view, x 123; 11, external lateral view, x 125. Fig. 12, paratype, carapace, OS 8138, lateral view from right, x 106; see also PI. 7, fig. 1. 195 TERTIARY OSTRACODA FROM THE LINDI AREA, TANZANIA 196 DIAGNOSIS. Elongate, subrectangular, with a beautiful poly- gonal reticulation recalling honeycomb. Anterior and pos- terior with strong marginal rims. Ho.Lorype. A carapace, OS 8150. Two other right valves, OS 8151-2, are paratypes (OS 8152 is broken). Sample FCRM 1578, coastal cliff west of Ras Tapuri; Middle Oligocene. No other material. DESCRIPTION. Carapace medium-sized, subrectangular in lateral view with greatest height at the anterior cardinal angle and greatest width in front of the posterior end. Anterior margin rounded, with a marked anterior cardinal angle; posterior margin subrounded and narrower. Dorsal and ventral margins straight and subparallel, converging very slightly posteriorly. External surface with a beautiful reticula- tion reminiscent of a honeycomb, enclosing a raised central area with a surrounding groove. Along the posterior, antero- dorsal and posteroventral margins there are deeper pits, numbering about nine posteriorly and five along the dorsal half of the anterior margin. There are strong anterior and posterior marginal rims. Eye tubercle very reduced and only present as an opaque spot. Duplicature moderately wide; inner margin very regular and slightly separated from the line of concrescence in the dorsal part of the anterior margin, leaving a narrow vestibule. Selvage very strongly developed, running halfway between inner and outer margins in the right valve; in the left valve it runs slightly nearer to the outer margin in the dorsal half and medially in the ventral half of the anterior margin. Marginal pore canals simple, short and parallel; they number 28-30, mostly concentrated in the anterior and anteroventral regions. Muscle scars consist of four adductor scars and a V-shaped frontal scar. Hinge weakly holamphidont. In the right valve, a small anterior tooth placed on an elongate platform, and an adjacent socket joined by a groove to the small conical posterior tooth. Left valve with complementary elements. DIMENSIONS (um). L H W Holotype, carapace OS 8150 745 345 315 Paratype, right valve OS 8151 600 270 135 Paratype, right valve OS 8152 720 355 160 REMARKS. Some specimens of L. paracastanea Swain 1955 have somewhat similar ornament, lateral outline and margi- nal pore canals, but the Tanzanian species can be easily distinguished by the conspicuous slope of its dorsal margin towards the posterior end. In addition, the anterior and posterior marginal rims do not seem to be present in Swain’s species, which also has a more complicated hinge. Lepto- cythere (Amnicythere) fallax Devoto 1965 has a very similar ornament of polygonal meshes and also a similar outline, but it has a different hinge. PLATE 7 AHMAD, NEALE & SIDDIQUI Leptocythere fastigata sp. nov. Pl. 6, figs 4-8 NAME. ‘Rising to a point’, with reference to its tapering to a point posteriorly. Dr1AGNosis. A small ostracod, subrectangular in side view. Lateral surface coarsely pitted, with a weak posteroventral marginal ridge. HOoLotyPe. A left valve, OS 8132. Three other valves, OS 8133-5, are paratypes. Sample FCRM 1566, Mongo Stream; Lower Miocene. OTHER MATERIAL. Two specimens (OS 8126-7) from FCRM 1989, Lower Miocene. DESCRIPTION. Carapace small, subrectangular, tapering pos- teriorly; highest at the anterior cardinal angle and widest slightly in front of the posterior end. Anterior margin rounded, posterior subrounded in the right valve and obliquely truncate in the left. Ventral margin almost straight, with a concave indentation anterior of mid-length when seen from inside. Dorsal margin straight, making a distinct cardinal angle at the posterior end. External surface coarsely reticu- late, the fossae being larger in the anterior half than in the posterior. A weak marginal ridge is present along pos- terior and posteroventral margins. Internally, margin very narrow; line of concrescence and inner margin coincide except anteriorly, where there is a very narrow vestibule. Normal pores few, coinciding with the ridges of the reticulate ornament externally. Muscle scars cannot be seen; hinge typical of the genus. DIMENSIONS (tim). i H W Holotype, left valve OS 8132 380 180 100 Paratype, left valve OS 8134 370 190 105 Paratype, right valve OS 8133 420 210 115 Right valve OS 8136 360 180 100 REMARKS. The small dimensions of the species, the very narrow duplicature, and the absence of sexual dimorphism suggest that the specimens may not be adult. However, since Leptocythere species tend to be small and the Tanzanian ostracods are rather small anyway, it seems more useful to name it than to leave it under open nomenclature. L. crepidula Ruggieri 1950 resembles the Tanzanian species somewhat, but the coarser reticulation and straight dorsal and ventral margins of L. fastigaia easily differentiate the two. Genus CALLISTOCYTHERE Ruggieri, 1953 TYPE SPECIES. Cythere littoralis Miller, 1894. Figs 14 Callistocythere jugosa sp. nov. Fig. 1, paratype, carapace, OS 8138, dorsal view, x 108; see also PI. 6, fig. 12. Figs 24, carapace, OS 7742; 2, dorsal view, * 129; 3, lateral view from left, x 125; 4, lateral view from right, 128. Figs 5-11 Leptocythere amoena sp. nov. Figs 5-8, holotype, carapace, OS 8150; 5, lateral view from left, x62; 6, lateral view from right, x61; 7, dorsal view, X64; 8, details of surface ornament, <300. Figs 9, 11, paratype, right valve, OS 8151; 9, internal lateral view, X77; 11, dorsal view, X75. Fig. 10, paratype, right valve (broken), OS 8152, internal lateral view, x65. Fig. 12 Tanella sp. B. Carapace, OS 8126, lateral view from left, x 105. TERTIARY OSTRACODA FROM THE LINDI AREA, TANZANIA 197 198 Callistocythere jugosa sp. nov. PI. 6, figs 9-12; Pl. 7, figs 14 NAME. ‘Full of ridges’, in reference to the many ridges on the lateral surface. DIAGNOSIS. A species of Callistocythere with the lateral surface covered with undulating ridges; an anteroventral and another posteroventral ridge extend along the margins and slightly modify the lateral outline of the valves. HooryPe. A right valve, OS 8140. Five paratypes, OS 8141-S. Sample FCRM 1989, Likonga bridge; Lower Miocene. OTHER MATERIAL. Ten specimens, including OS 7742 (FCRM 1575), pl. 7, figs 2-4, and OS 8138-9 (FCRM 1566). The latter are indicated as ‘A’ in Table 1, p. 260. Also occurs in FCRM 1575. DESCRIPTION. Carapace small, subquadrate in lateral view, and highest anteriorly. Anterior margin rounded, posterior comparatively narrower. Dorsal margin, modified by the marginal ridge, is straight to slightly arched; ventral margin straight to slightly convex in internal view. In dorsal view, carapace almost lens-shaped. Left valve slightly larger than right but overlap inconspicuous. External surface covered with strong knotty ridges, elongated along the margins. The anteroventral ridge originates near the anterior cardinal angle, follows the anterior margin, then runs along the ventral margin as far as the middle, where it turns upwards and merges into other small posterior ridges. Posterodorsal ridge runs from the posteroventral area towards posterior and dorsal margins, curving slightly behind the anterior margin and ending just above the anteroventral area. The smaller lateral ridges are distributed haphazardly; no particular pattern could be observed. Eye tubercle absent. Duplicature moderately wide along the anterior and posteroventral mar- gins; line of concrescence and inner margin coincide except in upper half of anterior margin, where there is a narrow vestibule. Selvage runs parallel to outer margins except anteriorly, where they coincide. Hinge in left valve consists of an anterior socket, followed by three individual small teeth and a crenulate bar with another socket posteriorly. DIMENSIONS (ym). E H W Holotype, right valve OS 8140 340 180 095 Paratype, left valve OS 8141 365 200 080 Carapace OS 8138 425 235 195 Carapace OS 7742 360 200 145 REMARKS. There is a single carapace (OS 7742) from FCRM 1575 (Mid-Oligocene) which is more rectangular and has slightly different ornament, but is morphologically identi- cal with this species. Some other specimens with reduced ridges are classified as Morphotype A. Leptocythere kiata Hornibrook 1953 has a very similar outline and ornament, but PLATE 8 AHMAD, NEALE & SIDDIQUI its truncated posterior margin and slightly different distribu- tion of ridges easily distinguish it. L. cranekeyensis Puri 1960 has marginal denticles, a tuberculate posterior rim and very low ridges compared with C. jugosa. The Tanzanian species differs from C. nipponica Hanai 1957a in not having the second marginal rim and in being much smaller. Genus TANELLA Kingma, 1948 TYPE SPECIES. Tanella gracilis Kingma, 1948. Tanella sp. A Pl. 8, figs 1-3 FIGURED SPECIMENS. A right valve, OS 8131; a left valve, OS 8127. Sample FCRM 1661, near top of old garnet mine, north Lindi; Lower Miocene. The only material. DESCRIPTION. Valves small, elongate in side view, ovate with greatest height in the middle. Dorsal margin gently convex, anterior symmetrically rounded, posterior very slightly curved in below. Ventral margin slightly concave before mid-length. External surface reticulate with fossae of varying shapes; muri mostly arranged longitudinally. Reticulation very faint along posterior, posteroventral and anterodorsal margins. Eye spot absent. Duplicature moderately wide; line of con- crescence and inner margin separate anteriorly to form a very narrow vestibule. There are four adductor muscle scars and a U-shaped frontal scar. Hinge of right valve consists of a bar thickening at the anterior end to form a low anterior tooth and at the posterior end to give a better-developed posterior tooth. Left valve with complementary elements. DIMENSIONS (1m). 1B H W Right valve OS 8131 380 170 090 Left valve OS 8127 400 205 090 Tanella sp. B Pls7, fig. 12 FIGURED SPECIMEN. A carapace, OS 8126. Sample FCRM 1661, near top of old garnet mine, north Lindi; Lower Miocene. The only specimen. DESCRIPTION. Elongate-ovate in side view, with greatest height in middle. Dorsal margin convex, anterior symmetri- cally rounded; posterior with marked cardinal angle and rounded posteroventrally; ventral margin concave in anterior half. Surface finely reticulate with low longitudinal ridges. Eye spot absent. No internal features were seen because there were no single valves. DIMENSIONS (jim). L H WwW Carapace OS 8126 435 195 190 Figs 1-3 Tanella sp. A. Fig. 1, Left valve, OS 8127, internal lateral view, x 113. Figs 2, 3, right valve, OS 8131; 2, external lateral view, x 145; 3, internal lateral view, 145. Figs 4-7 Krithe liebaui sp. nov. Fig. 4, paratype, female right valve, OS 8161, external lateral view, x65. Fig. 5, holotype, female left valve, OS 8322, external lateral view, x60. Fig. 6, paratype, male right valve, OS 8323, external lateral view, X70. Fig. 7, paratype, male left valve, OS 8324, external lateral view, x60; see also PI. 9, fig. 9 (slightly more oblique view). Figs 8-11 Krithe medioelata sp. nov. Figs 8, 9, holotype, carapace, OS 8166; 8, lateral view from left, x54; 9, lateral view from right, x55. Figs 10, 11, paratype, carapace, OS 8167; 10, lateral view from right, x58; 11, dorsal view, x59. Fig. 12 Krithe burdigalia sp. nov. Paratype, female carapace, OS 8164, lateral view from left, x60. See also PI. 9, fig. 1. TERTIARY OSTRACODA FROM THE LINDI AREA, TANZANIA 199 AHMAD, NEALE & SIDDIQUI TERTIARY OSTRACODA FROM THE LINDI AREA, TANZANIA Family CYTHERIDEIDAE Sars, 1925 Subfamily CYTHERIDEINAE Sars, 1925 Genus CLITHROCYTHERIDEA Stephenson, 1936 TYPE SPECIES. Cytheridea garretti Howe & Chambers, 1935. Clithrocytheridea? semiluna sp. nov. PI. 9, figs 11, 12; PI. 10, figs 1, 2 NAME. ‘Half moon’. DIAGNOsIs. A more or less egg-shaped species of Clithro- cytheridea? with carapace inflated ventrally; ventral surface almost flat with four longitudinal ridges in each valve. HoLortyPe. A carapace, OS 8154. Four paratypes, OS 8155-8. Sample FCRM 2033, Lindi Creek, east shore; Upper Eocene. OTHER MATERIAL. Three specimens from the same sample. Also occurs in FCRM 2045. DESCRIPTION. Carapace egg-shaped in lateral view, with greatest height almost in the middle and greatest width in the mid-ventral half. Anterior and posterior margins almost continuous with dorsal, each junction being marked by a slight angle. Dorsal margin symmetrically and broadly curved in front but sloping and almost straight posteriorly. Ventral margin straight to slightly concave in the middle while the ventrolateral surface is strongly concave. Lateral surface weakly reticulate. A thin, flexuous, sharply defined longitu- dinal ridge defines the boundary between the lateral and flattened ventral surfaces; the ventral ridge nearest to this is single anteriorly, dividing into two about mid-length; the next is single posteriorly, bifurcating towards the front. There are several more ridges on the ventral surface. Internally, the right hinge consists of crenulate anterior and posterior tooth plates separated by a smooth bar which has a distinct accommodation groove dorsal to it. Other internal features cannot be seen clearly. DIMENSIONS (1m). Cs Eas Holotype, carapace OS 8154 405-220 250 Paratype, right valve OS 8155 330 175 130 REMARKS. This Tanzanian species probably does not truly belong to Clithrocytheridea and may in fact represent a new genus. It is provisionally placed in it, however, because it resembles that genus in hinge details and general outline. It differs in the outline of its arched dorsal margin and in having ventral ridges; the muscle scars and other internal features are unknown. PLATE 9 201 Genus ROSTROCYTHERIDEA Dingle, 1969a TYPE SPECIES. Rostrocytheridea chapmani Dingle, 1969a. Rostrocytheridea? sp. Pl. 10, figs 3, 4 FIGURED SPECIMEN. A right valve, OS 7915. Sample FCRM 2033, Lindi Creek, east shore; Upper Eocene. OTHER MATERIAL. Two valves (e.g. OS 7914) from the same sample. DESCRIPTION. Right valve subovate to egg-shaped in outline, with greatest height equal to slightly more than half the length. Anterior margin symmetrically rounded, posterior incurved below. Dorsal margin convex, sloping both an- teriorly and posteriorly from the greatest height, which is about two-fifths the length from the anterior margin. Ventral margin convex. Lateral surface smooth except for some punctation, mostly concentrated above the centre. Internally, marginal pore canals, muscle scars and hinge are typical of the genus. DIMENSIONS (ym). L H W Right valve OS 7915 410 260 140 REMARKS. This Tanzanian species does not belong to Rostro- cytheridea s. str. but shows an evolutionary intermediate stage between the Cretaceous genus Rostrocytheridea, with a pointed posterior margin, and the Miocene—Recent Cyprideis, with almost equally rounded posterior and anterior margins. Family KRITHIDAE Brady, Crosskey & Robertson, 1874 Subfamily KRITHINAE Mandelstam, 1960 Genus KRITHE Brady, Crosskey & Robertson, 1874 TYPE SPECIES. [lyobates praetexta Sars, 1866. Krithe burdigalia sp. nov. PI. 8, fig. 12; Pl. 9, figs 1-3 NAME. A reference to its occurrence in the Burdigalian (Lower Miocene). DIAGNosIs. A species of Krithe with marked sexual dimor- phism. Presumed males subrectangular in lateral view; females are slightly higher behind the middle. Ho.otyre. A male carapace, OS 8163. Two female cara- paces, OS 8164-5, are paratypes. Sample FCRM 1989, Likonga bridge; Lower Miocene. OTHER MATERIAL. Four specimens from the same sample. Figs 1-3 Krithe burdigalia sp. nov. Fig. 1, paratype, female carapace, OS 8164, dorsal view, x60; see also PI. 8, fig. 12. Figs 2, 3, holotype, male carapace, OS 8163; 2, lateral view from left, x60; 3, dorsal view, X61. Figs 46 Ommatokrithe prolata Ahmad, 1977d. Figs 4, 6, holotype, female left valve, OS 7768; 4, external lateral view, X59; 6, internal lateral view, X59. Fig. 5, paratype, male left valve, OS 7769, external lateral view, x59. Fig. 7 Parakrithe cicatricosa sp. nov. Holotype, female left valve, OS 8168, external lateral view, X86. Figs 8-10 Krithe liebaui sp. nov. Figs 8, 10, paratype, male left valve, OS 8326; 8, external lateral view, X61; 10, internal lateral view, x62. Fig. 9, paratype, male left valve, OS 8324, external lateral view, X61; see also PI. 8, fig. 7. Figs 11,12 Clithrocytheridea? semiluna sp. nov. Paratype, right valve, OS 8155; 11, external lateral view, x 136; 12, internal lateral view, x 138. 202 DESCRIPTION. Sexual dimorphism marked; presumed male almost rectangular, with dorsal and ventral margins parallel, female trapezoidal, being higher and wider behind the middle. Females are also comparatively wider throughout than males. Anterior margin in both sexes symmetrically rounded; posterior margin meets the ventral margin abruptly but is continuous with it and forms part of the posterodorsal curve. Posterior end incised in dorsal view. Left valve over- laps right. Internal features typical of genus; duplicature not well developed and marginal pore canals not easy to see. DIMENSIONS (1m). L H WwW Holotype, male carapace OS 8163 745 320 280 Paratype, female carapace OS 8164 745 375 345 REMARKS. K. burdigalia looks very similar to K. liebaui but the two can be separated readily; the presumed females of K. burdigalia are higher behind mid-length, and the presumed males are not very slender, in both ways being different from K. liebaut. Krithe liebaui sp. nov. PI. 8, figs 4-7; Pl. 9, figs 8-10; Fig. 7a NAME. In honour of Dr Alexander Liebau. DIAGNOSIS. A species of Krithe with thirteen marginal pore canals along the anterior and three along the mid-ventral margin. There is marked sexual dimorphism. HOLortyPe. A female left valve, OS 8322. Four paratypes, OS 8161, 8323, 8324, 8326. Sample FCRM 1737, South Mtwero; Lower Miocene. OTHER MATERIAL. Seventeen complete specimens and 15 broken ones, from the same sample. Also occurs in FCRM 1738, 1742. DESCRIPTION. Shape of carapace depends on sex of specimen; right valves of presumed males slender and subtriangular with greatest height at the anterior cardinal angle. Right valves in females have the greatest height in the middle; female left valves have dorsal and ventral margins almost straight and parallel. Anterior margins rounded in both sexes; posterior margins acutely angled in lateral view and incised in dorsal view. Surface smooth. Internally, duplicature broad; line of concrescence and inner margin separated, forming a com- paratively wide anterior vestibule. Inner margin U-shaped and slightly broader towards the front. Selvage runs peri- pherally except at the posterior margin, where it runs well inside the lateral outline, giving the posterior an indented appearance. Seen from inside, the posterior margin is divided into two compartments. Marginal pore canals, about thirteen anteriorly and three ventrally, are mostly simple and more or less straight; for descriptive purposes they are numbered. MPC 1' is false and is the only one running in the dorsal half of the anterior margin. MPC 2 and 3 have a common origin and in some specimens do not separate until mid-length. PLATE 10 AHMAD, NEALE & SIDDIQUI Fig. 7 Krithidae. Internal lateral views showing nature of marginal pore canals and muscle scar patterns. a, Krithe liebaui sp. nov. Paratype, @ right valve OS 8161. 120. b, Ommatokrithe prolata Ahmad. Holotype, @ left valve OS 7768. x 100. c, Parakrithe cicatricosa sp. nov. Paratype, 2 right valve OS 8169. x 150. DIMENSIONS (1m). L H W Holotype, female left valve OS 8322 750 375 190 Paratype, male right vaive OS 8323 760 320 150 Paratype, male left valve OS 8324 755 370 190 Paratype, male left valve OS 8326 745 380 195 Paratype, female right valve OS 8161 705 345 170 REMARKS. K. cubensis van den Bold 1946 has more numerous marginal pore canals in the dorsal half of the anterior margin and along the posterior margin. In general shape and margi- nal pore canal pattern, K. dolichodeira van den Bold 1946, from the Miocene of the Caribbean region, resembles K. liebaui, but K. dolichodeira has shorter marginal pore canals and is also smaller; it has a length of about 560 um compared with over 700 um for K. liebaui. K. hiwanneensis Howe & Figs 1,2 Clithrocytheridea? semiluna sp. nov. Holotype, carapace, OS 8154; 1, lateral view from left, x 109; 2, dorsal view, 109. Figs 3,4 Rostrocytheridea? sp. Right valve, OS 7915; 3, external lateral view, *95; 4, internal lateral view, x 100. Figs S-9 Trachyleberis duplex sp. nov. Figs 5, 6, holotype, left valve, OS 7834; 5, dorsal view, X56; 6, external lateral view, X56. Figs 7-9, paratype, right valve, OS 7833; 7, external lateral view, 48; 8, dorsal view, x47; 9, internal lateral view, x48. Figs 10-12. Gujaratella? tanzaniensis sp. nov. Holotype, left valve, OS 7835; 10, internal lateral view, x89; 11, external lateral view, x86; 12, dorsal view, X88. TERTIARY OSTRACODA FROM THE LINDI AREA, TANZANIA 203 204 AHMAD, NEALE & SIDDIQUI TERTIARY OSTRACODA FROM THE LINDI AREA, TANZANIA Lea (in Howe & Law 1936) has shorter marginal pore canals. K. perattica Alexander 1934 resembles K. liebaui in general shape and in having the ends of the marginal pore canals thickened; however, the latter has marginal pore canals concentrated along the anterior margin while the former has them distributed all along the ventral and posterior margins. K. sawanensis Hanai 1959, from the Upper Pliocene of Japan, is easily distinguished from the Tanzanian species by its larger size, greater number of false marginal pore canals inter- spersed between true ones, and less pronounced sexual dimorphism. Krithe medioelata sp. nov. Pl. 8, figs 8-11 NAME. ‘Highest in the middle’. DIAGNOSIS. A species of Krithe with the greatest height in the middle or slightly in front of it. Dorsal margin strongly arched. HOLotyPe. A carapace, OS 8166. A carapace, OS 8167, is a paratype. Sample FCRM 2034, Lindi Creek, east shore; Upper Eocene. OTHER MATERIAL. Three specimens from the same sample. DESCRIPTION. Carapace subovate in lateral view with the greatest height slightly in front of the middle and greatest width almost at mid-length. Anterior margin rounded, dorsal strongly arched, ventral margin almost straight. Carapace lens-shaped in dorsal view, with a strongly incised posterior margin. No sexual dimorphism apparent. Left valve overlaps right. Lateral surface smooth, eye tubercle absent. Internal features typical of the genus; marginal pore canals not visible in the only single valve found intact. DIMENSIONS (ym). L H W Holotype, carapace OS 8166 820 435 390 Paratype, carapace OS 8167 790 425 375 REMARKS. K. echolsae Esker 1968, from the Danian of Tunisia, has a curved posterodorsal margin compared with the sloping margin of K. medioelata. K. whitecliffensis Crane 1965, K. rutoti Keij 1957, K. cubensis van den Bold 1946, K. contracta Oertli 1961, K. langhiana Oertli 1961, K. galei Crouch 1949, and some other species with similar outlines can be distinguished from K. medioelata by the fact that their greatest height in lateral view is behind the middle rather than in front of it as in the Tanzanian species. Genus OMMATOKRITHE Ahmad, 1977d TYPE SPECIES. Ommatokrithe prolata Ahmad, 1977d. Ommatokrithe prolata Ahmad, 1977d Pl. 9, figs 4-6; Fig. 7b 1977d Ommatokrithe prolata Ahmad: 131-134. PLATE 11 205 HOLOTYPE. A female left valve, OS 7768. Paratypes, three single valves, OS 7769-71. Sample FCRM 1737, South Mtwero; Lower Miocene. OTHER MATERIAL. Four single valves from the same sample. Also occurs in FCRM 1738. DESCRIPTION. Carapace clongate, subrectangular in lateral view, with dorsal and ventral margins straight and parallel; anterior margin rounded, posterior obliquely truncate. Pos- terior incised in dorsal view; posterior end divided into two compartments internally, behind the selvage. Lateral surface smooth except for a glassy round eye-tubercle just below anterior cardinal angle. Internally, duplicature wide. Inner margin and line of concrescence separated in the mid-anterior region, where there is a moderately wide vestibule. Inner margin extends anteriorly for a considerable distance; margi- nal pore canals are therefore short; for descriptive purposes they are numbered. MPC 1 occurs in the dorsal half and is long; MPC 2 and 3 bifurcate from a common canal; 4 to 12 are short, straight and parallel; 13 is elongate and curves towards the front; 14 runs along the inner margin; the ventral canals 15 to 17 occur along the midventral margin, MPC 16 being false. Normal pores large, sieve type and regularly distri- buted. Muscle scar pattern consists of four adductor scars decreasing in size from top to bottom, with a three-fold frontal scar and five to seven dorsal ones. Hinge adont, partly crenulate in the posterior quarter. DIMENSIONS (1m). L H W Holotype, female left valve OS 7768 785 375 170 Paratype, male left valve OS 7769 780 365 175 REMARKS. So far, no other Krithidae species with an eye tubercle has been described. Genus PARAKRITHE van den Bold, 1958a TYPE SPECIES. Cytheridea (Dolocytheridea) vermunti van den Bold, 1946. Parakrithe cicatricosa sp. nov. Pl. 9, fig. 7; Fig. 7c NAME. ‘Scarred’, in reference to the large number of dorsal muscle scars. DIAGNOsIS. A species of Parakrithe with a large number of dorsal muscle scars, and 16 anterior marginal pore canals, about half of which are false. Sexual dimorphism present. HoLotyre. A female left valve, OS 8168. Paratype a female right valve, OS 8169. Sample FCRM 1737, South Mtwero; Lower Miocene. OTHER MATERIAL. 48 specimens from samples FCRM 1737, 1738, 1742, 1989, 2014, 2016. DESCRIPTION. Carapace small, elongate, and subrectangular to subovate in lateral view. Anterior margin symmetrically rounded, posterior subrounded, rather broadly curved in the Figs 1-3. Carinocythereis sp. Carapace, OS 7991; 1, lateral view from right, X71; 2, dorsal view, x70; 3, lateral view from left, x71. Figs 46 Genus B sp. Left valve, OS 8113; 4, external lateral view, X74; 5, dorsal view, X79; 6, internal lateral view, x74. Figs 7-12 Occultocythereis africana sp. nov. Figs 7, 11, paratype, female left valve, OS 7974; 7, external lateral view, X89; 11, internal lateral view, X92. Figs 8, 12, paratype, female right valve, OS 7972; 8, internal lateral view, X91; 12, external lateral view, X89. Figs 9, 10, holotype, female carapace, OS 7976; 9, lateral view from left, x 107; 10, lateral view from right, x 107. 206 upper half and narrowly curved in the lower. Sexual dimor- phism occurs; dorsal and ventral margins diverge posteriorly in presumed females but are almost parallel in presumed males. Lateral surface smooth and without an eye tubercle. Internally, duplicature moderately wide, with a fairly wide anterior vestibule. About 30 straight marginal pore canals, 16 of them along the anterior margin, where true marginal pore canals are interspersed with false ones. Muscle scar pattern consists of four adductor scars arranged in a vertical row, with an elongate scar in front and seven to eight dorsal scars. Normal pores large, sieve type and widely scattered. DIMENSIONS (um). L H WwW Holotype, female left valve OS 8168 520 260 140 REMARKS. A large number of carapaces from places other than the type locality are almost identical in outline but it was not possible to see their marginal pore canals. These speci- mens are tentatively classified as P. cicatricosa. Family TRACHYLEBERIDIDAE Syvester-Bradley, 1948 Subfamily TRACHYLEBERIDINAE Sylvester-Bradley, 1948 Tribe TRACHYLEBERIDINI Sylvester-Bradley, 1948 Genus TRACHYLEBERIS Brady, 1898 TYPE SPECIES. Cythere scabrocuneata Brady, 1880. Trachyleberis duplex sp. nov. Pl. 10, figs S—9 NAME. ‘Double’, with reference to anterior and ventral spines occurring in pairs. DIAGNOsIS. A species of Trachyleberis with a double row of spines along the anterior margin and another along the ventral margin. Anterior cardinal angle well marked. HoLotyPe. A female left valve, OS 7834. Paratype a male right valve, OS 7833. Sample FCRM 2010, stream south-west of Mtwero; Lower Miocene. No other material. DESCRIPTION. Carapace elongate in side view, greatest length at mid-height and greatest height at anterior cardinal angle. Anterior margin evenly rounded, a double row of spines following the curve; outer spines smaller and more numerous than inner ones, evenly spaced and well developed. Posterior margin triangular, with spines, mostly bifid. Dorsal margin straight, with a row of spines, also mostly bifid. Ventral margin straight or slightly curved, with a double row of spines. Surface spiny, especially medially, where there is a scattered row, usually arranged in a zigzag way. Eye tubercle with a strong spine just behind it. Inner margin and line of concrescence coincide; hinge holamphidont. Other internal features typical of genus. DIMENSIONS (um). L H W Holotype, female left valve OS 7834 815 465 240 Paratype, male right valve OS 7833 955. 475 240 REMARKS. The pattern of ornament is similar to that of T. pennyi Neale 1975 from the Santonian of Western Australia, PLATE 12 AHMAD, NEALE & SIDDIQUI but in side view the Tanzanian species has a more triangular posterior end and strongly projecting anterodorsal margin. It is also larger than 7. pennyi. Genus GUJARATELLA Khosla, 1978 TYPE SPECIES. Gujaratella boldi Khosla, 1978. Gujaratella? tanzaniensis sp. nov. Pl. 10, figs 10-12 NAME. ‘From Tanzania’. Dr1AGnosis. A tuberculate species with reduced anterior denticulation and no spines, but with a well developed anterior vestibule. Ho otyPe. A female left valve, OS 7835. Paratype a female left valve, OS 7837. Sample FCRM 2010, stream south-west of Mtwero; Lower Miocene. The only surviving specimens, but see ‘Remarks’ below. DESCRIPTION. Carapace shape determined by sexual dimor- phism; in side view presumed males are elongate, subrectan- gular, with a straight dorsal margin and a straight or slightly concave ventral margin, these two margins converging pos- teriorly. Female has dorsal margin slightly arched, subparallel to ventral margin. Anterior margin evenly rounded, posterior rather produced below, and the posterodorsal margin slightly concave. Greatest height at the anterior cardinal angle and greatest length along ventral side. External surface tubercu- late. Eye tubercle elongate, running into the anterior margi- nal rim, which consists of a semicircular double line of tubercular spines joined to each other so as to form semicircu- lar enclosures open towards the front. Subcentral tubercle an elongated swollen boss. Anteroventral complex consists of three or four tubercles joined together and merging into a thin ventral ridge with another thin ridge below. Other ubercles, of various sizes, have normal pore canals opening at their tips. Internally, duplicature moderately wide, inner margin and line of concrescence separate; there is a fairly wide vestibule. Selvage placed almost at the middle of the duplicature, well developed and following a sinuous course along the ventral margin. Muscle scars cannot be seen clearly. Hinge of right valve consists of an anterior tooth with distal part low and proximal part higher; median groove crenulate and posterior tooth slightly elongate and smooth. Immedi- ately below and in front of the anterior hinge tooth there is a prominent ocular sinus. Hinge of left valve complementary to that of right. DIMENSIONS (1m). L, H.