Memoirs of the Museum of Victoria 54: 1-49 (1994) 30 June 1994 https://doi.org/10.24199/j.mmv.1994.54.01 MIOCENE OSTRACODA OF THE TRACHYLEBERIDIDAE AND HEMICYTHERIDAE FROM THE MUDDY CREEK AREA, SOUTH-WESTERN VICTORIA

By John V. Neil

Department of Geology, University of Melbourne Honorary Associate, Museum of Victoria 23 Michael St, Bendigo, Victoria 3550, Australia

Abstract

Neil, J.V., 1994. Miocene Ostracoda of the Trachyleberididae and Hemicytheridae from the Muddy Creek area, south-western Victoria. Memoirs of the Museum of Victoria 54: 1-49. Eleven samples in a vertical section of the Muddy Creek Marl at Clifton Bank, Victoria, Australia, and one large sample from the Marl at Hentys produced nearly 10000 ostracode specimens. The fauna consists of 186 species from 85 genera. Of the Trachyleberididae and Hemicytheridae, 36 species are present. Of these, 15 species are new: ?Alatahermanites septarca, Deltaleberis warnei, 'Hemicythere' lubrica, H'. temdcostata, Mackenzina fove- glyphica, Spinobradleya olata, Notocarinovalva yulecartensis, 'Hermanites ' thomasi, H. nodosa, Bradleya (Quasibradleya) pyxos, Quadracythere (Hornibrookellina) hentyensis, ?Dumontina cratis, Arculacythereis tatei and 'Ambostracon' recta. Three species are left 'Cytheral- in open nomenclature. Two previously described species have been reassigned: ison' postdedivis (Chapman, 1914) to ?Arculacythereis and Cythere flexicostata (Chap- man, 1914) to Chapmanella gen. nov. Three new genera and one new subgenus have been erected: Chapmanella, Mackenzina, Notocarinovalva and Quadracythere (Hornibrookel-

lina). . The faunas have a warm-temperate to subtropical character, and indicate a shallow-water, high-energy, near-shore environment of deposition, with abundant phytal associates. The that is, from age of the samples ranees from late Early to early Middle Miocene (N8-N10); stage, the basis of plank- late Batesfordian, through the Balcombian to early Bairnsdalian on Clifton Bank has occupied tonic foraminifers. The deposition of the beds in the section at Hentys is a long-ranging a period of approximately one million years. The sample from thanalacoenosis.

Introduction berididae and Hemicytheridae — in all, five species, of which only one, Bradleya [Bradleya] in The ostracode fauna of the Muddy Creek Marl praemackenziei, is a hemicytherid. south-western Victoria, Australia (Text-fig. 1) jhe dominant species (10% or more of the has been described by Neil (1992). Eleven sam- specimens) in the assemblages from the Clifton pies from Clifton Bank on Muddy Creek, and one B an k samples were Quadracythere (Q.) spica, Burn, pro- large sample form Hentys on Grange 'Hermanites ' thomasi and Hermanites glyphica. vided nearly 10000 specimens. The fauna con- Hermanites' thomasi, endemic to Clifton Bank, Within this the specimens in sists of 1 86 species from 85 genera. constituted more than 30% of fauna, 37 species are new, five new genera will one f these samples, whereas Whatley and be erected and 57 species have been left in open Downing (1983) found that Bradleya (B.) nomenclature. More than 40% of the specimens, praemackenziei, the most abundant of the five 36 species from 23 genera and 4 subgenera, are species of hemicytherids and trachyleberids members of Trachyleberididae and Hemi- referred to above, constituted only 7% of the total, cytheridae. Three genera, one subgenus, and 14 The Hentys sample had no dominant species as speci- species are described as new. Four species are defined above, but the commonest (>100 spica, Quadra- left in open nomenclature. This preponderance mens) were Quadracythere (Q.) hentyensis, Herman- of trachyleberids and hemicytherids is markedly cythere {Hornibrookellina) Chapmanella flexicostata. Of different from the Miocene fauna from Fossil ites glyphica and Beach Mornington Victoria which was mono- these species Q. (Hornibrookellina) hentyensis percentage, hemi- graphed by Whatley and Downing (1983). The is endemic to Hentys. By dominant at both localities — fauna had only 8.2% of individuals (as distinct cytherids were tor trachyleberids, from separate specimens) from the Trachyle- 34.7% compared to 5.4% JOHN V. NEIL

SCALE OF CHAINS 10 20 30 J

Text-figure Clifton 1. Bank and 'Hentys' localities, Yulecart, near Hamilton, southwestern Victoria.Vi MIOCENE TRACHYLEBERinilMH AND I IRMICYTllIiRIDAIi

though ihe latter group were more common at 1955, 1957, 1964; Hazel, 1967; Benson, 1972; Hentys (8.2%) than at Clifton Bank (3.3%). Hartmann and Puri, 1974; I.iebau, 1975, McKen- The figured specimens (numbers prefixed zie and Bonaduce, 1991). Pokorny's analysis NMV P) are housed in the Invertebrate Palaeon- suggested that whatever features are used to diag- tology Collections of the Museum of Victoria. nose these families, a horizontal, polyphylelic Fauna] slides from the samples used in the prepa- classification will result. In practical terms, ration of this study are in the collection of the progress has been made towards establishing author. some features as primitive and others as advanced. The Hemicytheridae are generally Provenance of the fossils agreed to be derived from Trachyleberididae. The To the west of Hamilton, the Wannon River has features about which there is the greatest agree been diverted along the margin of the Newer ment are the single v shaped or hooked frontal Basalt which forms much of the plains of the scar for the trachyleberids and the divided frontal Western District. Several tributaries, notably the scar for the hemicytherids, together with the six Grange Burn and its tributaries Muddy Creek and jointed antennula for most trachyleberids com- Violet Creek, have cut through the basalt cap- pared to the five-jointed one for hemicytherids ping, exposing sediments of Miocene and (McKen/.ie and Bonaduce, 1991), and the pres- Pliocene age (Text-fig. 2). These sediments, shal- ence of complex chitin supports in Ihe thoracic low marine further west, but grading or inter- limbs of hemicytherids versus simple chitin sup- grading into terrestrial deposits in the eastern sec- ports in Ihe legs of trachylcbcridids. Other Fea- tion nearer to Hamilton, are richly fossiliferous. tures such as subcenlral tubercles, spines, mar- The basement is mid-Palaeozoic rhyolite, on ginal denticulations and eye-spots can be taken as which thin shelf deposits have been laid down. part of a constellation of characters to determine The oldest of these is a limestone, in part crys- family-level classification but singly they cannot talline and described by Mallett (1977) as a be used safely for diagnostic purposes above coarse, yellow-brown calcarenitc. Overlying the genus, for the palaeontologist, soft-part differ- calcarenite is an unlithified calcareous silly sand, entiation cannot be applied. generally green-grey in colour, but tending to The classification of Hartmann and Puri (1974) fawn or brown in the Grange Burn outcrops as is generally followed here. They allowed some depth of deposition increased and glauconitic trachyleberids exceptionally lo have 2 or 3 frontal effects gave way to ferruginous ones. The pres- scars and refused to rule out Ihe possibility of ence of coarser lag deposits throughout this some hemicytherids having v shaped frontal sequence is notable, particularly in the upper sec- scars, although none is yet known. The basic rea- tion (Reeckmann, 1974). The base of the over- son for this equivocation is the widely accepted lying COquinas is defined by a phosphatic nodule transitional nature (in terms of carapace mor- bed which marks a discontinuity between the phology) of many genera. The erection of 'form 'marls' and the 'enquinas' (Gill, 1957; Carter, genera' on the basis of these morphological dif 1978). The lithologies in both the Grange Burn ferences may or may not be consistent with the and Muddy Creek exposures show considerable phylogcny of Ihe species and genera so defined lateral variation. In places. Ihe coquinas give way Hartmann and Puri endeavoured lo strike a bal- to shelly silts, grading upward into laminated and ance between neontological and palaeontologi- sparsely fossiliferous sills which include a tuffa- cal principles bul Pokorny's original warning ceous band. The final marine deposits at the top remains. The taxonomisl faced with Ihe practical of the sequence are represented by a coarse green problems of developing a phylogenetic classifi- calcarenite up to 4 m thick. Terrestrial and lacus- cation to cover both neonlological and palaeon- trine deposits cap the sequences immediately tological laxa must be subjective in weighting below the basalt, and in places a soil profile is characters. The acceptance of weighting is pari of developed in the top of the terrestrial beds (Gill, the legacy ol adopting a conservative taxonomy. 1957) which are fine white siliceous sands. In the approach adopted here, the frontal scar Trachyleberididae and Hemicytheridae characteristics are taken as diagnostic for fossil propo- trachyleberids and hemicylherids. If a cladistic There is partial agreement between the were shared -derived features nents of classificatory schemes for the Trachyle- approach adopted scars anil frontal scars would be berididae and Hemicytheridae (Nealc, 1959; such as muscle for and morphoclines, with or without Howe, Sylvester-Bradley, van den Bold and Rcy- looked would be to eliminate poly ment, 1961; van Morkhoven, 1962; Pokorny, polarity, established JOHN V. NEIL

phylogenetic ideas, neglecting the main part of

k B c observable data; old-fashioned form group con-

i cepts and general lack of adequate taxonomic standards)". Hartmann and Puri (1974) advised 1 N10 keeping the number of systematic units in the 30 Trachyleberididae and Hemicytheridae to a min-

" I 1 1 1 1 I 1 1 1 1 IV imum. They retained the Thaerocytherinae as a 2 subfamily within the Hemicytheridae, consonant 61 with Liebau's idea, and I concur with their deci- sion. 3 Trachyleberididae Sylvester-Bradley, 1948 92 HENTY'S Trachyleberidinae Sylvester-Bradley, 1948 s. s. 4 122 Tribe Trachyleberidini Sylvester-Bradley, N9 1948 5 Trachyleberis Brady, 1 898 153 I'll, llll HUll. ITrachyleberis robustus (Yassini and Jones) 6 comb. nov. 181

PI. 1 figs 1,2,3; pi. 14 fig. 1 7/| 199 Actinocythereis robustus Yassini and Jones, 1987: 823, 76 212 figs 4.1,4.2.

Figured specimens. NMVP123216 — PI. 1 fig I, PI. 14fig 1; 8 NMVP134937 — PI. I fig. 2; NMV P134938 — PI. 1 fig. 3. 242

Dimensions. (P 1 232 1 6) RV : L=0.92; H=0.50.

Material 23 specimens, Clifton Bank and 9 N8 Hentys, Muddy Creek Marl, early Middle Miocene. 273 Remarks. The muscle scar pattern, with two 10 293 frontal scars, a hooked dorsal adductor and a divided ventromedian adductor, is quite distinc-

tive for a trachyleberid (PI. 14 fig. 1). The two frontal Text-figure 2. Clifton Bank and 'Hentys' sections on scars are an unusual variant in Trachyle- Muddy Creek and Grange Burn. A, Clifton Bank sam- beridinae (Hartmann and Puri, 1974; Hazel, ple numbers. B, depth from surface in centimetres. C, 1967). There is a very large, broad-ended spine planktonic foraminiferal zones (Berggren, Kent and developed at the posteroventral angle, and the Flynn, 1985). D, 'Hentys' sample (time averaged). spines coalesce to form a ventral ridge, extend- ing from the anterior margin to short of the large spine at the posteroventral angle. Although the development and size of the phyletic and paraphyletic genera. Pokorny's tubercles/spines is greater in these specimens criticism of a horizontal classification would be than in the specimen of Actinocythereis robus- tackled at its source. tus figured by Yassini and Jones (1987), their Liebau (1975: 373) wrote: "New suprageneric placement and orientation is such that these spec- taxa should correspond to new information about imens may be conspecific. However, the assign- natural relationships. The production of tribes ment of this species to Actinocythereis cannot be and subfamilies within the taxonomy of the Tra- sustained since there is no linearity in the chyleberididae s.l. does not always correspond arrangement of the tubercles/spines, the major to an adequate increase of knowledge about evo- diagnostic feature of that genus (Moore, 1961: lution, nor to the development of a more practi- Q334; Von Morkhoven, 1963: 178). Assignment cal system either, but is mainly the result of 'tax- to Echinocythereis on the basis of the double onomic accidents' (subjective synonyms, caused frontal scar is ruled out because ?Trachyleberis by uncorrelated taxonomic studies; nebulous robustus has stout tubercles/spines, randomly MIOCENE TRACHYLEBERIDIDAE AND HEMICYTHERIDAE

distributed, unlike Echinocythereis, in which the The material exhibits some distinctive charac- spines are finer and the arrangement tends to con- ters. The eye tubercle is strong and prominent centric lines. and in some specimens reddish in colour. In the

I assign the species tentatively to Trachyleberis anterior section, the spines are in four, rather than on the basis of its tubercles/spines. Though this three, lines. The subcentral tubercle has two is a limited basis, Brady's (1898) diagnosis of prominent spines, and the marginal spine at the the genus refers only to the tubercles/spines of posterodorsal angle is terminally trifid. The the hard parts, the remainder of the diagnosis spines on the lateral surface of the valve termi- being entirely concerned with the soft parts. The nate with a pore opening. assignment is tentative because of the unusual Ponticocythereis McKenzie, 1967 muscle scar and frontal scar pattern, and the quadrate valves. This latter characteristic is Remarks. This genus, by original diagnosis, dif- shared with Ponticocythereis McKenzie, 1967 fers inter alia from Trachyleberis, which has a but ?T. robustus has well-developed spines all subacuminate posterior, in its subquadrate shape over the valve surface. On the other hand, T. tri- in lateral view. The species described hereunder dens Hornibrook, 1953 does show a very similar is tentatively placed in Ponticocythereis using pattern of tubercles/spines and has a subquadrate lateral valve shape as a fundamental diagnostic shape like ?T. robustus. The former species has feature. McKenzie (1967) remarked that for Pon- single frontal scar and no anterocentral tubercle ticocythereis the "pattern of surface ornament like ?T. robustus. Yassini and Jones (1987) did (which is consistent in all known species) suf- not refer to muscle scars in their description of fices to distinguish it from Trachyleberis which

?T. robustus. is spiny over the entire surface". This distin- ITrachyleberis robustus occurs at both locali- guishing characteristic, regarded as less funda- ties and is distributed among the samples simi- mental than valve shape by Whatley and Titter- larly to ^Actinocythereis sp. A. With more mate- ton (1981), is lost in the present case, where the

rial, it is possible that conspecificity will be '"scale'-like protuberances" (to use their termi- confirmed but assignment to Trachyleberis s.s. nology) substantially cover the lateral surface of will not be so resolved since the frontal scar is the valves. double and the adductors are unusual. ?Tra- 7 Ponticocythereis sp. aff. P. manis Whatley chyleberis robustus is another species from this and Titterton, 1981 fauna which appears to range from the Miocene to the Recent. PI. 2 figs 3, 4, 5

Actinocythereis Puri, 1953 (as diagnosed by Trachyleberis sp. 2. — Scott, 1974: 125, pi. 9 figs 97-98. Hazel, 1967) Figured specimens. NMV PI 34945 — PI. 2 fig. 3; NMV PI 34946 — PI. 2 fig. 4; NMV P123217 — PI. 2 fig. 5. ? Actinocythereis sp. A Dimensions. (P123217) RV: L=0.74; H=0.36 Material. 25 specimens, Clifton Bank (rare) and Hentys, PI. 1 figs 4, 5 Muddy Creek Marl, early Middle Miocene.

fig. Figured specimens. NMV P123221 — PI. 1 4; NMV Brief description. Very spinose, subquadrate P134939 — PI. 1 fig. 5. species of IPonticocythereis. Squamose spines ( 1 2322 ) LV : L=0.80; H=0.42. Dimensions. P 1 a flattened and somewhat 'daisy' -shaped Material. 39 specimens, Clifton Bank and Hentys, near have the appearance of hav- Hamilton. Muddy Creek Marl, early Middle Miocene. top (PI. 1 1 fig 2), giving ing been squashed in a direction normal to valve tentatively for Remarks. Actinocythereis is chosen surface (cf. Trachyleberis sp. 2. [Scott, 1974 of this species because of the linear arrangement unpublished]). 'Scales' cover valve surface spines. Marginal spinosity is marked. A v-shaped including dorsum and venter, except for furrows but the frontal scar is indistinct in one specimen parallel and close to anterior and posterior mar- co-inci- adductors cannot be seen because of the gins and 2 small central areas. Hinge strongly dence of two large spines with the muscle scar holamphidont. Muscle scars, with clearly v- the type node. There is minor resemblance to shaped frontal scar, of characteristic trachyle- Bassler) in species A. exanthemata (Ulrich and berid form. RPCs are numerous. type of ornament but insufficient characters can Remarks. This species is very similar to Pontic- be identified to attribute the species unequivocal- identity. ocythereis manis Whatley and Titterton, 1981, ly to this genus or to establish specific JOHN V. NEIL

from which it differs in lacking the more spinose genus. However, confirmed occurrences from the marginal tlenticulation and in having only a Eocene and Oligocene (McKenzie, 1979; small, inconspicuous eye tubercle. The 'scales' McKenzieet al., 1991) and Miocene of Australia show no concentration into a median ridge, as in (Whatley and Downing, 1983; M. T. Warne, Whatley and Titterton's species, nor is their sur- 1987 — pers. coram, and this paper) and uncon- face punctate. The valves of ?P. sp. aff. P. manis firmed ones from the Maastrichtian of Jamaica are more quadrate than of the other species which (Hazel in Benson, 1972) rule out Hermanites

has an anterior hinge ear. There is considerable tschoppi (H. paijenborchiam auctt.) as the ances- intraspecillc variation in the form and distribution tor. Benson (1972) suggested that Cletocythereis of the spines. Some specimens have a few could be antecedent to Hermanites, and this is squamose spines around the margins of the valve, supported by its occurrence in the Late Eocene of with the remainder of the spines being more Australia (McKenzie, 1979). It is clear that iden- rounded at the ends. Other specimens have open- tification of derived characters as a preliminary ings or 'pores' in the flattened 'scales'. to drawing phylogenetic inferences can be rather This species differs from P. militaris (Brady, subjective when the stratigraphic ranges of

/'. 1 866), icthyoderma (Brady, 1 890) and P. spin- species have not yet been investigated fully. Even osa Whatley and Tittcrton, 1981, all of which the v-shaped frontal scar, generally accepted as have large, often backward-directed spines with a relatively primitive feature, is not a safe guide a linear arrangement, in the nature and distribu- in the case of Cletocythereis. Benson (1972) tion of its spines. Sylvester Bradley and Benson referred to "a partially divided v-shaped frontal (1971) referred to the spines of Ponticocythereis scar", and consequently placed Cletocythereis militaris as 'clavae', where the terminal exten- early in the line of development from ancestral sion of the spine is longitudinal to the orienta- trachyleberids. Yet within the populations of tion of the valve, but the flattened 'scales' of Miocene Cletocythereis species described here- .'Ponticocythereis sp. aff. P. manis are not clavae. under, intraspecillc variations in the shape and The hinge structure shows the anti-slip bar of /'. divisions of the frontal scar or scars are consid- manis s.s. The quadrate shape of the valves and erable — ranging from a single v-shaped scar, the unusual form of the spines are sufficiently through partially divided scars and two scars, one distinctive from Ponticocythereis s.s. to suggest of which is v- or heart-shaped, to two or three that a new genus, inclusive of P. manis and ?P. more or less circular scars. Of these variations, sp. aff. P. manis, might be considered. however, the single v-shaped frontal scar is by far the most common. Cletocythereis Swain, 1963 In spite of the necessity for caution, I concur with Hartmann and Puri's placement (1974) of Discussion. The genus had a confusing begin- Cletocythereis in Trachyleberididae, because the ning, with Swain using Cythcrc rastranuugina- v-shaped frontal scar is the most common. The la Brady, 1880 as the type species, but not classification of Liebau (1975), which puts not redeseribing or refiguring it. Swain assigned a only Cletocythereis, but also such genera as new species, C. noblissimus, to the new genus, Oerlliella and Agrenocythere into Hcmicytheri- describing and figuring it in detail, and the diag- dac cannot be supported using the conservative nosis of Cletocythereis reflected this latter muscle-scar criterion. species rather than the type species. Since C. nohlissimus is not congeneric with C. rastro- Cletocythereis caudispinosa (Chapman and marginata (McKenzie, 1967: 232) and has been Crespin, 1928) assigned to ?Acanthocythereis by Hazel (1967) PL 1 figs 6, 7, 8, 9 the genus needs rediagnosis. Benson (1972) pub- lished figures of C. rastromarginata, established Cythcrc caudispinosa Chapman and Crespin in Chapman a lectotype, and referred to the problem. The el al.. 1928: 125, p|. 9 figs 64a, b .— MeKen/.ic, 1974: 160 generic concept of Cletocythereis is now much pl. I Tig. 4. Oerlliella caudispinosa, more firmly based and Malz (1980) discussed it — MeKen/.ie, 1981: 107. 'Oerttiella in detail, and erected new species and subspecies. ' caudispinosa, — McKenzie and Peypouquel

1984 : 293. The presumed derivation of Cletocythereis Cletocythereis caudispinosa. — Whatley and Downing from Hermanites (Holdert, 1967, 1976) was 198.1; pl. 382. 7 figs 10. 1 1. —Warne, 1987: 442. based on an assumption that Pliocene/Pleistocene ( 'Utocytherels • of. caudispinosa, — McKenzie et al, 199 1 Occurrences were the earliest appearances of the I72.pl. 8 fig. 14, pl. 9 fig. 6. MIOCENE TRACHYLEBERIDIDAE AND HEMICYTHERIDAE 7