-W Holotype, female left valve OS 7835 515 285 140 REMARKS. Unfortunately it has not been possible to figure the one male specimen of this species that was found, because of its fragility. The species is provisionally placed in the genus Figs 1-12. Leguminocythereis dinglei sp. nov. Figs 1, 2, paratype, male carapace, OS 8195; 1, lateral view from right, 55; 2, dorsal view, X57. Fig. 3, paratype, male carapace, OS 8196, lateral view from left, x60. Figs 4-6, holotype, female carapace, OS 8194; 4, lateral view from left, «57:5, lateral view from right, x54; 6, dorsal view, X55. Figs 7-9, paratype, female left valve, OS 8198; 7, external lateral view, X58; 8, internal lateral view, 57; 9, dorsal view, X58. Figs 10, 11, paratype, male carapace, OS 8199; 10, lateral view from right, x48; 11, dorsal view, X46. Fig. 12, paratype, juvenile? left valve, OS 8200, external lateral view, x67. TERTIARY OSTRACODA FROM THE LINDI AREA, TANZANIA 207 208 AHMAD, NEALE & SIDDIQUI TERTIARY OSTRACODA FROM THE LINDI AREA, TANZANIA Gujaratella because of its external appearance, although it has a distinct anterior vestibule not found in that genus. The muscle scars and marginal pore canals were not clearly observed in this material. Genus HAUGHTONILEBERIS Dingle, 1969b TYPE SPECIES. H. haughtoni Dingle, 1969b. Haughtonileberis radiata Dingle 1976 Pl. 13, figs 1-2 1976 Haughtonileberis radiatus (sic, recte radiata) Dingle: 46. 1976 Leguminocythereis? sp. 1 of Dingle: 44; fig. 6 (a, b); fig. 10 (23). FIGURED SPECIMEN. A female carapace, OS 8174. Sample FCRM 1578, coastal cliff west of Ras Tapuri; Middle Oligocene. OTHER MATERIAL. One right valve (OS 7810), also from FCRM 1578. Also occurs in FCRM 1576. DIMENSIONS (1m). L H WwW Female carapace OS 8174 895 435 380 REMARKS. Originally described from the Upper Oligocene— Upper Eocene of borehole SOEKOR JC-I off the coast of Natal, South Africa. The species described as Legumino- cythereis? sp. 1 by Dingle in the same paper is, in the present authors’ view, a female dimorph of H. radiata. Haughtonileberis rastapuriensis sp. nov. PI. 13, figs 3-6 NAME. After the type locality, Ras Tapuri. DIAGNOsIS. A species of Haughtonileberis with a prominent dorsal ridge curving towards, but stopping short of, the median ridge, which bifurcates in the anterior half of the valve. There are two ventrolateral ridges joined at their posterior ends, and an ocular ridge along the anterodorsal margin. HOLoTyPE. A male carapace, OS 7802. Two paratypes, OS 7803, OS 7804. Sample FCRM 1575, shore south-west of Ras Tapuri; Middle Oligocene. OTHER MATERIAL. Six specimens in the BM(NH) from the same sample, including OS 7807. Another 20 specimens from FCRM 2010, Lower Miocene, are kept at the BP Research Centre, Sunbury-on-Thames. Also occurs in FCRM 1574, 1576 and 1578. DESCRIPTION. Carapace medium-sized, elongate in side view, tapering posteriorly, with greatest height at anterior cardinal angle. Anterior margin rounded, dorsal margin straight and PLATE 13 209 sloping towards posterior. Ventral margin straight to slightly concave; posteroventral margin convex and posterodorsal concave. Sexes distinct, presumed males being slightly more slender and elongated than presumed females. External ornament consists of a series of ridges. There is a dorsal ridge, slightly concave downward, in the anterior half; a median ridge, bifid in the anterior part and curved dorsally at the posterior end in some specimens; a pair of ventrolateral ridges joined at their posterior ends; and an ocular ridge running along the anterodorsal margin. Two short ridges lie between the dorsal and median ones, and another two lie ventral to the ventrolateral ridges; of these last, one is short and lies in the middle third, while the other, longer, lies in the anterior half of the length. Duplicature fairly wide; marginal pore canals fine, straight and simple; there are 10 or 11 anteriorly and 6 or 7 posteriorly, the latter tending to occur in pairs. There are four adductor muscle scars in a vertical! row, decreasing in size from dorsal to ventral; the two uppermost join at their posterior ends; and there is a V-shaped frontal scar which opens upwards. Hinge typical of genus, consisting of an anterior tooth, a small postjacent socket, a crenulate groove in the median section and a round knob-like posterior tooth in the right valve. DIMENSIONS (pm). L, H WwW Holotype, male carapace OS 7802 735 305 = =240 Paratype, female carapace OS 7803 700 310 250 REMARKS. The Lower Miocene specimens (FCRM 2010) are comparatively large (L = 800 um), and have slightly less ornamentation, but otherwise seem to be the same species as H. rastapuriensis; they and the Mid-Oligocene specimens are therefore included in that species. It was difficult to decide whether H. rastapuriensis should be a new species, a sub- species or a morphotype of H. fissilis Dingle 1969b. The two are extremely close in general shape, ornament and other features. However, the Tanzanian species is larger and has two ventrolateral ridges instead of the single ridge of the South African species. The two are also from very different horizons; the South African species is reported from the Upper Senonian (?Upper Cretaceous) of Pondoland, while the Tanzanian species comes from Mid-Oligocene and Lower Miocene samples. For all these reasons, the new species is regarded as distinct from H. fissilis. There are some speci- mens from samples JOZ 889 and JOZ 896, from the Pliocene of the coastal area between Pangani, Tanzania, and Mombasa, Kenya, which are more akin to H. fissilis; these are hard to reconcile with the distribution of the present species, which occurs both geologically and geographically between the JOZ specimens and those from South Africa. Genus ACANTHOCYTHEREIS Howe, 1963 TYPE SPECIES. Acanthocythereis araneosa Howe, 1963. Figs 1,2 Haughtonileberis radiata Dingle, 1976. Female carapace, OS 8174; 1, lateral view from right, X51; 2, dorsal view, x50. Figs 36 Haughtonileberis rastapuriensis sp. nov. Figs 3, 5, holotype, male carapace, OS 7802; 3, lateral view from right, x63; 5, dorsal view, x61. Figs 4, 6, paratype, female carapace, OS 7803; 4, lateral view from left, X64; 6, lateral view from right, x64. Figs 7-12 Acanthocythereis postcornis Siddiqui, 1971. Figs 7-9, female carapace, OS 8331; 7, lateral view from left, x98; 8, dorsal view, x 107; 9, lateral view from right, x 106. Figs 10-12, male carapace, OS 8330; 10, lateral view from left, x99; 11, dorsal view, x99; 12, lateral view from right, x98. 210 AHMAD, NEALE & SIDDIQUI TERTIARY OSTRACODA FROM THE LINDI AREA, TANZANIA Acanthocythereis postcornis Siddiqui, 1971 Pl. 13, figs 7-12 1971 Trachyleberis (Acanthocythereis) postcornis Siddiqui: 82; pl. 41, figs 9, 10; pl. 42, figs 1, 2, 7, 10. FIGURED SPECIMENS. Two carapaces, a male OS 8330, and a female OS 8331. Sample FCRM 1578, coastal cliff west of Ras Tapuri; Middle Oligocene. OTHER MATERIAL. Three carapaces (OS 8332-4) from sample FCRM 1575. Also occurs in FCRM 1578. DIMENSIONS (yum). L H WwW Male carapace OS 8330 460 240 160 Female carapace OS 8331 420 230 160 REMARKS. The Tanzanian specimens differ slightly from the holotype of this species, showing characters reminiscent of Acanthocythereis procapsus (Siddiqui 1971); they could be placed in either species. However, because of their size and distinctive posterodorsal process, they appear closer to A. postcornis and are so classified here. Genus FALSOCYTHERE Ruggieri, 1972 TYPE SPECIES. Occultocythereis? maccagnoi Ciampo, 1971. Falsocythere maccagnoi (Ciampo, 1971) _ Pl. 17, figs 4-6 1971 Occultocythereis? maccagnoi Ciampo: 27; pl. 2, figs 7-9; pl. 3, fig. 1; pl. 7, fig. 1. 1972 Falsocythere maccagnoi (Ciampo) Ruggieri: 91. 1975 Falsocythere maccagnoi (Ciampo); Bonaduce, Ciampo & Masoli: 51; pl. 26, figs 6-7. FIGURED SPECIMEN. A left valve, OS 7820. Sample FCRM 1566, Mongo Stream, Lindi; Lower Miocene. The only specimen. DIMENSIONS (um). L H W Left valve OS 7820 480 240 130 REMARKS. The Tanzanian specimen has a slightly more concave posterodorsal margin than Ciampo’s species, but this is the only apparent difference. Tribe COSTAINI Hartmann & Puri, 1974 Genus CARINOCYTHEREIS Ruggieri, 1956 TYPE SPECIES. Cytherina carinata Roemer, 1838. Pl. 11, figs 1-3 FIGURED SPECIMEN. A carapace, OS 7991. Sample FCRM 1575, shore south-west of Ras Tapuri; Middle Oligocene. Carinocythereis sp. PLATE 14 211 OTHER MATERIAL. Two specimens from Sample FCRM 1578 (OS 8335-6). Also occurs in FCRM 1576, 1578. DESCRIPTION. Carapace subrectangular with greatest height at anterior cardinal angle; valves very slightly tapering behind. Anterior margin symmetrically rounded, posterior truncate to somewhat rounded, both margins being denticulate. Dorsal and ventral margins modified by marginal ridges; these appear straight, subparallel, and slightly converging behind. Antero- dorsal margin protrudes above prominent glassy eye tubercle. Surface ornamentation consists of an anterior peripheral rim joined to a ventral ridge which continues along the posterior margin. There are four other ridges, all with contiguous undercut clavae in the anterior third and with spines in the posterior two-thirds. Except for occasional spines and/or tubercles between the ridges, the lateral surface is smooth. DIMENSIONS (pm). L H W Carapace OS 7991 645 350 300 REMARKS. The Tanzanian specimens have carapaces inter- mediate in shape between the European Carinocythereis and the Indo-Pacific Ponticocythereis. Unfortunately only three specimens were found, one of which was not well preserved, and no detailed work was possible. Genus COSTA Neviani, 1928 TYPE SPECIES. Cytherina edwardsi Roemer, 1838 (subsequent designation, Howe 1955). Costa? hullinasp. nov. PI. 14, figs 10-12; Pl. 15, figs 1-3 NAME. After the University of Hull, Great Britain. DIAGNOSIS. A species of Costa(?) with a weakly developed median ridge which curves dorsally and joins the better- developed dorsal ridge. Fossae mostly crimped and very variable in shape. HOLotype. A carapace, OS 7715. Another carapace, OS 7716, a juvenile, is a paratype. Sample FCRM 2033, Lindi Creek, east shore; Upper Eocene. OTHER MATERIAL. Three specimens from samples FCRM 2033, 2034. DESCRIPTION. Carapace subquadrate in lateral view, slightly tapering towards posterior margin; greatest height at the anterior angle and greatest width at about one-third of the length from posterior end. Anterior margin broadly rounded, posterior slightly concave above the middle and straight to slightly curved below. Dorsal margin straight, slightly modified by the dorsal ridge, and sloping towards the posterior. Ventral margin straight to slightly concave anteriorly. Right valve overlaps left. Surface ornament consists of three lateral ridges with pitted intercostal areas. Dorsal and ventral ridges strongly developed, former occurring only in posterior half Figs 1-9 Costa trudis Ahmad, 1977c. Figs 1, 4, 6, holotype, male left valve, OS 7692; 1, external lateral view, X55; 4, internal lateral view, paratype, female left valve, OS 7694; 5, external lateral view, X55; 7, internal lateral view, x54. Figs 8, 9, paratype, female right valve, OS 7695; 8, external lateral view, x54; 9, internal lateral view, X55. Figs 10-12 Costa? hullina sp. nov. Holotype, carapace, OS 7715; 10, lateral view from right, X56; 11, dorsal view, 58; 12, lateral view from left, x57. 212 and latter mostly in anterior half; both these ridges curve upwards at the posterior end. Median ridge weakly developed and curves upward to join dorsal ridge at the back. Subcentral tubercle forms part of median ridge just in front of mid- length. Fossae in intercostal areas variable in shape and have crimped margins. Anteroventral and posteroventral margins denticulate, denticles along the posterior margin being fewer and stronger than the anterior ones. Eye tubercle well developed. As no single valves were found no interior details were seen. DIMENSIONS (um). L H WwW Holotype, carapace OS 7715 805 390 400 Paratype (juvenile), carapace CS 7716 650 = 325.260 REMARKS. Except for the weakly developed median ridge, Costa? hullina could be classified as a subspecies of Hermanites paijenborchiana Keij, 1957, from the Eocene of Belgium and France; no Hermanites species has a median ridge. The Tanzanian species also differs in having a shorter ventral ridge and a less developed subcentral tubercle. C.? hullina also differs from the typical Costa in that the median ridge is rather more weakly developed and bends upwards rather than downwards at the posterior end. Hermanites haidingeri (Reuss) subsp. rectangularis Ruggieri, 1962, resembles C.? hullina in outline and ornament, but has no median ridge and the ventral ridge is longer. Costa trudis Ahmad, 1977c 1977c Costa trudis Ahmad: 127-130. HOLotyPe. Male left valve, OS 7692. Seventeen paratypes, OS 7693-709. Sample FCRM 2010, stream south-west of Mtwero; Lower Miocene. Pl. 14, figs 1-9 OTHER MATERIAL. Five single valves from samples FCRM 1745, 1989, 2010, 2015. DESCRIPTION. Carapace elongate, slender, with greatest height at anterior cardinal angle, greatest width in posterior half, and greatest length along median line. Anterior margin symmetrically rounded, posterior pointed, with the point at mid-height; posterodorsal margin straight. Dorsal margin strongly modified in lateral view by dorsal ridge; ventral margin straight to slightly concave. Sexual dimorphism present; presumed females higher anteriorly than the more slender males. Surface ornament consists of three prominent ridges. Dorsal ridge runs from about one-third of the length from anterior end to just in front of posterior margin, where it curves downwards and disappears. Median ridge runs from just behind anterior margin, steps up a short distance further on, whence it runs parallel to dorsal ridge and curves down posteriorly. Ventral ridge subparallel to other two. Ocular ridge prominent, running from eye tubercle along anterior and ventral margins. Areas between ridges are strongly PLATE 15 AHMAD, NEALE & SIDDIQUI reticulate, the shapes of the fossae varying from triangular to subrectangular and subrounded. Internally, inner margin uniformly wide along free margin; marginal pore canals cannot be seen clearly. Muscle scars and hinge are typical of genus and eye tubercle is invisible from within. Right valve hinge consists of a slightly stepped but strongly produced anterior tooth, a socket, a crenulate bar and a posterior tooth which looks like a smooth knob in lateral view, but is elongate in dorsal view. DIMENSIONS (tm). L H W Holotype, male left valve OS 7692 850 385 220 Paratype, male right valve OS 7693 860 370 150 Paratype, female left valve OS 7694 830 430 200 Paratype, female right valve OS 7695 845 390 190 REMARKS. Costa trudis can be distinguished from Costa punctatissima punctatissima Ruggieri 1961 by its more acum- inate posterior and lack of a marginal rim. Costa variabilicosta muhlemanni van den Bold 1966 is also closely related, but the three-pronged ridge which runs vertically from the median to the ventral ridge in that species is missing in C. trudis; there are other differences in ornamental details. Genus TRACHYLEBERIDEA Bowen, 1953 TYPE SPECIES. Cythereis prestwichiana Jones & Sherborn, 1889. Trachyleberidea? cirrata sp. nov. PI. 18, figs 6-10 NAME. ‘Fringed’, with reference to the muri having tufted spines projecting into the fossae. DIAGNOsIS. A species of Trachyleberidea with a low sub- central tubercle, and an internal snap-knob at the mid-ventral margin of the right valve. Ho.otyPe. A female carapace, OS 7988. Another female carapace, OS 8128, is a paratype. Sample FCRM 2010, stream south-west of Mtwero; Lower Miocene. OTHER MATERIAL. Two specimens from samples FCRM 1575 (OS 7993) and 1628 (OS 8129). DESCRIPTION. Carapace subtriangular in side yiew, with greatest height at anterior cardinal angle. Anterior margin symmetrically rounded, posterior end triangular with postero- dorsal margin straight to slightly concave. Dorsal margin straight, ventral slightly concave. Sexual dimorphism marked, presumed females being subtriangular compared with sub- rectangular presumed males; however, see remarks below. Lateral surface reticulate, fossae being concentrically arranged around subcentral tubercle. Muri have short spines which project into the fossae. A prominent thin median longitudinal ridge runs obliquely from subcentral tubercle towards postero- Figs 1-3 Costa? hullina sp. nov. Paratype, juvenile carapace, OS 7716; 1, lateral view from right, x71; 2, dorsal view, X69; 3, lateral view from left, x70. Figs 4-10 Stigmatocythere bornhardti sp. nov. Figs 4, 5, holotype, female carapace, OS 8170; 4, lateral view from right, x76; 5, dorsal view, 84. Figs 6, 9, paratype, male carapace, OS 8172; 6, lateral view from left, «70; 9, dorsal view, x74. Figs 7, 8, 10, paratype, female carapace, OS 8173; 7, dorsal view, x80; 8, lateral view from left, x80; 10, lateral view from right, x80. Figs 11, 12 Stigmatocythere intexta sp. nov. Holotype, carapace, OS 8176; 11, lateral view from left, x83; 12, lateral view from right, x86. TERTIARY OSTRACODA FROM THE LINDI AREA, TANZANIA Poe ae Sy BY a op & . Pre FORM + AHMAD, NEALE & SIDDIQUI TERTIARY OSTRACODA FROM THE LINDI AREA, TANZANIA dorsal margin, curving down at its posterior end. Dorsal ridge not well marked; no ventral ridge. Few internal details visible. Hinge holamphidont, with a rounded knoblike anterior tooth in right valve, a round, slightly stepped tooth posteriorly and a median element consisting of an anterior socket and smooth postjacent groove. Right valve has a midventral snap-knob. DIMENSIONS (1m). L H WwW Holotype, female carapace OS 7988 700 350 265 Paratype, female carapace OS 8128 700 355-290 REMARKS. The two different forms could possibly be regarded as separate species, but as they have the same basic pattern of ornament and occur together, they are taken to be male and female dimorphs of the same species. The generic assignment of this new species is difficult, but it agrees with Trachyleberidea in shape and visible internal details; however, none of the other Trachyleberidea species so far described has a snap- knob. The Tanzanian species also lacks the distinct ventral ridge of typical Trachyleberidea. Genus STIGMA TOCYTHERE Siddiqui, 1971 TYPE SPECIES. Stigmatocythere obliqua Siddiqui, 1971. Stigmatocythere bornhardti sp. nov. Pl. 15, figs 4-10 NAME. After W. Bornhardt, the German geologist who first established the broad geological outlines of the Lindi area. DIAGNOsIS. A species of Stigmatocythere with strong reticula- tion and well-marked sexual dimorphism. HoLotyee. A female carapace, OS 8170. A female right valve OS 8171, a male carapace OS 8172, and a female carapace OS 8173, are paratypes. Sample FCRM 1745 (OS 8173 from 1746), Mbanja River; Lower Miocene. OTHER MATERIAL. Four specimens from samples FCRM 1742 (Lower Miocene) and FCRM 1576, 1578 (Middle Oligocene). Additional specimens are in the collections of the BP Research Centre, Sunbury-on-Thames, from samples FCRM 1647, 1963 and 1964. DESCRIPTION. Sexual dimorphism pronounced, affecting shape. Carapace of presumed male rectangular in side view; presumed female subquadrate. Anterior margin symmetrically rounded, posterior truncate. Dorsal margin modified by dorsal ridge, ventral margin slightly concave in the middle; these margins converge slightly towards posterior end. A strong ridge runs along dorsal, posterior and ventral margins. Entire surface reticulate, with the fossae arranged in no particular order. Some specimens are less strongly reticulate and in them three longitudinal ridges can be seen. Internal features typical of genus. PLATE 16 215 DIMENSIONS (ym). L H W Holotype, female carapace OS 8170 S550 310 = =270 Paratype, male carapace OS 8172 610 310 260 Paratype, female carapace OS 8173 560 310 275 REMARKS. Stigmatocythere bornhardti is similar in shape to S. obliqua Siddiqui 1971, but there are a number of differences in detail; S. obliqua has a well developed eye tubercle and a ridge overhanging the ventral margin; S. bornhardti has a reduced eye tubercle and no overhanging ventral ridge. Siddiqui’s species is smoother in the anterior third, while the Tanzanian species is equally reticulate all over. Sexual dimorphism also differs in the two; the presumed females of Siddiqui’s species have strongly converging dorsal and ventral margins while the Tanzanian females are subquadrate. S. bornhardti also resembles S. intexta sp. nov. (below) but is more strongly reticulate. Carbonnel’s Stigmatocythere aff. obliqua Siddiqui (Carbonnel 1986: 110, figs 12-15) shows some resemblence to S. bornhardti but differs in its accentuated anterodorsal hinge ‘ear’. The pattern of ornament, although somewhat similar, is less well developed, although this may be partly a matter of preservation. Stigmatocythere intexta sp. nov. PI. 15, figs 11-12; Pl. 16, figs 1-4, 6 NAME. ‘Interlaced’, with reference to the ornament. DIAGNOSIS. A species of Stigmatocythere which is almost uniformly reticulate. The ridges are subdued and the fossae shallow. HOLOTYPE. A carapace, OS 8176. Six paratypes, OS 8177-82. Sample FCRM 2045, Lindi-Mingoyo Road; Upper Eocene. OTHER MATERIAL. One specimen from the same sample. Also occurs in FCRM 1745, 1575 and 1628. DESCRIPTION. Carapace medium sized, subrectangular in lateral view. Anterior margin symmetrically rounded, posterior truncate to rounded. Dorsal margin straight, ventral margin slightly concave in the middle. Eye tubercle glassy and well developed. Entire surface reticulate, the fossae being sub- rectangular, shallow and almost equal in size. The three ridges, dorsal, median and ventral, present but very much reduced; in some specimens ventral ridge almost non-existent. Internal features typical of genus. DIMENSIONS (um). L H W Holotype, carapace OS 8176 530 245 210 Paratype, right valve OS 8177 560 145 130 Paratype, carapace OS 8178 510 250 205 REMARKS. S. intexta only differs from S. bornhardti sp. nov., above, in having subdued ridges and therefore shallower Figs 14,6 Stigmatocythere intexta sp. nov. Figs 1, 2, paratype, right valve, OS 8177; 1, internal lateral view, 80; 2, external lateral view, x81. Figs 3, 4, 6, paratype, carapace, OS 8178; 3, dorsal view, X91; 4, lateral view from left, 89; 6, lateral view from right, x90. Figs 5,7-9 Buntonia sp. Left valve, OS 8183; 5, muscle scars, X450; 7, external lateral view, X87; 8, dorsal view, X99; 9, internal lateral view, x89. Figs 10-12 Ambocythere sp. Carapace, OS 7975; 10, lateral view from left, x95; 11, dorsal view, X95; 12, lateral view from right, X95. AHMAD, NEALE & SIDDIQUI 16 + TERTIARY OSTRACODA FROM THE LINDI AREA, TANZANIA fossae. A number of specimens have intermediate ornamen- tation, and it is difficult to classify them with certainty in either species. Tribe PTERYGOCYTHEREIDINI Puri, 1957a Genus INCONGRUELLINA Ruggieri, 1958 TYPE SPECIES. Incongruellina semispinescens Ruggieri, 1958. Incongruellina tonsa sp. nov. PI. 17, fig. 12; Pl. 18, figs 1-5 NAME. ‘Oar’, referring to the ventrolateral alae. DIAGNOSIS. A species of Incongruellina with prominent alae which make the valves wider than high. Posteriorly the alae end in spines. HoLortyPe. A carapace, OS 7908. Two carapaces, OS 7909, 7910, are paratypes. Sample FCRM 2010, stream south-west of Mtwero; Lower Miocene. OTHER MATERIAL. Seven specimens, including OS 7992 from FCRM 1746. Also occurs in FCRM 1745. DESCRIPTION. Carapace strongly calcified, medium-sized to large; greatest height at anterior cardinal angle, tapering posteriorly. Anterior margin symmetrically rounded, with 10 to 12 marginal denticles. Posterior bluntly produced at the bottom, with posterodorsal margin almost straight. Dorsal margin in left valve gently arched, almost straight in right. Left valve larger than right, overlap being conspicuous along mid-dorsal margin. Externally, ventrolateral marginal keel well developed and almost parallel to ventral margin, ending posteriorly in a spine. Ventral to the keel, two thin ridges run parallel to margin. Except for the glossy eyespot, lateral surface smooth. Internally duplicature moderately wide; line of concrescence and inner margin separated by a narrow vestibule. No marginal pore canals were seen, and a V- shaped frontal scar alone was visible in the muscle scar field. DIMENSIONS (1m). L H WwW Holotype, carapace OS 7908 780 590 510 Paratype, carapace OS 7910 810 485 495 Paratype, carapace OS 7909 800 450 510 REMARK. Incongruellina tonsa is very like I. semispinescens Ruggieri 1958, but lacks a long posterior spine in the left valve. Tribe ECHINOCYTHEREIDINI Hazel, 1967 Genus HENRYHOWELLA Puri, 1957b TYPE SPECIES. Cythere evax Ulrich & Bassler, 1904. 217 Henryhowella sentosa sp. nov. PI. 17, figs 7-11 NAME. ‘Thorny’; with reference to the surface ornamentation. DIAGNOSIS. A species of Henryhowella with spines typically trifid and arranged somewhat concentrically. Ho.otyPe. A left valve, OS 7985. A juvenile right valve, OS 7986, is a paratype. Sample FCRM 2010, stream south-west of Mtwero; Lower Miocene. OTHER MATERIAL. Two specimens from Samples FCRM 2010 and 2016. DESCRIPTION. Carapace shape typical of genus. In side view, anterior margin evenly rounded; posterior obliquely curved below; posteroventral margin almost straight. Dorsal and ventral margins almost straight and parallel. Eye tubercle indistinct; anterior cardinal angle with a well-developed spine. Surface covered with spines, mostly trifid but some- times bifid or quadrifid, concentrically arranged in anterior half and posterior third of carapace. Spines very small in posterior and posterodorsal regions, larger in ventral region. Internal features typical of genus except that median element of hinge is not crenulate; frontal scar not visible. DIMENSIONS (pm). L H WwW Holotype, left valve OS 7985 660 410 200 Paratype, juvenile right valve OS 7986 = =590 350-180 REMARKS. Henryhowella sentosa resembles the Echino- cythereis? sp. of Swain 1971, an immature valve from the Pleistocene of the south-eastern Pacific Ocean, but this does not have the characteristic trifid spines. The ornamentation and shape of the Tanzanian species are very similar to those of Cythere acanthoderma Brady from the Gulf of Mexico, but the latter has stronger marginal spines and a more broadly rounded posterior margin. The indistinct eye tubercle and concentrically arranged spines of the Tanzanian species resemble those of Hystricocythere Bate 1972, but the hinge is different. Subfamily BUNTONIINAE Apostolescu, 1961 Genus BUNTONIA Howe & Chambers, 1935 TYPE SPECIES. Buntonia shubutaenis Howe & Chambers 1935 (= young of ?Cythereis israelski Howe & Chambers, 1935). Buntonia sp. Pl. 16, figs 5, 7-9 FIGURED SPECIMEN. A left valve, OS 8183. Sample FCRM 1628, Kitunda Jetty road; Middle Oligocene. OTHER MATERIAL. Three specimens in the collection of the BP Research Centre, Sunbury-on-Thames, from samples FCRM 1645, 1742, and 1745. DESCRIPTION. Carapace pear-shaped in lateral view, with PLATE 17 Figs 1-3 Idiocythere sp. A. Carapace, OS 8186; 1, lateral view from left, x85; 2, dorsal view, X85; 3, lateral view from right, 85 Figs 46 Falsocythere maccagnoi (Ciampo, 1971). Left valve, OS 7820; 4, external lateral view, 94; 5, dorsal view, X96; 6, internal lateral view, X97. Figs 7-11 Henryhowella sentosa sp. nov. Figs 7, 10, 11, holotype, left valve, OS 7985; 7, external lateral view, X65; 10, internal lateral view, 66; 11, dorsal view, X69. Figs 8, 9, paratype, juvenile right valve, OS 7986; 8, dorsal view, X78; 9, external lateral view, 75 Fig. 12 Incongruellina tonsa sp. nov. Holotype, carapace, OS 7908, lateral slightly oblique view from right, ¥53. See also Pl. 18, fig. 3 218 greatest height at two-fifths of the length, and greatest width about three-fifths of the length from anterior margin. Anterior margin elliptical and narrowly rounded; posterior margin upturned and rounded towards the dorsal. Dorsal margin merges imperceptibly into anterior margin, has an almost straight middle section, and slopes posteriorly, forming a distinct posterior cardinal angle. Ventral margin slightly convex upwards. External surface smooth along anterior margin (possibly a preservation phenomenon), but the rest is covered with small pits. Ventral half has six ridges running almost parallel to ventral margin. Dorsal half, separated from ventral by a longitudinal groove, has two small ridges at an angle to the dorsal margin. Marginal area and pore canals could not be seen because of poor preservation; the specimens in the BP Research Centre collection are better preserved and had 11 anterior marginal pore canals. There are four adductor scars with a V-shaped frontal scar. Hinge hol- amphidont; in left valve, an anterior socket is followed by a strong knob, a crenulate bar and a posterior socket. DIMENSIONS (1m). L H W Left valve OS 8183 460 315 170 Genus AMBOCYTHERE van den Bold, 1958b TYPE SPECIES. Ambocythere keiji van den Bold, 1958b. Ambocythere sp. Pl. 16, figs 10-12 FIGURED SPECIMEN. A carapace, OS 7975. Sample FCRM 1566, Mongo Stream, Lindi; Lower Miocene. The only specimen. DESCRIPTION. Carapace small, highest at one-third length from anterior end. Anterior margin symmetrically rounded; posterior end somewhat bluntly produced with posterodorsal part straight to slightly concave and posteroventral part rounded, with six denticles, three strong and three reduced. Dorsal margin strongly modified posteriorly by dorsal ridge; ventral margin almost straight. Dorsal and ventral margins converge posteriorly. Surface ornament consists of a carina- like rim extending from mid-dorsal ridge along anterior margin and continuing along ventral and posterior margins. Three short longitudinal ridges run from mid-length towards the back. The dorsal ridge thickens posteriorly where it curves downwards; the shorter median ridge bifurcates at its posterior end and meets dorsal and ventral ridges; ventral ridge straight, also bifurcating at posterior end. Small rounded pits occur in the central part of the carapace. As there is only a carapace internal details are unknown. DIMENSIONS (um). L H WwW Carapace OS 7975 495 230 175 PLATE 18 AHMAD, NEALE & SIDDIQUI REMARKS. This Tanzanian Ambocythere is more rectangular and has shorter ridges than any other species so far described. Genus OCCULTOCYTHEREIS Howe, 1951 TYPE SPECIES. Occultocythereis delumbata Howe, 1951. Occultocythereis africana sp. nov. Pl. 11, figs 7-12 NAME. ‘From Africa’. DIAGNosIs. A species of Occultocythereis with a prominent anterior marginal ridge; dorsal ridge in the posterior half curving sharply down at the posterior end. A ventrolateral swelling. Surface ornamented with round pits. HovortyPe. A female carapace, OS 7976. Two specimens, OS 7972, 7974, are paratypes. Sample FCRM 1989, Likonga bridge; Lower Miocene. OTHER MATERIAL. One specimen (OS 7978) from sample FCRM 2010. DESCRIPTION. Carapace small, greatest height at anterior cardinal angle. Anterior end rounded, posterior subrounded below, concave to straight posterodorsally; dorsal and ventral margins almost straight, converging behind. Sexual dimorphism present; presumed males elongate compared with presumed females. Externally, a strong rim runs along free margins. A short dorsal ridge runs in posterior half, curving sharply at posterior end; another rather indistinct ridge, appearing as a ventrolateral swelling, ends in a short spine posteriorly. Five or six elongate marginal spines occur along posteroventral margin and there are a few very short ones at anterior end. Eye tubercle present as an opaque spot. Surface ornamented with round pits except in the anteroventral area, which is almost smooth. Inside, duplicature moderately wide; line of concrescence and inner margin coincide and there is no vestibule. Selvage runs at a short distance from outer margin. Marginal pore canals not clearly visible. Muscle scar pattern consists of four adductor scars in a vertical row with a V- shaped frontal scar. Hinge holamphidont, with a conical anterior tooth and an adjacent socket joined to a posterior tooth in right valve; corresponding elements occur in left. DIMENSIONS (um). L H W Holotype, female carapace OS 7976 435 215 170 Paratype, female left valve OS 7974 500 260 115 Paratype, female right valve OS 7972 500% (255: :- 115 REMARKS. O. africana is probably the same as the Gen. Indet. 