Figured specimens. NMV P 134939 — PL 1 fig. 6; NMV Chapman and Crespin's description empha- PI 34940 — PL 1 fig. 7; NMV PI 34941 — PL 1 fig. 8; NMV sised the acuminate spinose posterior, anterior PI 23327 — PL 1 fig. 9. and ventral ridges, and reticulation pattern. Dimensions. (P123327) LV L=0.67; H=0.39. Although they stated that 'the aureole of the Material, 65 specimens from Clifton Bank and Hcntys, near median area is not distinctly radiate', in some Hamilton. C. caudispinosa also occurs in the Wuk Wuk Marl specimens the reticulation around the subcentral at Bairnsdale in Gippsland; in the lower section of the Mor- is regularly developed, except gan Limestone at Blanchetown, SA; and in the Mannum For- tubercle very mation at the Mannum Pumping Station, SA. A related and directly ventral to the tubercle. In the figured possibly ancestral form occurs in the Tortachilla Limestone specimen, the reticulation is marked by substan- and the Blanche Point Marls of the Port Willunga area of SA tial 'celation' (Sylvester-Bradley and Benson, (personal collections) and was noted by McKenzie et al. tend to obscure the 197 1 ) or intergrowths which (1991). pattern (PI. 11 fig. 1). Age. Muddy Creek Marl, early Middle Miocene. Horizon and A possibly ancestral form from Eocene beds If the specimens from the Wuk Wuk Marl and the Morgan in South Australia differs from the Muddy Creek Limestone are conspecific, they are also contemporaneous specimens in that the dorsal ridge has spines (Abele in Douglas and Ferguson. 1988; Lindsay, 1985). rather than nodes, the ventral ridge is not contin-

Description. There is a distinct eye tubercle. uous with the anterior ridge, and the posterior Halfway along the dorsal margin a 'rim tooth' spines are less well-developed. However, the (McKenzie, 1974) or 'aussenzahn' (Malz, 1980) acuminate posterior and reticulation strongly sug- projects above the general line of the LV and in gest C. caudispinosa rather than C. rastromar- dorsal view overlaps the RV. Hinge strongly ginata. Muscle scars were not observed in these holamphidont with smooth simple teeth and a specimens so a possible relationship with the smooth median bar. Anterior margin finely den- genus Oertliella cannot be established, even as the ticulate and fused zone broader than at other parts though other morphological features such of the margin. Approximately 20 simple, spinose dorsum suggest it. unbranched radial pore canals. Anterior margin- Cletocythereis sp. cf. C. rastromarginata al ridge thin, sharply defined and stands up nor- (Brady, 1880) mal to lateral surface of the valve. Ventral ridge

continuous with anterior ridge, thin and also PI. I fig. 10, PI. 2 figs 1,2 sharply defined, at least in specimens from Cvthere rastromarginata Brady. 1 880 (partim, sensu Hold- less clearly defined Muddy Creek. Dorsal ridge en, 1967): 83, pi. 16 figs la-d (not figs 2a-d = C. bradyi than for C. rastromarginata (Brady, 1 880) but a Holdcn, 1967). — Puri and Hulings, 1976: 286, pi. 9 figs series of 3 well-developed subacuminate nodes 10-14 [not 9 = C. bradyi Holden, 1967]. gives a broken dorsal profile in lateral view. Bradteya rastromarginata. — Hornibrook, 1952: 17. Cletocythereis rastromarginata. — Swain, 1963: 823. —

Posterodorsal angle marked by development Benson, 1972: 22-23, 28, 56, pi. 1 figs 1-4. — Hartmann, of a short spine, as remarked by Chapman et al. 1981: 108, pi. 5 figs 15, 16. — Yassini and Wright, 1988: 169, - 20-21, pi. 6 fig. pi. 8 figs Muscle scars consist of 4 adductors in a near- ver- figs 6 McKenzie et al., 1990: 9, 11, 12. tical row, each scar obliquely aligned to the ven- Cletocythereis cf. rastromarginata. — McKenzie, 1967: tral margin. Dorsal and ventral scars short and 95, pi. 13 figs 1-2, Qg. 6b, figs lOa-b. — Hartmann, 1978: rounded, the middle two scars are elongate and 96, pi. 6 fig. 16. — Hartmann, 1979: 234, pi. 6 figs 5-7. — Frontal scars vary, somewhat dumbbell-shaped. Malz, 1980: 382. — Wame, 1987: 442. — McKenzie et al., but the commonest form is a small, circular scar, 1991: 171, pi. 8 fig. 13, pi. 9 fig. 2. with a larger v- or heart-shaped scar below it in Cletocythereis sp. — McKenzie, 1979: 91, pi. 2 figs 4, 5. lateral view. In some specimens the larger frontal Figured specimens. NMV P134942 — PL 1 fig. 10; NMV scar has the apex of the v pointing anteriorly, PI34943 _ p|. 2 fig. 1; NMV P134944 — PL 2 fig. 2, larg- rather than ventrally. In juvenile forms, the Dimensions. (P134942) Male LV L=0.77; H=0.36. er frontal scar is more attenuated in shape, and the Material. 48 specimens from Clifton Bank and Hcnlys, near smaller dorsal scar may be absent. Hamilton, Muddy Creek Marl, early Middle Miocene.

Remarks. Chapman and Crespin's description of Brief description. Elongate species of Cleto- the holotype is not detailed. Unlike the type cythereis with finely denticulate anterior and species, Cletocythereis rastromarginata (Brady, strongly denticulate posteroventral margin. Dor- 1880), for which Benson (1972) illustrated and sal margin straight. Posterodorsal margin con- designated a lectotype, C. caudispinosa has not cave. Ventral margin slightly concave. Fine- been redescribed. ribbed reticulation, tending to concentric about JOHN V. NEIL

the subcentral tubercle. Strong ventral marginal anterior and posterior margins (where not bro- rib. ken or worn); denticulations continued along anteroventral and posteroventral margins. Thick Remarks. These specimens differ from the lecto- marginal anterior and posterior marginal ribs, types figured by Puri and Hulings ( 1 976) in being covered with nodules; these ribs separated from much less inflated and in lacking the nodes on reticulated lateral surface of valves by deep sulci, the ventral ridge. Holden's (1967) resolution of with nodules protruding into them. Ornamenta- the problem of alate and non-alate forms of C. tion of fine-meshed, flat ribs, bordering deep, rel- rastromarginata (Brady) by treating them as sep- atively small fossae, which have a longitudinal arate species is correct (Malz, 1980). Since the trend in ventral half of valve; irregularly specimens from Clifton Bank and Hentys are distrib- uted on remainder. Sub-central tubercle non-alate forms, they are referred to C. rastro- marked by smaller or no fossae, scarcely marginata. Some variation occurs in the form of protruding above valve surface. On some specimens, the anterior ridge but this is also evident from the v- shaped frontal scar visible on external figures in Benson (1972). Sexual dimorphism in expression of tubercle. Prominent, clear terms of length/height ratios confirms Holden's eye tubercle at anterodorsal angle. division of Brady's original specimens into two Hinge strongly species. Benson (1972) did not include an holamphidont; anterior tooth in RV curved; amended diagnosis to replace Swain's original median elements smooth in both valves. Inner lamella description (1963) and, unfortunately, the mate- of moderate width in ante- rior and posterior, rial available to me is insufficient in quantity and narrower ventrally. No vestibules. quality to enable an amended diagnosis to be RPCs numerous (15-20 in anterior; included. 10-12 in posterior), unbranched; occasionally paired or grouped, generally single. Muscle scar Tribe Veeniini Puri, 1973 pattern difficult to determine because of reticu- lation. V-shaped frontal scar distinct in some Dumontina Deroo, 1 966 specimens, adductors not determined. Sexual Discussion. This genus is not represented by any dimorphism — males longer and shorter than other described or figured species from Aus- females. tralian fossil or Recent faunas, except for one Etymology. L. cratis = a hurdle; a reference to species listed by Warne (1987). However, hinge- the wickerwork appearance of the reticulation. ment and Cythereis-Wke shape, with the tra- chyleberid muscle scar of IDumontina cratis sp. Affinities. IDumontina cratis sp. nov. differs nov. suggest this genus. Erection of a new genus from the type species D. puncturata (Bosquet, for this species and IDumontina sp. A may be 1854) figured by Deroo (1966) in the absence of warranted after further study. any marked dorsal marginal rib and the presence of denticulations. D. puncturata does not have IDumontina cratis sp. nov. the deep sulci which characterise ?Z>. cratis sp. PI. 2 figs 6, 7, 8 nov.

Holotype. NMV P123218 — Hentys — PI. 2 fig. 8. IDumontina sp. A Paratypes. NMV PI 232 1 9 (not figured); NMV PI 34947 — PI. 2 fig. 6; NMV PI34948 — PI. 2 fig. 7. PI. 2 figs 9, 10 Dimensions. Holotype LV: L=0.73; H=0.38 Paratype Figured (PI23219)RV:L=0.64;H=0.35. specimens. NMV PI 134949 — PI 2 fig 9- NMV P123220— Material. 57 specimens, Clifton Bank (older samples only — PI. 2 fig. 10. Dimensions. 7 to 10) and Hentys, Muddy Creek Marl, early Middle (PI 23220) RV: L=0.63; H=0.32. Miocene. Material. 32 specimens, Clifton Bank (very rare) and Hen- tys, Muddy Creek Marl, early Middle Miocene. Diagnosis. Robust Dumontina-Wkt species with strongly developed, finely-meshed reticulation Brief description. Reticulate Dumontina-hke and deep sulci in anterior and posterior. species with spines confined to posterior margin and denticulate anterior margin. Flat-surfaced Description. Valves strongly calcified and thick; muri bound small, deep fossae. Anterior dorsal furrow and ventral margins straight; valve tapered crossed by narrow ribs. Reticulation covers sub- posteriorly; anterior smoothly and broadly round- central area. Marginal spines clavellate. ed; posterior rounded U- with slight angularity at shaped frontal scar is only scar which can be dis- extremity. Strong, stub-like denticulations on full criminated. Hinge holamphidont. MIOCENE TRACHYLEBERIDIDAE AND HEMICYTHERIDAE

Remarks. Dimensions indicate that IDumontina anteroventral sector with small vestibule; fused sp. A is not an instar of IDumontina cratis sp. zone broad anteriorly. nov. although the reticulation is quite distinctive Hinge holamphidont, but not strongly so. Sex- and suggests possible affinities with that species, ual dimorphism — males more elongate and less from which IDumontina sp. A differs by the inflated than females. absence of the deep anterior sulcus, the marked Etymology. For Dr M. T. Warne, in recognition posterior spinosity, and the greater taper posteri- of his work on the ostracode faunas of south- orly. The u-shaped frontal scar differs from the eastern Australia. v-shaped scar of ID. cratis. The holamphidont hinge is also less strongly developed than in ID. Affinities. The valve surfaces of Deltaleberis cratis sp. nov. warnei, with their ornamentation a combination of smooth inflated ribs or ridges and finely punc- Deltaleberis McKenzie, Reyment and tate interareas, are very similar to those of the Reyment, 1991 type species Deltaleberis rugosapytta McKenzie Deltaleberis warnei sp. nov. et al., 1991. Deltaleberis warnei sp. nov. differs from the type species in its more elongate shape, PI. 3 figs 1,2,3 even in females, and pattern of transverse ribs. It

Holotype. NMV P123224 — PI. 3 fig. 2. differs from D. delicata McKenzie et al., 1993 Paratopes. NMV P123223 (not figured); NMV P134950 — in having a straight posterior margin, different PL 3 fig. 1; NMV P134951 — PI. 3 fig. 3. rib pattern, and notably a different style of fine Dimensions. Holotype RV: L=0.64; H=0.27 Paratypc ornamentation (PI. 1 1 fig. 4). (P123223) LV: L=0.57; H=0.32. Material. 43 specimens, Clifton Bank and Hentys, near Alatahermanites Whatley and Titterton, 1981 Hamilton. (A closely related, and possibly ancestral, form in my collection also occurs in SA, in the early Late Eocene lAlatahermanites septarca sp. nov. Tortachilla Limestone at the type section 'Uncle Tom's

Cabin'. ) Muddy Creek Mark, early Middle Miocene. PI. 3 figs 4, 6

Diagnosis. Deltaleberis with broad transverse Holotype. NMV PI23221 — Hentys — PI. 3 fig. 4. rounded ribs, posterior one marked by round, pit- Paranpes. NMV P123222 (not figured); NMV P134952 — ted depression; anterior by central constriction. PI. 3 fig. 6. Dimensions. Holotype RV: L=0.85; H=0.40 Paratype Description. Valves subequal; hyaline in fresh (P123222) LV, instar: L=0.73; H=0.35 specimens. Subtrapezoidal in lateral view; elon- Material. 17 specimens, Hentys, Muddy Creek Marl, early gate. Anterior broadly rounded; finely denticulate Middle Miocene. anteriorly; greatest length medially. Dorsal mar- Diagnosis. Medium to large (up to 1 mm) lAlata- posterodorsal cardinal angle approx- gin straight; hermanites, with strongly ponticulate, 7-arched, imately 135° posterodorsal margin straight. Pos- ; alar ventral ridge; prominent subcentral tubercle teroventral margin subrounded, with and pitted surface ornamentation. denticulations. Ventral margin slightly sinuous, concave medially. Lateral valve surface irregu- Description. Valves subrectangular in lateral larly inflated in 2 transverse rounded ridges (vari- view; somewhat elongate because of reduction able from specimen to specimen). Subcentral in height from anterior to posterior. Dorsal and swelling (not a tubercle). Posteroventral region ventral margins straight. Anterior broadly and compressed, bordered by rounded ridge. evenly rounded with greatest length at mid- Valve surface smooth on ridges (under high height; posterior angulate, with greatest exten- magnification very small pores irregularly dis- sion below mid-height, posterodorsal margin tributed over these smooth surfaces); small punc- slightly concave and posteroventral margin

tae on other surfaces (PI. 1 1 fig. 4). Punctae form straight. Anterior very finely denticulate; poste- clearly defined patterns giving sieve-like appear- rior with 4 or 5 spines well-developed in ventral ance to surface of valve. Eye tubercle indistinct half. Anterodorsal cardinal angle moderately and merged with transverse ridge. Muscle scars defined; posterodorsal cardinal angle more so. as for the genus. RPCs simple, unbranched — Prominent 'hinge' tubercle (cf. Treatise p. Q339) few (7-8) on anterior margin; more closely developed at the anterodorsal angle. No eye spaced on posteroventral margin (also 7-8). Nor- tubercle or interior eye sinus. A dorsal rib clear- mal pores widely scattered; simple. Line of con- ly developed from anterior of sulcus behind crescence and inner margin coincident except for 'hinge' tubercle to its termination short of the 10 JOHN V. NEIL

posterodorsal angle; subponticulate, with no Remarks. This species is only tentatively attrib- apertures in the arches. A strongly-developed rib uted to Alatahermanites because of some shared linking the 'hinge' tubercle with the dorsum features with Idiocythere. This occurrence through a loop not in contact with the subcentral implies thai Alatahermanites may range into the tubercle — the loop outlining a deep sulcus. Ven- Middle Miocene. Although the specimens allow tral rib very strongly developed from the antero- the erection of a new species, the details of the ventral margin to its culmination in a very promi- hinge structure and muscle scar pattern need to nent rounded knob, projecting substantially from be clarified with better preserved material. Many the lateral surface of the valve. This rib ponticu- of the specimens have damaged hinge lines. late in form with seven clearly differentiated Triebel, arches. Idiocythere 1958

Ornamentation: fine pattern of pits covering Idiocythere sp. lateral surface of valves, large arched ribs link- aff. /. thalassea McKenzie, Reyment and ing body of valve to dorsal, anterior and ventral Reyment, 1991 margins. (In some specimens small pits cover all surfaces except ribs and tubercles.) Hinge strong- PI. 3 fig. 5; PI. 11 fig. 5 ly but modified holamphidont, with very large, Figured specimen. NMV P12336I — PI. 3 fig. 5; PI. 1 1 fig. stepped, anterior tooth and socket, narrow medi- 5. an bar and small posterior tooth right on cardinal Dimensions. LV L=0.63; H=0.32. in angle RV; LV corresponding but median Material. I specimen, Clifton Bank. Muddy Creek, near groove not strongly marked. The unusual anteri- Hamilton, Muddy Creek Marl, late Early Miocene. or tooth in the LV ('conical pessular' tooth of Remarks. One valve possibly conspecific with Idiocythere, cf. Treatise: Q339) present in adult

Idiocythere thalassea McKenzie et al., 1991 : pi. specimens with hingeline intact. 9 fig. 9 occurs in Muscle scars not readily resolvable. Frontal the fauna from Clifton Bank, 10. Its hingeline is scar single, distinctly U-shaped with long arms; Sample broken. adductors a row of 4 with dorsal smallest and Tribe Incertae sedis ('Australimoosellini' middle 2 scars very elongate; ventral scar not dis- Howe and McKenzie, 1989.) tinguished easily because of inner curvature of muscle scar depression (subcentral tubercle). Mackencythere Malz and Ikeya, 1982 Inner margin and line of concrescence coincide. Mackencythere sp. A. Radial pore canals numerous, straight and unbranched on anterior margin. PI. 3 fig. 7 Etymology. From the Latin for the seven arches Figured specimen. NMV P 1 23360 — PI. 3 fig. 7. characterising the ventral ridge. Dimensions. RV L=0.46; H=0.22. Material. 3 specimens, Hentys on Grange Burn, Muddy Affinities. 1Alatahermanites septarca sp. nov. Creek Marl, early Middle Miocene. differs from the type species A. hastatus What- ley and Titterton, 1981 in its ornament, which is Remarks. These specimens belong to a species ponticulate on both dorsal and ventral margins, of Mackencythere with a narrow anterior ridge and pitted on the lateral surface, rather than the and two concentric posterior ridges, a complex 'very strong coarse reticulation' of A. hastatus. reticulation of narrow rounded ribs, and a mar- Although it shares the subrectangular shape of ginal, reticulated posterior flange. The muscle Alatahermanites. its posterior is distinctive in platform diagnostic of the genus is clearly being strongly denticulate and somewhat cau- marked. M. sp. A differs from the type species, date, and there is a strong 'hinge' tubercle which M. venata (Brady), 1866 in the absence of a is not characteristic of Alatahermanites. ?A. median ridge and a more rounded posterior. It septarca shares some characteristics with Idio- differs from M. sp. 1 Warne, 1987 in its narrow- cythere Triebel, 1958 in its pitted surface orna- er anterior ridge, its finer reticulation and its mentation and denticulate posterior but lacks the rounded, reticulate posterior. tapered shape of that genus. The modified holam- phidont hinge, diagnostic of Alatahermanites, Arculacythereinae Hartmann, 1981 also shares a characteristic with Idiocythere, Arculacythereis Hartmann, 1981 notably the additional anterior rim tooth in the LV. On balance, tentative placement in Alata- Discussion. The use of Arculacythereis Hart- hermanites is preferred. mann, 1981 for the following species is based on 1