5 sp. 1 of Dingle, 1976. Occultocythereis hatraensis A\- Sheikhly, 1982, shows some resemblance to this species but Figs 1-5 Incongruellina tonsa sp. nov. Figs 1, 2, paratype, carapace, OS 7910; 1, lateral view from right, x56; 2, dorsal view, 54. Fig. 3, holotype, carapace, OS 7908, lateral view from left, x56; see also Pl. 17, fig. 12. Figs 4, 5, paratype, carapace, OS 7909; 4, lateral view from left, x56; 5, ventral view, <51. Figs 6-10 Trachyleberidea? cirrata sp. nov. Figs 6, 9, holotype, female carapace, OS 7988; 6, lateral view from left, x66; 9, dorsal view, x66. Figs 7, 8, 10, paratype, female carapace, OS 8128; 7, dorsal view, X65; 8, lateral view from right, x65; 10, lateral view from left, x65. Figs 11,12 Ruggieria (Ruggieria) furcilla sp. nov. Fig. 11, holotype, left valve, OS 8201, external lateral view, X39; see also PI. 19, fig. 4. Fig. 12, paratype, carapace, OS 8202, lateral view from right, x42; see also Pl. 19, fig. 3. TERTIARY OSTRACODA FROM THE LINDI AREA, TANZANIA 219 / bea 220 differs from it in having a median ridge, a better-developed dorsal ridge and a punctate rather than a pitted surface. Genus IDIOCYTHERE Triebel, 1958 TYPE SPECIES. J. lutetiana Triebel, 1958. Idiocythere sp. A Pl. 17, figs 1-3 FIGURED SPECIMEN. A carapace, OS 8186. Sample FCRM 1746, Mbanja River; Lower Miocene. The only specimen. DESCRIPTION. Carapace subrectangular in side view, with almost straight dorsal and ventral margins. Anterior margin rounded, posterior concave posterodorsally; both ends denticulate. Anterior marginal rim and dorsal and ventral ridges all well developed. Subcentral tubercle prominent; the rest of the surface pitted in the middle and smooth along the margins. No internal features were seen. DIMENSIONS (1m). L H WwW Carapace, OS 8186 535 270. 200 Subfamily CAMPYLOCYTHERINAE Puri, 1960 Tribe LEGUMINOCYTHERINI Howe, 1961 Genus LEGUMINOCYTHEREIS Howe (in Howe & Law, 1936) TYPE SPECIES. L. scarabaeus Howe & Law (in Howe & Law, 1936). Leguminocythereis dinglei sp. nov. Pl. 12, figs 1-12 NAME. In honour of Prof. R.V. Dingle, for his work on the South African ostracod fauna. DIAGNOsIS. A species of Leguminocythereis with obliquely rounded anterior and produced truncated posterior margins. Lateral surface reticulate with coarse striae concentrically arranged at the margins but straight in the middle of the valve. HOLOTYPE. A female carapace, OS 8194. Six specimens, OS 8195-200, are paratypes. Sample FCRM 1578 (OS 8196, FCRM _ 1575), coastal cliff west of Ras Tapuri; Middle Oligocene. OTHER MATERIAL. 23 specimens from samples FCRM 1574 and 1576. DESCRIPTION. Carapace medium to large, with greatest width in posterior half. Subtriangular to suboval in side view, tapering towards posterior end. Anterior margin cut away PLATE 19 AHMAD, NEALE & SIDDIQUI below, with spines along the ventral part; dorsal margin straight to gently arched, posterior end produced and truncate with a straight to concave posterodorsal margin. Ventral margin strongly modified by a swelling which appears convex in side view but is concave in the middle from below or internally. Carapace ovate in dorsal view. Sexual dimorphism present; in dorsal view presumed males less swollen anteriorly than are females. Six longitudinal ridges run along ventrolateral swelling, curving along anterior margin and following dorsal margin. Lateral surface reticulate; fossae rounded, more prominent centrally and almost non-existent along margins. Degree of development of the lateral ridges varies widely; a few specimens have reduced reticulation and may be almost smooth, though the original pattern of reticulation can usually be discerned. However, even when ornamentation is reduced, no other differences are visible, so this is regarded as intraspecific variation. Reduction in ornament may be directly proportional to size of carapace, but this is not an invariable rule. Duplicature fairly wide; line of concrescence and inner margin slightly separated anteriorly, forming a narrow vestibule. Selvage strongly developed along anteroventral and ventral margins. Marginal pore canals obscure due to strong calcification; in some specimens false marginal pore canals visible. Details of muscle scars difficult to see; in most specimens only two adductor scars are visible, with the middle two not apparent and frontal scars placed irregularly. In some specimens there are four adductor scars arranged in a row with two rounded scars in front. Hinge strongly holamphidont; in right valve a sharp anterior tooth projects from a platform the lower side of which has a socket joined to a crenulate groove, followed by a smooth elongate tooth which thickens posteriorly. DIMENSIONS (1m). L H WwW Holotype, female carapace OS 8194 830 480 465 Paratype, male carapace OS 8195 800 456 290 Paratype, male carapace OS 8196 765 415 420 Paratype, female left valve OS 8198 790 450 270 Paratype, male carapace OS 8199 950 520 530 Paratype, juvenile(?) left valve OS 8200 665 355 195 REMARKS. The outline of the posterior margin, which is produced and truncate in L. dinglei, differentiates this from other species of Leguminocythereis; in fact this feature recalls the Mesozoic genera Neocythere and Centrocythere, which have a completely different hinge. Genus RUGGIERIA Keij, 1957 Subgenus RUGGIERIA Keij, 1957 TYPE SPECIES. Cythere micheliniana Bosquet, 1852. Figs 14 Ruggieria (Ruggieria) furcilla sp. nov. Fig. 1, paratype, carapace, OS 8204, ventral view, x39. Fig. 2, paratype, right valve, OS 8205, dorsal view, X44. Fig. 3, paratype, carapace, OS 8202, dorsal view, 43; see also PI. 18, fig. 12. Fig. 4, holotype, left valve, OS 8201, internal view, X39; see also PI. 18, fig. 11. Figs 5-8 Procythereis aligera sp. nov. Figs 5, 6, holotype, left valve, OS 8215; 5, external lateral view, x69; 6, internal lateral view, x65. Fig. 7, paratype, right valve, OS 8216, internal lateral view, X73. Fig. 8, paratype, carapace, OS 8217, dorsal view, x65. Figs 9, 10 Procythereis radiata sp. nov. Holotype, left valve, OS 8219; 9, internal lateral view, x75; 10, external lateral view, x76. Figs 11,12 Aurila concentrica sp. nov. Holotype, female right valve, OS 8207; 11, dorsal view, x78; 12, external lateral view, x70. TERTIARY OSTRACODA FROM THE LINDI AREA, TANZANIA 221 ee seit gt 9 5 s i vy ivwe ate NG es SS te iy EA Fatt Pct FONG f2 74a CVSS," op hp] Ruggieria (Ruggieria) furcilla sp. nov. Pl. 18, figs 11-12; Pl. 19, figs 1-4 NAME. ‘Little fork’, with reference to lateral ridges which form a fork-like pattern. DIAGNOSIS. A species of Ruggieria with ridges which are convex upward in the dorsal part, almost straight in the middle, and concave upward in the ventral part of the lateral surface. HOLoryPe. A left valve, OS 8201. Five specimens, OS 8202— 6, are paratypes. Sample FCRM 2014, stream south-west of Mtwero; Lower Miocene. OTHER MATERIAL. 33 specimens from samples FCRM 2014, 2015. Additional specimens are in the collection of the BP Research Centre, Sunbury-on-Thames, from samples FCRM 1745, 1746. DESCRIPTION. Carapace elongate, oval-shaped in lateral view. Dorsal margin straight; ventral margin strongly modified by ventrolateral swelling, appearing convex in lateral view but from inside concave anteriorly and convex posteriorly. Anterior margin symmetrically rounded; posterior upturned, straight in upper half and gently rounded below. Greatest height behind anterior margin, and greatest width in ventral half, behind mid-length. Eye tubercle prominent. Ornament consists of longitudinal ridges which are curved up in the dorsal half of the carapace, almost straight in the middle of it, and curved down in the ventral half. Intercostal areas smooth. Marginal zone moderately wide except at ventral margin, where it is narrow; inner margin and zone of concrescence coincide except along anteroventral margin, where there is a narrow vestibule. Normal pore canals widely spaced; marginal pore canals straight and wide apart. Muscle scar pattern with four adductor scars with their axis concave towards anterior end; second scar from the top relatively long. Two dorsal scars just above and a V-shaped frontal scar just in front of the adductor scars. Hinge typical of genus; in right valve it consists of a conical anterior tooth, a post-jacent socket which merges into a serrated straight groove, and a smooth ovate posterior tooth. Left valve has corresponding sockets, a conical anterior tooth, and a median crenulate bar. DIMENSIONS (ym). L H W Holotype, left valve OS 8201 1140 530 320 Paratype, right valve OS 8205 1050 515 285 Paratype, carapace OS 8204 1175 540 560 Paratype, carapace OS 8202 1035 S500 510 REMARKS. R. (R.) furcilla has some affinity with the genus Keijella Ruggieri 1967 because of its anteroventral vestibule, but it is placed in Ruggieria s. str. because, though a vestibule is present, it is confined to the antero- ventral margin; in species of Keijella it extends along PLATE 20 AHMAD, NEALE & SIDDIQUI the entire anterior margin. Also, the hinge is more like that of Ruggieria s. str., and the outline of the carapace resembles that of some described species. R. furcilla probably represents an intermediate stage in the evolu- tionary development of Ruggieria s. str. into Keijella. Keen (1974) described some Ruggieria-like ostracods from the Tertiary and Recent of West Africa. Only his Ruggieria sp. from Recent deposits of Sierra Leone shows any resemblence to R. furcilla, but differs in shape posteroventrally and in details of ornament, particu- larly in the ventrolateral region of the shell. Ruggieria furcilla is closest to R. triangulata Omatsola 1972, a Recent species from the western Niger Delta, as figured by Babinot 1981 from the Oligocene of the Cote dIvoire, and R. aff. triangulata Carbonnel 1986 from the Eocene of Senegal. Carbonnel gives good line diagrams of the ornamentation pattern of these forms and the Tanzanian species differs in the detailed rib pattern, especially the four lower costae which swing upwards in the anterior half of their course. Although distinct, the present species is closely allied to the Senegal, Cote d'Ivoire and Niger forms and should be included in the R. triangulata species group. Family HEMICYTHERIDAE Puri, 1953 Subfamily HEMICYTHERINAE Puri, 1953 Tribe AURILINI Puri, 1974 Genus AURILA Pokorny, 1955 TYPE SPECIES. Cythere convexa Baird, 1850. Aurila concentrica sp. nov. Pl. 19, figs 11-12, Pl. 20, figs 1-6 NAME. In reference to the concentric arrangement of fossae. DIAGNosIs. A medium-sized species of Aurila, subovate in lateral view, highest just behind the middle. Anterior and posterior margins together form an arc; posterior produced into a caudal process. Surface strongly reticulate with fossae arranged concentrically. HootypPe. A female right valve, OS 8207. Five specimens, OS 8208-12, are paratypes. Sample FCRM 1566, Mongo Stream, Lindi; Lower Miocene. OTHER MATERIAL. 106 specimens from samples FCRM 1566 1989, 2010. Additional specimens are in the collection of the BP Research Centre, Sunbury-on-Thames, from samples FCRM 1575, 1576, 1578, 1689, 1692. Also occurs in FCRM 1574, 1737, 1745, 1746 and 2015. DESCRIPTION. Carapace subovate, almond shaped, with Figs 1-6 Aurila concentrica sp. nov. Fig. 1, paratype, female left valve, OS 8208, external lateral view, x69. Fig. 2, paratype, female left valve, OS 8210, internal lateral view, x70. Fig. 3, paratype, female right valve, OS 8209, external lateral view, 73. Figs 4, 5, paratype, male right valve, OS 8211; 4, external lateral view, x74; 5, internal lateral view, X76. Fig. 6, paratype, female carapace, OS 8212, dorsal view, x62. Figs 7-9 Aurila concentrica sp. nov., Morphotype A. Figs 7, 8, female carapace, OS 8213; 7, lateral view from right, x58; 8, lateral view from left, x58. Fig. 9, male right valve, OS 8214, external lateral view, x62. Fig. 10 Aurila concentrica sp. nov., Morphotype B. Male right valve, OS 8222, external lateral view, X67. Figs 11,12 Hermanites carchesium sp. nov. Paratype, male carapace, OS 8224; 11, lateral view from left, x54; 12, lateral view from right, x57. TERTIARY OSTRACODA FROM THE LINDI AREA, TANZANIA ed a a Date eeeeck 224 greatest height just behind the middle and greatest width in posterior half. Anterior and dorsal margins almost continuous, forming an arc; posterior margin produced into a caudal process almost at right angles to dorsal margin, joining ventral margin obliquely. Ventral margin slightly concave anteriorly and convex posteriorly. Sexual dimorphism pronounced, presumed females being slightly wider and higher but less elongate than presumed males. Left valve larger than right with a pronounced overlap along dorsal margin. Eye tubercle glassy, elongate. Surface coarsely reticulate, the fossae being subrectangular and arranged concentrically in six rows. Duplicature moderately wide; line of concrescence and inner margin slightly separated anteriorly to give a narrow vestibule. Selvage well developed, running parallel to outer margin. Marginal pore canals straight, mostly simple, including a few false ones. There are 35—40 at the anterior end and 6-8 at the posterior. Muscle scar pattern consisting of four adductor scars, the top three being divided into two, and three frontal scars. Hinge holamphidont; anterior tooth in right valve moderately high and sharp, followed by a socket joined to the elongate incised posterior tooth by a groove. Left valve with complementary hinge elements. DIMENSIONS (1m). I H WwW Holotype, female right valve OS 8207. = 555.3345. 210 Paratype, female left valve OS 8208 560 380 240 Paratype, female right valve OS 8209 550 340 175 Paratype, female left valve OS 8210 555. 365185 Paratype, female carapace OS $212 695 450 405 REMARKS. The Tanzanian species is difficult to place firmly in either Aurila or Pokornyella. While the hinge is more like that of Aurila, the number of anterior marginal pore canals is closer to the 20-25 of Pokornyella than to the 80 of Aurila. This probably represents an intermediate evolutionary stage between the earlier genus Pokornyella (Eocene—Oligocene) and the later Aurila (Oligocene—Recent). Two morphotypes are distinguished: see below. Morphotype A Pl. 20, figs 7-9 FIGURED SPECIMENS. A female carapace, OS 8213 (sample FCRM 1566), and a male right valve, OS 8214 (sample FCRM 1746); Mongo stream and Mbanja river, respectively; Lower Miocene. DIMENSIONS (1m). L H W Female carapace OS 8213 660 430 375 Male right valve OS 8214 680 410 220 REMARKS. In this morphotype the anterior and dorsal margins together form an arc. The ornamentation is flatter than in the type. Morphotype B PI. 20, fig. 10 FIGURED SPECIMEN. A right valve, OS 8222. Sample FCRM 1578, coastal cliff west of Ras Tapuri; Middle Oligocene. Also occurs in FCRM 1576. DIMENSIONS (um). L H W Right valve OS 8222 595 370 190 REMARKS. The fossae are numerous but smaller and shallower than in typical Aurila concentrica. The ridges are almost non- existent, but the eye tubercle is better developed than in the type. AHMAD, NEALE & SIDDIQUI Genus PROCYTHEREIS Skogsberg, 1928 TYPE SPECIES. Cythereis (Procythereis) torquata Skogsberg, 1928. Procythereis aligera sp. nov. Pl. 19, figs 5-8 NAME. ‘Winged’, with reference to the ala-like ventrolateral ridge. DIAGNnosIs. A species of Procythereis with an ala-like ridge running along the ventrolateral swelling. Lateral surface reticulate but the fossae not prominent. Ho.otypPe. A left valve, OS 8215. Three specimens, OS 8216-8, are paratypes. Sample FCRM 2010, stream south- west of Mtwero; Lower Miocene. OTHER MATERIAL. Two specimens from the same locality and horizon (OS 8221). DESCRIPTION. Carapace medium to large, heavily calcified. Subovate in lateral view with greatest height at anterior cardinal angle and greatest width behind mid-length. Anterior margin broadly and obliquely rounded towards venter, posterior produced in ventral half and concave in dorsal half. Dorsal margin almost straight, ventral slightly concave, strongly modified in lateral view by the ventral inflation. Surface irregularly reticulate with poorly developed fossae. Three median ridges run longitudinally from behind anterior margin, bending upwards in front of posterior end. Eye tubercle only moderately developed. The dorsal of the two ventrolateral ridges is ala-like and prominent. Duplicature narrow to moderately wide; line of concrescence and inner margin coincide. Selvage runs along outer margin except at mid-venter, where it stands out prominently. Muscle scar pattern consists of four adductor scars in a vertical row with two frontal scars in front of them. Hinge strongly holamphidont. DIMENSIONS (um). 1M H WwW Holotype, left valve OS 8215 660 400 205 Paratype, right valve OS 8216 605 335 225 Paratype, carapace OS 8217 675 415 380 REMARKS. Procythereis aligera is not a typical Procy- thereis in shape but is assigned to this genus because of its two frontal muscle scars; Kingmania and Nephokirkos both have only one, though they are more like P. aligera in shape. The new species can be distinguished from other Procythereis in being more ovate than rectangular and having a less prominent eye tubercle. Procythereis radiata sp. nov. Pl. 19, figs 9-10 NAME. ‘Rayed’, with reference to the lateral ridges which radiate from the anteroventral region. DIAGNosis. A subrectangular species of Procythereis with reticulate ornamentation, the longitudinal ridges radiating from the anteroventral region. Two parallel ridges originate from the eye tubercle and run along the anterior and ventral margins. Ho.otyPe. A left valve, OS 8219. A left valve, OS 8220 (missing), is a paratype. Sample FCRM 1566, Mongo Stream, Lindi; Lower Miocene. TERTIARY OSTRACODA FROM THE LINDI AREA, TANZANIA OTHER MATERIAL. One specimen from the same locality and horizon. DESCRIPTION. Carapace subrectangular in lateral view, with ventral region strongly inflated, especially in posterior half. Anterior margin rounded, posterior bluntly produced in ventral half and concave posterodorsally. Dorsal margin straight, ventral hidden by the swelling in lateral view but straight and subparallel internally. Surface reticulate, the fossae being equal-sized and rounded; longitudinal ridges present, radiating from the anteroventral region. Eye tubercle prominent and elongate. Internally, duplicature moderately wide; line of concrescence and inner margin coincide; vestibule absent. Marginal pore canals straight, simple and fairly numerous. Muscle scar pattern consists of four adductor scars and three frontal; one or both of the median adductor scars probably divided but this is hard to see. Hinge strongly holamphidont. In left valve there is an anterior socket with a post-jacent knob-like tooth, followed by a smooth bar with an elongate socket behind. DIMENSIONS (1m). L H WwW Holotype, left valve OS 8219 59052320! 225 REMARKS. Procythereis radiata has a slightly different hinge from that of the type species, the median bar being smooth instead of crenulate as in P. torquata Skogsberg, 1928. So far, very few Procythereis species have been described; P. radiata can easily be distinguished from any of them by its rectangular shape, symmetrically rounded anterior margin, and the obliquely truncate and ventrally produced outline of the posterior margin. Subfamily THAEROCYTHERINAE Hazel, 1967 Tribe THAEROCYTHERINI Hazel, 1967 Genus HERMANITES Puri, 1955 TYPE SPECIES. Hermania reticulata Puri, 1954. Hermanites carchesium sp. nov. Pl. 20, figs 11-12; Pl. 21, figs 1-6; Pl. 22, fig. 11 NAME. Latin carchesium, a Greek style of cup slightly contracted in the middle; with reference to the slight contrac- tion in the middle of the carapace. DIAGNOsIS. A strongly reticulate species of Hermanites with broadly rounded anterior margin, dorsal margin strongly modified in lateral view by a wavy marginal ridge, and the ventral margin modified by a straight ridge. HOLotTyPe. A female carapace, OS 8223. Two male carapaces, OS 8224-5, are paratypes. Sample FCRM 2033, Lindi Creek, east shore; Upper Eocene. OTHER MATERIAL. Eight specimens from the same locality and horizon, including OS 8321 (juvenile), pl. 22, fig. 11. DESCRIPTION. Carapace subquadrate, with greatest height at anterior end and greatest width in posterior half at about two- thirds the length from anterior margin. Anterior margin symmetrically rounded, with 23 short denticles; posterior produced just below middle; five to seven strong denticles along posteroventral edge. Dorsal margin strongly modified by a wavy dorsal ridge. Posterodorsal margin concave, ventral margin straight to slightly concave in the middle and convex 225 in posterior half. Sexual dimorphism present, presumed females being more quadrate and wider than males. Surface strongly reticulate. Strong anterior marginal ridge present; ventral ridge running from about a quarter to about three- fifths the length from the anterior margin, then curling upwards to form a loop. Subcentral tubercle elongate, not well developed; eye tubercle strongly developed. Fossae vary in shape, being quadrate and subrectangular in some parts and polygonal or triangular in others. Muscle scars and marginal pore canals not seen in the one poorly preserved adult single valve. Other internal features typical of genus. DIMENSIONS (1m). L H W Holotype, female carapace OS 8223 750 440 370 Paratype, male carapace OS 8224 745 440 345 Paratype, male carapace OS 8225 750 460 400 REMARKS. It is very difficult to place H. carchesium in either Hermanites or Quadracythere solely on the basis of shape and ornamentation. There is a group of species closely allied with H. carchesium which could belong to either genus, these genera being distiguished only by the type of frontal scar, which could not be seen in the Tanzanian species. However, H. carchesium is most like Hermanites in dorsal view , and therefore is here placed in that genus. H. carchesium resembles H. dameriacensis Keij, 1958 in outline and ornament, differing only in having no pronounced loop connecting the dorsal and ventral ridges in the posterior half. Hermanites mongoensis sp. nov. Pl. 22, figs 1-2 NAME. After Mongo Stream, the type locality. DIAGNOsIS. A species of Hermanites with dorsal ridge strongly modified in posterior half by the posterodorsal loop, which joins it to the median ridge; ventrolateral carina strongly developed. HOLoryPe. Right valve, OS 8232. Another valve, OS 8233 is a paratype. Sample FCRM 1566, Mongo Stream, Lindi; Lower Miocene. OTHER MATERIAL. Five specimens from the same sample. Also occurs in FCRM 1745 and 2010. DESCRIPTION. Carapace medium-sized, subquadrate to sub- rectangular, with greatest height at anterior end, tapering towards posterior. Anterior margin symmetrically rounded, posterior subacuminate and produced subventrally. Dorsal margin, with its marginal ridge, is almost straight and slopes posteriorly; it is strongly modified in posterior half by the posterodorsal loop which joins it to the median ridge. Ventral margin almost straight. Ventrolateral carina well developed, curving upwards near posterior end to join posterodorsal loop. Entire lateral surface reticulate, with broad fossae. Eye tubercle well developed. Duplicature moderately wide; inner margin regular, slightly separated from line of concrescence, leaving a narrow vestibule. Selvage a little distance from anterior margin, continuous along entire free edge. 20-25 marginal pore canals, mainly concentrated along the antero- ventral margin, are mostly short, straight and simple. Four adductor muscle scars, located in the deep subcentral pit, are arranged in a vertical row and decrease in size from dorsal to ventral; one crescentic to U-shaped frontal scar. Hinge strongly holamphidont. DIMENSIONS (1m). I H W Holotype, right valve OS 8232 680 380 240 226 AHMAD, NEALE & SIDDIQUI TERTIARY OSTRACODA FROM THE LINDI AREA, TANZANIA REMARKS. Oligocene specimens vary somewhat from the holotype and are distinguished as Morphotypes A and B, below. H. dameriacensis Keij 1958 has a similar shape to H. mongoensis but differs in its less angular posterodorsal loop, its smooth rounded subcentral tubercle, and in the way the posterodorsal ridge joins the dorsal and ventral ridges; this junction is defined better than in H. mongoensis. Pl. 22, figs 3-7 FIGURED SPECIMENS. Two female valves, OS 8238-9, and a male left valve, OS 8240. Sample FCRM 1578, coastal cliff west of Ras Tapuri; Middle Oligocene. Morphotype A OTHER MATERIAL. Seven specimens. DIMENSIONS (um). L H W Female right valve OS 8238 810 450 270 Female left valve OS 8239 745 445 245 Male left valve OS 8240 840 455 280 REMARKS. Morphotype A differs from typical H. mongoensis in details of ornamentation; the posterodorsal loop is less sharp and the parts of the median ridge are differently arranged. Morphotype A clearly represents an earlier stage in the evolutionary development of Hermanites mongoensis, s. str. Morphotype B Pl. 22, figs 8-10 FIGURED SPECIMEN. A male left valve, OS 8242. Sample FCRM 1578, coastal cliff west of Ras Tapuri; Middle Oligocene. The only specimen. DIMENSIONS (pm). L H W Male left valve OS 8242 710 370 = 235 REMARKS. Morphotype B is rectangular. In lateral view the ventral margin is strongly modified by the overhanging ventral ridge, which gives it a distinctive shape. Hermanites percultus sp. nov. Pl. 21, figs 7-12; Fig. 8 NAME. ‘Highly ornamented’, with reference to the strongly reticulated surface. DIAGNOsIS. A species of Hermanites with a strongly reticulate lateral surface, a straight, pronounced ventral ridge and a raised posterodorsal tubercle, which gives it a characteristic appearance in dorsal view. HOoLotyPe. A female carapace, OS 8226. Five carapaces, OS 8227-31, are paratypes. Sample FCRM 2033, Lindi Creek, east shore; Upper Eocene. OTHER MATERIAL. Two specimens. PLATE 21 227 Fig. 8 Hermanites percultus sp. nov. Paratype OS 8227. Carapace from left, lateral surface showing the ornament. 110. 1-8, the ridges described in the text. DESCRIPTION. Carapace subrectangular in lateral view, with greatest height at anterior cardinal angle. Dorsal and ventral margins straight, converging slightly towards posterior. Anterior margin broadly rounded with a very distinct anterior cardinal angle; it has 18-20 marginal denticles. Posterior margin curving into ventral margin in lower half and concave posterodorsally; it has three to five large, strong marginal denticles. In dorsal view, greatest width in anterior third. Posterodorsal tubercles give carapace a winged appearance. Sexes distinct; while presumed females are more rectangular, with dorsal and ventral margins subparallel, presumed males taper posteriorly. Surface strongly reticulate, fossae being subrectangular. There are eight longitudinal ridges, here numbered from top to bottom for convenience in description. Ridge 1-3 are well developed posteriorly and subparallel forward to mid-length, losing their identities further forward; ridge 4 runs from anterior to posterior and includes the rather small subcentral tubercle; 5 and 6 are subparallel to 4 anteriorly but lose their identities further back; ridge 7 is straight and strong, running parallel to the ventral margin; ridge 8 is a continuation of the anterior marginal rim and runs as far as mid-venter, where it is replaced by another short ridge running parallel to the ventral margin. Duplicature fairly wide, narrowing slightly towards anterodorsal margin. Selvage very well developed, running almost in the middle of marginal zone but curving in mid-ventral region, where it is raised and is concave to outer margin. Normal pore canals few and widely spaced. Marginal pore canals fairly numerous, straight and simple, mostly concentrated along the antero- dorsal margin. Muscle scars cannot be seen in any adult specimens, but in the less calcified juveniles the frontal scar is crescentic. Hinge strongly developed, consisting of a strong anterior knob-like tooth, post-jacent socket, a crenulate bar and a very backwardly placed, elongate posterior tooth. Figs 1-6 Hermanites carchesium sp. nov. Figs 1, 2, paratype, male carapace, OS 8225; 1, lateral view from left, x55; 2, lateral view from nght, x54. Fig. 3, paratype, male carapace, OS 8224, dorsal view, X63. Figs 4-6, holotype, female carapace, OS 8223; 4, lateral view from left, x55; 5, lateral view from right, X57; 6, dorsal view, X59. Figs 7-12 Hermanites percultus sp. nov. Figs 7-9, paratype, male carapace, OS 8227; 7, lateral view from left, X57; 8, lateral view from mght, x56; 9, dorsal view, X61. Figs 10-12, holotype, female carapace, OS 8226; 10, lateral view from left, X59; 11, lateral view from right, X58; 12, dorsal view, X65. 