MIOCENE TRACHYLEBERIDIDAE AND HEMICYTHERIDAE 11 the distinctive thickening of the shell wall below and higher than males. Juveniles with reticula- and behind the anterior hinge elements on the tion more marked, muri narrower than in adults; interior of the valve, and the distinctive pattern of hinge hemiamphidont. Very large, indistinctly ornamentation. The former characteristic is ornamented specimens common. shared by genera such as Australimoosella Hart- Affinities. ?Arculacythereis mann, 1978, Doratocythere McKenzie, 1967, postdeclivis (Chap- man, 1914) shows some affinities Waiparacythereis Swanson, 1969 and Yassini- with Lanka- cythere cythere Howe and McKenzie, 1989 (McKenzie, coralloides (Brady, 1 886) from which it differs in its more ovate pers. comm. 1989). However, the ornamentation fossae, the absence of the ear-shaped posterior ridge and the less dis- of these genera is quite different from that of Arculacythereis. tinct eye tubercle (Bhatia and Kumar, 1979). However, it is on the basis of its dorsal 'stub' or 1Arculacythereis postdeclivis (Chapman, ridge that the species is tentatively assigned to 1914) Arculacythereis rather than to Lankacythere, since Bhatia and Kumar make no reference to PI. 3 figs 8, 9, 10 such a feature in their diagnosis of the latter genus. Cythere postdeclivis Chapman, 1914: 39-40, pi. 7 figs Lankacythere has a trachyleberid v- 23a, b. shaped frontal scar as in other campylocytherinid Cytheralison postdeclivis. — McKenzie, 1981: 106. genera, whereas these specimens have the hemi- cytherid divided frontal scar consisting of two Figured specimens. NMV PI 23225 — Hentys — PI. 3 fig. subrounded scars. To retain the species in a tra- 8; NMV PI 34953 — PI. 3 fig. 9; NMV PI 34954 — PI. 3 fig. 10. chyleberidine genus raises the significance of Dimensions. (P123225) RV: L=1.08; H=0.56; W=0.29. frontal scar configuration in Trachyleberididae Material. 17 specimens, Hentys and Clifton Bank, near and Hemicytheridae. Hamilton, Muddy Creek Marl, early Middle Miocene. It is possible that the assignment of ?Arcula- cythereis postdeclivis (Chapman, 1914) might be Diagnosis. Large ?Arculacythereis with posteri- confirmed when further studies of the genera or depression; thick shell; reticulation marked by Australimoosella Hartmann, 1978, Yassini- a tendency for longitudinal rather than lateral cythere Howe and McKenzie, 1989, Dorato- alignments; bean-shaped valves with slight medi- cythere McKenzie, 1967 and Waiparacythereis an 'waist' or narrowing, and divided frontal scar. Swanson, 1 969 have been completed. At present, the significance of the anterodorsal thickening of Description. Valves large, tumid, thick-walled the shell below the anterior hinge elements is and bean-shaped. Anterior broadly rounded and equivocal, since it is also a diagnostic feature of slightly recurved ventrally. Posterior also broad- these genera. ly rounded, with very slight caudal process in ventral half. Eye tubercle indistinct. Ornamenta- Remarks. Chapman's original description is tion of deep subcircular to oval or elongate fos- inadequate. Surface ornament, hinge develop- sae, bounded by broad, flat-surfaced muri. Retic- ment and muscle scar configuration vary sub- ulation pattern oriented vertically rather than stantially intraspecifically. Very large thick- laterally. Little evidence of subcentral tubercle shelled specimens often show considerable wear on external surface of valves. and abrasion. The muri are enlarged and the fos- Muscle scars adjacent to, but not in, subcen- sae small and shallow — in extreme cases the tral pit on interior surface of valves. Two frontal surface is almost without a pattern of ornament. scars, subcircular and separate; dorsal smaller Bhatia and Kumar (1979) referred to variations than ventral; 4 adductor scars, the dorsomedian in the form and pattern of the muri, which they in some specimens elongate, in others divided; suggested may be ecological. The frontal scars ventromedian and ventral scars subequal and are occasionally joined to form one Grinioneis- closely associated, or even conjoined so as to style scar; dorsomedian adductor frequently give appearance of only 3 adductors. Shell thick- divided also. ening below anterior hinge elements, in a slight- Arculacythereis tatei sp. nov. ly elongate ridge. Hinge weakly holamphidont. Hinge elements PI. 3 figs 11, 12 smooth. Inner margin and line of concrescence Holotype. NMV P123266 — Hentys — PI. 3 fig. 1 coincident. RPCs numerous but difficult to dis- Paratypes. NMV P123267 (not figured); NMV P134955 — tinguish. Sexual dimorphism — females shorter PI. 3 fig. 12. 12 JOHN V. NIHIL

Dimensions. Hototype KV: L=0.78; H=0.39. Paralypc Material. I Specimen, Clifton Hank, near Hamilton, Muddy

(I' 1 23267) I. V: I. =0,70; H=0.34. Creek Marl, early Middle Miocene.

Material. 36 specimens, Clifton Bank and I Icniys, aesr Hamilton. Muddy Creek Marl, early Middle Miocene Brief description. Arculacythereis species simi- lar lo A. thomasi McKenzie el al., 1991 but dif- Diagnosis, Arculacythereis species with reticu- fering in its Straight rather than slightly convex late/punctate ornamentation and distincl pos- dorsal margin, more compressed posteroventral teroventral compressed Range. area, narrower posterior and dorsal depression or Description. Wei Lcalci lied subreclangular pit. Because the range of inlraspecific variation in A. thomasi is not inflated valves, with maximum inflation on pos- known, the assignment is ten- teroventral area, bordering marked posteroventral tative. flange. Dorsal margin straight; ventral margin A rculiityl hercinidae slightly sinuous, subparallel to dorsal margin. Anterior very broadly rounded; posterior more Arculacythcreinid gen. indet. sp. A narrowly rounded, with maximum lateral exten- sion slightly above mid-height. Valve surface PI. 4 fig. 3 covered with indistinct pattern of rounded ribs, Figured specimen. NMV PI23268 — PI. 4 fig. 3; wilh punclae rather than fossae within the mesh NMV I'l 2326') (mil ligured). of ribs. Larger, deeper fossae in arc parallel to Dimensions. (P123268) LV: L=0.85; anterior and posteroventral margins. Slight den- 11=0.43. (P123259)

KV, juvenile: I .=0 ; 11=0 .36. ticulations on posteroventral margin. No sub- 7 1

Material. 1 central tubercle. 1 specimens, llenlys only. Muddy Creek Marl, early Middle Miocene. Hinge shows a thin, elongated tooth in KV. Median element appears to be smooth but diffi- Brief description. Arculacythereinid wilh deep cult lo determine. Only the u-shaped frontal scar anterior furrow; strongly inflated valve and sur- visible; adductor pattern nol known. Inner lamel- face ornamentation consisting of primary la broad in anterior, less so in posterior. No swellings and ribs, with fine-ribbed secondary vestibules. RPCs clustered in groups of up lo reticulation and micropunctate surface. Anterior live; numerous; some branched. Interior of valve furrow and irregularly inflated surface reminis- subdivided by swellings nol matched by sulci on cent of New Zealand species Waiparacythereis valve exterior. Very prominent dorsomedial pro- joanae and Waiparacythereis caudata Swanson, jecting stub. Sexual dimorphism not evident. 1969. Caudal development minimal differing Juveniles show some evidence of slight sulci on from clear posteroventral caudae of Waipara- external valve surface; dorsomedian sluh well- cythereis species. Posterior tic veloped. compressed and sharply divided from medial inflated section of valve. Etymology. Lor Professor Ralph Tate who col- Muscle scars include a u-shaped frontal scar, lected and described fossils from this locality in group of 4 elongate adductors and large sub- the late nineteenth century. rounded ventral mandibular scar. Flattened dor- somedial stub projecting into interior of valve Affinities. Arculacythereis tatei differs from ihe (diagnostic of arculacytherinid group of genera). type species A. vacciformis I Hivtnuum, OK I j n Unequivocal generic assignment not possible. having a straight dorsum, very slightly concave Tribe Ptcrygocythcreidini venter and no 'b'einskulptur'. although Ihe gen- Puri, 1957 eral pattern of is ornamentation similar. A. tatei ?Pterygocythereis Blake, 1933 is closer in shape to A. sp. Howe and McKenzie, 1989, bul the latter is uniformly inflated, with no IPterygocythereis sp. indet. posteroventral flange. PI. 1 3 fig. 7 Arculacythereis sp. aff. A. thomasi McKenzie, Figured specimen. NMV PI23362 — PI. 13 fig, 7, Reyment and Reyment, 1991 Dimensions. LV L=0.43; 11=0.28.

Material. I specimen, llenlys on Grange Hum, Muddv Creek H. 4 figs 1,2 Mail, early Middle Miocene.

Figured specimens, NMV PI34956 PI. 4 fig. l;NMV Remarks. Phis specimen is a juvenile bul P123265— PI.4fig 2 because of the strongly developed, broad, flat- Dimensions. (P123265) LV L 070,11 0.34 topped spines and absence of perforations and .

MIOCENE TRACHYLEBERIDIDAE AND HEMICYTHERIDAE 13

butresses in the ventral ridge is placed in IPtery- ventral margins straight; anterior curved but not gocythereis rather than Alataleberis (McKenzie broadly rounded; posterior with blunt caudal and Warne, 1986) or Ponticulocythere Dingle, process in ventral half. Posterodorsal margin 1981. The relationships of the genera Alatale- slightly concave. Anterodorsal cardinal angle beris, Pterygocythereis and Alatacythere were rounded, projecting slightly above the dorsum. discussed by McKenzie and Warne (1986) where A hinge-ear more marked in LV than RV. reference was also made to Ponticulocythere as Surface smooth and shiny, with strong round- a possible ancestor of A /ata/e/w/.v. This juvenile ed protuberances posterodorsal ly and pos- does not provide clear evidence of any relation- teroventrally; former more posteriorly located ship with Ponticulocythere. than latter. Subcentrai tubercle below mid-height but not strongly developed. Valve surfaces with Tribe ?Pterygocythereidini Puri, 1957 smoothed irregularities but neither ornamenta- Alataleberis McKenzie and Warne, 1986 tion nor ribs. Normal pores scattered over sur- face, type not known. Few small denticulations Alataleberis miocenica McKenzie and Warne, on posteroventral margin. Eye tubercle indistinct. 1986 Hinge strongly holamphidont; anterior tooth in PI. 4 figs 4, 5, 6 RV stepped; median bar smooth. Anteromedian tooth in LV rounded. Sockets deep. Muscle scar Alataleberis miocenica McKenzie and Warne, 1986: 38 pattern complex and variable within the species figs 2d. 3n-r. (PI. 14 figs 2, 3). Holotype with 2 rounded frontal Figured specimens. NMV P134957 — PI. 4 fig. 4; NMV scars (some specimens have 3); 4 adductors in PI34958 — PL 4 fig. 5; NMV P123363 — PL 4 fig. 6. very oblique row on side of muscle scar pit; dor-

Dimensions. (PI Carapace L=0.83; ; W=0.3 1 23363) H=0.4 1 sal scar small, subrounded; 2 median scars clear- Material. 32 specimens, Clifton Bank and Hentys near ly divided (undivided in some specimens); ven- Hamilton, Muddy Creek Marl, early Middle Miocene. tral scar slightly elongate. Remarks. These specimens are clearly conspe- Marginal zone relatively broad in anterior and cific with those figured by McKenzie and Warne posteroventral sector; narrow vestibules. Approx- (1986) some of whose specimens came from the imately 15-20 simple, unbranched RPCs on ante- Clifton Bank locality. The figured specimen has rior margin; few on posterior. Normal pores not a strongly developed eye tubercle, and regularly observed on holotype, but possibly simple, from but sparsely distributed normal pores. evidence on other specimens. Juveniles more Hemicytheridae Puri, 1953 rounded in lateral view; hinge ears not developed; hinge merodont. Sexual dimorphism not Hemicytherinae Puri, 1953 observed.

Tribe Hemicytherini Puri, 1953 Remarks. Although the generic assignment of this

species to Hemicythere is uncertain, it undoubt- Hemicythere Sars, 1 925 edly belongs to the tribe Hemicytherini rather 'Hemicythere' lubrica sp. nov. than to Aurilini (Hartmann and Puri, 1974). Hemicythere has been recently ignored as with PI. 4 figs 7, 8; PI. 14 figs 2, 3 other genera established when an abundant and distinctive group is initially tackled. Holotype. NMV PI 23226 — Clifton Bank — PI. 4 fig. 7, PL Under these 14 fig. 2. circumstances the generic diagnosis tends to be Paratypes. NMV P123227 — PL 4 fig. 8, PI. 14 fig. 3; too all-embracing, although in the case of Hemi- PI 23228 (Not figured). cythere, Sars' diagnosis (1922-28) remains more Dimensions. Holotype RV: L=0.7I; H=0.38. Paratype LV: precise than some contemporary ones. The type H=0.38; L=0.70; H=0.4I. Paratype Carapace: L=0.70; genus no longer serves as a catch-all for species W=0.34. better related to more recently erected genera Material. 154 specimens, Clifton Bank, near Hamilton, (Van Morkhoven, 1962). This scenario occurs Muddy Creek Marl, early Middle Miocene. more than once in the Hemicytheridae, e.g. Diagnosis. Smooth, shiny-surfaced, subrectan- Hornibrook's (1952) Quaclracythere and gular hemicytherid, with distinct posterodorsal Bradleya. and posteroventral protuberances and subcentrai Recently fewer species have been referred to tubercle below mid-height. Hemicythere s.s. Hazel (1967) refers to the 'sub- Description. Valves thick-shelled; dorsal and reniform shape, distinctive hingement and 14 JOHN V. NEIL

muscle scars' as important features characteris- Surface of valves very lightly pitted in ventral

ing its type species. The assignment of 'A/. ' lubri- half (very difficult to discern in worn specimens); ca sp. nov. to the genus needs justification in narrow, horizontal ridges, very lightly developed view of its subrectangular shape and absence of except ventrally, and slightly radiate in the pos- ventral inflation. It does not look like a Herni- terior. Parallel ventral ridges more marked; one cythcre species. The muscle scar pattern of the ridge defining the slight ventral inflation of holotype, same as that of the type species, varies valves; otherwise valves compressed. No sub- within the population from Muddy Creek. On the central tubercle but muscle scars visible on exte- '//. other hand, hingement is typical. ' lubrica rior surface in some specimens. Weakly devel- cannot be assigned to another genus (Hartmann oped eye tubercle below anterodorsal cardinal and Puri, 1974) even though Hemicythere s.s. is angle. characteristically a Northern Hemisphere cool Muscle scars — 4 adductors; dorsal and dor- temperate genus. somedian elongate (latter divided in some spec- imens); ventromedian and ventral scars sub- Etymology. Latin lubricus — slippery; a refer- rounded and aligned obliquely to the trend of ence to the shiny surface of the valves. other adductors. Two subrounded frontal scars, ventral Affinities. 'H. ' lubrica has no close affinities with larger. Two clearly marked dorsal scars, other species of Hemicythere. Tenedocythere anterior v-shaped, apex of v pointing anteriorly. nuda McKenzie el al., 1991 is similar to 'H'. Fulcra! point between dorsal scars marked by lubrica in lateral view and size and may even be opaque area (PI. 14 fig. 4.) conspecific. However, an assignment to Tenedo- Hinge strongly holamphidont. RV anterior cythere cannot be sustained on the basis of gen- tooth smooth and simple; posterior tooth narrow

eral shape since I believe the ornamentation and and blade-like, triangular in lateral view; large the smooth posterior tooth in RV are diagnostic anteromedian socket; smooth median bar with and 'H'. lubrica has no ornamentation and a distinct ventrally directed angulation at posteri- lobed posterior tooth. On the other hand, the mus- or end. LV anterior socket deep, with rounded cle scar pattern is given greater weight in my retaining bar across ventral portion; posterior assignment. socket on posterodorsal margin, elongate and narrowed at ends; anteromedian tooth simple, 'Hemicythere' tenuicostata sp. nov. smooth and rounded; median groove narrow and curved at posterior PI. 4 figs 9, 10; PI. 5 fig. 1, PI. 14 fig. 4 end round posterodorsal angle. Fused zone narrow, except anteriorly; Holotype, NMV P123230 — Clifton Hank - PI. 4 fig 10 inner margin and line of concrescence coincident PI. 14 fig. 4. throughout. RPCs difficult to determine. f'uralypes. Normal NMV PI 23229 (Not figured); PI 2323 1 (Not fig- pores ured); numerous and open. Sexual dimorphism P134959 — PL 4 fig. 9; PI 34960— PI. 5 fig. 1. — females shorter Dimensions. Holotype RV: L=0,66; 11=0.39. Paratype and higher than males. No (PI 23229) LV: L=0.64; H=0.38. Paratype Carapace juveniles in this population. (PI 23231): l.=0.73; 11=0.41; W=0.29. Etymology. Latin tenuis thin; Material. 50 specimens, mostly at Clifton Bank, but also — casta — a rib; a rarely al llentys. Muddy Creek Marl, early Middle Miocene. reference to the fine, narrow ridges on the valves.

Affinities. '//. Diagnosis. Compressed, lightly-ridged hemi- ' tenuicostata has the characteristic cytherid, with narrow ventral flange, medially hemicytherid shape and narrow ventral ridge. It and posteriorly. differs from the type species H. villosa Sars, 1866 in being only lightly pitted and in its muscle scar Description. Valves characteristic hemicytherid pattern. As few Australian fossil species have shape in lateral view, with broadly rounded ante- been referred to Hemicythere (H. tarakohensis rior; slightly acuminate posterior, terminating in Hornibrook, 1952 appears to be a Quadra- ventral half of valve; dorsal and ventral margins cythere) '//. ' tenuicostata has no close relation- subparallel. Dorsal margin straight, with slight ships with described species of this genus. It is at projections anterodorsal and posterodorsal markedly different '//. in shape from ' lubrica sp. angles. Posterodorsal margin slightly convex and nov. Although '//. ' tenuicostata has some points broken at midpoint by additional small projec- which link it to Hartmann's (1979) subgenus tion, giving an angled profile. Ventral margin sin- Procythereis (Serratocythere), it cannot be uous, with 2 or 3 small, widely separated dentic- placed in that taxon because its muscle scar pat- ulations towards posterior. tern does not fit the 1-1-2-1(2) formula given MIOCENE TRACHYLEBER1DIDAE AND HEMICYTHERIDAE 15

in Hartmann's diagnosis (1979); its shape is Mackenzina foveolata sp. nov bemicytherid rather than nurilinid and it has a PI. 5 figs 3, 4, 5, 6 distinct, it small, caudal process, more noticc- ahle in the RV. In addition, Serratocythert is Holotype. NMV P1233 S3 Hentys - l'l. 5 tig. 3. as foveolate ('punctate' in diagnosed Paratopes. NMV P1232 W l'l 5 fig -1. P123237 — l'l. 5

Sylvester-Bradley and Benson's P)7I terminol- fig .6; HI .14% I —PI. 5 fig. 5. 7/. 1.-0,70; Haralype ogy), whereas ' tenuicostata is only very light- Dimensions. Ilolotype KV: H«0.42. Haratype (HI2T217) ly pitted. (HI2.l2.lo) I.V: 1=0.7.*, lhO.4.1. RV, inslar: I. ()(,?. II 0.36, 'Hentlcythere' sp. ef, '//'. tenuicostata Material 95 specimens, Hentys, on Grange Burn, Muddy Creek Marl, early Middle Miocene PI. 5 fig. 2 Diagnosis. Mackenzina with bifid posleroventral Figured specimen. NMV P123364 PI 3 Bg. 2 spine, small equally spaced spines on the ventral Dimensions, l.v L=Q.59; 11-0 36. side of cauda, anil regularly pitted lateral surface. Material. 22 specimens, Clifton Hank and Hentys, new Marl, early Middle Miocene, Hamilton, Muddy Creed Description. Subquadralc valves; dorsal and ven-

tral margins parallel in I, V; dorsal margin slight- Remarks. This specimen is a 'Hemicxthere' sim- ly curved in RV; anterior gently rounded; great ilar to 'H'. tenuicostata. hut differing in more length slightly below mid-height. Posterior acuminate posterior, greater inflation of the est with subacuminale cauda slightly above mid valves and the posterior reticulation network. height of valve in lateral view. Posleroventral Hemicytlierid gen. el sp indet. margin Straight and angled al 315°, with 2 or 3 short, broad spines. Outer margin and outline PI. 1 3 fig. 6 coincidenl in lateral view except where bifid spine projects slightly beyond margin. Valve clo Figured Specimen. NMV P123365 l'l 13 Bg, 8. sure in dorsal anil ventral view, excepl Dimensions, l.v L-0.32;H=0.17, Straight anterior Bifid ol Material. 9 Specimens, Hilton Hank ami Hentys. neat Hanul for slight sinus in RV, character tun. Muddy Crock Marl, early Middle Miocene ventral spine clearly evident in ventral view. I.V overlaps RV slightly at anlerodorsal cardinal is characteristic ven- Remarks. Although there a angle. muscle scat pat- tral inflation and hemicytlierid Ornamentation of regular small pits over lateral elongate and tern, these specimens are more surface of valves, concentric to anterior margin, 'Hemicythere' species acuminate than the but not markedly linear over the rest. Pits on base described above. Purtherniore, the slightly irreg of bifid spine. Row of larger fossae above ven- surface is punctate, rather than ridged. ular tral ridge anterior to spine. Anterior and posteri- beyond family level is not possible. Assignment or margins compressed as generally unorna flange. Ventral ridge extending into bifid, Mackenzina gen. nov. merited bladelike spine ai its posterior termination, with Type species. Mackenzina foveolata sp. nov. proximal and dislal components of subei|tial size, Small denliculatioiis on anterior margin of less Diagnosis. Hemicytlierid with well-developed abraded specimens. Suhcenlral tubercle slightly surface bifid posleroventral spine, pitted lateral below midline and in anterior of valve; free of and subacuniinate cauda. pils; not prominent; gentle swelling only. Eye tubercle clear, distinct and glassy; well below Etymology. For Dr K. G. McKenzie in recogm dorsal margin in lateral view. tion of his pioneering work on Australian Ceno- Inner lamella broadest anteriorly, but general zoic ostracoda. ly narrow. Inner margin and line of concrescence numerous Remarks. Mackenzina differs from members of coincident (i.e. no vestibules). RPCs unbranched more apparent in juvenile the Aurilini Puri, 1973. It is unlike Mutilus and and I'oko specimens. Normal pores not observed because Aurila in its muscle scar pattern and unlike matrix. rnyelia in shape. Its double frontal scar suggests ofadherent Hemicythcrini Puri, 1953 and its prominent bifid Muscle scars - 2 subroiinded frontal sears spine together with other diagnostic features is (fused in some specimens); 4 adductors in vcrli regarded morphologically as warranting generic cal row; vetilroinediaii scar small and sub status. JOHN V. NEIL

circular; other adductors elongate and oblique. Tribe Aurilini Puri, 1973 Sexual dimorphism not detected. Hinge strong- Pokornyella ly holamphidont; RV with strong, peg-like ante- Oertli, 1956 rior tooth; elongate triangular posterior tooth; 'Pokornyella' sp. indet. anteromedian socket bounded ventrally by a ridge extending from the anterior tooth; median PI. 6 fig. 1 groove smooth. LV with deep anterior socket; Figured specimen. NMV PI 23368 — PI. 6 fig. I. shallower and slightly longitudinal posterior Dimensions. RV L=0.67; H=0.45. socket; median bar faintly crenulate. Material. Juvenile 1 specimen, Clifton Bank on Muddy Creek, Muddy specimens with pitting around subcentral tuber- Creek Marl, early Middle Miocene. cle; outer areas smooth; some RPCs branched; Brief description. Uuniformly punctate 'Poko- few RPCs on cauda; bifid spine clearly devel- rnyella' with the size of punctae decreasing from oped, more acute and pointed than in adults; centre to margins. Truncate caudal process in the valve margins thinner and more flange-like; A7 ventral half of the posterior. Prominent instar with merodont hinge; A8 with holamphi- eye tuber- cle. dont hinge.