228 AHMAD, NEALE & SIDDIQUI TERTIARY OSTRACODA FROM THE LINDI AREA, TANZANIA DIMENSIONS (yum). L H WwW Holotype, female carapace OS 8226 695 440 340 Paratype, male carapace OS 8227 760 445 = 350 REMARKS. H. percultus is quite distinct from all the other Hermanites species described so far, but is tentatively placed in that genus because of some internal details and the pattern of exterior ridges. In general shape it also re- sembles a number of species described under Bradleya Hornibrook 1952, and Agrenocythere Benson 1972. H. per- cultus differs from typical Hermanites in the following respects: (i) There is a vestibule, and the line of concrescence and the inner margin do not coincide as in other Hermanites. (ii) The posterior tooth is very backwardly placed in the new species. (iii) The marginal pores are simple, not thickened in the middle as in most species of Hermanites. (iv) H. percultus is rectangular, compared with the usual tapering shape of Hermanites species. (v) The subcentral tubercle is unlike that of typical Hermanites, being more like what Benson (1972) called a bridte. Tribe BRADLEYINI Benson, 1972 Genus BRADLEYA Hornibrook, 1952 TYPE SPECIES. Cythere arata Brady, 1880. Bradleya? sp. A Pl. 23, figs 1-3 FIGURED SPECIMEN. A right valve, OS 8187. Sample FCRM 1566, Mongo Stream, Lindi; Lower Miocene. The only specimen. DESCRIPTION. A species of Bradleya? with strong ventro- lateral carina, posterodorsal loop and subcentral tubercle. Surface smooth with underlying reticular ‘ghost’ pattern. Carapace subrectangular to suboval in lateral view, with greatest height at anterior cardinal angle; tapering posteriorly. Anterior margin symmetrically rounded, posterior bluntly produced and truncate. Dorsal margin modified by dorsal ridge but otherwise straight; ventral margin straight to slightly concave in the anterior half. Ornament consists of a postero- dorsal loop, a ventrolateral carina and a subcentral tubercle. Lateral surface smooth, but with the sort of underlying reticulation termed ‘reticular ghosts’ by Benson (1972). Duplicature moderately wide; selvage well developed, running almost halfway between inner margin and flange. Flange groove prominent. Marginal pore canals, about 17 anteriorly PLATE 22 229 and 8 posteriorly, mostly simple, short and equally spaced. There are four adductor muscle scars, the second from the top being longest, all arranged in a row behind a divided frontal scar. Hinge strongly holamphidont. DIMENSIONS (um). L H W Right valve OS 8187 820 450 310 REMARKS. Bradleya lactea pakaurangia Hornibrook 1952 resembles Bradleya? sp. A in general shape but has a strong posterodorsal loop with the median ridge well developed in the posterior half, whereas Bradleya? sp. A has no median ridge. The conspicuous normal pores of Hornibrook’s species are not present in our African one. B. semiarata Hornibrook is also closely allied to Bradleya? sp. A but has an almost straight posterior marginal outline compared with the bluntly produced posterior of the latter. The generic placement of Bradleya? sp. A is tentative; though it probably belongs to the same genus as B. lactea pakaurangia, it is doubtful whether the latter is congeneric with the type species B. arata (Brady). Bradleya? sp. B Pl. 23, figs 4-5 FIGURED SPECIMEN. A carapace, OS 8328. Sample FCRM 1578, coastal cliff west of Ras Tapuri; Middle Oligocene. OTHER MATERIAL. Four carapaces, including OS 8329, from FCRM 1578. DESCRIPTION. Carapace subrectangular in side view, with greatest height at anterior cardinal angle, valves tapering posteriorly. Anterior margin denticulate, broadly rounded; posterior margin strongly concave in the posterodorsal half and convex posteroventrally. Dorsal margin strongly modified by dorsal ridges; ventral margin slightly concave in anterior half, to almost straight behind. Ornament consists of a marginal ridge running from well-developed eye tubercle along anterior, ventral and posterior margins and parallel to them. Posterodorsal loop-like ridge prominent; subcentral tubercle well developed. Surface smooth except for small compartments enclosed by low ridges along posterodorsal, anterior and ventral margins. No single valves were found so no internal details were seen. DIMENSIONS (1m). iS H WwW Carapace OS 8328 570 315 280 REMARKS. This species is less subrectangular than Bradleya? sp. A, and the dorsal ridge is loop-like rather than straight and mostly parallel to the dorsal margin; also, the ghostly ornamentation is absent. The present species resembles B. lactea pakaurangia Hornibrook, but the outline of the posterior margin is different and the maximum height is Figs 1,2 Hermanites mongoensis sp. nov. Holotype, right valve, OS 8232; 1, external lateral view, x63; 2, internal lateral view, x64. Figs 3-7 Hermanites mongoensis sp. nov., Morphotype A. Figs 3, 4, female right valve, OS 8238; 3, external lateral view, x54; 4, internal lateral view, X54. Figs 5, 6, female left valve, OS 8239; 5, external lateral view, X56; 6, internal lateral view, X59. Fig. 7, male left valve, OS 8240, external lateral view, «54. Figs 8-10 Hermanites mongoensis sp. nov., Morphotype B. Female left valve, OS 8242; 8, external lateral view, 65; 9, ventral view, X65; 10, internal lateral view, x64. Fig. 11 Hermanites carchesium sp. nov. Juvenile left valve, OS 8321, external lateral view, x72. Fig. 12 Bythoceratina sp. A. Right valve, OS 8317, external lateral view, X75. 230 AHMAD, NEALE & SIDDIQUI Sy VSS Oe ER = e; ere Oe Set Oe TERTIARY OSTRACODA FROM THE LINDI AREA, TANZANIA subventral rather than at mid-height as in Hornibrook’s species. Genus QUADRACYTHERE Hornibrook, 1952 TYPE SPECIES. Cythere truncula Brady, 1898. Quadracythere arcana (Lubimova & Guha, 1960) 1960 Cythereis arcanus (sic, recte C. arcana) Lubimova & Guha (in Lubimova et al.): 33; pl. 34, figs 3-5. 1971 Quadracythere (Hornibrookella) arcana (Lubimova & Guha) Siddiqui: 67; pl. 34, figs 3—S. Quadracythere arcana cornigera subsp. nov. Pl. 25, figs 4-8 NAME. ‘Horned’, with reference to the strong posterodorsal alae. HooryPe. A female carapace, OS 7844. Two specimens, OS 7845, 8258, are paratypes. Sample FCRM 2033, Lindi Creek, east shore; Upper Eocene. OTHER MATERIAL. 74 specimens, including juveniles, from samples FCRM 1575, 1578, 2033. See Remarks below for specimens from FCRM 1566 (Lower Miocene), e.g. OS 8257. DIMENSIONS (tm). L H W Holotype, female carapace OS 7844 570. 350 = 330 Paratype, male carapace OS 7845 620 355 350 Juvenile left valve (? this species) OS 8257 485 300 150 REMARKS. The new subspecies differs from Q. arcana s. str., from the Middle Eocene of Kutch, India, in having stronger posterodorsal alae, which give it a different shape in dorsal view. It also shows distinct sexual dimorphism, the presumed males being subrectangular compared with the more quadrate females. Only provisionally classified here are a large number of juvenile single valves from Lower Miocene samples (e.g. FCRM 1566; PI. 25, fig. 8) which may not belong here, but this is the only species which they resemble in shape. Quadracythere? acuta sp. nov. Pl. 24, figs 4-7 NAME. ‘Pointed’, with reference to the posterior extremity. DIAGNOSIS. A species of Quadracythere(?) with coarsely reticulate ornament, the ridges being blade-like. HouotyPe. A female carapace, OS 8245. A male carapace, PLATE 23 231 OS 8247, is a paratype. Sample FCRM 2033, Lindi Creek, east shore; Upper Eocene. OTHER MATERIAL. Two carapaces. Also occurs in FCRM 1578. DESCRIPTION. Carapace medium-sized to large, with greatest height at anterior cardinal angle and greatest length in ventral half. Anterior margin rounded; posterior end acuminate in lateral view, making a pronounced posterior cardinal angle; both margins denticulate. Dorsal margin almost straight, ventral concave in the middle and convex on either side; posterodorsal margin concave. Sexes distinct, presumed males being shorter and more slender than females. Surface coarsely reticulate with sharp muri running predominantly longitudinally. Eye tubercle strongly developed. No internal details seen. DIMENSIONS (1m). L H W Holotype, female carapace OS 8245 810 S00 390 Paratype, male carapace OS 8247 820 485 385 REMARKS. The produced and upturned posterior margin, sharp muri and shape intermediate between Quadracythere and Agrenocythere suggest that this species could be placed in either genus. However, Agrenocythere has no eye tubercle, so the species is tentatively assigned to Quadracythere. Quadracythere distenta sp. nov. Pl. 24, fig. 12; Pl. 25, figs 1-3 NAME. ‘Swollen’, with reference to the carapace. DIAGNosIs. A species of Quadracythere almost quadrate in lateral view, with length to height ratio of 3:2. Ridges on the surface slope longitudinally from the posterodorsal to the anteroventral region. HOLotTyPe. A carapace, OS 8250. Another carapace, OS 8251, is a paratype. Sample FCRM 1989, Likonga bridge; Lower Miocene. OTHER MATERIAL. Four specimens from samples FCRM 1566 (e.g. OS 8252), 1989. DESCRIPTION. Carapace tumid, subquadrate, with greatest height at anterior cardinal angle and greatest width about two-thirds of the length from the front. Anterior margin broadly rounded, posterior margin produced subventrally and obliquely truncated. Posterodorsal margin concave; dorsal and ventral margins modified in lateral view by marginal keels, dorsal margin being otherwise straight and ventral margin concave in the middle. Lateral surface reticulate, predominant lateral ridges sloping from posterodorsally to anteroventrally. Ridges are subparallel to margins along anterior and posterior ends. Duplicature moderately wide. Normal pores fairly numerous and widely scattered. Muscle scars could not Figs 1-3 Bradleya? sp. A. Right valve, OS 8187; 1, external lateral view, X55; 2, internal lateral view, X52; 3, ‘ghost’ reticulation on external lateral surface, < 123. Figs 4,5 Bradleya? sp. B. Carapace, OS 8328; 4, lateral view from right, x76; 5, dorsal view, X79. Figs 6-12 Quadracythere vanga sp. nov. Figs 6, 9, paratype, female left valve, OS 8255; 6, internal lateral view, x63; 9, external lateral view, x63. Fig. 7, paratype, male carapace, OS 8254, lateral view from left, X68. Fig. 8, holotype, male carapace, OS 8253, lateral view from right, x68. Figs 10-12, paratype, female carapace, OS 8256; 10, lateral view from right, 62; 11, dorsal view, x70; 12, ventrolateral view from left, x62. 4 EPS - AHMAD, NEALE & SIDDIQUI TERTIARY OSTRACODA FROM THE LINDI AREA, TANZANIA be seen; hinge and other internal features typical of the genus. DIMENSIONS (um). L Fis Wi Holotype, carapace OS 8250 675 435 410 Left valve OS 8252 640 415 250 REMARKS. Q. hornibrooki Holden 1967 differs from Q. distenta in having the greatest height just behind the anterior margin. Q. kenti sp. nov. (below) is very similar to Q. distenta, but as they have slightly different patterns of ornamentation and Q. distenta is larger, the two are here considered to be distinct species. Quadracythere kenti sp. nov. Pl. 24, figs 8-11 NAME. In honour of the late Sir Peter Kent, F.R.S., in recognition of his contribution to Tanzanian geology. DIAGNOsIs. A subrectangular species of Quadracythere with reticulate surface, about ten ridges running from the posterior towards the anteroventral area. The three ventral ridges curve along, and run parallel to, the anterior and posterior margins. HOLotyPE. A male carapace, OS 8248. A female carapace, OS 8249, is a paratype. Sample FCRM 1989, Likonga bridge; Lower Miocene. OTHER MATERIAL. Two carapaces from the type locality and horizon. DESCRIPTION. Carapace medium-sized, subrectangular in lateral view, with greatest height at anterior cardinal angle and greatest width at mid-length. Anterior margin asymmetrically rounded, posterior produced subventrally. Dorsal margin almost straight; ventral margin straight to slightly concave in the middle. Sexual dimorphism present, presumed females being subquadrate compared with males, which taper pos- teriorly. In dorsal view, carapace lens-shaped. Surface retic- ulate. About ten ridges run posterodorsally to anteroventrally. The three ventral ridges continue along, and run parallel to, the anterior and posterior margins. Ridges alate posterodorsally and posteroventrally. DIMENSIONS (1m). L H WwW Holotype, male carapace OS 8248 640 380 330 Paratype, female carapace OS 8249 595. 360 = 325 REMARKS. Q.? sulcatopunctata (Reuss) subsp. mediterranea Ruggieri, 1962 is the only species of Quadracythere with some resemblance to Q. kenti, but besides some other minor differences of ornamentation, Ruggieri’s subspecies does not have ridges running parallel to the posterior margin. For comparison with Q. distenta see remarks under that 233 Quadracythere subquadra Siddiqui, 1971 P|. 24, figs. 1-3 1971 Q. (Hornibrookella) subquadra Siddiqui: 68; pl. 34 figs 6-11. FIGURED SPECIMEN. A carapace, OS 8243. Sample FCRM 1575, shore south-west of Ras Tapuri; Middle Oligocene. OTHER MATERIAL. 29 specimens from samples FCRM 1574-8. DIMENSIONS (1m). L H W Carapace OS 8243 670 380 320 REMARKS. Siddiqui (1971) described this species from the Upper Chocolate Clays (Upper Eocene) of the Zao River, Pakistan. The Tanzanian specimens differ slightly from these in being more produced posteriorly; they also lack the distinct subcentral tubercle which is characteristic of Pakistani ones. Quadracythere trijugis Holden, 1976 Pl. 25, fig. 9 1976 Quadracythere trijugis Holden: 23, figs 14-15; pl. 5, fig. 24. FIGURED SPECIMEN. A_ right valve, OS 7843. Sample FCRM 2010, stream south-west of Mtwero; Lower Miocene. OTHER MATERIAL. 11 specimens from samples FCRM 1575, 1578, 2010. REMARKS. This species was originally described from the Upper Miocene of the Sand Island hole and the Lower Miocene of the Reef hole, Midway area, Hawaiian Islands. The Tanzanian specimens are identical with Holden’s para- type USNM 184435 (1976: pl. 5, fig. 24) which has been described as ‘young’. The internal details of the Tanzanian specimens suggest that these are juveniles as well. DIMENSIONS (yum). Is H W Right valve, juvenile? OS 7843 595 330-160 Quadracythere vanga sp. nov. Pl. 23, figs 6-12 NAME. ‘A spade’ (late Latin), with reference to the shape in lateral view. DIAGNOosIs. A species of Quadracythere with a strongly protruding anterior cardinal angle, particularly in left valve. HOLotyPe. A male carapace, OS 8253. Three specimens, OS 8254-6, are paratypes. Sample FCRM 1578, coastal cliff west of Ras Tapuri; Middle Oligocene. species. OTHER MATERIAL. Two specimens. PLATE 24 Figs 1-3. Quadracythere subquadra Siddiqui, 1971. Carapace, OS 8243; 1, lateral view from left, x64; 2, lateral view from right, 64; 3, dorsal view, X69. Figs 4-7 Quadracythere? acuta sp. nov. Fig. 4, holotype, female carapace, OS 8245, lateral view from left, x54. Figs 5-7, paratype, male carapace, OS 8247; 5, lateral view from right, X51; 6, dorsal view, X56; 7, lateral view from left, x53. Figs 8-11 Quadracythere kenti sp. nov. Figs 8-10, holotype, male carapace, OS 8248; 8, lateral view from left, x63; 9, lateral view from right, x67; 10, dorsal view, X67. Fig. 11, paratype, female carapace, OS 8249, lateral view from left, x69. Fig. 12} Quadracythere distenta sp. nov. Holotype, carapace, OS 8250, lateral view from right, X58. See also Pl. 25, fig. | AHMAD, NEALE & SIDDIQUI TERTIARY OSTRACODA FROM THE LINDI AREA, TANZANIA DESCRIPTION. Carapace medium-sized, with greatest height at anterior cardinal angle and greatest length subventral. Anterior margin broadly and obliquely rounded towards venter; posterior end with subventral caudal process. Anterior cardinal angle strongly protruding particularly in left valve; dorsal margin almost straight. Lateral surface reticulate. Carapace alate both dorsally and ventrally in the posterior half, ventral alae being sharper and more triangular than dorsal ones. Posterior margin has two or three marginal spines. Sexual dimorphism present, presumed males being narrower posteriorly than females. Duplicature moderately broad and very regular, selvage well developed mid-ventrally. Marginal pore canals obscure but seven or eight false ones visible. Muscle scars also obscure; only a V-shaped frontal scar and two adductor scars are visible. Hinge strongly holamphidont. DIMENSIONS (jim). L H W Holotype, male carapace, OS 8253 585 370 320 Paratype, female left valve, OS 8255 630 405 220 Paratype, male carapace, OS 8254 540 345 285 Paratype, female carapace, OS 8256 610 410 350 REMARKS. Q. vanga is distinguished from the other Tanzanian species and from Q. brachypygaia van den Bold, 1965, from the Oligo-Miocene of Puerto Rico, by its strongly protruding anterior cardinal angle. In this respect it resembles Q. orbignyana (Bosquet) emend. Keij, 1957, but the latter has stronger reticulation. Quadracythere sp. A Pl. 25, figs 10-11 FIGURED SPECIMEN. A carapace, OS 8244. Sample FCRM 2033, Lindi Creek, east shore; Upper Eocene. The only specimen. DESCRIPTION. Carapace subrectangular in lateral view, with greatest height at anterior cardinal angle and greatest width just behind mid-length. Anterior margin broadly rounded; posterodorsal margin concave, posteroventral bluntly pro- duced. Dorsal margin almost straight, making a pronounced cardinal angle with posterior margin. Ventral margin straight to slightly concave in the middle. Lateral surface strongly reticulate, with foveolate muri and the ridges mostly long- itudinal. Ocular ridge strongly developed, running parallel to anterior and ventrolateral margins. No internal details visible. DIMENSIONS (yim). L H WwW Carapace OS 8244 780 490 415 REMARKS. Quadracythere (Hornibrookella) sp. A of Siddiqui, 1971, from the Middle-Upper Eocene Upper Chocolate Clays PLATE 25 235 of the Zao River section, Sulaiman Range, Pakistan, is very similar to Quadracythere sp. A from Tanzania. But while the Tanzanian species is wider behind the middle, Siddiqui’s species is wider in the anterior half. In addition, the fossae in the Tanzanian species are arranged longitudinally, while in the Pakistani species they are somewhat concentrically arranged around the subcentral tubercle. Genus CRENALEYA nov. NAME. From botanical Latin crena, a rounded projection; with reference to the round projecting snap-knob in the right valve of the type species. DIAGNOSIS. Carapace elongate in side view, subrectangular, with dorsal and ventral margins straight and slightly converg- ing posteriorly. Valves inflated ventrally, with greatest width about a third of the length from posterior end. Sexual dimorphism marked. Lateral surface reticulate, with deep fossae and crimped muri; eye tubercle present. Muscle scars not clearly visible in adults, but in less calcified juveniles the pattern consists of four adductor scars arranged in a row, with a V-shaped frontal scar. Hinge strongly holamphidont, closure further strengthened by a ventral snap-knob in right valve. There is no socket in left valve; instead the knob rests against the external surface of the mid-ventral margin. TYPE SPECIES. Crenaleya tuberis sp. nov. REMARKS. The new genus appears to be related to Oertliella Pokorny, 1964a, Bradleya Hornibrook, 1952, Urocythereis Ruggieri, 1950, Agrenocythere Benson, 1972, Phalcocythere Siddiqui, 1971, and some species of Hermanites Puri, 1955. It can be distinguished from Oertliella by the absence of a strong ventrolateral ridge, a dorsal ridge often reduced to spines, and a hemiholamphidont hinge, all of which are characteristic of Oéertliella. Crenaleya differs from Bradleya in lacking dorsal and ventral ridges, which are found in that genus. In side view, Crenaleya resembles Urocythereis, but in dorsal view the latter is lens-shaped, while the former is trapezoid, being very wide posteriorly; also, Urocythereis has the frontal muscle scar divided. Phalcocythere has a ventral ridge, distin- guishing it from the new genus. Some species of Agrenocythere (e.g. A. pliocenica (Segueza)) and Hermanites (e.g. H. volans Neale, 1975) resemble the new genus, but they all have dorsal and/or ventral ridges; Agrenocythere also lacks eye tubercles. The new genus is further distinguished by the ventral snap- knob in the right valve and by the posteroventral inflation. It is not known whether Bradleya? cornuelina (Bosquet) emend. Keij, 1957, B.? voraginosa Siddiqui, 1971, Oertliella sp. A of Donze et al. , 1970, and Genus Indet. Sp. 1 of Dingle, Figs 1-3. Quadracythere distenta sp. nov. Fig. 1, holotype, carapace, OS 8250, dorsal view, X64; see also PI. 24, fig. 12. Figs 2, 3, left valve, OS 8252; 2, external lateral view, X61; 3, internal lateral view, 66. Figs 4-8 Quadracythereis arcana (Lubimova & Guha) cornigera subsp. nov. Fig. 4, paratype, male carapace, OS 7845, lateral view from right, x72. Figs 5-7, subspecific holotype, female carapace, OS 7844; 5, lateral view from left, 72; 6, lateral view from right, 71; 7, dorsal view, x82. Fig. 8, juvenile left valve, possibly not this species (see text, p. 231), OS 8257, external lateral view, x85. Fig. 9 Quadracythere trijugis Holden, 1976. Juvenile? right valve, OS 7843, external lateral view, 76. Figs 10, 11 Quadracythere sp. A. Carapace, OS 8244; 10, lateral view from left, x53; 11, dorsal view, X56. Fig. 12 Crenaleya tuberis gen. et sp. nov. Holotype, female right valve, OS 8259, snap-knob as seen at mid-ventral margin, X 600. See also PI. 26, figs 1, 3. 136 AHMAD, NEALE & SIDDIQUI TERTIARY OSTRACODA FROM THE LINDI AREA, TANZANIA 1976 have a snap-knob mechanism or not, but on the basis of shape and ornamentation these species belong to Crenaleya. Crenaleya tuberis sp. nov. PI. 25, fig. 12; Pl. 26, figs 1-5, 9 NAME. ‘With a swelling’, in reference to its ventrolateral swelling. DiaGnosis. A Crenaleya with elongate, subrectangular carapace, gently tapering posteriorly in lateral view; ventro- lateral swelling terminating in a tubercle in the posterior third. Sexual dimorphism pronounced. Surface reticulate, with trifoliate pits. Ho.otyPe. A female left valve, OS 8259. Ten specimens, OS 8260-1, 8263-70, are paratypes. Sample FCRM 1578, coastal cliff west of Ras Tapuri; Middle Oligocene. OTHER MATERIAL. 18 specimens from the locality and horizon above. Also occurs in FCRM 1575 and 1576. DESCRIPTION. Carapace medium-sized to large, subrectangular in side view; dorsal and ventral margins subparallel, tapering slightly posteriorly. Anterior margin symmetrically rounded, posterodorsal margin concave; gently convex posteroventral margin slightly produced. There are 14-17 anteroventral and 4-6 posterior marginal denticles. Sexual dimorphism marked; presumed females higher in proportion to their length and wider than males. Lateral surface reticulate. The muri have short spines projecting into the fossae, giving them a crimped and trifoliate shape. Subcentral tubercle present, less prominent than a wide tuberculate ventrolateral swelling at about a third the length from posterior end, where carapace attains greatest width. Eye tubercle prominent and glassy. Duplicature moderately wide; line of concrescence coincides with inner margin so there is no vestibule. Right valve has a midventral snap-knob which rests against the mid-ventral margin of left. Hinge strongly holamphidont; in the right valve the conical anterior tooth has a post-jacent socket joined to an elongate elevated tooth by a smooth groove. DIMENSIONS (1m). ay Wi Holotype, female right valve OS 8259 = =700° 410 220 Paratype, female carapace OS 8263 720 420 420 Paratype, male right valve OS 8260 810 425 255 REMARKS. C. tuberis resembles Gen. Indet. 3 sp. 1 of Dingle, 1971, but the latter has a distinct marginal rim which the new species lacks. Crenaleya sp. A Pl. 26, figs 10-12 FIGURED SPECIMEN. A carapace, OS 8271. Sample FCRM 2014, stream south-west of Mtwero; Lower Miocene. The only specimen. DESCRIPTION. A distinctive rectangular species of Crenaleya with two very strong horn-like spines at the posteroventral PLATE 26 237 angle. Carapace large, elongate; rectangular in side view with greatest width in posterior half. Dorsal and ventral margins parallel; anterior symmetrically rounded with about 14 marginal denticles. Posterodorsal margin makes a prominent cardinal angle with dorsal, meeting posteroventral margin at an obtuse angle at a point slightly below mid-height. Posterior margin has two posterodorsal and two much larger horn-like posteroventral spines. Lateral surface reticulate; muri have short spines which project into the fossae, giving them an ornate three- to six-rayed appearance. Eye tubercle well developed and glassy. A right valve, from Mafia SP/40’, kept at the BP Research Centre, Sunbury-on-Thames, has a mod- erately wide duplicature with line of concrescence separated from inner margin by a vestibule; there is a ventral snap- knob. There are four adductor scars and a V-shaped frontal scar as in the less calcified juveniles of the type species; hinge holamphidont. DIMENSIONS (1m). L H W Carapace OS 8271 1090 525 510 Crenaleya? sp. Pl. 26, figs 6-8 FIGURED SPECIMEN. A male left valve, OS 8262. Sample FCRM 1578, coastal cliff west of Ras Tapuri; Middle Oligocene. The only specimen. DIMENSIONS (jum). L H W Male left valve OS 8262 1070 520 325 REMARKS. This specimen is placed in the genus Crenaleya with reservations because it differs markedly from the type species C. tuberis in lateral outline, particularly at the posterior margin. It is highest at the posterior third, in this differing from both C. tuberis and C. sp. A, which are highest at the anterior cardinal angle. Genus UROCYTHEREIS Ruggieri, 1950 TYPE SPECIES. Cytherina favosa Roemer, 1838. Urocythereis salebrosa sp. nov. Pis2/, tig: 1 NAME. ‘Rough, rugged’, with reference to the surface ornamentation. DraAGnosis. A species of Urocythereis with coarsely reticulate surface and fossae forming characteristic ventrolateral slits. Ho.otyPe. A left valve, OS 7987. Two valves, OS 8272-3, are paratypes. Sample FCRM 2010, stream south-west of Mtwero; Lower Miocene. OTHER MATERIAL. Two single valves from the same locality and horizon. DESCRIPTION. Carapace medium-sized, subrectangular in side view, with greatest height at anterior cardinal angle. Anterior Figs 1-5,9 Crenaleya tuberis gen. et sp. nov. Figs 1, 3, holotype, female right valve, OS 8259; 1, external lateral view, x61; 3, internal lateral view, X63; see also PI. 25, fig. 12. Figs 2, 9, paratype, female carapace, OS 8263; 2, dorsal view, X62; 9, lateral view from right, x66. Figs 4, 5, paratype, male right valve, OS 8260; 4, external lateral view, X58; 5, dorsal view, x58. Figs 6-8 Crenaleya? sp. Male left valve, OS 8262; 6, external lateral view, 43; 7, internal lateral view, 43; 8, dorsal view, x43. Figs 10-12 Crenaleya sp. A. Carapace, OS 8271; 10, lateral view from left, X41; 11, lateral view from right, X41; 12, dorsal view, x41 238 margin well rounded, somewhat oblique below; posterior bluntly produced, with straight to concave posterodorsal margin; marginal denticles very few or absent. Dorsal and ventral margins straight and subparallel. Surface coarsely reticulate with some fossae joining to form prominent slits, especially ventrolaterally. Eye tubercle very weakly developed. Duplicature narrow, hinge typical of genus. No other internal features were seen. DIMENSIONS (1m) L H W Holotype, left valve OS 7987 760 410 270 REMARKS. The shape and pattern of U. salebrosa have some affinity with those of U. sorocula (Seguenza) of Uliczny, 1969, but in other details the two are dissimilar. The most apparent difference is that U. sorocula has an elongate groove more or less parallel to the anterior margin and the Tanzanian species has not. Urocythereis? apolegma sp. nov. Pl. 27, figs 2-4 NAME. ‘Hem of a robe’ (Greek), with reference to the marginal rim. DIAGNOsIS. A species with a well-developed marginal rim and a single row of deep subquadrate fossae along the anterior and posterior margins. HoLotyPe. A male carapace, OS 8276. Five specimens, OS 8275, 8277, 8279-81, are paratypes. Sample FCRM 1578, coastal cliff west of Ras Tapuri; Middle Oligocene. OTHER MATERIAL. Two specimens from the same locality and horizon, and one (OS 8278) from FCRM 2010, Lower Miocene. Also occurs in FCRM 1576. DESCRIPTION. Carapace medium-sized to large, subrectangular- elongate in side view, with greatest width in front of posterior margin. Anterior margin rounded, posterior subrounded to angulate in the middle; anterior and posteroventral margins denticulate. Dorsal margin straight; ventral margin gently concave. Species dimorphic; in dorsal view, presumed females more swollen than presumed males. Lateral surface reticulate; a strong marginal rim is present all round the carapace, with a row of deep fossae just within the anterior and posterior parts. Elsewhere fossae are elongate, with muri bearing short spines giving them a crimped appearance. Eye tubercle more or less distinct. Duplicature moderately wide along anterior and posterior margins and considerably wider along ventral margin; duplicature coincides with inner margin. Selvage runs near, and parallel to, outer margin; selvage groove well developed. Muscle scars not visible; hinge weakly holamphidont. PLATE 27 Fig. 1 AHMAD, NEALE & SIDDIQUI DIMENSIONS (um). L H W Holotype, male carapace OS 8276 870 400 355 REMARKS. Gen. Indet. 