Remarks. Because of some similarity in shape to Etymology. Latin — foveola, a small depression Neobuntonia batesfordiense, the specimen is (even though the depressions may be large only tentatively assigned to Pokornyella. 'Poko- enough in some specimens to warrant the desig- rnyella' sp. indet. differs from Pokornyella aus- nation 'punctae'). traliae McKenzie et al., 1991 in being punctate rather than reticulate. It differs from Pokornyel- Remarks. M.foveolata sp. nov. is the only species la s.l. McKenzie, 1979, which is a punctate form, attributed to Mackenzina, and is most nearly in its general shape, more elongate and distinct- related to Hemicythere s.s. The ornamentation of ly caudate. The rarity of Pokornyella in these M.foveolata raises the question of differentiating generally warm temperate to subtropical faunas between a smooth pitted surface and one with a is consistent with its preference for a cooler reticulation of muri. Such a question becomes palaeoenvironment. Thus the report by McKen- one to be resolved by SEM micrographs. With zie et al. (1991) of 83 from Bells Headland and the light microscope, the boundaries between pits Point Addis suggests or some Late Oligocene cool- fossae and the surrounding muri, or valve sur- ing in south-eastern Australia. This isolated spec- face are critical. If the boundaries are sharp and imen is probably right-angled allochthonous. or acutely angled and if the inter- vening spaces between the pits/fossae are rela- Thaerocytherinae Hazel, 1967 tively flat, the surface can be described as 'pitted' Tribe Thaerocytherini Hazel, 1967 (Sylvester-Bradley and Benson, 1971). If the boundaries are less precisely defined and the Hermanites Puri, 1955 intervening spaces are seen to be continuous with the sides Remarks. Hermanites was of the fossae, the surface is reticulated erected to include (Sylvester-Bradley species from the United States and Benson, 1971). In the and has remained case of a characteristic Western M.foveolata sp. nov. the former applies. Hemisphere genus although its use Each moult represents the complete for Eastern Hemisphere species expression was of the genotype for initially quite acceptable (Moos, 1965). Siss- that stage provided there is enough calcite ingh (1972) and Liebau (1975) revised available. Greater or lesser pitting European or reticulation Trachyleberididae and Hemicytheridae, as compared with that in the adult is a indicative result of which species with similar only of the pattern for the particular external char- juvenile acteristics of valve shape and ornamentation stage, unless there is insufficient ambi- for- ent calcite merly in Hermanites were reassigned available to allow full expression to new oen- Variation does era. Sissingh (1972) erected Tenedocythere\s not reflect loss of some shell a material through subgenus of Quadracythere on the basis development of more pits/fos- of lon- gitudinal ribbing, features sae or addition of material through of the hingement and the develop- RPCs. ment of more Liebau (1975) erected Grinioneis as muri (Roer and Dillaman, 1984) a sub- Potential genus of Cletocythereis, with Hermanites for these variations to provide some pai- jenborchiana Keij, palaeoenvironmental information 1957 as type species. Both has not been workers investigated. placed their genera in the Trachyleberi- didae in spite of difficulties in establishing a MIOCENE TRACHYLEBERIDIDAE AND HEMICYTHERIDAE 17

diagnosis which incorporated frontal scars. As drawn out, ventral slightly more extended. Two >early as 1963 von Morkhoven recognised the subcircular frontal scars. potential confusion. Hermanites is used for Hinge holamphidont; smooth median bar; pos- I species from this fauna where the original diag- terior tooth smooth, blade-like and at 45° to the nosis covers their main characteristics. Tenedo- dorsal median ridge/groove. Sexual dimorphism cythere and Grinioneis are excluded because the not clearly established; females broad and short; diagnostic characteristics of the Muddy Creek males relatively longer and narrower. Shell mate- species do not fit satisfactorily. rial hyaline. No signs of 'spongeous' reticula- tion. Juveniles do not show the strong reticulation Hermanites glyphica sp. nov. pattern, but have fine network over finely punc- PI. 7 figs 3, 4, 5, 6, 7, 8; PL 12 fig. 4 tate surface (PI. 12 figs 5, 6). Juveniles all males in this population. Holotype. NMV P123249 — Hentys — PI. 7 fig. 3.

Paratypes. NMV PI 23250 (Not figured); PI 23251 — PI. 7 Etymology. Greek, glyphe — a carving, with ref-

fig. 5; PI. 12 fig. 4; P134968 — PI. 7 fig. 4; P134969 — PI. erence to the appearance of the heavy reticula-

7 fig. 6; P134970 — PI. 7 fig. 7; P134971 — PI. 7 fig. 8. tion. Dimensions. Holotype LV: L=0.92; H=0.59. Paratype Affinities. H. bireticulata Al-Furaih, 1980 has 3 (P123250) LV: L=0.97; H=0.59. Paratype (P123251) RV, frontal scars and differs from H. glyphica in its instar: L=0.77; H=0.46. curved anterodorsal profile, absence of process- Material. 426 specimens, Clifton Bank and Hentys, near es at the ends of ribs, less regular anterior orna- Hamilton, Muddy Creek Marl, early Middle Miocene. mentation and its three frontal scars. In other Diagnosis. Large, thick-shelled Hermanites with respects it is fairly similar. H. soliporosa. Al- coarse, rounded reticulation, developed only in Furaih, 1980 and//. tranquilis Al-Fttfam,*T980 the adult form. are much less rectangular and have different pat- terns of reticulation. H.fungosa Butler, 1963 has Description. Valves large, heavy, thick-walled; no lateral rows in the reticulation. The H. tschop- coarse reticulation. Lateral surface of valves pi (Bold, 1946) plexus has different muscle scars, inflated and irregular; dorsal rib short and ill- regularity of reticulation and size. H. glyphica defined. Anterior margin with numerous small differs from the type species, H. reticulata Puri, denticulations, often abraded. Slight caudal 1953, in its less well-developed subcentral tuber- process below mid-line of valve, fringed by 5-6 cle, smooth median bar in the hinge and less well- specimens. Eye short spines in well-preserved developed cauda. H. immodica Al-Furaih, 1984 Subcentral tubercle high, tubercle not prominent. has no mediodorsal tubercle. H. straba Al- reticulation, but not large in area. Pos- covered by Furaih, 1983 is longer and less high, with less terodorsal termination of dorsal rib a blade-like marked reticulation. I agree with Neale's (1975) reticulation. Ventral rib process with 2 muri of comment that H. volans Neale, 1975 belongs in terminates posteriorly in blunt process. Blade- another genus. With H. dameriacensis Keij, 1 958 ventral closure (sinus). In like protuberance on the subcentral tubercle is clear of reticulation, arrow-shaped. Character- dorsal view carapace unlike in the case of H. glyphica sp. nov. istic semi-circular pit below subcentral tubercle, bounded by muri. Behind rim of anterior margin 'Hermanites' thomasi sp. nov. a row of 6-7 fossae beginning anterior to eye PI. 7 figs 9, 10; PI. 8 figs 1,2; PI. 10 fig. 9; PL tubercle. Second, less-well-defined row of fos- 12 figs 7, 8; PL 14 fig. 6 sae posterior to first row and separated from it by strong rounded rib. RPCs numerous along IGrinioneis sp. I . — Warne 1987: 443, pi. 3 fig. 1. anterior margin (25-30 straight, unbranched and occasionally paired); 8-10 RPCs on caudal Holotype. NMV P123242 — Clifton Bank — PI. 7 fig. 9, PI, 14 fig. 6. process. Line of concrescence and inner margin Paratypes. NMV PI 23243, PI 23244 (Not figured); PI 34972 coincident. — PI.7 fig. 10;P134973 — PI. 8 fig. 1. PI. 12 fig. 7; PI 34974 Muscle scars in pit internally, expressed as sub- — PI. 8 fig. 2; P134992 — PI. 10 fig. 9, PI. 12 fig. 8. oblique row of" 4 central tubercle externally; Dimensions. Holotype LV,2: L=0.66; H=0.39. Paratype see adductors (sometimes appearing as 3, (PI23243) RV, male: L=0.71; H=0.38. Paratype (P123244)

description of 'H. ' lungulata ) — dorsal long, Carapace: L=0.64; H=0.36; W=0.29. dorsomedian dumbbell-shaped and longest, ven- Material. 471 specimens, Clifton Bank, Muddy Creek, near tromedian small and circular (in some specimens 1 lamilton. Muddy Creek Marl, early Middle Miocene. JOHN V.NEIL

Diagnosis. Small Hermanites-Wke, with well- Although 'H'. thomasi has a linear reticulation defined subcentral tubercle and reticulation lat- pattern, it is quite unlike Sissingh's (1972) Fig- erally radiate from it; prominent alate pos- ures of Tenedocythere prava (Baird, 1850), T. teroventral process; posterodorsal spine. mediterranea Ruggieri, 1962 and T. salebrosa