3 sp. 1 of Dingle (1976: 52, fig. 9(4)) is extremely similar to U.? apolegma, but Dingle’s species has less well developed anterior and dorsal marginal ridges. The uncertainty about the muscle scars and the general external habitus make it doubtful that this species belongs to Urocythereis; however, no closer assignment is possible at present. Subfamily ORIONININAE Puri, 1974 Genus ANTEROCYTHERE McKenzie & Swain, 1967 TYPE SPECIES. Anterocythere purii McKenzie & Swain, 1967 Anterocythere sp. B of Swain & Gilby, 1974 Pl. 27, figs 11-12; Pl. 28, fig. 1 1974 Anterocythere sp. B Swain & Gilby: 316; pl. 7, fig. 2. FIGURED SPECIMEN. An immature right valve, OS 7813. Sample FCRM 1566, Mongo Stream, Lindi; Lower Miocene. OTHER MATERIAL. Eight immature single valves, from FCRM 1566 (OS 7821), 1737, 1738, 1742, 1745, 1989, 2014, 2015. DIMENSIONS (1m). L HW Right valve OS 7813 465 235 095 REMARKS. The genus Anterocythere seems to have been based on external ornamentation, which differs slightly from that of Caudites and Orionina, all three genera being identical internally. Orionina is well established and differs substantially from Caudites, being reticulate rather than smooth in the intercostal areas, but Anterocythere is neither well established nor much different from the other two. In fact an analogy may be drawn with some other genera which were erected a very long time ago on the basis of external ornament inter- mediate between that of two related genera, but which are still a source of considerable confusion. No adult specimens of Anterocythere were found in the Tanzanian sediments, hence Swain & Gilby’s open nomenclature is retained; while the genus is retained here, grave doubt must attach to its value as a separate entity. There is a striking resemblance between this taxon and Caudites cf. rosaliensis Swain, p. 240 (compare Pi. 28, fig. 1 with Pl. 27, fig. 7). However, in Anterocythere sp. B the principal posterior rib terminates in the middle of the posterior Urocythereis salebrosa sp. nov. Holotype, left valve, OS 7987, external lateral view, x60. Figs 24 Urocythereis? apolegma sp. nov. Holotype, male carapace, OS 8276; 2, lateral view from right, x53; 3, dorsal view, x52; 4, lateral view from left, «52. Fig. 5 Bythoceratina? asteria sp. nov. Holotype, left valve, OS 8116, external lateral view, x65. Figs 6,10 Caudites sp. Right valve, OS 7812; 6, external lateral view, 92; 10, internal lateral view, x94. Figs 7-9 Caudites cf. rosaliensis Swain, 1967. Carapace, OS 7822; 7, lateral view from right, x80; 8, dorsal view, X82; 9, lateral view from left, x79. Figs 11,12 Anterocythere sp. B of Swain & Gilby, 1974. Right valve, OS 7813; 11, dorsal view, x99; 12, internal lateral view, x101. See also PI. 28, fig. 1. TERTIARY OSTRACODA FROM THE LINDI AREA, TANZANIA 239 240 margin of the caudal process, whereas in C. cf. rosaliensis it terminates in the ventral margin of the caudal process. We consider that the one cannot be regarded as a juvenile of the other. Nevertheless, the similarity sustains our doubts about the distinction of Anterocythere as a seperate genus from Caudites. Genus CAUDITES Coryell & Fields, 1937 TYPE SPECIES. C. medialis Coryell & Fields, 1937. Caudites sp. Pl. 27, figs 6, 10 FIGURED SPECIMEN. A right valve, OS 7812. Sample FCRM 1661, near top of old garnet mine, Lindi; Lower Miocene. OTHER MATERIAL. Four specimens, including one broken valve from FCRM 1989, and two valves (e.g. OS 7815) from FCRM 1566. DESCRIPTION. Valves robust, tapering posteriorly, with gently sloping dorsal, and strongly concave posterodorsal, margins. Greatest height at anterior cardinal angle, greatest length below mid-height. Anterior margin gently rounded towards venter; posterior end drawn out, giving valves a subtriangular shape. Ventral margin slightly concave. External ornament consists of a number of strongly developed ridges; one runs from eye tubercle towards anteroventral margin; another runs from anteroventral margin to mid-length, where it forms a subcentral tubercle, then turns down and runs for a short distance parallel to ventral margin. The ventral ridge, less well developed than the upper one, runs parallel to the latter and joins it below the subcentral tubercle. There is a typical Caudites U-shaped ridge in the posterior half. Intercostal reticulation absent. Internally, marginal pore canals numerous, short, straight, and parallel to each other. No inframarginal pillar structures or muscle scars visible; hinge holamphidont. DIMENSIONS (um). L H W Right valve OS 7812 490 275 120 REMARKS. The subcentral tubercle-like knot formed by the median ridge distinguishes the Tanzanian species from most others; the intermarginal pillar structures so characteristic of this genus were not seen in this species. Caudites cf. rosaliensis Swain, 1967 Pl. 27, figs 7-9 cf. 1967 cf. 1967 Caudites rosaliensis Swain: 80; pl. 5, figs 9-11, 13. Caudites rosaliensis Swain; McKenzie & Swain: 295; pl. 20, fig. 17a—c; text-fig. 20. Caudites rosaliensis Swain, Swain: 467; pl. 3, figs 4a—c, 7a—b; pl. 10, figs 10a—b. cf. 1969 PLATE 28 Fig. 1 AHMAD, NEALE & SIDDIQUI Caudites sp. C Swain: 467; pl. 3, figs 6a—b. Caudites rosaliensis Swain; Swain & Gilby: 311; pl. 4, figs 10-11, 13. cf. 1969 cf. 1974 FIGURED SPECIMEN. A_ carapace, OS 7822; specimen lost. Sample FCRM 2010, stream south-west of Mtwero; Lower Miocene. DIMENSIONS (1m). I: Ho W Carapace OS 7822 570 255 170 REMARKS. The Tanzanian species is similar to Swain’s in its outline and ornament. The only apparent difference between the two is that in the Tanzanian species the median ridge does not run from the posterior end towards the anteroventral margin; instead it is stepped, and joined to the ventral marginal ridge. Family LOXOCONCHIDAE Sars, 1926 Subfamily LOXOCONCHINAE Sars, 1926 Genus LOXOCONCHA Sars, 1866 TYPE SPECIES. Cythere rhomboidea Fischer, 1855. Subgenus LOXOCONCHA Sars, 1866 Loxoconcha (Loxoconcha) mbanjaensis sp. nov. PI. 28, figs 11-12; Pl. 29, figs 1-5 NAME. After the Mbanja river, the type locality. DIAGNOSIS. A subrhomboidal species of Loxoconcha, with the greatest height and width in the middle. Surface with concentrically arranged pits. Ho.otyPe. A female carapace, OS 8096. A female left valve OS 8097, and a male carapace, OS 8099, are paratypes. Sample FCRM 1746, Mbanja River; Lower Miocene. OTHER MATERIAL. Seven specimens from FCRM_ 1566 (OS 8101-2), 1661 (OS 8100), 1989 (OS 8103-4), and 2015 (8105-6). Also occurs in FCRM 1737, 1745, 2010 and 2016. DESCRIPTION. Carapace subrhomboidal in lateral view, with greatest height and width almost in the middle. Anterior margin obliquely rounded; posterior end slightly produced subdorsally, with concave posterodorsal margin and convex posteroventral margin. Dorsal margin concave to very gently curved, ventral straight to concave in anterior half and convex in posterior half. Sexual dimorphism marked, carapaces of presumed males being narrower and more elongate. Left valve overlaps right; overlap not pronounced. Lateral surface pitted; pits elongate and arranged concentrically along valve Anterocythere sp. B of Swain & Gilby, 1974. Right valve, OS 7813, external lateral view, X97. See also PI. 27, figs 11-12. Figs 2~7_ Hemicytherura subulata sp. nov. Fig. 2, holotype, male right valve, OS 8300, external lateral view, x 126. Figs 3, 6, paratype, female left valve, OS 8301; 3, external lateral view, x 132; 6, internal lateral view, x 135. Fig. 4, male left valve, OS 8305, external lateral view, x 133. Figs 5, 7, paratype, female right valve, OS 8304; 5, dorsal view, x 147; 7, external lateral view, x 134. Figs 8-10 Kangarina sp. Carapace, OS 7983; 8, dorsal view, < 134; 9, lateral view from left, x 131; 10, lateral view from right, x 137. Figs 11,12 Loxoconcha (Loxoconcha) mbanjaensis sp. nov. Fig. 11, paratype, female left valve, OS 8097, external lateral view, x78. Fig. 12, holotype, female carapace, OS 8096, dorsal view, X99; see also PI. 29, fig. 5. TERTIARY OSTRACODA FROM THE LINDI AREA, TANZANIA 241 PRs Sao Pe OSG Ra ae (ee: 242 AHMAD, NEALE & SIDDIQUI TERTIARY OSTRACODA FROM THE LINDI AREA, TANZANIA margins, rounded on lateral surface. Eye spot very low, consisting of a large, opaque surface. Duplicature wide anteriorly and ventrally; inner margin and line of concrescence coincide except along anterior and posterodorsal margins where narrow vestibules are present. Selvage prominent. Marginal pore canals simple, straight and widely spaced. Normal pores moderately numerous, scattered and of various sizes. Hinge typically gongylodont, consisting of an anterior socket followed by a crenulate bar and an elongate posterior socket in the left valve. DIMENSIONS (um). L H W Holotype, female carapace OS 8096 465 305 255 Paratype, female left valve OS 8097 485 305 150 Paratype, male carapace OS 8099 610 375 315 Female right valve OS 8100 460 275 140 REMARKS. The present species is closest to L. yazooensis Huff 1970, but the less concentric arrangement of pits and the smooth muri of the Tanzanian species easily distinguish them. Subgenus LOXOCORNICULUM Benson & Coleman, 1963 TYPE SPECIES. Cythere fischeri Brady, 1869a. Loxoconcha (Loxocorniculum) postnodosa sp. nov. Pl. 29, figs 11-12; Pl. 30, figs 1-4 NAME. A reference to the posterodorsal node. DIAGNOSIS. A species of Loxoconcha with pronounced sexual dimorphism. In lateral view, the valves are rhomboidal, with the dorsal and ventral margins almost parallel to each other. HOLOTYPE. A male carapace, OS 8092. A female carapace, OS 8093, is a paratype; specimen lost. Sample FCRM 1566, Mongo Stream, Lindi; Lower Miocene. OTHER MATERIAL. Ten specimens from samples FCRM 1566 (e.g. OS 8091), 1575. Also occurs in FCRM 1574, 1576, 1578, 1628 and 1989. DESCRIPTION. Carapace thickly calcified, rhomboidal, with greatest height and width in the middle. Anterior margin obliquely rounded towards the venter; posterior end up- turned, forming a caudal process above mid-height. Dorsal margin straight and parallel to ventral, which is straight in the anterior half and curves upwards just behind mid-length. In dorsal view, carapace lens-shaped. Sexual dimorphism very pronounced, presumed males being more elongate than presumed females; females more tumid. Left valve larger than right; overlap not pronounced. Lateral surface coarsely pitted, pits being arranged almost parallel to outer margins. PLATE 29 243 There is a prominent tubercle just below the posterior cardinal angle, also an eyespot. Internal features characteristic of genus. DIMENSIONS (yum). LL H W Holotype, male carapace OS 8092 540 305 250 Paratype, female carapace OS 8093 465 295 240 REMARKS. Loxoconcha abrupta Hornibrook 1952 is compar- atively more ovate and has a stronger posterior tubercle; the posterior margin of L. abrupta is truncate in dorsal view whereas it is slightly produced in the new species. L. pentockensis Kingma 1948 is another species resembling L. postnodosa in some respects, but it differs in having a comparatively concave ventral margin and a more curved dorsal margin. L. postdorsalata Puri 1960 has a sinuous ventral margin with slight concavity anterior to the middle, whereas L. postnodosa has an almost straight ventral margin. Two morphotypes are distinguished: see below. Morphotype A Pl. 30, fig. 5 FIGURED SPECIMEN. A male right valve, OS 8094. Sample FCRM 1575, shore south-west of Ras Tapuri; Middle Oligocene. REMARKS. Morphotype A differs from typical Loxoconcha (Loxocorniculum) postnodosa in being more oblong, with a greater length/height ratio. The posteroventral curve is more gentle, and the posterodorsal tubercle is much reduced. DIMENSIONS (um). L H WwW Male right valve OS 8094 530 260 140 Morphotype B Pl. 30, figs 6-7 FIGURED SPECIMEN. A male carapace, OS 8095. Sample FCRM 1575, shore south-west of Ras Tapuri; Middle Oligocene. REMARKS. Morphotype B is like Morphotype A in most respects, but differs in having more and smaller pits, all of which are circular, and in the ventral margin being compar- atively straight. In dorsal view it is more pencil-shaped than the lenticular L. postnodosa, s. str. DIMENSIONS (tm). 7 H W Male carapace OS 8095 530 305° 250 Loxoconcha (Loxocorniculum) tricornis sp. nov. Pl. 30, figs 8-9 Name. ‘Three-horned’, with reference to three tubercles in the posterior half of the valves. Figs 1-5 ~Loxoconcha (Loxoconcha) mbanjaensis sp. nov. Fig. 1, female right valve, OS 8100, internal lateral view, x92. Figs 2-4, paratype, male carapace, OS 8099; 2, lateral view from left, x69; 3, lateral view from right, X69; 4, dorsal view, X77. Fig. 5, holotype, female carapace, OS 8096, lateral view from left, X77; see also Pl. 28, fig. 12. Figs 6-10 Loxoconcha (Loxocorniculum) cf. longispina Keij, 1953. Figs 6, 7, female carapace, OS 7958; 6, ventrolateral view from left, x81; 7, anteroventral view, X81. Figs 8, 9, female left valve, OS 7959; 8, external lateral view, X88; 9, internal ventrolateral view, X86. Fig. 10, female left valve, OS 7960, internal lateral view, x88. Figs 11, 12 Loxoconcha (Loxocorniculum) postnodosa sp. nov. Holotype, male carapace, OS 8092; 11, lateral view from left, x80; 12, lateral view from right, 82. See also PI. 30, fig. 1. 244 AHMAD, NEALE & SIDDIQUI TERTIARY OSTRACODA FROM THE LINDI AREA, TANZANIA DIAGNOsIS. Valves small and subrectangular. Surface with two prominent ridges in the anterior half and three tubercles in the posterior half. HoLotype. A female left valve, OS 8107. Three specimens, OS 8108-10, are paratypes. Sample FCRM 1566, Mongo Stream, Lindi; Lower Miocene. MATERIAL. Five specimens from FCRM 1566, 2014 (e.g. OS 8111-2). Also occurs in FCRM 2015 and 2016. DESCRIPTION. Carapace subrectangular in side view, with obliquely rounded anterior margin; posterodorsal margin concave to straight; posteroventral margin convex to straight. Dorsal and ventral margins subparallel. Sexual dimorphism marked, higher forms being interpreted as females. External surface strongly reticulate, with two prominent longitudinal ridges in anterior half and three tubercles in posterior half of each valve. Eye tubercle strongly developed. Duplicature moderately wide. Selvage strongly developed, running near outer margin. Muscle scars, hinge and other internal details characteristic of genus. DIMENSIONS (um). Ie Fle ci on WV. Holotype, female left valve OS 8107 470 265 150 Paratype, male left valve OS 8108 450 235 - REMARKS. L. antillea var. rugosa van den Bold, 1946, is related to Loxoconcha tricornis, but differs in having a rather irregular posteroventral margin; the two anterior ridges seem to be shorter and more convergent than in the Tanzanian species. Loxoconcha (Loxocorniculum) cf. longispina Keij, 1953 Pl. 29, figs 6-10 cf. 1953. Loxoconcha alata Brady var. longispina Keij: 160; pl. 1, figs 10a, b. cf. 1967 Loxoconcha longispina Keij; Holden: 32-34, figs 23a-d. cf. 1976 Loxoconcha longispina Keij; Holden: F32; pl. 4, fig. 14; pl. 5S, figs 3-6; pl. 14, figs 12-15. FIGURED SPECIMENS. A female carapace, OS 7958; two valves, OS 7959, 7960. Sample FCRM 1578, coastal cliff west of Ras Tapuri; Middle Oligocene. OTHER MATERIAL. Seven specimens, from the same sample. Also occurs in FCRM 1576, 2014 and 2016. REMARKS. The Tanzanian specimens are very similar to Holden’s from the Midway area, Hawaiian Islands, and may even be conspecific. Holden (1976) mentions that this species PLATE 30 245 is very variable, the Pleistocene(?) specimens not being as strongly alate as his Miocene specimens. The Tanzanian specimens are strongly alate and come from the Mid- Oligocene. It seems therefore that the species originated as a strongly alate form on the western coast of the Indian Ocean. DIMENSIONS (tm). L H W Female carapace OS 7958 470 290 350 Female left valve OS 7959 475 285 220 Female left valve OS 7960 480 290 200 Subgenus MYRENA Neale, 1967 TYPE SPECIES. Loxoconcha meridionalis Miiller, 1908. Loxoconcha (Myrena) loculus sp. nov. _ PI. 30, figs 10-12 NAME. ‘Box’ or ‘purse’, with reference to its shape in side view. DIAGNOSIS. A species of Loxoconcha with a dorsal marginal ridge and strongly reticulate surface. HOLOTYPE. A carapace, OS 8282. Six specimens, OS 8283-8, are paratypes. Sample FCRM 2033, Lindi Creek, east shore; Upper Eocene. OTHER MATERIAL. Three specimens from samples FCRM 2034 and 2046. Also occurs in FCRM 2045. DESCRIPTION. Carapace small, subrectangular, with almost uniform height but varying width. Anterior margin broadly rounded towards venter; posterior produced subdorsally. Dorsal and ventral margins straight and subparallel; poster- odorsal and posteroventral margins straight to slightly con- cave. External surface reticulate, with comparatively large rectangular fossae arranged parallel to margin. Dorsal margin strongly modified by a wavy rim. Left valve overlaps right slightly. Eye tubercle well developed. Internal details not visible because of small size and poor preservation. DIMENSIONS (1m). Is H W Holotype, carapace OS 8282 370 220 = ©220 REMARKS. The ornament and shape are somewhat akin to those of Kuiperiana nystiana (Bosquet) Keij 1957, but the Tanzanian species is much smaller and has a more produced posterior margin. Figs 1-4 Loxoconcha (Loxocorniculum) postnodosa sp. nov. Fig. 1, holotype, male carapace, OS 8092, dorsal view, X86; see also PI. 29, figs 11-12. Figs 24, paratype, female carapace, OS 8093 (specimen lost); 2, lateral view from left, x84; 3, lateral view from right, *86; 4, dorsal view, X101. Fig. 5 Loxoconcha (Loxocorniculum) postnodosa, Morphotype A. Male right valve, OS 8094, external lateral view, X81. Figs 6,7 Loxoconcha (Loxocorniculum) postnodosa, Morphotype B. Male carapace, OS 8095; 6, lateral view from right, x77; 8, dorsal view, x88. Figs 8,9 Loxoconcha (Loxocorniculum) tricornis sp. nov. Fig. 8, holotype, female left valve, OS 8107, external lateral view, X93. Fig. 9, paratype, male left valve, OS 8108, internal lateral view, x93. Figs 10-12 ~Loxoconcha (Myrena) loculus sp. nov. Holotype, carapace, OS 8282; 10, lateral view from left, x 109; 11, dorsal view, x 115; 12, lateral view from right, X 118. 246 Subgenus PALMOCONCHA Swain & Gilby, 1974 TYPE SPECIES. Palmoconcha laevimarginata Swain & Gilby, 1974. Loxoconcha (Palmoconcha) pinguis sp. nov. Pl. 31, figs 1-3 NAME. ‘Fat’, with reference to the ventral swelling. D1aGnosis. A species of Loxoconcha with pronounced ventrolateral swelling and distinct eye tubercle. Ho.otype. A carapace, OS 828°. A carapace, OS 8290, is a paratype. Sample FCRM 1746, Mbanja River; Lower Miocene. OTHER MATERIAL. Two carapaces from the same locality and horizon. Also occurs in FCRM 1628. DESCRIPTION. Carapace small, subrectangular in side view. Anterior margin obliquely rounded towards venter; posterior margin curved towards dorsum. Dorsal margin straight, ventral margin with concavity about one-third length from front, slightly modified by the overhanging ventrolateral swelling. In dorsal view lens-shaped, much like any other species of Loxoconcha at this angle, in contrast to the striking difference in outline in lateral view. Left valve overlaps right. Surface reticulate; central fossae largest and arranged concentrically. Muri on ventrolateral swelling are stronger than elsewhere. Eye tubercle prominent. DIMENSIONS (um). L H W Holotype, carapace OS 8289 390 235 = =200 REMARKS. From their size, these specimens might appear to be juveniles, but the other Loxoconcha species with similar shapes are all rather small in size. L. watervalleyensis Krutak 1961 is 0-40 long and 0-24 mm high; L. angustata Brady 1869b: 48 is 0-46 mm long (%s inch). Carbonnel (1986) describes a number of Loxoconcha species from the Tertiary of the Senegal-Guinea Bissau Basin. Of these, only his Neogene (Serravallian?/Tortonian?) L. kafountinensis resembles any of our species. This differs from L. pinguis in that the accentuated horizontal costae in the central part of the shell continue to the dorsal margin, whereas in our species they are absent in the upper half of the shell which is occupied by fine pitting. Genus PHL YCTOCYTHERE Keij, 1958 TYPE SPECIES. Phlyctocythere eocaenica Keij 1958. Phlyctocythere reniformis sp. nov. Pl. 31, figs 46 NAME. ‘Kidney-shaped’, with reference to its resemblance to a kidney. PLATE 31 AHMAD, NEALE & SIDDIQUI DIAGNOSIS. A species of Phlyctocythere with a gently arched dorsal margin and compressed posteroventral margin. HouotyPe. A carapace, OS 8292. Seven carapaces, OS 8291, 8293-8, are paratypes. Sample FCRM 1989, Likonga bridge; Lower Miocene. OTHER. MATERIAL. Five carapaces from the same sample. Also occurs in FCRM 1745. DESCRIPTION. Carapace small to medium-sized, kidney- shaped to subrhomboidal in lateral view, with greatest height in middle and greatest width at mid-length or slightly in front of it. Anterior margin rounded, dorsal margin arched; ventral margin almost straight, curved posteroventrally; posterior produced subdorsally. In dorsal view, carapace lens-shaped with slightly elongate posterior margin. Left valve overlaps right, overlap being clearly visible along anterior and ventral margins. Eye tubercle lacking; lateral surface smooth. No internal details visible, since there are no single valves. DIMENSIONS (um). Is H WwW Holotype, carapace OS 8292 425. 265 240 REMARKS. This species resembles Hemicytherura? nealei Swain 1976 in general shape, but is 1-5 times larger and has a compressed zone which is confined to the posteroventral margin, instead of extending to the anterior, posterior and posteroventral margins as is the case in H.? nealei. Family PARACYTHERIDEIDAE Puri, 1957c Genus PARACYTHERIDEA Miiller, 1894 TYPE SPECIES. Paracytheridea depressa Miller, 1894. Paracytheridea anapetes Ahmad, 1977a Pl. 31, figs 10-12; Pl. 32, figs 1-6 1977a_ Paracytheridea anapetes Ahmad: 41-42. FIGURED SPECIMENS. Holotype, female carapace, OS 7757. Paratypes, female left valve, OS 7758; male right valve, OS 7760. Sample FCRM 2034, Lindi Creek, east shore; Upper Eocene. Also male left valve, OS 7759 (not a paratype) from sample FCRM 2033. OTHER MATERIAL. Ten specimens from FCRM 1574 (e.g. OS 7764), 1575 (e.g. OS 7795), 1578, 1627, 1628, 1981, 2014, 2033 (e.g. OS 7759). Also occurs in FCRM 1661, 1989 and 2010. DESCRIPTION. Carapace medium-sized, subtriangular to sub- oval in shape, with greatest height and width in posterior half. Anterior margin rounded, posterior produced into a sub- Figs 1-3. Loxoconcha (Palmoconcha) pinguis sp. nov. Holotype, carapace, OS 8289; 1, lateral view from left, x 115; 2, dorsal view, x 115; 3, lateral view from right, x 105. Figs 4-6 from right, x89. Phlyctocythere reniformis sp. nov. Holotype, carapace, OS 8292; 4, lateral view from left, x89; 5, dorsal view, 105; 6, lateral view Figs 7-9 Uroleberis? sp. Carapace, OS 8308; 7, lateral view from left, x68; 8, dorsal view, x66; 9, lateral view from right, x65. Figs 10-12 Paracytheridea anapetes Ahmad, 1977a. Fig. 10, 12, male left valve, OS 7759; 10, external lateral view, x70; 12, details of ornament in the median area of the surface, 300. Fig. 11, paratype, male right valve, OS 7760, dorsal view, X86; see also PI. 32, fig. 6. TERTIARY OSTRACODA FROM THE LINDI AREA, TANZANIA 248 dorsal caudal process. Dorsal margin strongly modified in lateral view by a bulbous posterodorsal swelling, appearing straight to concave anteriorly and strongly convex posteriorly. In dorsal view dorsal margin straight, carapace broadly arrow- shaped. Sexual dimorphism marked, presumed females having a bulbous swelling and small alar prolongations posterodorsally, while males have a reduced swelling but larger alar prolonga- tions. Lateral surface almost smooth anterodorsally and posteriorly; other areas covered with a characteristic pattern of ridges. A strong ridge runs from mid-anterior margin towards posterodorsal area, where it branches to form several small ones. Ornament completed by other small ridges meeting these branches almost at right angles. Internally, duplicature wide; line of concrescence and inner margin coincide throughout. A very narrow vestibule may be present along anterodorsal margin; this was impossible to verify. Only three anterior and one posterior marginal pore canals visible. There are four adductor muscle scars and a U-shaped frontal scar. Hinge varies slightly from typical Paracytheridea; right valve hinge has 14-15 additional small denticles in front of anterior cusped dental area; left hinge has corresponding sockets. DIMENSIONS (1m). L H WwW Holotype, female carapace OS 7757 595. 325 = 305 Paratype, female left valve OS 7758 560 280 195 Male left valve OS 7759 630 330 290 Paratype, male right valve (juvenile) OS 7760 525. 270 220 REMARK. This species was originally described (Ahmad 1977a) on the present material. Paracytheridea culmen sp. nov. Pl. 32, figs 8-12 NAME. ‘Ridge’, with reference to the ventrolateral ridge. DIAGNOsIS. A species of Paracytheridea with a ventral alar ridge, notched posteriorly. Surface strongly reticulate. HoLotyPe. A female left valve, OS 7790. Three specimens, OS 7839-41, are paratypes. Sample FCRM 2010, stream south-west of Mtwero. OTHER MATERIAL. Ten specimens from samples FCRM 1566, 1575 (e.g. OS 7788), 1578 (e.g. OS 7789), 1648, 2010 (e.g. OS 7791-3), 2014 (e.g. OS 7786-7). Also occurs in FCRM 1989. DESCRIPTION. Carapace small, subtriangular in lateral view, with greatest height at anterior cardinal angle and greatest width in midventral region. Anterior margin symmetrically rounded; posterior produced into a subventral caudal process. Dorsal and ventral margins almost straight, converging posteriorly. Sexual dimorphism occurs, presumed males being lower in proportion to their length. Surface strongly PLATE 32 AHMAD, NEALE & SIDDIQUI reticulate, with thin ridges, irregular swellings and a prominent ventrolateral alar ridge; latter notched just before posterior end and merging gradually with the valve anteriorly. Duplicature moderately wide, not well differentiated. Line of concrescence and inner margin coincide. About eight straight, simple, parallel marginal pore canals occur anteriorly and two posteriorly. Muscle scar pattern obscure; a frontal V-shaped scar and two adductor scars can be seen. Hinge very weakly developed. DIMENSIONS (1m). L H W Holotype, female left valve OS 7790 500 250 190 Paratype, female right valve OS 7788 440 230 140 Paratype, male left valve OS 7787 450 210 150 REMARKS. Compared with P. gradata (Bosquet) emend. Keij, 1957, P. fenestrata (Bosquet) emend. Keij, 1957, and P. belhavensis Howe & Chambers, 1935, P. culmen is more triangular and has a slightly different pattern of ornamentation. : A morphotype is distinguished: see below. Morphotype A Pl. 32, fig. 7 FIGURED SPECIMEN. A male left valve, OS 7838. Sample FCRM 2010, stream south-west of Mtwero; Lower Miocene. OTHER MATERIAL. One valve. DESCRIPTION. Carapace elongate, subrectangular in side view, with greatest height at anterior cardinal angle and greatest length subventrally. Dorsal margin straight to slightly modified by posterodorsal swelling; ventral margin strongly modified externally by ventrolateral alar ridge, but straight when seen from inside. Anterior margin rounded, posterior margin truncate. Surface reticulate, with thin ridges, irregular swel- lings and a prominent anterolateral ridge which is divided in front of the posterior end. Smaller ridges arranged longitudinally below the ventrolateral alar ridge. DIMENSIONS (1m). I H W Male left valve OS 7838 490 230 160 REMARK. Compared with typical P. culmen, Morphotype A is more elongate, less triangular and has a slightly different ornament. Family CYTHERURIDAE Miller, 1894 Subfamily CYTHERURINAE Miller, 1894 Genus TANZANICYTHERE Ahmad, 1977e TYPE SPECIES. Cladarocythere pterota Ahmad, 1977b. Tanzanicythere pterota (Ahmad, 1977b) _ PI. 33, figs 1, 2 1977b Cladarocythere pterota Ahmad: 45-48. Figs 1-6 ~Paracytheridea anapetes Ahmad, 1977a. Figs 1-3, holotype, female carapace, OS 7757; 1, lateral view from left, x79; 2, dorsal view, 81; 3, lateral view from right, x77. Figs 4, 5, paratype, female left valve, OS 7758; 4, external lateral view, x80; 5, internal lateral view, x82. Fig. 6, paratype, male right valve, OS 7760, external lateral view, X91; see also PI. 31, fig. 11. Fig. 7 Paracytheridea culmen sp. nov., Morphotype A. Male left valve, OS 7838, external lateral view, X93. Figs 8-12 Paracytheridea culmen sp. nov. Figs 8, 9, holotype, female left valve, OS 7790; 8, dorsal view, X90; 9, external lateral view, x93. Figs 10, 11, paratype, female right valve, OS 7788; 10, external lateral view, < 101; 11, internal lateral view, x 101. Fig. 12, paratype, male left valve, OS 7787, external lateral view, x 102. TERTIARY OSTRACODA FROM THE LINDI AREA, TANZANIA 249 igs epee Fig. 9 Hemicytherura subulata sp. nov. Holotype OS 8300, @ right valve external lateral view, showing the arrangement of fossae. x 260. FIGURED SPECIMENS. Holotype, right valve OS 7772. Paratypes (unfigured here, but see Ahmad 1977b), left valve OS 7774, right valve OS 7773. Sample FCRM 2010, stream south-west of Mtwero; Lower Miocene. OTHER MATERIAL. Sixteen single valves from samples FCRM 1738, 2010 (e.g. OS 7784-5 and paratypes OS 7775-6), 2015. Also occurs in FCRM 2014. DESCRIPTION. Carapace small to medium-sized, with greatest height at anterior end and greatest width at middle; very fragile. Anterior margin modified externally by the ventrolateral frill but symmetrically rounded when seen from inside. Dorsal margin almost straight; posterior narrowly produced, giving a beaker-shaped appearance in internal view. Seen obliquely from inside, ventral margin almost straight, sub-parallel to dorsal margin, but in external view completely hidden by the overhanging lateral frill. Frill starts in ventral half of anterior margin, gradually increases in width and terminates abruptly anterior to caudal process. Lateral surface smooth except for frill. Three fine longitudinal ridges occur ventral to the frill. One runs just below top of the frill for its full length; the others are much shorter, and stronger in the posterior half than anteriorly. Internally, duplicature moderately wide; vestibule absent. Ten or eleven normal pore canals divide the frill into compartments; these canals are very much like marginal ones, and have been described by Maddocks (1966) as ‘thick straight pore canals’, while Hornibrook (1952) described those in Manawa as ‘septa in the frill’, and Ishizaki (1973) refers to them simply as ‘marginal pore canals’. Three marginal pore canals visible. Four small adductor muscle scars in a vertical row, with three PLATE 33 AHMAD, NEALE & SIDDIQUI larger frontal scars placed dorsally, the lowest of which is V- shaped. Hinge very weak; crenulate anterior and posterior tooth plates in right valve, each with four or five teeth, connected by a crenulate bar. Left valve has complementary elements. DIMENSIONS, including frill (um). L H WwW Holotype, right valve OS 7772 490 270 235 REMARK. This species was originally described (Ahmad 1977b) on the present material. Genus HEMICYTHERURA Elofson, 1941 TYPE SPECIES. Cythere cellulosa Norman, 1865. Hemicytherura subulata sp.nov. __ PI. 28, figs 2-7; Fig. 9 NAME. ‘Awl-shaped, pointed’, with reference to the shape and the pointed posterior end. DIAGNOSIS. A small species of Hemicytherura with a marginal ridge running along the dorsal, anterior and ventral margins but slightly within the posterior margin. The fossae along the margins are large and of various shapes while those in the centre are small and round. The greatest height is at about mid-length. HovoryPe. A female right valve, OS 8300. Four single valves, OS 8301-4, are paratypes. Sample FCRM 1566, Mongo Stream, Lindi; Lower Miocene. OTHER MATERIAL. Two single valves from samples FCRM 1989 and 2015 (OS 8305). DESCRIPTION. Anterior margin of carapace obliquely rounded towards the venter, with four or five denticles. Dorsal margin outline differs in the two valves, right being strongly arched, left with flatter curve. Ventral margin straight; posterior with caudal process just above mid-height. Sexual dimorphism marked, presumed females higher in proportion to length than males. Ornament typical of genus. For descriptive purposes the fossae have been numbered from 1 to 12, following Hoskin (1975). Fossa 1 is divided in some valves into 1, 1’, and 1”; 1 is rectangular, while 1’, 1” and 2 are rounded. Fossa 3 is large, elongated, and broader anteriorly; fossa 3’ is narrowly separated from it and is semicircular to subtriangular. Fossae 4 and 5 are elongate and run along the ventral margin, separated from each other by a long murus. Fossa 6 is large, subtriangular, and separated from a small similar fossa 7. Fossa 8 is subrectangular and divided unequally into 8 and 8’. Fossa 9 is subrounded, 10 sub- quadrate, 11 narrow and subrectangular; these are large. Figs 1,2 Tanzanicythere pterota (Ahmad, 19776). Holotype, right valve, OS 7772; 1, external lateral view, x93; 2, dorsal view, x95. Fig. 3 Genus C sp. Right valve, OS 8320, external lateral view, 78. Figs 4-7 Semicytherura opeata sp. nov. Figs 4, 5, holotype, female carapace, OS 8313; 4, lateral view from right, x94; 5, dorsal view, x94. Figs 6, 7, paratype, male carapace, OS 8314; 6, lateral view from left, x92; 7, dorsal view, 93. Figs 8-11 Semicytherura emphysema sp. nov. Figs 8-10, holotype, female carapace, OS 8309; 8, lateral view from left, x 116; 9, dorsal view, «119; 10, lateral view from right, x 122. Fig. 11, paratype, male right valve, OS 8311, external lateral view, x 110. Fig. 12 Semicytherura sp. A. Carapace, OS 8316, lateral view from right, «110. TERTIARY OSTRACODA FROM THE LINDI AREA, TANZANIA Fossa 12, the largest, is subrectangular. The arrangement of the fossae is shown in Fig. 9. A left valve from sample FRCM 2015, interpreted as a male dimorph, shows a slightly different pattern, but the overall arrangement of fossae is compatible with that of the holotype. The 25—30 normal pore canals are widely scattered. Six or seven marginal pore canals are visible along the posterior margin, but it is difficult to discern any at the anterior end. Hinge artiperatodont, as described by Bate (1972: 45). DIMENSIONS (uum). | H W Holotype, female right valve OS 8300 = =325 205 = 085 Paratype, female left valve OS 8301 310 195 095 Paratype, female right valve OS 8304 320 200 085 Male left valve OS 8305 330 170 075 REMARKS. Hemicytherura sp. of McKenzie, 1974, from the Jangukian (Mid? Oligocene) of south-east Australia, has a very similar shape; fossae 8-12 have almost identical outlines, but fossae 1 and 3’ are missing in the Australian species. The Tanzanian species has the same pattern of ornament as H. videns videns (Miller, 1894), but the slightly different fossae, especially 6 and 8 which are shorter and more triangular in H. subulata, easily distinguish them. Genus SEMICYTHERURA Wagner, 1957 TYPE SPECIES. Cythere nigrescens Baird, 1838. Semicytherura emphysema sp. nov. Pl. 33, figs 8-11 NAME. ‘Something inflated’ (Greek), with reference to its ventral inflation. DIAGNOSIS. A species of Semicytherura with ventrally inflated valves; the muri of the fossae are more developed in the ventral half than in the dorsal. HOoLotyPe. A female carapace, OS 8309. Three specimens, OS 8310-2, are paratypes. Sample FCRM 1989, Likonga bridge; Lower Miocene. OTHER MATERIAL. One specimen from the same sample. Also occurs in FCRM 1737 and 2010. DESCRIPTION. Carapace rectangular to subrounded in side view, with subparallel dorsal and ventral margins, and straight to concave posterodorsal margin. Anterior margin sym- metrically rounded, posterior produced into a median caudal process. Valves inflated ventrally; carapace lenticular and slightly acuminate posteriorly in dorsal view. Sexual dimorph- ism present; presumed females much shorter and more tumid than presumed males. External surface pitted to reticulate; pits smaller and muri not as well developed in the dorsal half as in the ventral half of the valves. Internal features could not be seen clearly, except for the hinge, which is typical of the genus. DIMENSIONS (tim). I H WwW Holotype, female carapace OS 8309 390 190 190 Paratype, male carapace OS 8311 400 205 120 REMARKS. The difference in length between the presumed females and males suggests that the female carapace may represent the penultimate stage rather than the adult. The duplicature is not well developed in the single valves, which AHMAD, NEALE & SIDDIQUI also suggests that the specimens may be juveniles. However, the sexual dimorphism can be clearly seen, and the size, though small, is within the limits of adults found in this genus. It was therefore thought better to name this species than to leave it under open nomenclature. S. sella (Sars, 1866) agrees in shape with the new species but differs from it in having coarser ridges and smaller pits. Semicytherura opeata sp. nov. Pl. 33, figs 4-7 NAME. From Greek opeas, ‘awl’, with reference to the shape, especially in dorsal view. DIAGNosIs. A species of Semicytherura with 13 to 15 ridges, with lines of small rounded pits arranged longitudinally between them. The posterior is produced subventrally. Sexual dimorphism present. Ho.otyPe. A female carapace, OS 8313. Two carapaces, OS 8314-5, are paratypes. Sample FCRM 1989, Likonga bridge; Lower Miocene. The only specimens. DESCRIPTION. Carapace elongate-ovate in side view; dorsal margin strongly convex, almost continuous with the asym- metrically curved anterior margin and straight sloping poster- odorsal margin. Ventral margin slightly concave in the middle and convex posteriorly; posterior produced into a ventral caudal process. Greatest height in the middle; greatest width just in front of posterior end. Sexual dimorphism present, presumed females being shorter and higher than males, and easily distinguished. In dorsal view, however, presumed males look more swollen than females. External surface ornamented with longitudinal ridges, about 13-15 in number when counted at mid-length; anteriorly and posteriorly the numbers decrease as adjacent ridges fuse. These ridges have lines of rounded pits arranged longitudinally between them. Lacking single valves, internal features were not seen. DIMENSIONS (1m). L Hy Ww Holotype, fernale carapace OS 8313 490 210 170 Paratype, male carapace OS 8314 520 215 190 REMARKS. Since no internal features were seen placement of this species in Semicytherura and not Cytherura is based only on comparison with species such as Semicytherura sulcata (Miller, 1894). This resembles the new species’ in shape and ornament, but in S. opeata the caudal process is ventral while in S. sulcata it is located subdorsally. Semicytherura sp. A Pl. 33, fig. 12 FIGURED SPECIMEN. A carapace, OS 8316. Sample FCRM 1575; shore south-west of Ras Tapuri; Middle Oligocene. OTHER MATERIAL. One specimen from the same sample. DESCRIPTION. Carapace subrectangular in side view; dorsal margin gently convex, anterior margin rounded. Postero- dorsal and posteroventral margins concave, with a subdorsal caudal process. Ventral margin concave in the middle and strongly convex posteriorly, with greatest height in posterior third. Sexual dimorphism present, the presumed female being shorter than the male. External surface ornamented with 8 or 9 longitudinal ridges but no pits. Internally, hinge typical for the genus; other features cannot be seen clearly. TERTIARY OSTRACODA FROM THE LINDI AREA, TANZANIA DIMENSIONS (yum). L H WwW Carapace OS 8316 390 =200 =160 REMARKS. S. sella (Sars, 1866) and Semicytherura sp. A are very similar but can be distinguished by the patterns of the ridges. In S. sella the ridges in the dorsal half curve strongly towards the mid-anterior region, whereas in Semicytherura sp. A the curvature of these ridges is less abrupt. S. sella also has thin transverse ridges meeting the stronger longitudinal ones; these are absent in the Tanzanian species. Subfamily CYTHEROPTERINAE Hanai, 1957b Genus CYTHEROPTERON Sars, 1866 TYPE SPECIES. Cythere latissima Norman, 1865. Cytheropteron epelyx sp. nov. Pl. 34, figs 1-3 NAME. ‘Overshadowing’ (Greek), with reference to the overhanging ventrolateral part of the carapace. DIAGNOSIS. A species of Cytheropteron with overhanging ventrolateral margin and an acuminate posterior margin. HOoLotyee. A right valve, OS 7849. 36 single valves, OS 7850-85, are paratypes. Sample FCRM 1578, coastal cliff west of Ras Tapuri; Middle Eocene. OTHER MATERIAL. 21 specimens from the same sample (e.g. OS 7756). Also occurs in FCRM 1574, 1575 and 1576. DESCRIPTION. Carapace medium-sized, well calcified, with greatest height slightly in front of the middle. Anterior margin obliquely rounded towards the venter; posterior acuminate. Dorsal margin asymmetrically arched, divisible into strongly sloping anterior, gently sloping middle and steeply sloping to concave posterior portions. Ventral margin strongly modified, especially about one-third from posterior end, by the overhanging ventrolateral ala. Lateral surface reticulate but not uniformly so; surface almost smooth dorsally, becoming gradually more reticulate ventrally. There are four weak longitudinal ridges, without reticulation, on the ventral surface between the margin and the alae. Another weak ridge runs along the ventral swelling. Marginal pore canals very few and widely separated. Muscle scars not clearly seen but consist of four adductor scars with a V-shaped frontal scar open towards ventral margin. Hinge like that in the C. latissimum (Norman, 1865) group of species. Right valve hinge has five denticles on either end with a crenulate bar between; left valve has corresponding elements. DIMENSIONS (1m). L H W Holotype, right valve OS 7849 550 325 220 Paratype, right valve OS 7850 590 340 = 220 REMARKS. Cytheropteron subreticulatum Bold, 1946, is closely related to C. epelyx, but has a more strongly curved dorsal margin and less distinct posterior point. Cytheropteron cf. nipeensis Bold, 1946 Pl. 34, figs 6-9 cf. 1946 Cytheropteron nipeensis Bold: 113; pl. 16, fig. 1. 253 FIGURED SPECIMENS. Male carapace, OS 7961; female carapace, OS 7962 (lost). Sample FCRM 2033, Lindi Creek, east shore; Upper Eocene. OTHER MATERIAL. Eight specimens from the same sample (e.g. OS 7963). DIMENSIONS (1m). i, H W Female carapace OS 7962 385 205 150 Male carapace OS 7961 395. 215 165 REMARKS. The Tanzanian species agrees with C. nipeensis Bold in outline; Bold’s figure is not very informative, so it is not possible to say with certainty whether they are the same. Sexual dimorphism occurs in the Tanzanian species, the presumed males being longer and less high than the females; Bold does not mention dimorphism in C. nipeensis. Cytheropteron sp. A Pl. 34, figs 4-5 FIGURED SPECIMEN. A carapace, OS 7846; the only well- preserved specimen. Sample FCRM 2033, Lindi Creek, east shore; Upper Eocene. DESCRIPTION. Carapace strongly alate, highest in the middle. Anterior margin rounded towards venter, dorsal margin arched; posterior margin produced in a median caudal process. Ventral margin strongly modified by the ala in side view, but when seen obliquely from inside it is straight to slightly concave in anterior half and convex in posterior half. The strongly developed ventrolateral alae bifurcate at their posterior ends. Lateral surface smooth except for very fine hexagonal reticulations along the middle and four weak longitudinal ridges on ventral surface of ala. No internal details were seen. DIMENSIONS (im). L H WwW Carapace OS 7846 420 240 315 REMARKS. This species has a typical Cytheropteron shape but its bifurcated alae distinguish it from any other known species. Genus KANGARINA Coryell & Fields, 1937 TYPE SPECIES. K. quellita Coryell & Fields, 1937. Kangarina sp. Pl. 28, figs 8-10 FIGURED SPECIMEN. A carapace, OS 7983. Sample FCRM 2033, Lindi Creek, east shore; Upper Eocene. The only specimen. DESCRIPTION. Carapace subtriangular in side view, with rounded anterior margin; posterior with a subcentral caudal process. Dorsal margin convex, posterodorsal concave, and ventral modified by the ventrolateral ridge. Ornament varies in different areas. Six ridges run back from the anterior end: two of them start above the middle and curve towards the dorsal margin; the other four start below the middle and tend to converge behind. Central dorsal area ornamented with transverse ridges; anterodorsal area reticulated with rounded fossae. The posteroventral and centroventral areas are retic- ulated with rounded fossae arranged longitudinally. No internal details visible. i) nN AHMAD, NEALE & SIDDIQUI TERTIARY OSTRACODA FROM THE LINDI AREA, TANZANIA DIMENSIONS (1m). L H W Carapace OS 7983 335. 175 165 REMARKS. Although the Tanzanian specimen has a shape which is comparable with that of some Tertiary Kangarina species, the ornament is completely different. Family XESTOLEBERIDIDAE Sars, 1928 Genus UROLEBERIS Triebel, 1958 TYPE SPECIES. Eocytheropteron parnensis Apostolescu, 1955. Uroleberis kyma sp. nov. PI. 34, figs 10-12; PI. 35, figs 1-3 1988 Uroleberis kymus Ahmad, MS; Neale & Singh: 89; pl. 1, figs 9, 13 (‘Aynus’ on p. 87). NAME. ‘Swollen’ (Greek), with reference to carapace. DIAGNOsIS. A dimorphic species of Uroleberis with strongly convex dorsal margin and almost straight ventral margin. HOLotyPe. A female carapace, OS 8189. Four specimens, OS 8188, 8190-3, are paratypes. Sample FCRM 2033, Lindi Creek, east shore; Upper Eocene. OTHER MATERIAL. Seven specimens from the same sample. DESCRIPTION. Carapace ovate in female, ovate—-elongate in male. Dorsal margin strongly convex, ventral margin almost straight. Anterior margin obliquely rounded below, posterior with laterally flattened caudal process slightly below mid- height. Left valve larger than right. Surface with concentric- ally arranged pits except along the ventral edge, where they are longitudinal. Eyesocket distinct from inside, with a reniform ‘xestoleberis’ spot behind it. Duplicature moderately wide; line of concrescence and inner margin separate through- out, forming an anterior vestibule. Marginal pore canals numerous, simple and straight, a few of them false. Four adductor muscle scars and a V-shaped frontal scar. Right valve hinge of crenulate terminal teeth, each with eight to ten denticles, connected by a narrow smooth groove. Left valve with corresponding terminal crenulate sockets connected by a narrow smooth ridge with a noticeable accommodation groove above. DIMENSIONS (1m). L H WwW Holotype, female carapace OS 8189 485 385 360 Paratype, female carapace OS 8188 470 360 335 Paratype, male right valve (specimen lost) OS 8192 450 285 260 REMARKS. Sohn’s genus and species indet. 4 from the Middle PLATE 34 255 to Late Eocene of Pakistan (Sohn 1970: 68; pl. 4, figs 10-12) is most similar to U. kyma; however, the Tanzanian species has a less pitted surface and a straighter ventral margin. The present species is much smaller and has a better-developed caudal process than Cythere ranikotiana Latham, 1938, from Dandot, Pakistan. Uroleberis armeniaca Neale & Singh, 1985, is smaller and has a less arched dorsal margin than Uroleberis kyma. Uroleberis? sp. Pl. 31, figs 7-9 FIGURED SPECIMEN. A carapace, OS 8308. Sample FCRM 1989, Likonga bridge; Lower Miocene. The only specimen. DESCRIPTION. Carapace rounded, subtriangular with greatest height two-fifths the length from posterior end. Greatest length below midline. Dorsal margin strongly arched, cardinal angles absent; ventral margin almost straight. Anterior and posterior margins both curve strongly towards the venter. Left valve overlaps right. Surface punctate centrally, becom- ing smooth peripherally; there are longitudinal ridges along the ventral margin. DIMENSIONS (1m). L H W Carapace OS 8308 600 415 390 REMARKS. The present specimen shows some resemblance to U. batei Neale, 1975, but can easily be distinguished by its larger size and pitted surface. Family BYTHOCYTHERIDAE Sars, 1866 Genus BYTHOCERATINA Hornibrook, 1952 TYPE SPECIES. Bythoceratina mestayerae Hornibrook, 1952. Bythoceratina? asteria sp. nov. Pl. 27, fig. 5 NAME. ‘Spotted with stars’ (Greek); with reference to its ornamentation. DIAGNOsIS. A species of Bythoceratina? with a_ very prominent eye-tubercle, and a ventrolateral swelling ending in a prominent sharp spine posteriorly. Hovorypee. A left valve, OS 8116. Nine specimens, OS 8117- 25, are paratypes. Sample FCRM 2010, stream south-west of Mtwero; Lower Miocene. No other material. DESCRIPTION. Carapace quadrate in lateral view, tapering posteriorly, with the greatest height at the anterior cardinal angle. Anterior margin evenly rounded, posterior somewhat produced with straight posterodorsal margin. Dorsal and ventral margins almost straight. Marginal spines present at anterior and posterior margins, the posterior spines being Figs 1-3. Cytheropteron epelyx sp. nov. Figs 1, 2, holotype, right valve, OS 7849; 1, external lateral view, X71; 2, ventral view, X85. Fig. 3, paratype, right valve, OS 7850, internal oblique view, X73. Figs 4,5 Cytheropteron sp. A. Carapace, OS 7846; 4, lateral view from left, X96; 5, dorsal view, X83. Figs 6-9 Cytheropteron cf. nipeensis Bold, 1946. Figs 6-8, female carapace, OS 7962 (specimen lost); 6, lateral view from right, X 119; 7, lateral view from left, x119; 8, dorsal view, x 121. Fig. 9, male carapace, OS 7961, slightly ventrolateral view from left, 111. Figs 10-12 Uroleberis kyma sp. nov. Fig. 10, paratype, female carapace, OS 8188, lateral view from left, X70; see also PI. 35, fig. 1. Figs 11, 12, holotype, female carapace, OS 8189; 11, dorsal view, X73; 12, lateral view from right, x74. AHMAD, NEALE & SIDDIQUI TERTIARY OSTRACODA FROM THE LINDI AREA, TANZANIA strongly developed. A glassy round eye tubercle is present. External surface reticulate with trefoil-shaped ornamenta- tion. Ventrolaterally each valve bears a hollow, sharp spine directed posteriorly. Median sulcus extremely shallow. Duplicature very narrow; radial pore canals very few and straight. Muscle scars not perfectly seen but probably the same as in Bythoceratina, consisting of five adductor scars arranged in a row. Right valve hinge consists of two elongate, crenulate terminal teeth with a crenulate median groove. Left valve has corresponding sockets and bar. The closure is additionally strengthened by a very weakly developed ventral snap-knob in the right valve and socket in the left valve. DIMENSIONS (1m). L H WwW Holotype, left valve OS 8116 675 385 —- (Specimen cracked, too fragile to measure width.) REMARKS. The distinct eye tubercle, snap-knob/socket mechanism, different hinge with crenulate terminal teeth, and slightly different shape distinguish this from other Bythoceratina species. However, the very narrow duplicature, suggesting that the specimens may be juveniles, and the imperfectly known muscle scars, do not justify the erection of a new genus. For the present this Tanzanian species is placed with doubt in Bythoceratina. Leguminocythereis bisanensis Okubo, 1975, agrees with this species in having similar spines directed posteriorly; internally, the marginal zone is equally narrow, and the terminal hinge elements are crenulate. How- ever, the two can readily be distinguished. Bythoceratina? asteria is subrectangular in shape, has a well-developed eye tubercle, a shallow median sulcus and trefoil-shaped ornamentation, while Leguminocythereis bisanensis is more ovate, has an indistinct eye tubercle, no median sulcus, and rounded to subrectangular fossae. Pl. 22, fig. 12 FIGURED SPECIMEN. A right valve, OS 8317. Sample FCRM 2010, stream south-west of Mtwero; Lower Miocene. Bythoceratina sp. A OTHER MATERIAL. Five single valves (none well preserved; all broken). DESCRIPTION. Carapace oblong in lateral view with greatest height about one-quarter length from posterior end; greatest width in posterior half. Anterior margin narrowly rounded, posterior produced into a median caudal process. Dorsal and ventral margins run almost parallel for about one-third of the length and then diverge towards the posterior, the dorsal running almost straight and sloping upwards and the ventral strongly convex. Externally, the lateral surface has a shallow vertical sulcus at mid-length. The strong ventrolateral swel- ling terminates in a spine. Except for some sloping ridges on the swelling, the valve surface is smooth and punctate. Left valve hinge a crenulate median bar with weakly developed PLATE 35 25] sockets at either end. Other internal features not clearly visible. DIMENSIONS (1m). I H W Right valve OS 8317 575 345 280 REMARKS. All other species of Bythoceratina described so far have the caudal process in line with the hinge or just below it, but in Bythoceratina sp. A the caudal process is at mid-height. Bythoceratina variabilis Carbonnel 1969 is closely allied to Bythoceratina sp. A, but, besides the difference in the positions of the caudal processes, the two species have a different dorsal margin. The dorsal margin of Carbonnel’s species is concave in the middle, whereas that of the Tanzanian species is concave in the anterior third. Superfamily CYPRIDACEA Baird, 1846 Family MACROCYPRIDIDAE Miller, 1912 Genus MACROCYPRIS Brady, 1867 TYPE SPECIES. Cythere minna Baird, 1850. Macrocypris? sp. A Pl. 35, figs 10-12 FIGURED SPECIMEN. A carapace, OS 8306. Sample FCRM 1711, east flank of Kitulo Hill; Palaeocene. The only specimen. DESCRIPTION. Carapace subtriangular in lateral view, with greatest height at about mid-length and valves tapering strongly posteriorly. Dorsal margin strongly curved in anterior half, sloping posteriorly; ventral margin almost straight. Anterior margin rounded, posterior acuminate. Right valve strongly overlaps left. No internai details visible. DIMENSIONS (1m). IL; H WwW Carapace OS 8306 610 335 290 REMARKS. On the basis of shape this is not a typical Macro- cypris, but no better assignment could be made in the circumstances so it is here doubtfully assigned to that genus. The only other described species which shows any resem- blance to this specimen is the Macrocypris? sp. aff. M.? dimorpha Hazel & Holden, of Holden 1976; however the more acuminate posterior end of the Tanzanian specimen distinguishes it from Holden’s species. Macrocypris sp. B Pl. 35, figs 46 FIGURED SPECIMEN. A carapace, OS 8307. Sample FCRM 1989, Likonga bridge; Lower Miocene. The only specimen. DESCRIPTION. Carapace elongate, with dorsal margin arched; ventral margin slightly concave in the middle. Anterior end rounded, with some incurving below; posterior end narrowly > Figs 1-3 Uroleberis kyma sp. nov. Fig. 1, paratype, female carapace, OS 8188, dorsal view, X68; see also PI. 34, fig. 10. Figs 2, 3, paratype, male carapace, OS 8192 (specimen lost); 2, dorsal view, 98; 3, lateral view from left, x84. Figs 46 Macrocypris sp. B. Carapace, OS 8307; 4, lateral view from right, X38; 5, dorsal view, x40; 6, lateral view from left, x38 Figs 7-9 Genus A sp. Carapace, OS 7980; 7, lateral view from right, slightly oblique from dorsal, X88; 8, dorsal view, X90; 9, lateral view from left, slightly oblique from ventral, x87. Figs 10-12 Macrocypris? sp. A. Carapace, OS 8306; 10, lateral view from right, X67; 11, dorsal view, X75; 12, lateral view from left, X67 258 rounded. Left valve larger than right. No internal details visible. DIMENSIONS (1m). L H W Carapace OS 8307 1170 545 370 REMARKS. Macrocypris sp. B strongly resembles Macrocypris similis Brady 1880, but the narrower anterior end and strongly concave ventral margin distinguish it from that species. This species differs from M.? sp. A in being more elongate and less triangular. INCERTAE SEDIS Genus A sp. Pl. 35, figs 7-9 FIGURED SPECIMEN. A carapace, OS 7980. Sample FCRM 1989, Likonga bridge; Lower Miocene. OTHER MATERIAL. Five carapaces from the same locality and horizon. DESCRIPTION. Anterior margin asymmetrically rounded, posterior end produced. Dorsal margin bent at mid-length, ventral margin concave. Right valve strongly overlaps left. No single valves found hence no internal details seen. DIMENSIONS (um). L H W Carapace OS 7980 510 270 170 REMARKS. Six specimens of this small new genus were found but naming it cannot be justified because of the absence of single valves. The specimens are unique in being very strongly bent at mid-length, behind which they narrow sharply. The smooth external surfaces and right-over-left overlap suggest that the genus is closely related to Macrocypris. M. acuticaudata Bate, in Bate & Bayliss 1969, from the Albian sediments of Kiwanga, Tanzania, is probably an ancestor of this Tertiary species. Genus B sp. Pl. 11, figs 4-6 FIGURED SPECIMEN. A left valve, OS 8113. Sample FCRM 2010, stream south-west of Mtwero; Lower Miocene. OTHER MATERIAL. Two specimens from the same locality and horizon. Also occurs in FCRM 2015. DESCRIPTION. A species with concentrically arranged fossae; posteroventral complex consisting of three or four tubercles joined together. Anterior margin rounded, posterior sub- ventrally produced, with a slightly concave posterodorsal margin; marginal spines present at both ends. Dorsal margin straight, ventral slightly concave; the two margins converge slightly behind. External surface reticulate with a few super- imposed tubercles; eye tubercle present as an opaque spot. Muri thick and arranged concentrically, enclosing elon- gate fossae. Posteroventral complex conspicuously raised. Internally, duplicature fairly wide, with line of concrescence and inner margin slightly separated to give a narrow anterior vestibule. Selvage well developed at anterior and anteroventral margins. Marginal pore canals not visible; four adductor scars and a V-shaped frontal scar. Hinge holamphidont. DIMENSIONS (um). L H W Left valve OS 8113 570 330 =160 REMARKS. While Genus B sp. is trachyleberine, it differs AHMAD, NEALE & SIDDIQUI completely from Trachyleberis and cannot be placed in any of the other genera. It is here left under open nomenclature. Genus C sp. PI. 33; fiess FIGURED SPECIMEN. A right valve, OS 8320. Sample FCRM 1738, South Mtwero; Lower Miocene. OTHER MATERIAL. Two single valves from FCRM 1737 (OS 8319) and 1738. DESCRIPTION. A species with reticulate surface, the muri being crimped. The right valve has a snap-knob which fits into the snap-socket of the left. Carapace subquadrate in lateral view, with greatest height near anterior cardinal angle. Anterior rounded, with marginal denticles; posterior margin truncated in upper half, rounded below and slightly produced. Dorsal and ventral margins straight and subparallel, slightly converging towards posterior end. Surface ornament consist- ing of a reticulate pattern of ridges, the muri being strongly crimped. Position of adductor muscle scars marked by an ovoid subcentral depression; eye tubercle elongate and not clearly developed. Three ridges are especially prominent; one, beginning near the posterior cardinal angle, runs forward parallel to the dorsal margin until it turns downwards about two-thirds of the way along and merges into other small ridges. The other two ridges are ventrolateral, the lower one running along the ventral margin and the upper one, about the same length and running parallel to it, ending in a small spine just in front of the posterior margin. Duplicature moderately wide. Line of concrescence and inner margin coincide throughout, so there is no vestibule. Selvage prominent along anterior and posterior margins, running at a little distance from outer margin. There is a unique snap- knob/socket mechanism; four small toothlike knobs in the right valve, behind the strong mid-ventral knob, correspond with sockets in the left. Marginal pore canals short, parallel and numerous, about 30 anteriorly and 8-9 posteriorly. Normal pore canals present all over the surface. Four adductor muscle scars, in a vertical row, with a fused V-shaped frontal scar which cannot be seen clearly. Hinge holamphidont; right valve has a smooth knob-like anterior tooth followed by a crenulate posterior tooth. DIMENSIONS (jim). I H WwW Right valve OS 8320 545 335 160 REMARKS. Only one of the three specimens found is adult so the genus is left under open nomenclature. There is little in the literature with which this species can be compared. At the generic level, Agulhasina Dingle 1971 resembles it in outline and ornament, but has surface spines, no eye tubercle, and fewer marginal pore canals. Australileberis Dingle, 1976, agrees with this genus in some details but has different ornament. Stigmatocythere Siddiqui, 1971, has similar dorsal and ventral ridges and the hinge and marginal pore canals are similar also, but the frontal scar in Stigmatocythere is oval. The surface ornament is also different, the fossae in Stigmatocythere being subrectangular and shallow, while those of the new genus are trifoliate, crimped and deeper. The new genus differs from all the others in its snap-knob/ socket mechanism. Palaeoecologically, Genus C has only been found in silty shaly clays, and is associated with deeper water genera such as Krithe and Parakrithe. TERTIARY OSTRACODA FROM THE LINDI AREA, TANZANIA PALAEOECOLOGY When the ecology at the species level is unknown, certain limitations are placed upon the interpretation of palaeocology. Based on the generally accepted habitat of certain genera, however, it has been possible to reach conclusions which are given below. We make the following assumptions. (1) Certain genera with a strongly reticulate or ornamented lateral surface, strongly calcified carapace and well-developed eye tubercle inhabit shallow marine water. These genera are Aurila, Quadracythere, Haughtonileberis, Leguminocythereis, Stigmatocythere, Cytheropteron (thick shelled), Callistocythere, Costa, Hermanites and Hemicytherura. (2) A second group of shallow-water marine genera is almost confined to tropical and subtropical waters, only living in or around reefs. This group includes Triebelina, Paranesidea and Loxoconcha (Loxocorniculum). The genera Cytherelloidea, Uroleberis, Kangarina and Triebelina may also be taken as indices for warm temperatures, above the 10°C isocryme according to Sohn (1964) for Cytherelloidea, and about 20°-25°C for all four genera according to McKenzie (1974). (3) A third group of genera is often regarded as indicating moderately deep marine waters (>75 m). This includes Krithe, Parakrithe, Paijenborchella and Henryhowella. Based on these assumptions, the following grouping of sample localities is suggested: (1) Shallow water: FCRM 2010. (2) Shallow water but indicating an approach to a reef environment: FCRM 1566, 1574, 1575, 1576, 1578, 1627, 1628, 1661, 1689, and 1692. (3) Deep water: FCRM 1737, 1738; and less deep, FCRM 1742, 1745. (4) Mixed fauna: FCRM 2033, 2034; these have a mixed fauna mostly indicating a shallow reef environment but with some deeper water incursions. For other samples nothing conclusive can be said except that they contain mostly shallow-water genera. Ostracods are sensitive to many factors in the environment and consideration of various ecological parameters suggests that the Lindi fauna comes from waters with the following characteristics: 1. Depth: Apparently shallow water with some deep water incursion in Lower Miocene (FCRM 1737, 1738). 2. Oxygen: Generally well oxygenated. As the water was warm it would have held less oxygen, but no reducing environments are evident and none of the ostracods are pyritized. The ostracods are generally robust, indicating fairly high energy waters; this may also account for the lack of pyritization of the fauna. 3. Salinity: All the Lindi ostracod genera which are still living at the present time are now restricted to water with salinities in the range of 30 to 40%; Lindi ostracods probably lived in waters of this salinity range. 4. Clarity: Well-developed eye tubercles suggest that the waters were extremely clear. The deep-water genus Krithe, with its numerous species, is blind but its close relative Ommatokrithe, which occurs here, has eye tubercles and was separated from Krithe for that very reason. 5. Temperature: The size of these ostracods is generally small which suggests that waters were warm, temperatures at times reaching 20°-25°C, 259 An attempt was made to deduce the comparative rate of sedimentation on the basis of the ratio of single valves to carapaces. Pokorny (1964b) had observed that, in the case of Karsteneis karsteni (Reuss) and Cythereis longaeva Pokorny, the percentage of closed carapaces was higher in regions of rapid sedimentation. Oertli (1971), working on abundant ostracod material, concluded that in conditions of slow sedimentation the carapace opens because of bacterial de- composition of muscles and ligaments, but in rapid sedimen- tation conditions the dead ostracods quickly sink by their own weight far enough into the sediment for the valves not to be separated. Comparing the ostracods from the surface samples of Lindi with those from borehole samples of Lamu (Kenya), where the rate of sedimentation was almost the same (Kent, in Kent et al. 1971), the percentage of closed carapaces was found to be higher in the Lamu samples than in those from Lindi. It was also found that the ratio depended on the genera or species concerned. For example, in the Lindi area, species of Costa, Paracytheridea and Tanzanicythere were mostly found as single valves, but species of Xestoleberis, Clithrocy- theridea?, Phlyctocythere, and Incongruellina were mostly present as entire carapaces, the two groups occurring together. Based on the ten most productive samples from the three periods, we deduced that the maximum rate of sedimentation occurred during the Lower Miocene; the rate was slightly less for the Eocene. For the Oligocene, however, it was about half of the maximum deduced for the Lower Miocene. These results corroborate the comparative rates of sedimentation calculated by Kent et al. (1971: 89); a comparative chart is given in Fig. 6, p. 184. It is therefore concluded that during the Upper Eocene the water was mostly shallow with some deeper water incursions at times, and the rate of sedimenta- tion was faster than in the overlying Oligocene. During the Oligocene there was a general regression, the water becoming shallower but with a greater development of reefs and much slower sedimentation. During the Lower Miocene a trans- gression occurred, the water being shallow near reefs but deeper in other places, and with a greater rate of sedimenta- tion than previously. The greater diversity of the fauna in Lower Miocene times supports this speculation. FAUNAL ASSEMBLAGES During the Upper Eocene, Paijenborchella, Hermanites, Uroleberis, Clithrocytheridea?, Quadracythere, Stigmatocy- there, Triebelina, Paranesidea, Cytherella, Bairdia and Cytherelloidea became well established. Some of the Cytherell- oidea species are distinctive in having the selvage of the left valve grown out behind the anterior part of the hinge to form a tooth. Most of these genera continued to exist during the Oligocene, only Cytherelloidea and Clithrocytheridea? being absent in sediments younger than Eocene. Paijenborchella disappeared for a while, to reappear in the Lower Miocene. A number of new genera appeared during this time, including Loxoconcha (Loxocorniculum), Leguminocythereis, Haughtonileberis, Crenaleya, Carinocythereis and Semicy- therura. Paracytheridea became rare. It appears that Aitkenicythere Bate (1976), which existed in Tanzania during the Bajocian—Tithonian (Jurassic), may be a distant ancestor of Haughtonileberis, which appeared during the Campanian in South Africa and during the Oligocene at 260 AHMAD, NEALE & SIDDIQUI Table 1 Range table of ostracod species. This table also includes data from the BP ostracod LOWER MIOCENE 2L-M. UPPER EOCENE collection kept at Sunbury-on-Thames; see OLIGOCENE 2 mi el al @ 11-20 specimens. ASSEMBLAGE ZONES egumino- Cytherella mediocalva cythereis vine dinglei FCRM SAMPLE NUMBER OSTRACODS =e NAN Cytherella mediocalva Ambocythere sp. Bradleya? sp. A Callistocythere jugosa A Falsocythere maccagnoi Procythereis radiata Caudites sp. Leptocythere fastigata Quadracythere distenta Hemicytherura subulata Loxoconcha (Loxocorniculum) ° tricornis Krithe burdigalia Aurila concentrica A Paijenborchella cf. iocosa Hermanites mongoensis Loxoconcha (L.) ribanjaensis Anterocythere sp. B Tanella sp. A Tanella sp. B Macrocypris sp. B Phlyctocythere reniformis Quadracythere kenti Semicytherura opeata Uroleberis ? sp. | Occultocythereis africana Trachyleberidea ? cirrata Trachyleberis duplex Gujaratella ? tanzaniensis Bythoceratina ? asteria Bythoceratina sp. A Semicytherura emphysema Caudites cf. rosaliensis Procythereis aligera Quadracythere trijugis Urocythereis salebrosa Henryhowella sentosa Bairdia cf. attenuata Costa trudis @ Incongruellina tonsa Tanzanicythere pterota @ Bairdia cf. schulzi e Genus B sp. Crenaleya sp. A Pe Paijenborchella quasimalaiensis dilata : Idiocythere sp. A Ruggieria furcilla @ Loxoconcha (Palmoconcha) pinguis Aurila concentrica B Paijenborchella disadunca C Paijenborchella disadunca Paijenborchella disadunca A Parakrithe cicatricosa ° Ommatokrithe prolata Krithe liebaui Crenaleya sp. Table 1 Range table of ostracod species. This table also includes data from the BP ostracod collection kept at Sunbury-on-Thames; see p. 264. e < 10 specimens. @ 11—20 specimens. @ > 20 specimens. TERTIARY OSTRACODA FROM THE LINDI AREA, TANZANIA 261 ?L-M. LOWER MIOCENE OLIGOCENE ASSEMBLAGE ZONES Legumino- Cytherell Cytherella mediocalva_ | cythereis ra pts Cua dinglei indiensis FCRM SAMPLE NUMBER UPPER EOCENE mnoonn OSTRACODS SOONNN ALN err Genus A sp. ° Genus C sp. Callistocythere jugosa ° e Buntonia sp. Paracytheridea culmen ° e Paracytheridea culmen A Aurila concentrica @ |. ele Loxoconcha (Loxocorniculum) postnodosa Tels Stigmatocythere bornharati Urocythereis ? apolegma Leguminocythereis dinglei Loxoconcha cf. longispina Loxoconcha postnodosa B een eren epelyx aughtonileberis rastapuriensis Quadracythere subquadra Loxoconcha postnodosa A Crenaleya tuberis Acanthocythereis postcornis Semicytherura sp. A Leptocythere amoena Carinocythereis sp. Quadracythere vanga Haughtonileberis radiata Quaadracythere ? acuta Hermanites mongoensis A Bradleya ? sp. B Paijenborchella disadunca B Stigmatocythere intexta Quadracythere arcana cornigera ‘ é Bairdia amygdaloides oblongata Cytherella lindiensis Paracytheridea anapetes ele Triebelina howei Hermanites carchesium Hermanites percultus Clithrocytheridea ? semiluna Cytherelloidea gemellata Cytherelloidea patagiata Cytherelloidea sp. Cytheropteron cf. nipeensis pielepieren sp. A angarina sp. Paijenborchella disadunca D Costa ? hullina Loxoconcha (Myrena) loculus Paijenborchella quasimalaiensis Paranesidea fracticorallicola Paranesidea nigrescens Paranesidea cf. fortificata ° Quaadracythere sp. A Rostrocytheridea ? sp. Uroleberis kyma Pane cloldes sp. A rithe medioelata Paranesidea sp. A Macrocypris ? sp. A 262 AHMAD, NEALE & SIDDIQUI aGE|EUROPEAN LINDI ZONES | ZONES AMERICAN STAGES EAST AFRICA BLOW(1969) PROPOSED | STAGES Massive mostly sandy reef limestone. Cytherella Grey buff clay. mediocalva VICKSBURGIAN Legumino- Rubbly silty cythere/s limestone, calcareous dinglei siltstones and some clay Fene oO Lu ee z Lu Y) Lu a Oo Lu ao z =) LATTORFIAN | RUPELIAN CHAT TIAN AQUITANIAN Cytherella Sandy reef (indiensis limestone and marls AUVERSIAN-BARTONIAN JACKSONIAN LUTETIAN SANUEN EOCENE OLIGOCENE LOWER MIOCENE Fig. 10 Correlation of proposed ostracod biozones with those of Blow (1969). TERTIARY OSTRACODA FROM THE LINDI AREA, TANZANAI Lindi; it is not known if it existed in Tanzania during the intervening time. The Lower Miocene was a time of strong transgression, resulting in a very diverse fauna. New species appeared in the genera Ommatokrithe, Bythoceratina, Ruggieria, Costa, Hemicytherura, Phlyctocythere, Tanzanicythere, Incongruel- lina and Xestoleberis. Species of Cytherella and Aurila became abundant; Paijenborchella and Krithe, which first appeared in the Eocene and disappeared in the Oligocene, became re- established. OSTRACOD BIOZONES Planktonic foraminiferal biozones of the Lindi area and their relationships elsewhere in the world have been established by Eames et al. (1962) and Blow (1969). The ostracod zones suggested here are local Assemblage Zones; their correlation with Blow’s Zones are shown in Fig. 10. (1) Cytherella lindiensis Zone (= Upper Eocene). Correspond- ing roughly with Blow’s Zones P15 to P17, this zone is defined by the abundance of Cytherella lindiensis sp. nov. and by the presence of the following species. (The species marked * are also known to occur elsewhere): Cytherelloidea gamellata sp. nov. Cytherelloidea patagiata sp. nov. Clithrocytheridea? semiluna sp. nov. Hermanites carchesium sp. nov. Hermanites percultus sp. nov. Krithe medioelata sp. nov. Loxoconcha (Myrena) loculus sp. nov. Paijenborchella (Eopaijenborchella) quasimalaiensis sp. nov. Uroleberis kyma sp. nov. * Paracytheridea anapetes Ahmad, 1977 * Paranesidea cf. reticulopunctata (Benson) * Stigmatocythere intexta sp. nov. The type locality for the Cytherella lindiensis Zone is the Lindi Creek, east shore, Tanzania, at FCRM 2033. (2) Leguminocythereis dinglei Zone (= ?Lower to Middle Oligocene). This zone corresponds with Blow’s Zones P18 and P19 and is characterized by the absolute range of the nominate taxon and by the presence of the following species: Crenaleya tuberis gen. et sp. nov. Cytheropteron epelyx sp. nov. Haughtonileberis rastapuriensis sp. nov. Hermanites mongoensis, Morphotype A Leptocythere amoena sp. nov. Quadracythere subquadra Siddiqui, 1971 Quadracythere vanga sp. nov. * Acanthocythereis postcornis (Siddiqui, 1971) * Loxoconcha (Loxocorniculum) cf. longispina Keij, 1953 *Loxoconcha (Loxocorniculum) postnodosa sp. nov. * Triebelina howei (Stephenson) There is an absence of such deeper-water genera as Krithe and Ommatokrithe. The type locality for this zone is the shore south-west of Ras Tapuri, Tanzania, at FCRM 1576, which is also jointly the type locality for the Globigerina oligocaenica Zone of Blow & Banner (in Eames et al. 1962). 263 (3) Cytherella mediocalva Zone (= Lower Miocene). This zone corresponds roughly with Blow’s Zones N4 to N9 and is defined by the presence of Cytherella mediocalva sp. nov., which is limited in range to this zone, and by the presence of the following species: Bythoceratina? asteria sp. nov. Tanzanicythere pterota (Ahmad, 1977) Costa trudis Ahmad, 1977 Hemicytherura subulata sp. nov. Hermanites mongoensis sp. nov. Incongruellina tonsa sp. nov. Krithe liebaui sp. nov. Occultocythereis africana sp. nov. Leptocythere fastigata sp. nov. Loxoconcha (Loxoconcha) mbanjaensis sp. nov. Loxoconcha (Loxocorniculum) tricornis sp. nov. Ommatokrithe prolata Ahmad, 1977 Phlyctocythere reniformis sp. nov. Paijenborchella (Eopaijenborchella) disadunca sp. nov. Ruggieria (Ruggieria) furcilla sp. nov. * Aurila concentrica sp. nov. * Callistocythere jugosa sp. nov. * Paracytheridea culmen sp. nov. The type locality is the Mongo Stream, Lindi, at FCRM 1566. CONCLUSIONS The Tanzanian fauna forms part of the West Indian Ocean Ostracod Province. The fauna is linked to that of Pakistan by the presence of Quadracythere subquadra, Q. arcana, Acan- thocythereis postcornis, and Stigmatocythere bornhardti (closely related to S. obliqua from Pakistan). Many more species common to the two regions may be found when the younger (Oligocene—Miocene) Pakistan fauna is fully docu- mented. The Lindi fauna is related to the South African fauna by the presence of Occultocythereis africana (=Gen. Indet. 5, sp. | of Dingle, 1976), Haughtonileberis radiata, H. rastapuri- ensis (very similar to H. fissilis), and a number of other species. The Malagasy ostracod fauna is not well known, but the presence of the genus Tanzanicythere, so far found only in these two regions, suggests that they have close connections. McKenzie’s (1973: 479) suggestion that ‘the Caribbean, Mediterranean, Indo—West Pacific and Australasian marine provinces are the spoor of Tethys’ is supported by the Tanzanian ostracod fauna, which is linked to the Caribbean by the presence of Triebelina howei (Stephenson), and to Nicaragua by Anterocythere sp. B of Swain & Gilby. The presence of Paijenborchella (Eopaijenborchella) quasimalai- ensis sp. nov. (closely related to P. malaiensis Kingma from Indonesia, and to P. cymbula Ruggieri from the Mediterranean), indicates a link, albeit rather tenuous, with all these areas. Similarly, the presence of Quadracythere trijugis Holden suggests a link with the Pacific. The biogeog- raphy of these species supports Keij’s (1976) view that Tertiary to Recent tropical, shallow marine ostracods show a wide geographical distribution. No links, however, have been found with the West African, South American or Atlantic ostracod faunas. Palaeontologically, too, the relationships are closer with faunas of the southern hemisphere; for example for south-eastern Australia and New Zealand high temperatures 264 have been documented for the Upper Eocene and Oligo- Miocene (Gill 1968, Jenkins 1968 and McKenzie 1973). During this time the absence of any cold water taxa combined with the small size of ostracods, a factor normally attributed to tropical environments, suggests warm water temperatures for the Lindi area. If one accepts the suggestion by McKenzie (1973) that the presence of Cytherelloidea and Uroleberis indicates 20°—-25° C, then the temperature during the Upper Eocene was at times as high as that. The strengthening of carapace closure by a snap-knob/socket mechanism in species such as Bythoceratina? asteria, Trachyleberidea? cirrata, Crenaleya tuberis and Genus C sp. suggests that the water may have been turbulent. Another interesting feature of this fauna is the appearance of eye tubercles in genera which usually lack them, e.g. Bythoceratina, Idiocythere and Ommatokrithe (closely related to Krithe). This may indicate unusually clear water, which indeed occurs around tropical reefs. Eames et al. (1962) mention the presence of laterally discontinuous reef-like conditions for only short periods during the Upper Eocene and Oligocene, and more wide- spread reef conditions during the Lower Miocene. The presence of Triebelina, Paranesidea and Loxoconcha (Loxo- corniculum) is often associated with reef conditions. The presence of Krithe and Parakrithe is often associated with deep water; they occur in samples FCRM 1737 and 1738, but no other evidence of deep water sediments has yet been found. As in some other areas changes in the ostracod distribution closely follow regional geological events. The Mid-Oligocene regression resulted in a great number of specimens and species, whilst the Lower Miocene transgression resulted in a very diverse fauna. This corroborates Kent’s (1974) chrono- logy of East African tectonic events (Fig. 5c, p. 183). More- over, the rates of sedimentation calculated on valve/carapace ratios also show some agreement with Kent’s (in Kent et al. 1971) estimates. In summary, it is suggested that the Lindi Tertiary ostracod fauna may be regarded as indicative of a warm, clear-water deposit laid down in a shallow shelf area, whose depth may have been mostly less than 50 m but sometimes deepened to well over 75 m, and whose minimum temperature was not less than 10° C. During the Oligocene there was a general regression which was followed by a widespread Miocene transgression. Three ostracod biozones corresponding roughly to well- established Planktonic Foraminifera zones occur (Fig. 10, p. 262). FCRM SAMPLE DATA The sample prefix FCRM refers to material collected by the BP-Shell geologist F.C.R. Martin in 1951-57 (Eames et al. 1962: 62); the locality and lithological information was given by him in a private report to BP-Shell in 1957. See Fig. 3, p. 181. More than one-third of the samples were provided as washed residues; from some others only the ostracods which had been picked out and placed in the BP Research Centre, Sunbury-on-Thames, were available. Consequently most of the sample descriptions are based on the original accounts by Martin and other BP-Shell geologists. Wherever enough material was available, thin sections were made and studied and the descriptions amended where necessary. Sample FCRM 1566 FCRM 1574 FCRM 1575 FCRM 1576 FCRM 1578 FCRM 1627 FCRM 1628 FCRM 1644 & 1645 FCRM 1647 & 1648 FCRM 1661 FCRM 1689 FCRM 1692 FCRM 1711 Location Mongo Stream, Lindi Shore south- west of Ras Tapuri, c. 6 km north of Lindi Shore south- west of Ras Tapuri, as above Shore south- west of Ras Tapuri, about 18 m north of FCRM 1575 Shore south- west of Ras Tapuri, as above Kitunda Jetty road, near bottom of slope Kitunda Jetty road, c.3m above FCRM 1627 North end of Kitunda slope, just above shore level Kitunda slope, from c. 3m toc. 15 m above shore level Near top of old garnet mine, north Lindi Old quarry above road, east of Mchole salt works Old quarry below road, east of Mchole salt works Stream south- west of upper Wireless Station, Kitulo Hill AHMAD, NEAL Lithology Sandy detrital fos- siliferous limestone Grey-buff silty sandstone Grey calcareous silt- stone with quartz grains; some bivalve & echinoid remains; abundant orbitoids Buff-grey biomicrite with abundant orbitoids Hard sandy limestones and grey-buff silty sands Green-grey shaley clays Shelly calcareous sand & orbitoidal clay with thin ribs of cemented orbitoidal rock Grey-green clays with interbedded thin marly limestones Grey-green silty clays with some thin-bedded marly foraminiferal limestones Dark grey-brown gypseous clays Dark buff-grey silty clays Dark grey-brown clays Massive rotten soft marly limestone; micrite E & SIDDIQUI Age Lower Miocene Mid-Oligocene Mid-Oligocene Mid-Oligocene Mid-Oligocene Mid-Oligocene Mid-Oligocene Upper Eocene Upper Eocene Lower Miocene Upper Eocene Upper Eocene Palaeocene? Se eee TERTIARY OSTRACODA FROM THE LINDI AREA, TANZANIA Sample FCRM 1737 & 1738 FCRM 1742 FCRM 1745 & 1746 FCRM 1792 FCRM 1963 FCRM 1964 FCRM 1981 FCRM 1989 FCRM 2010 FCRM 2014 —2016 FCRM 2033 FCRM 2034 FCRM 2045 & 2046 Location South Mtwero, in sisal waste gully Mbanja River Mbanja River, upstream of FCRM 1742 Beside Mingoya Road, about 1g miles from the Lindi bridge Lindi-Mingoyo road, south-west of Lindi (not covered by Fig. 3) Kitunda slopes Kikwetu factory refuse gully On west side of road bridge, 9° 49.4'S, 39° 43.8’E, south of Likonga estate Cliff on left bank of stream south-west of Mtwero Estate Location given as ‘various points up- stream of FCRM 2010 East shore of Lindi Creek East shore of Lindi Creek, about 10 m south of FCRM 2033 Lindi-Mingoyo road, above 2g km south of Lindi Lithology Bedded grey silty shaly clays with thin modular clay- stones Buff-grey silty foraminiferal clay Fine-grained limestone Buff-grey, slightly gypsiferous clay Soft buff-grey sands Dark grey, brown- stained shaly clay Thin bedded micritic limestone with a little quartz Foraminiferal lime- stone, about 95% carbonate material Buff-grey highly fossiliferous carbon- ate muddy sands Buff-grey silty nodular shaly clays Brown silty clay with foraminifera and shell fragments Grey buff-stained clay Fragmented buff-grey clay (reworked?) Age Lower Miocene Lower Miocene Lower Miocene Upper Eocene Upper Eocene Lower Miocene Lower Miocene Lower Miocene Lower Miocene Upper Eocene Upper Eocene Upper Eocene 265 ACKNOWLEDGEMENTS. We wish to thank Dr R. H. Bate, formerly of the British Museum (Natural History), for providing the samples which formed the basis of this study, and Dr C. G. Adams, Dr F. T. Banner and Mr R. L. Hodgkinson for access to materia! in the British Museum (Natural History). Dr W. J. Clarke, formerly of the British Petroleum Company, Sunbury-on-Thames, and Dr D. A. L. Jenkins, BP Exploration Co. Ltd., supplied various maps and allowed the examination of the BP ostracod collection and private reports. We are also grateful to Professor W. A. van den Bold for the loan of a paratype of Parakrithe robusta and Dr J. E. Whittaker for measure- ments of the widths of some specimens; Dr Whittaker also compiled the systematic index. Finally we would like to record our appreciation of the editorial help afforded by Mrs U. M. Grigg, Halifax, Nova Scotia, and Mr D. L. F. Sealy, British Museum (Natural History), and the technical assistance of Mr J. Garner, Mr P. McSherry and Mr T. Sinclair, of the University of Hull. REFERENCES Ahmad, M. 1977a-e. On Paracytheridea anapetes Ahmad sp. noy. Stereo-Atlas of Ostracod Shells, Leicester, 4 (7): 41-44 (1977a). On Cladarocythere pterota Ahmad gen. et sp. nov. /bid. 4 (8): 45-48 (1977b). On Costa trudis Ahmad sp. nov. [bid. 4 (21): 127-130 (1977c). On Ommatokrithe prolata Ahmad gen. et sp. nov. [bid. 4 (22): 131-134 (1977d). On Tanzanicythere Ahmad nom. nov. /bid. 4 (27): 153 (1977e). Alexander, C. I. 1927. The stratigraphic range of the Cretaceous ostracod Bairdia subdeltoidea and its allies. J. Paleont., Chicago, 1: 29-33. —— 1929. Ostracoda of the Cretaceous of North Texas. Bull. Univ. Texas, Austin, 2907: 1-137. —— 1934. Ostracoda of the Midway (Eocene) of Texas. J. Paleont., Menasha, 8: 206-237. Al-Sheikhly, S. S. J. 1982. Some new species of the genus Occultocythereis H. V. Howe, 1951 (Trachyleberidinae, Ostracoda) from the Maastrichtian— Eocene of north and western Iraq. J. geol. Soc. Iraq, Baghdad, 15: 69-83. Anderson, F. W. 1964. A new species of the Ostracod Genus Paijenborchella Kingma. Geol. Mag., Hertford, 101: 40-43. Apostolescu, V. 1955. Description de quelques Ostracodes du Lutétien du Bassin de Paris. Cah. géol. Thoiry, 28-29: 241-279. Babinot, J. F. 1981. Ostracodes du Crétacé supérieur — Cenozoique de Cote d'Ivoire. Cah. Micropaléont., Paris, 1981 (2): 53-70, 4 pls. Baird, W. 1837-38. The Natural History of the British Entomostraca. Mag. Zool. Bot., Edinburgh, London & Dublin, 1: 35-41, 309-333, 514-526; 2: 132-144, 400-412. —— 1846. Arrangement of the British Entomostraca, with a List of Species, particularly noticing those which have as yet been discovered within the bounds of the Club. Hist. Berwicksh. Nat. Club, 2 (13): 145-158. — 1850. The Natural History of the British Entomostraca. 364 pp (ostracods 138-182). London (Ray Society). Barbeito-Gonzales, P. J. 1971. Die Ostracoden des Kiistenbereiche von Naxos (Griechenland) und ihre Lebensbereiche. Mitt. hamburg. Zool. Mus. Inst., Hamburg, 67: 255-326. Bate, R. H. 1969. Jn Bate, R. H. & Bayliss, D. D., An outline account of the Cretaceous and Tertiary Foraminifera and of the Cretaceous ostracods of Tanzania. Proc. 3rd African micropalaeont. Colloquium, Cairo: 113— 164. —— 1972. Upper Cretaceous Ostracoda from the Carnarvon Basin, Western Australia. Spec. Pap. Palaeont., London, 10: 1-85. — 1975. Ostacods from Callovian to Tithonian sediments of Tanzania, East Africa. Bull. Br. Mus. nat. Hist., London, (Geol.) 26 (5): 161-223. — 1976. New name for Rhadinocythere Bate, 1975. Geol. Mag., Cambridge, 113: 489. Benson, R. H. 1972. The Bradleya problem, with descriptions of two new psychrospheric ostracode genera, Agrenocythere and Poseidonamicus (Ostracoda: Crustacea). Smithson. Contr. Paleobiol., Washington, 12: 1-138. —— R. H., Berdan, J. M., Bold, W. A. van den, Hanai, T., Hessland, L., Howe, H. V., Kesling, R. V., Levinson, S. A., Reyment, R. A., Moore, R. C., Scott, H. W., Shaver, R. H., Sohn, I. G., Stover, L. E., Swain, F. M., Sylvester-Bradley, P. C. & Wainwright, J. 1961. Arthropoda 3. Crustacea, Ostracoda. Jn Moore, R. C. (ed.), Treatise on Invertebrate Paleontology, Q 422 pp., textfigures. Kansas. 266 —— & Coleman, G. L. 1963. Recent marine ostracodes from the eastern Gulf of Mexico. Paleont. Contr. Univ. Kansas, Lawrence, Arthropoda Art. 2: 1-52, 8 pls. Blow, W. H. 1969. Jn Bronnimann, P. & Renz, H. H. (eds), Planktonic Foraminiferal Biostratigraphy. Proc. First International Conference on Planktonic Microfossils, Geneva, 1: 1-442. Bold, W. A. van den 1946. Contribution to the study of Ostracoda, with special reference to the Tertiary and Cretaceous micro-fauna of the Caribbean Region. 167 pp. Amsterdam (Reprinted 1970). —— 1958a. Ostracoda of the Brasso Formation of Trinidad. Micropaleonto- logy, New York, 4: 391-418. —— 1958b. Ambocythere, a new genus of Ostracoda. Ann. Mag. nat. Hist., London, (12) 10 (119): 801-813. —— 1965. Middle Tertiary Ostracoda from northwestern Puerto Rico. Micro- paleontology, New York, 11: 381-414. — 1966. Ostracoda of the Pozon Section, Falcon, Venezuela. J. Paleont., Tulsa, 40 (1): 177-185. 1974. Ornate Bairdiidae in the Caribbean. Geosci. Man, Baton Rouge, 6: 29-40. Bonaduce, G., Ciampo, G. & Masoli, M. 1975. Distribution of Ostracoda in the Adriatic Sea. Pubbl. Staz. zool. Napoli, Naples, 40 (Suppl.): 1-304. Bosquet, J. 1852. Description des entomostracés fossiles des terrains Tertiares de la France et de la Belgique. Mém. Acad. r. Sci. Lett. Belg., Brussels, 24: 1-142. Bowen, R. N. C. 1953. Ostracoda from the London Clay. Proc. Geol. Ass., London, 64: 276-292. Brady, G. S. 1867. A synopsis of the British Ostracoda. Intellect. Obs., London, 12: 110—130. — 1869a. In Folin, L. de & Périer, L. 1867-1871. Les Fonds de la Mer, 1. 316 pp., 32 pls. —— 1869b. Contributions to the study of the Entomostraca. IV. Ostracoda from the River Scheldt and the Grecian Archipelago. Ann. Mag. nat. Hist., London, (4) 3: 45-50. — 1880. Report on the Ostracoda dredged by H.M.S. Challenger during the years 1873-1876. Rep. scient. Results Voy. Challenger, London, (Zool.) 1: 1-184. 1898. On new or imperfectly known species of Ostracoda, chiefly from New Zealand. Trans. zool. Soc. Lond. , 14: 429-452. ——. Crosskey, H. W. & Robertson, D. 1874. A monograph of the Post- Tertiary Entomostraca of Scotland including species from England and Ireland. 232 pp. Palaeontogr. Soc. [Monogr.], London. Carbonnel, G. 1969. Les Ostracodes du Miocene Rhodanien. Docum. Lab. Géol. Fac. Sci. Lyon, 33: 1-469. —— 1986. Ostracodes tertiares (Paleogene a Néogeéne) du bassin sénégalo- guinéen. Docums Bur. Rech. géol. miniéres, Orléans, 101 (2): 33-243. Ciampo, G. 1971. Gli ostracodi delle argille pleistoceniche del Mar Piccolo (Taranto). Boll. Soc. Nat. Napoli, 80: 49-88. Coryell, H. N. & Fields, S. 1937. A Gatun ostracode fauna from Cativa, Panama. Am. Mus. Novit., New York, 956: 1-18. Crane, M. J. 1965. Upper Cretaceous ostracodes of the Gulf Coast area. Micropaleontology, New York, 11: 191-254. Crouch, R. W. 1949. Pliocene Ostracoda from Southern California. J. Paleont., Tulsa, 23: 594-599. Deroo, G. 1966. Cytheracea (Ostracodes) du Maastrichtien de Maastricht (Pays-Bas) et des régions voisines; résultats stratigraphiques et paléontolo- giques de leur étude. Meded. geol. Sticht., Maastricht, (C) 2: 1-197. Devoto, G. 1965. Lacustrine Pleistocene in the Lower Liri Valley (southern Latium). Geologica romana, Rome, 6: 291-368. Dingle, R. V. 1969a. Marine Neocomian Ostracoda from South Africa. Trans. R. Soc. S. Afr., Cape Town, 38: 139-163. —— 1969b. Upper Senonian ostracods from the coast of Pondoland, South Africa. Trans. R. Soc. S. Afr., Cape Town, 38: 347-385. —— 1971. Some Cretaceous ostracodal assemblages from the Agulhas Bank (South African continental margin). Trans. R. Soc. S. Afr., Cape Town, 39: 393-418. —— 1976. Palaeogene ostracods from the continental shelf off Natal, South Africa. Trans. R. Soc. S. Afr., Cape Town, 42: 35-79. Donze, P., Porthault, B., Thomel, G. & Villoutreys, O. de 1970. Le Sénonien inférieur de Puget-Théniers (Alpes-Maritimes) et sa microfaune. Géobios, Lyon, 3: 41-106. Eames, F. E., Banner. F. T., Blow, W. H. & Clarke, W. J. 1962. Fundamentals of Mid-Tertiary Stratigraphical Correlation. 163 pp., 17 pls, folding tables. Cambridge. —— & Kent P. E. 1955. Miocene beds of the East African coast. Geol. Mag., Hertford, 92: 338-344. Elofson, O. 1941. Zur Kenntnis der marinen Ostracoden Schwedens mit besonderer Beriicksichtigung des Skageraks. Zool. Bidr. Uppsala, 19: 215-534. Esker, G. C. 1968. Danian ostracodes from Tunisia. Micropaleontology, New York, 14: 319-333. AHMAD, NEALE & SIDDIQUI Fischer, S. 1855. Beitrag zur Kenntnis der Ostracoden. Abh. bayer. Akad. Wiss., Munich, 7 (3): 635-666, pls XIX—XX. Gill, E. D. 1968. Oxygen isotope palaeotemperature determinations from Victoria, Australia. Jn Dawson, J. W. (ed.), The Tertiary Climate of New Zealand, 16: 56-61. Tuatara. Hanai, T. 1957-59. Studies on the Ostracoda from Japan. I. Subfamily Leptocytherinae n. subfam. J. Fac. Sci. Tokyo Univ., (11) 10: 431-468 (1957a). III. Subfamilies Cytherurinae G. W. Muller (emend. G. O. Sars 1925) and Cytheropterinae n. subfam. /bid. 11: 11-36 (1957b). IV. Family Cytherideidae Sars 1925. Ibid. 11: 291-308 (1959). Hartmann, G. 1964. Zur Kenntnis der Ostracoden des Roten Meeres. Kieler Meeresforsch. , Kiel, 20: 35-127. —— & Puri, H. S. 1974. Summary of Neontological and Paleontological Classification of Ostracoda. Mitt. hamburg. zool. Mus. Inst. ,'70: 7-73. Hazel, J. E. 1967. Classification and distribution of the Recent Hemicytheridae and Trachyleberididae (Ostracoda) off northeastern North America. Prof. Pap. U.S. geol. Surv., Washington, 564: 1-45. Holden, J. C. 1967. Late Cenozoic Ostracodes from the drowned terraces in the Hawaiian Islands. Pacific Sci., Hawaii, 21: 1-50. 1976. Late Cenozoic Ostracoda from Midway Island Drill Holes. Prof. Pap. U.S. geol. Surv., Washington. 680F: 1-43. : Hornibrook, N. de B. 1952. Tertiary and Recent marine Ostracoda of New Zealand. Their origin, affinities, and distribution. Palaeont. Bull. Wellington, 18: 1-82. —— 1953. Some New Zealand Tertiary marine Ostracoda useful in strati- graphy. Trans. R. Soc. N. Z., Dunedin, 81: 303-311. Hoskin, I. R. 1975. Comparison of valve ornamentation in various species of Hemicytherura from western Ireland, the Mediterranean and the Red Sea. Revta esp. Micropaleont., Madrid, 7: 91-98. Howe, H. V. 1951. New Tertiary ostracode fauna from Levy County, Florida. Geol. Bull. Fla, Tallahassee, 34 (1): 143. — 1955. Handbook of Ostracod Taxonomy. 386 pp. Baton Rouge, La. (Louisiana Univ. Studies Phys. Sci. No. 1.) —— 1961. In Benson, R. H. et al. (q.v.) —— 1963. Type saline Bayou Ostracoda of Louisiana. Bull. geol. Surv. La, Baton Rouge, 40: 1-62. — & Chambers, J. 1935. Louisiana Jackson Eocene Ostracoda. Geol. Bull. La, New Orleans, 5: 1-65. —— & Law, J. 1936. Louisiana Vicksburg Oligocene Ostracoda. Geol. Bull. La, New Orleans, 7: 1-96, 6 pls. Huff, W. J. 1970. The Jackson Eocene Ostracoda of Mississippi. Bull. Miss. geol. econ. topogr. Surv., Jackson, 114: 1-289. Ishizaki, K. 1973. Discovery of the Family Punciidae, Ostracoda (Crustacea), from Okinawa Island, Japan. Sci. Rep. Tohoku Univ., Sendai, (2 ser., geol.) spec. vol. 6: 403405. Jenkins, D. G. 1968. Variations in the numbers of species and subspecies of planktonic Foraminiferida as an indicator of New Zealand Cenozoic paleo- temperatures. Paleogeogr. Palaeoclimat. Palaeoecol., Amsterdam, 5: 309-313. Jones, T. R. 1849. A Monograph of the Entomostraca of the Cretaceous Formation of England. 40 pp. Palaeontogr. Soc. [Monogr.], London. —— & Sherborn, C. D. 1889. A supplemental monograph of the Tertiary Entomostraca of England. 55 pp. Palaeontogr. Soc. [Mongr.], London. Keen, M. C. 1974. Some Ruggieria-like ostracods from the Tertiary and Recent of West Africa. Proc. Vth African micropaleont. Colloquium, Addis Ababa, (1972): 451-469. Keij, A. J. 1953. Preliminary note on the Recent Ostracoda of the Snellius expedition. Proc. K. ned. Akad. Wet., Amsterdam, (B) 56: 155-168. 1957. Eocene and Oligocene Ostracoda of Belgium. Mem. Inst. r. Sci. nat. Belg., Brussels, 136: 1-210. —— 1958. Note on the Lutetian Ostracoda of Damery (Marne), France. Proc. K. ned. Akad. Wet., Amsterdam, (B) 61: 63-73. —— 1966. Southeast Asian Neogene and Recent species of Paijenborchella (Ostracoda). Micropaleontology, New York, 12: 343-354. 1976. Notes on Havanardia and Triebelina species (Ostracoda). Proc. K. ned. Akad. Wet., Amsterdam, (B) 79: 36-44. Kent, P. E. 1974. Continental margin of East Africa—A Region of vertical movements. Jn Burk, C. A. & Drake, C. L. (eds), The Geology of Continental Margins: 313-320. Berlin, Heidelberg, New York. —— , Hunt, J. A. & Johnstone, D. W. 1971. The geology and geophysics of coastal Tanzania. Geophys. Pap. Inst. geol. Sci., London, 6: 1-101. Khosla, S. C. 1978. Lower Miocene Ostracoda from Jamnagar and Porbandar Districts, Gujarat, India. Micropaleontology, New York, 24: 251-290. Kingma, J. T. (1948). Contributions to the Knowledge of the Young-Caenozoic Ostracoda from the Malayan Region. 119 pp. Thesis, Univ. Utrecht (unpubl.). Krutak, P. R. 1961. Jackson Eocene Ostracoda from the Cocoa Sand of Alabama. J. Paleont., Tulsa, 35: 769-788. Latham, M. H. 1938. Some Eocene Ostracoda from North-West India. Proc. R. Soc. Edinburgh, 59: 38-48. TERTIARY OSTRACODA FROM THE LINDI AREA, TANZANIA Latreille, P. A. 1806. Cohors secunda. Ostracoda. In: Genera crustaceorum et insectorum, 1: 17-18. Paris. Lubimova, P. S., Guha, D. K. & Mohan, M. 1960. Ostracoda of Jurassic and Tertiary deposits from Kutch and Rajasthan (Jaisalmer), India. Bull. geol. min. metall. Soc. India, Calcutta, 22: 1-61. M‘Coy, F. 1844. A Synopsis of the Characters of the Carboniferous Limestone Fossils of Ireland. 207 pp. (ostracods 163-168). Dublin. McKenzie, K. G. 1973. Cenozoic Ostracoda. In Hallam, A. (ed.), Atlas of Palaeobiogeography: 477-487. Amsterdam. —— 1974. Cainozoic Ostracoda of Southeastern Australia with the description of Hanaiceratina new genus. Geosci. Man, Baton Rouge, 6: 153-182. — & Swain, F. M. 1967. Recent Ostracoda from Scammon Lagoon, Baja California. J. Paleont., Tulsa, 41: 281-305. Maddocks, R. F. 1966. Distribution patterns of living and subfossil podocopid ostracodes in the Nosy Bé area. Paleont. Contr. Univ. Kansas, Lawrence, 12: 1-72. ——— 1969. Revision of Recent Bairdiidae (Ostracoda). Bull. Smithson. Inst., Washington, 295: 1-126. Mandelstam, M. I. 1960. /n: Ostracoda. Jn Chernousova, H. E. (ed.), Osnovy Paleontologii 8 (Chenistonogie, Trilobitoobraznie i Rakoobraznie): 264-413, pl. 17. Moscow. Morkhoven, F. P. C. M. van 1963. Post-Palaeozoic Ostracoda. Their Morph- ology, Taxonomy and Economic Use. 2, Generic descriptions. 478 pp. Amsterdam. Miiller, G. W. 1894. Die Ostracoden des Golfes von Neapel und abgrenzenden Meeres-Abschnitte. Fauna und Flora des Golfes von Neapel, 21. 404 pp. Berlin. —— 1908. Die Ostracoden der Deutschen Siidpolar-expedition 1901-1903. In Drygalski, E. von (ed.), Deutsch Stidpolar-expedition, 10 (Zool. II): 51-181, 19 pls. Berlin. —. 1912. Ostracoda. In Schulze, F. E. (ed.), Das Tierreich, 31. xxxitix+434 pp. Berlin. Neale, J. W. 1967. An ostracod fauna from Halley Bay, Coats Land, British Antarctic Territory. Scient. Rep. Br. Antarct. Surv., London, 58: 1—S0. —— 1975. The Ostracod Fauna from the Santonian Chalk (Upper Cretaceous) of Gingin, Western Austalia. Spec. Pap. Palaeont., London, 16: 1-88. — & Singh, P. 1985. Ostracoda from the Middle Eocene of Assam. Palaeontology, London, 28: 355-385. —— — 1988. Some problems associated with the genus Uroleberis. In: Hanai, T., Ikeya, M. & Ishizaki, K. (eds), Evolutionary Biology of Ostra- coda. Dev. Palaeont. Stratigr., Amsterdam, 11: 81-92. Neviani, A. 1928. Ostracodi fossili d’Italia. I: Vallebiaja (Calabriano). Memorie pont. Accad. Sci. nuovi Lincei, Rome, (2) 11: 1-120, 2 pls. Norman, A. M. 1865. Report on the Crustacea. Jn Brady, G. S., Report of Deep Sea Dredging on the Coasts of Northumberland and Durham, 1862-4. Nat. Hist. Trans. Northumb., Newcastle, 1 (1): 12-29, pls V—VII. Oertli, H. J. 1961. Ostracodes du Langhien-type. Riv. ital. Paleont., Milan, 67: 17-44. — 1971. The aspect of Ostracode faunas—A possible new tool in petroleum sedimentology. In Oertli, H. J. (ed.), Paléoécologie des Ostracodes. Bull. Cent. Rech. Pau, 5 suppl.: 137-151. Okubo, I. 1975. Callistocythere pumila Hanai, 1957 and Leguminocythereis bisanensis sp. nov. in the Inland Sea, Japan (Ostracoda). Proc. jap. Soc. syst. Zool., Tokyo, 11: 23-31. Omatsola, M. E. 1972. Recent and Subrecent Trachyleberididae and Hemi- cytheridae (Ostr., Crust.) from the western Niger Delta, Nigeria. Bull. geol. Instn Univ. Upsala, (N.S.) 3: 37-120. Poag, C. W. 1974. Ostracode biostratigraphy and correlation of the Chick- asawhay stage (Oligocene) of Mississippi and Alabama. J. Paleont., Tulsa, 48: 344-356. Pokorny, V. 1955. Contribution to the morphology and taxionomy of the Subfamily Hemicytherinae Puri. Acta Univ. Carol., Prague, 1955 (3): 1-36. —— 1964a. Oertliella and Spinicythereis, new ostracod genera from the Upper Cretaceous. Vest. ustred. Ust. geol., Prague, 39: 283-284. 1964b. Some palaeoecological problems in marine ostracode faunas, demonstrated on the Upper Cretaceous ostracodes of Bohemia, Czechoslovakia. Pubbl. Staz. zool. Napoli. , 33 suppl.: 462-479. Puri, H. S. 1953. The ostracode genus Hemicythere and its allies. J. Wash. Acad. Sci., Washington, 43: 169-179. —— 1954. Contribution to the study of the Miocene of the Florida Panhandle. Bull. Fla St. geol. Surv., Tallahassee, 36 [for 1953]: 215-309. —— 1955. Hermanites, new name for Hermania Puri, 1954. J. Paleont., Tulsa, 29: 558. —— 1957a. Postscript notes on the ostracode subfamily Brachycytherinae. J. Wash. Acad. Sci., Washington, 47: 306-308. —— 1957b. Henryhowella, new name for Howella Puri 1956. J. Paleont., Tulsa, 31: 982. —— 1957c. Notes on the ostracode subfamily Cytherideidinae Puri, 1952. J. Wash. Acad. Sci., Washington, 47: 305—306 (precedes 1957a). 267 —— 1960. Recent Ostracoda from the West Coast of Florida. Trans. Gulf Cst Ass. geol. Socs, New Orleans, 10: 107-149. —— 1974. Normal pores and the phylogeny of Ostracoda. Geosci. Man, Baton Rouge, 6: 137-151. Ramsay, V. W. 1968. A new morphological aspect of the Ostracod genus Cytherelloidea Alexander. Micropaleontology, New York, 14: 348-356 Roemer, F. A. 1838. Die Cytherinen der Molasse-Gebirges. Neues Jb. Min Geogn. Geol. Petrefakt., Stuttgart, 1838: 514-519, pl. VI —— 1840-41. Die Versteinerungen des norddeutschen Kreidegebirges. 145 pp., 16 pls. Hannover. Rome, R. 1962. Ostracodes. In: Exploration hydrobiologique du Lac Tanganyika (1946—]947). Résultats Scientifiques 3 (8). 305 pp. Brussels (Inst R. Sci. nat. Belg.). Ruggieri, G. 1950. Gli Ostracodi delle sabie grigie quaternarie (Milazziano) di Imola. I. G. Geol. , Bologna, (2) 21: 1-57. —— 1951. Una nuova Paijenborchella del Pliocene della Calabria. G. Geol. , Bologna, (2) 21: 59-63. —— 1953. Eta e faune di un terrazzo marino sulla Costa Ionica della Calabria G. Geol., Bologna, (2) 23: 17-168. 1956. La suddivisione degli Ostracodi gia compresi nel genere Cythereis proposta da Neviani nel 1928. Aéti Soc. ital. Sci. nat., Milan, 95: 161-175. —— 1958. Alcuni Ostracodi del Neogene italiano. Aditi Soc. ital. Sci. nat., Milan, 97: 127-146. —— 1961. Alcuni Ostracodi Quaternari e Recenti pertinenti al genere Costa Neviani. Boll. Soc. paleont. ital., Modena, 1: 3-9. — 1962. Gli Ostracodi marini del Tortoniano (Miocene medio-superiore) di Enna, nella Sicilia centrale. Palaeontogr. ttal., Pisa, 56: 1-68. — 1967. Due Ostracofaune del Miocene alloctono della Val Marecchia (Appennino settentrionale). Riv. ital. Paleont., Milan, 73: 351-384. —— 1972. Su alcuni Ostracodi marini plio-pleistocenici mediterranei. Atti Soc. ital, Sci. nat., Milan, 113: 89-113. Sars, G. O. 1866. Oversigt af Norges marine ostracoder. Forh. VidenskSelsk. Krist., Kristiana, 7: 1-130. —— 1888. Nye Bidrag til Kundskaben om Middlehavets Invertebratfauna. 4. Ostracoda Mediterranea. Arch. Math. Naturv., Oslo, 12: 173-324. — 1910. Zoological results of the Third Tanganyika Expedition, conducted by W. A. Cunnington, F. Z. S., 1904-1905. Report on the Ostracoda. Proc. zool. Soc. Lond. , 1910: 732-760. 1925-8. An account of the Crustacea of Norway. 9 Ostracoda. Parts IX & X, Cypridae (concluded), Cytheridae (part): 137-176 (1925). Parts XIII & XIV, Cytheridae (continued): 209-240 (1926). Parts XV & XVI, Cytheridae (concluded): 241-277 (1928). Bergen. Sexton, J. W. 1951. The ostracode Cytherelloidea in North America. J. Paleont., Tulsa, 25: 808-816. Siddiqui, Q. A. 1971. Early Tertiary Ostracoda of the Family Trachyleberididae from West Pakistan. Bull. Br. Mus. nat. Hist., London, (Geol. suppl.) 9: 1-98. Sissingh, W. 1972. Late Cenozoic Ostracoda of the South Aegean Island Arc. Utrecht micropaleont. Bull. , 6: 1-187. Skogsberg, T. 1928. Studies on marine ostracods Part I. External Morphology of the genus Cythereis with descriptions of twenty-one new species. Occ. Pap. Calif. Acad. Sci., San Francisco, 15: 1-155. Sohn, I. G. 1964. The ostracode genus Cytherelloidea, a possible indicator of paleotemperature. Pubbl. Staz. zool. Napoli, 33 suppl.: 529-534. — 1970. Early Tertiary ostracodes from West Pakistan. Mem. geol. Surv. Pakist., Quetta, 3 (1): 1-91, 4 pls. Stephenson, M. B. 1936. Shell structure of the ostracode genus Cytheridea. J. Paleont., Menasha, 10: 695-703. — 1946. Glyptobairdia, a new genus of Ostracoda. J. Paleont., Tulsa, 20: 345-347. —— 1947. Notes on the ostracode genus Triebelina. J. Paleont., Tulsa, 21: 577-579. Swain, F. M. 1955. Ostracoda of San Antonio Bay, Texas. J. Paleont., Tulsa, 29: 561-646. — 1967. Ostracoda from the Gulf of California. Mem. geol. Soc. Am., Washington, 101: 1-139. 1969. Taxonomy and ecology of near-shore Ostracoda from the Pacific Coast of North and Central America. /n Neale, J. W. (ed.), The Taxonomy, Morphology and Ecology of Recent Ostracoda: 423-474. Edinburgh — 1971. Pleistocene Ostracoda from deep-sea sediments in the southeastern Pacific Ocean. Jn Funnell, B. M. & Riedel, W. R. (eds), The Micropalaeon- tology of Oceans: 487-492. Cambridge. 1976. Lower and Middle? Cretaceous Ostracoda from the Atlantic Ocean off Guiana and off West Africa. J. Paleont., Tulsa, 50: 734-753 —— & Gilby, J. M. 1974. Marine Holocene Ostracoda from the Pacific Coast of North and Central America. Micropaleontology, New York, 20 257-352. Sylvester-Bradley, P. C. 1948. The Ostracode Genus Cythereis. J. Paleont., Tulsa, 22: 792-797. 268 Triebel, E. 1949. Zur Kenntnis der Ostracoden-Gattung Paijenborchella. Senckenbergiana, Frankfurt a.M., 30: 193-203. —-— 1958. Zwei neue Ostracoden-Gattungen aus dem Lutet des Pariser Beckens. Senckenberg. leth., Frankfurt a.M., 39: 105-117. Uliezny, F. (1969). Hemicytheridae und Trachyleberididae (Ostracoda) aus dem Pliozdn der Insel Kephallinia (Westgriechenland). 152 pp. Dissertation, Univ. Munich (unpubl. ). Ulrich, E. O. & Bassler, R. S. 1904. Superorder Ostracoda. In: Systematic paleontology, Miocene, Arthropoda. Md geol. Surv. stratigr. Mem., Baltimore, Miocene: 98-130. Wagner, C. W. 1957. Sur les ostracodes du Quaternaire—Récent des Pays-Bas et leur utilisation dans l'étude géologique des dépdts holocénes. 257 pp. The Hague. SYSTEMATIC INDEX New taxonomic names and page numbers of the prin- ciple references are printed in bold type. Asterisks denote illustrations. Acanthocythereis 209-211; see also Trachyleberis araneosa 209 postcornis 208* , 211, 261, 263 procapsus 211 Agrenocythere 229, 231, 235 pliocenica 235 Agulhasina 258 Aitkenicythere 259 Ambocythere 218 keiji 218 sp. 214*, 218, 260 Amnicythere, see Leptocythere Anterocythere 238-240 purit 238 sp. B (of Swain & Gilby, 1974) 238, 239*, 241*, 260, 263 Aurila 222-224, 259, 263 concentrica 221* , 222-224, 223*, 261, 263; Morphotype A 223*, 224, 260; Morphotype B 223*, 224, 260 Australileberis 258 Bairdia 187-188, 259 amygdaloides oblongata 187-188, 189*, 261 attenuata 188; cf. attenuata 188, 189* , 260 curta 187 fortificata 188 nigrescens 188 cf. schulzi 188, 190* , 260 subdeltoidea 188; var. rotunda 191 Bairdiidae 186-191 Bairdoppilata planolata 188 Bradleya 229-231, 235 lactea pakawangia 229 semiarata 229 Bradleya? cornuelina 235 voraginosa 235 sp. A 229, 230*, 260 sp. B 229-231, 230*, 261 Buntonia 217-218 shubutaensis 217 sp. 214*, 217, 261 Buntoniinae 217-220 Bythoceratina 255-257, 263, 264 mestayerae 255 variabilis 257 sp. A 228*, 257, 260 Bythoceratina? asteria 239* , 255-257, 260, 263, 264 Bythocytheridae 255-257 Callistocythere 196-198, 259 Jjugosa 195*, 196-198, 197*, 260, 261, 263 nipponica 198 Campylocytherinae 220-222 AHMAD, NEALE & SIDDIQUI Carinocythereis 211, 259 sp. 204*, 211, 261 Caudites 238, 240 medialis 240 rosaliensis 240; cf. rosaliensis 238, 239* , 240, 260 sp. 239*, 240, 260 sp. C (of Swain, 1969) 240 Centrocythere 220 Cladarocythere pterota 248, 250 Clithrocytheridea 201, 259 Clithrocytheridea? semiluna 200* , 201, 203* , 261, 263 Costa 211-212, 259, 263 punctatissima punctatissima 212 trudis 210* , 212, 260, 263 variabilicosta muhlemanni 212 Costa? hullina 210* , 211-212, 213*, 261 Crenaleya 178, 235—237, 259 tuberis 234* , 235, 236* , 237, 261, 263, 264 sp. A 236*, 237, 260 Crenaleya? sp. 236* , 237, 260 Cyprideis 201 Cythere acanthoderma 217 arata 229 cellulosa 250 convexa 222 evax 217 fischeri 243 latissima 253 littoralis 196 micheliniana 220 minna 257 nigrescens 252 pellucida 194 ranikotiana 255 rhomboidea 240 scabrocuneata 206 truncula 231 williamsoniana 184 Cythereis arcana 231 israelski 217 longaeva 259 prestwichiana 212 Cythereis (Procythereis) torquata 224 Cytherella 179-184, 259, 263 cretensis 184 lindiensis 179-182, 185* , 260, 261, 262, 263 mediocalva 182-184, 185* , 260, 261, 262, 263 ovata 182 tumidosa 182 vandenboldi 184 Cytherellidae 179-186 Cytherelloidea 179, 184-187, 259, 264 andersoni 184, 187 beckmanni 187 gemellata 184, 186*, 261, 263 patagiata 184-187, 186*, 261, 263 wayensis 184, 187 sp. A 186*, 187, 261 sp. B 184, 186*, 187, 189*, 261 Cytheridae 191-194 Cytheridea garretti 210 Cytheridea (Dolocytheridea) vermunti 205 Cytherideidae, Cytherideinae 198-199 Cytherina carinata 211 edwardsi 211 favosa 237 ovata 179 Cytherinae 191-194 Cytheropterinae 253-255 Cytheropteron 253, 259 epelyx 253, 254*, 261, 263 latissimum 253 nipeensis 253; cf. nipeensis 253, 254*, 261 subreticulum 253 sp. A 253, 254*, 261 Cytherura 252 Cytheruridae 248-255 Cytherurinae 248-253 TERTIARY OSTRACODA FROM THE LINDI AREA, TANZANIA 269 Dolocytheridea, see Cytheridea Leguminocythereis 220, 259 bisanensis 257 Echinocythereis? sp. 217 dinglei 207" , 220, 260, 261, 262, 263 Eocytheropteron parnensis 255 scarabaeus 220 Eopaijenborchella, see Paijenborchella Leguminocythereis? sp. 1 209 Leptocythere 194-196 Falsocythere 211 amoena 194-196, 197* , 261, 263 maccagnoi 211, 217*, 260 cranekeyensis 198 crepidula 196 Genus A sp. 256*, 258, 261 fastigata 195* , 196, 260, 263 Genus B sp. 204*, 258, 260 kiata 198 Genus C sp. 251*, 258, 261, 264 paracastanea 196 Gen. et sp. indet. 4 (of Sohn, 1970) 255 Leptocythere (Amnicythere) fallax 196 ' Genus Indet. sp. 1 (of Dingle, 1976) 235 Leptocytheridae 194-198 Gen. Indet. 3 sp. 1 (of Dingle, 1971) 237, 238 Loxoconcha abrupta 243 Gen. Indet. 5 sp. 1 (of Dingle, 1976) 218, 263 alata var. longispina 245 Glyptobairdia howei 191 angustata 246 Gujaratella 206-209 antillea var. rugosa 245 Gujaratella? tanzaniensis 203* , 206-209, 260 kafountinensis 246 longispina 245 Haughtonileberis 209, 259 meridionalis 245 fissilis 209, 263 pentockensis 243 haughtoni 209 postdorsalata 243 radiata 208*, 209, 261, 263 watervalleyensis 246 rastapuriensis 208* , 209, 261, 263 yazooensis 243 Hemicytheridae 222-240 Loxoconcha (Loxoconcha) 240-243 Hemicytherinae 222-225 mbanjaensis 240-243, 241*, 242*, 260, 263 Hemicytherura 250-252, 259, 263 Loxoconcha (Loxocorniculum) 243-245, 259, 264 subulata 241*, 250*, 250-252, 260, 263 cf. longispina 242* , 245, 261, 263 videns videns 252 postnodosa 242* , 242, 244*, 261, 263; Morphotype A 243, 244*, 261; sp. 252 Morphotype B 243, 244*, 261 Hemicytherura? nealei 246 tricornis 243-245, 244* , 260, 263 Henryhowella 217, 259 Loxoconcha (Myrena) 245 sentosa 216* , 217, 260 loculus 244* , 245, 261, 263 Hermania reticulata 225 Loxoconcha (Palmoconcha) 246 Hermanites 212, 225-229, 235, 259 pinguis 246, 247* , 260 carchesium 223* , 225, 226* , 228*, 261, 263 Loxoconchidae; Loxoconchinae 240-246 dameriacensis 225 Loxocorniculum, see Loxoconcha haidingeri rectangularis 212 mongoensis 225-227, 228* , 260, 263; Morphotype A 227, 228*, 261; Macrocyprididae 257-258 Morphotype B 227, 228* Macrocypris 257-258 paijenborchiana 212 acuticaudata 258 percultus 226* , 227*, 227-229, 261, 263 similis 258 volans 235 sp. B 256*, 257-258, 260 Hornibrookella, see Quadracythere Macrocypris? sp. A 256*, 257, 258, 261 Hystricocythere 217 sp. aff. M.? diamorpha 257 Manawa 250 Idiocythere 220, 264 Myrena, see Loxoconcha lutetiana 220 sp. A 216*, 220, 260 Neocythere 220 Ilyobates praetexta 210 Neonesidea nigrescens 188 incertae sedis 258 schulzi 188 Incongruella 217, 259, 263 Nephokirkos 224 semispinescens 217 tonsa 216*, 217, 219*, 260, 263 Occultocythereis 218-220 africana 204* , 218-220, 260, 263 Kangarina 253-255, 259 delumbata 218 quellita 253 hatraensis 218, 220 sp. 241*, 253, 261 Occultocythereis? maccagnoi 211 Karsteneis karsteni 259 Oertliella 235 Keijella 222 sp. A 235 Kingmania 224 Ommatokrithe 205, 259, 263, 264 Krithe 201-205, 258, 259, 263, 264 prolata 200* , 202*, 205, 260, 263 burdigalia 199* , 100*, 201-202, 260 Orionina 238 contracta 205 Orionininae 238-240 cubensis 202, 205 dolichodeira 202 Paijenborchella cymbula 192, 263 echolsae 205 geoffreyi 192 galei 205 tocosa 191, 192 hiwanneensis 202 lomata 192 langhiana 205 malaiensis 192, 263 liebaui 199* , 200*, 202*, 202-205, 260, 263 solitaria 192 medioelata 199* , 205, 261, 263 Paijenborchella (Paijenborchella) 191-192, 259, 263 perattica 205 cf. iocosa 191-192, 193* , 260 rutoti 205 Paijenborchella (Eopaijenborchella) 192-194, 259, 263 sawanensis 205 disadunca 193* , 194, 260, 263; Morphotype A 193°, 194, 260; Morphotype B whitecliffensis 205 193*, 194, 195*, 261; Morphotype C 194, 195°, 260; Morphotype D 193°, Krithidae; Krithinae 199-203 194, 261 Kuiperiana nystiana 245 quasimalaiensis 190* , 192, 194, 261, 263; q. dilata 190" , 192-194, 193°, 260, 263 270 Palmoconcha, see Loxoconcha laevimarginata 246 Paracytheridea 246-248, 259 anapetes 246-248, 247*, 249*, 261, 263 belhavensis 248 culmen 248, 249* , 261, 263; Morphotype A 248, 249*, 261 depressa 246 fenestrata 248 gradata 248 Paracytherideidae 246-248 Parakrithe 205-206, 258, 259, 264 cicatricosa 200* , 202* , 205-206, 260 Paranesidea 188-191, 259, 264 cf. fortificata 188-191, 189*, 261 fracticorallicola 185*, 188, 261 nigrescens 188, 189*, 261 cf. reticulopunctata 263 sp. A 189*, 191, 261 Phalcocythere 235 spinosa 179; cf. spinosa 179 Phlyctocythere 246, 259, 263 eocaenica 246 reniformis 246, 247* , 260, 263 Pokornyella 224 Ponticocythereis 211 Procythereis 224-225; see also Cythereis aligera 221* , 224, 260 radiata 221* , 224-225, 260 torquata 225 Quadracythere 225, 231-235, 259 arcana 231, 263; a. cornigera 231, 234*, 261 brachypygaia 235 distenta 231-233, 232*, 234*, 260 hornibrooki 233 kenti 232* , 233, 260 orbignyana 235 subquadra 233, 234*, 261, 263 trijugis 233, 234*, 260, 263 vanga 230* , 233-235, 261, 263 sp. A 235, 236*, 261 Quadracythere? acuta 231, 232*, 261 sulcatopunctata mediterranea 233 Quadracythere (Hornibrookella) arcana 231 subquadra 233 sp. A 235 Rostrocytheridea 201 chapmani 201 AHMAD, NEALE & SIDDIQUI Rostrocytheridea? sp. 201, 203*, 261 Ruggieria triangulata 222; aff. triangulata 222 Ruggieria (Ruggieria) 220-222, 263 furcilla 219* , 221* , 222, 260, 263 Semicytherura 252-253, 259 emphysema 251* , 252, 260 opeata 251* , 252, 260 sella 252, 253 sulcata 252 sp. A 251*, 252-253, 261 species BA (of Maddocks, 1966) 188 Stigmatocythere 215-217, 258, 259 bornhardti 213* , 215, 261, 263 intexta 213* , 214*, 215-217, 261, 263 obliqua 215, 263; aff. obliqua 215 Tanella 198 gracilis 198 sp. A 198, 199*, 260 sp. B 197*, 198, 260 Tanzanicythere 248-250, 259, 263 pterota 248-250, 251*, 260, 263 Thaerocytherinae 225-238 Trachyleberidea 212-215 Trachyleberidea? cirrata 212-215, 219* , 260, 264 Trachyleberididae 203-222 Trachyleberidinae 203-217 Trachyleberis 206, 258 duplex 203* , 206, 260 pennyi 206 Trachyleberis (Acanthocythereis) postcornis 211 Triebelina 191, 259, 264 howei 179, 189*, 191, 261, 263; cf. howei 179 indopacifica 191 schulzi 188 Urocythereis 235, 237-238 salebrosa 237-238 , 239* , 260 sorocula 238 Urocythereis? apolegma 238, 239* , 261 Uroleberis 255, 259, 264 armeniaca 255 batei 255 kyma 254*, 255, 256*, 261, 263 Uroleberis? sp. 247* , 255, 260 Xestoleberididae 255 Xestoleberis 259, 263 Bulletin of the British Museum (Natural History) Geology Series Most earlier Geology Bulletins are still in print. A full list of available titles can be obtained from Publication Sales (address inside front cover). Vol. 36 No.3. The Ordovician Graptolites of Spitsbergen. R. A. Cooper & R. A. Fortey. 1982. Pp. 157-302, 6 plates, 83 figs, 2 tables. £20.50 Vol. 36 No.4 Campanian and Maastrichtian sphenodiscid ammonites from southern Nigeria. P. M. P. Zaborski. 1982. Pp. 303-332, 36 figs. £4.00 Vol. 37 No. | Taxonomy of the arthrodire Ph/yctaenius from the Lower or Middle Devonian of Campbellton, New Brunswick, Canada. V.T. Young. 1983. Pp. 1-35, 18 figs. £5.00 Vol. 37 No. 2. Ailsacrinus gen. nov., an aberrant millericrinid from the Middle Jurassic of Britain. P. D. Taylor. 1983. Pp. 37-77, 48 figs, | table. £5.90 Vol. 37 No.3 Miscellanea: Permian Glossopteris in Turkey—Wealden Theriosuchus—Wealden conifer—Permian plants of Saudi Arabia Carboniferous Edrioasteroidea—British cicadas—Dittonian cephalaspids. 1983. Pp. 79-171. £13.50 Vol. 37 No. 4 The relationships of the palaeoniscid fishes, a review based on new specimens of Mimia and Moythomasia from the Upper Devonian of Western Australia. B. G. Gardiner. 1984. Pp. 173-428, 145 figs, 4 plates. 0 565 00967 2. £39.00 Vol. 38 No. | New tertiary pycnodonts from the Tilemsi valley, Republic of Mali. A. E. Longbottom. 1984. Pp. 1-26, 29 figs, 3 tables. 0 565 07000 2. £3.90 Vol. 38 No. 2. Silicified brachiopods from the Visean of County Fermanagh, Ireland. (II]) Rhynchonellids, Spiriferids and Terebratulids. C. H.C. Brunton. 1984. Pp 27-130, 213 figs. 0 565 07001 0. £16.20 Vol. 38 No.3 The Llandovery Series of the Type Area. L. R. M. Cocks, N. H. Woodcock, R. B. Rickards, J. T. Temple & P. D. Lane. 1984. Pp. 131-182, 70 figs. 0 565 07004 S. £7.80 Vol. 38 No. 4 Lower Ordovician Brachiopoda from the Tourmakeady Limestone, Co. Mayo, Ireland. A. Williams & G. B. Curry. 1985. Pp. 183-269, 214 figs. 0 565 07003 7. £14.50 ‘Vol. 38 No. 5. Miscellanea: Productacean growth and shell shape—Jurassic alga Palaeosiphonium—Upper Ordovician brachiopods and trilobites—Lower Devonian Osteostraci from Podolia—Hipparion from Diavata—Preparation and study of Singa skull—Carboniferous and Permian bryozoa—Lower Eocene trionychid—Montsech fossil insects. 1985. Pp. 271-412. 0 565 07004 5. £24.00 Vol. 39 No. | Upper Cretaceous ammonites from the Calabar region, south-east Nigeria. P. M. P. Zaborski. 1985. Pp. 1-72, 66 figs. 0 565 07006 1. £11.00 Vol. 39 No. 2. Cenomanian and Turonian ammonites from the Novo Redondo area, Angola. M. K. Howarth. 1985. Pp. 73-105. 33 figs. 0 565 07006 I. £5.60 Vol. 39 No.3 The systematics and palaeogeography of the Lower Jurassic insects of Dorset, England. P. E. S. Whalley. 1985. Pp. 107-189, 87 figs, 2 tables. 0 565 07008 8. £14.00 Vol. 39 No. 4 Mammals from the Bartonian (middle/late Eocene) of the Hampshire Basin, southern England. J. J. Hooker, 1986. Pp. 191-478, 71 figs, 39 tables. 0 565 07009 6. £49.50 Vol. 40 No. | The Ordovician graptolites of the Shelve District, Shropshire. I. Strachan. 1986. Pp. 1-58, 38 figs. 0 565 07010 X. £9.00 Vol. 40 No.2 The Cretaceous echinoid Boletechinus, with notes on the phylogeny of the Glyphocyphidae and Temnopleuridae. D. N. Lewis. 1986. Pp. 59-90, 1 figs, 7 tables. 0 565 07011 8. £5.60 Vol.40 No.3 The trilobite fauna of the Raheen Formation (upper Caradoc), Co. Waterford, Ireland. A. W. Owen, R. P. Tripp & S. F. Morris. 1986. Pp. 91-122, 88 figs. 0 565 07012 6. £5.60 Vol. 40 No. 4 Miscellanea I: Lower Turonian cirripede—Indian coleoid Naefia—Cretaceous—Recent Craniidae—Lectotypes of Girvan trilobites—Brachiopods from Provence—Lower Cretaceous cheilostomes. 1986. Pp. 125-222. 0 565 07013 4. £19.00 Vol. 40 No. 5 Miscellanea II: New material of Kimmerosaurus—Edgehills Sandstone plants—Lithogeochemistry of Mendip rocks— Specimens previously recorded as teuthids—Carboniferous lycopsid Anabathra—Meyenodendron, new Alaskian lepidodendrid. 1986. Pp. 225-297. 0 565 07014 2. £13.00 Vol. 41 No. | The Downtonian ostracoderm Sclerodus Agassiz (Osteostraci: Tremataspididae), P. L. Forey. 1987. Pp. 1-30. II figs. 0 565 07015 0. £5.50 Vol. 41 No.2 Lower Turonian (Cretaceous) ammonites from south-east Nigeria. P. M. P. Zaborski. 1987. Pp. 31-66. 46 figs. 0 565 07016 9. £6.50 ‘ Vol. 41 No.3 The Arenig Series in South Wales: Stratigraphy and Palaeontology. I. The Arenig Series in South Wales. R. A. Fortey & R. M. Owens. II. Appendix. Acritarchs and Chitinozoa from the Arenig Series of South-west Wales. S. G. Molyneux. 1987. Pp. 67-364. 289 figs. 0 565 07017 7. £59.00 Vol. 41 No.4 Miocene geology and palaeontology of Ad Dabtiyah, Saudi Arabia. Compiled by P. J. Whybrow. 1987. Pp. 365-457, 54 figs. 056507019 3. £18.00 Vol. 42 Cenomanian and Lower Turonian Echinoderms from Wilmington, south-east Devon. A. B. Smith, C. R. C. Paul, A. S. Gale & S. K. Donovan. 1988. 244 pp., 80 figs, 50 pls. 0 565 07018 S. £46.50 Vol.43 A Global Analysis of the Ordovician—Silurian boundary. Edited by L. R. M. Cocks & R. B. Rickards. 1988. 394 pp., figs. 0565 07020 7. £70.00 Vol. 44 No. | Miscellanea: Palaeocene wood from Mali—Chapelcorner fish bed—Heterotheca coprolites—Mesozoic Neuroptera and Raphidioptera. 1988. Pp. 1-63. 0 565 07021 S. £12.00 Vol.44.No.2 Cenomanian brachiopods from the Lower Chalk of Britain and northern Europe. E. F. Owen. 1988. Pp. 65-175. 0 56507022 3. £21.00 Vol. 44 No. 3. The ammonite zonal sequence and ammonite taxonomy in the Douvilleiceras mammillatum Superzone (Lower Albian) in Europe. H. G. Owen. 1988. Pp. 177-231. 0 565 07023 1. £10.30 Vol. 44 No. 4 Cassiopidae (Cretaceous Mesogastropoda): taxonomy and ecology. R. J. Cleevely & N. J. Morris. 1988. Pp, 233-291 0 565 07024 X. £11.00 Vol. 45 No. | Arenig trilobites—Devonian brachiopods—Triassic demosponges—Larval shells of Jurassic bivalves—Carboniferous marattialean fern—Classification of Plectambonitacea. 1989. Pp. 1-163. 0 565 07025 8. £40.00 Vol. 45 No. 2. A review of the Tertiary non-marine molluscan faunas of the Pebasian and other inland basins of north-western South America. C. P. Nuttall. 1990. Pp. 165-371. 456 figs. 0 565 07026 6. £52.00 Vol. 46 No. | Mid-Cretaceous Ammonites of Nigeria—new amphisbaenians from Kenya—English Wealden Equisetales—Faringdon Sponge Gravel Bryozoa. 1990. Pp. 1-152. 0 565 070274. £45.00 CONTENTS 153 The Carboniferous pteridosperm frond Neuropteris heterophylla (Brongniart) Sternberg. Christopher J. Cleal & Cedric H. Shute 175 Tertiary Ostracoda from the Lindi area, Tanzania. Manzoor Ahmad, John W. Neale & Oadeer A. Siddiqui Bulletin British Museum (Natural History) GEOLOGY SERIES Vol. 46, No. 2, January 1991