Uliczny, 1969 in that it has a subcentral tubercle Description. Valves small; LV overlapping RV free of reticulation, and its muri are somewhat slightly in anterior; dorsal and ventral margins flat-surfaced. Assignment to Tenedocythere is subparallcl, straight to slightly sinuous; anterior inappropriate. rounded; greatest lateral extension in ventral half There are some similarities to Margocythere with distinct acuminate caudal process. Three McKenzie et al., 1991 but the absence of the short spines on posteroventral margin; pos- eponymous broad margin, the smooth, rather terodorsal margin concave. Dorsal margin with than 'rugged' reticulation, and relatively small small anterior 'hinge ear' on both valves. Eye size rule out assignment to that genus. Accord- tubercle distinct and clearly below dorsal mar- ing to Hartmann and Puri (1974: 35) frontal scars gin. are indeterminate between trachyleberids and Ornamentation a clear reticulation of broad hemicytherids but I place this species in Hemi- rounded muri bounding narrow, deep fossae; cytheridae, not only on the basis of frontal scars reticular pattern laterally radiate from smooth, but also because of similarity to such non-tra- subcentral rounded tubercle. Muscle scars visible chyleberids as the bradleyine genera. On the basis on external surface of tubercle. Strong ribbing on of muscle scars alone, the species might be ventral surface of alar processes. Ventral rib assigned to the Aurilini but it does not have auri- strong. Anterior margin marked by rounded rib. line ventral inflation, nor the notched posterior Small dorsal rib terminated posteriorly by strong, and stepped anterior teeth of auriline hingement. projecting angular node. Hinge holamphidont; median bar smooth. Hermanites' lungulata (McKenzie, Reyment Muscle scar pattern (PI. 14 fig 6.) a cluster of 3 andReyment, 1991) frontal scars, all subcircular, 2 larger, with small- PL 6 figs 9, 10; PI. 7 figs 1 , 2; PI. 14 fig. 7 er one between. Obliquely vertical row of 4 adductor scars; dorsomedian clearly divided; pos- Bradkya lungulata McKenzie et al., 1991 : 162, pi. 6 flg. teromedian elongate. Two dorsal scars above 8, pi. 10 figs 9, 10. main cluster. Muscle scar pattern substantially 'Bnidkya limgulcini. — McKenzie et al., 1993: 1 13, pi. consistent throughout population. 7 fig. 13, pi. 8 fig. 19. Inner margin and line of concrescence coinci- Figured specimens. NMV P123245 — P1.6fig. 10, PI. 14fig. dent. Fused zone relatively narrow. RPCs and 7; P123246 (Not figured); P123247 — PI. 7 fig. 1; P123248 normal pores not observed. Sexual dimorphism (Not figured); P134966 — PI. 6 fig. 9; P134967 — PI. 7 fig. marked; males longer and less high than females. 2. No juveniles present in this population. Dimensions. (PI 23245) RV: L=0.84; H=0.43. (PI 23246) LV: L=0.91; H=0.48. (P123247) Carapace: L=0.90; H=0.43; Etymology. For Dr G. A. Thomas, who assisted W=0.64. (PI 23248) LV, instar: L=0.66; H=0.35. in the supervision of this project. Material. 68 specimens, Hentys and Clifton Bank, near Hamilton, Muddy Creek Marl, early Middle Miocene.

Remarks. Although the muscle scar pattern is Brief description. Medium to large consistent throughout the population and differs Hermanites- like species with 'spongeous' or celated from the two frontal scars diagnostic for Her- reticu- lation; regular lateral surface reticulation bound- manites s.s., H. thomasi is tentatively placed in ed by narrow, flat-surfaced muri; prominent this genus for reasons similar to those set out '//. subcentral tubercle, free of reticulation. below for ' lungulata. The muscle scar pattern is characteristic of the auriline genera Mutilus Affinities. This species is close to H. (Grinioneis) and Aurila but the hingement of H. thomasi lacks paijenborchiana (Keij, 1957) in terms of reticu- the notched posterior tooth and stepped anterior lation and shape, but specimens from Muddy tooth of aurilinids, and its shape in lateral view Creek differ in having three subcircular frontal is quite unlike their ventrally inflated forms. The scars. It differs from other Hermanites as dis- specimen figured by Warne (1987) is probably cussed below for H. glyphica, in having only conspecific with '//'. thomasi but its frontal scar small nodules at the ends of the dorsal and ven- pattern rules out the trachylcberid Grinioneis. tral ribs. It is also close to Quadracythere MIOCENE TRACHYLEBERIDIDAE AND HEMICYTHERIDAE 19

quadrazea Hornibrook, 1952. It appears quite Bradleyinae Benson 1972 similar to Limburgina quadrazea (Hornibrook) Spinobradleya McKenzie, Reyment and (Benson, 1972: pi. 1 fig. 6), which specimen is Reyment, 1991 quite large (L=0.93 mm), and lacks a cauda and the strong ventral ridge of 'Hermanites' lungu- Spinobradleya nodosa sp. nov. lata. PI. 6 fig. 8 of McKenzie et al. (1991) differs PI. 8 figs 4, 6 from the other illustrated specimens in having 3, 5, reticulation on the subcentral tubercle, in its pat- Holotype. NMV P123252 — Clifton Bank — PI. 8 fig. 3. tern of reticulation without clearly defined con- Parah'pes. NMV P123253, P123254 (Not figured); P134975 centric sequence of reticules around the tubercle — PI. 8 fig. 4;P134976 — PI. 8 fig. 5; P134977 — PI. 8 fig. and in the rounded surfaces of the muri. 6. Dimensions. Holotype LV: L=0.83; H=0.45 Paratype Remarks. "H' .lungulata is tentatively included in (P123253) RV: L=0.81; H=0.43. Paratype (P123254) LV, Hermanites because of its shape, caudal process, instar: L=0.63; H=0.36. Material. 337 specimens, Hentys on Grange Burn, and dorsal and ventral alate ventral ribs. However, its Clifton Bank on Muddy Creek, near Hamilton, Muddy Creek muscle scar pattern is somewhat anomalous in Marl, early Middle Miocene. having three frontal scars (Muddy Creek speci- mens only) and two ventral adductors so closely Diagnosis. Subrectangular Spinobradleya with associated that they sometimes appear as one strongly developed blade-like dorsal and ventral undivided scar (PI. 14 fig. 7). These variations ridges; finely divided reticulation with nodes are within the range of hemicytherids (Hartmann developed at intersections of ridges; reticulation and Puri, 1974) and further underline the need and nodes covering subcentral tubercle. for caution in using muscle-scar patterns as diag- Description. Valves subrectangular, with dorsal nostic at the generic level in "transitional" hemi- and ventral margins parallel; anterior broadly cytherids. rounded; posterior with small caudal process in The use of the term 'divided' to describe a ventral half; posterodorsal margin slightly con- muscle scar is ambiguous. It is difficult to sepa- cave. Dorsal margin in lateral view broken by rate single, original adductor scars divided division into 2 blade-like ridges. Ventral ridge because of evolutionary, ecophenotypic or func- developed posteriorly into alar process terminat- tional trends from separate scars fused. It is ing in small node. difficult to specify separate adductor equally Ornamentation a small-meshed reticulation, scars if closely associated. Divisions even with nodes at intersections. (Great intraspecific associated laterally are usu- between components variation in the development of these nodes.) scar, whereas ally regarded as dividing a single Reticulation and nodes continue over prominent associat- divisions between components closely subcentral tubercle. Anterior margin with ridge- the lit- ed vertically are not. It is not clear from like flange bearing small denticulations. Orna- erature whether the adductor muscle attachment mentation developed on venter, and bounded by points reflect the separation of fibres into clusters ridges and margins of alar process. or not but these muscles tend to be separated ver- Muscle scars — 2 subcircular frontal scars, tically rather horizontally. In 'H' .lungulata, divi- dorsal smaller; 4 adductor scars, dorsal ovate, sion of the closely associated scars is vertical so remaining 3 elongate; ventromedian and ventral that it would be generally regarded that the scars closely associated, but separate. Normal species had four adductor scars, the ventral two pores clearly visible on interior of valve (type occurs very closely associated or fused. Variation unknown) — equally spaced and related to retic- intraspecifically at one location, as well as ulation mesh. Line of concrescence and inner between locations. margin coincident. RPCs on anterior margin but Bradleya lungalata McKenzie etal., 1991 and not clearly visible. 'Bradleya' lungulata McKenzie et al., 1993 can- Hinge strongly holamphidont, with anterior not belong to Bradleya because of their distinct tooth in RV stepped. Median bar finely crenu- reticulation pat- cauda, flat-surfaced muri, radiate late. Sexual dimorphism — males longer and less tern, relatively small reticules and smooth sub- high than females. Juveniles develop spiny nodes central tubercle, none of which fits Benson's before the reticulation mesh. (1972) diagnosis of Bradleyinae. Consequently, this species should be re-assigned to Hermanites Etymology. Referring to the nodes on the muri s.l. of the reticulation. 20 JOHN V. NEIL

Remarks. The development of nodes in the orna- and Warrambine Creek in the Leigh R. area; in the Wuk Wuk mentation and the muscle scar pattern are char- Marls, Gippsland (characterised by a continuous median acteristic of this genus. Spinobradleya nodosa ridge) and in the Morgan Limestone at Blanchetown, SA (own collections). A related, and differs from the type species S. acantha McKen- possibly ancestral form occurs in the Late Eocene Blanche Point Formation Perkana zie et al., 1991 with its interspine reticulation Member as defined in Lindsay (1985). A distinctive species rather than separate spines; its more strongly in the older Tuketja Member of the same formation shows developed subcentral tubercle and the absence of sufficient morphological similarities to B. (B.) praemacken- dorsal spines. It is more similar to S. echinata ziei and the related form in the Perkana Member referred to McKenzie et al., 1993 which has interspine retic- above to be investigated as part of the phylogeny of south- ulation but differs in not having eastern the posterior flat- Australian bradleyines (McKenzie et al., 1991). tening. S. nodosa is not placed in Jugosocythereis Muddy Creek Marl, early Middle Miocene for the Hamilton Puri 1957 in spite of the reticulation and nodes specimens. Approximately the same age for those from the being noticeably developed on the subcentral Fyansford Formation (Balcombe Clay), the Sherwood Marl and the Wuk Wuk Marls. Those tubercle. There is no development of longitudi- from the Morgan Limestone may be younger. nal ridges or of the 'bridge' structure regarded as phylogenetically significant in Jugosocythereis Remarks. It is clear from Whatley and Down- by Benson (1972). The ridges on the subcentral ing's (1983) and McKenzie and Peypouquet's tubercle which McKenzie (pers. comm. 1986) (1984) figures that their specimens are conspe- and Holden (1967) regarded as diagnostic of cific — they are from virtually the same locality Jugosocythereis are not mentioned in the origi- and horizon. nal diagnosis, but implied in the name from the Whatley and Downing (1983) found this Latin jugum - a yoke or ridge. Such ridges also species to be a substantial element in the Bal- occur in Tenedocythere Sissingh, 1972. combian fauna from Fossil Beach, Mornington (30 individuals — 7% of total assemblage). Bradleya Hornibrook, 1952 s.s. In a smaller sample, McKenzie and Peypouquet Remarks. The original generic concept of Horni- (1984) stopped their count at 50 individuals — brook was too broadly based to remain 15% of the assemblage. In the Muddy Creek untouched. Subsequent refinement, particularly Marl, Bradleya species contribute a much lower by Benson (1972), has enabled taxonomists to proportion, B. (B.) praemackenziei having only discriminate among this range of deep- and shal- 12 confirmed specimens (0. 1 %). With two other low-water hemicythcrids and to establish species species Bradleya contibutes only 40 specimens with important distinctive phylogenetic and/or (0.4%). A feature of the specimens from Muddy palaeoecologic characteristics (Whatley et. al., Creek is the development of the posterior end of 1983, 1984). As a result, the generic concept of the ventral ridge into a flattened, spine-like Bradleya is now more precise than in many other process. The eye tubercle is well-developed as Tertiary hemicytherid and trachyleberid genera. would be expected in a relatively shallow water Bradleya species form a small consistent element form. in the fauna of the Muddy Creek Marl and this Some of the better preserved specimens show enables comparisons to be made both with south- aggradation (sensu McKenzie and Peypouquet, eastern Australia and more widely. 1984) but it is difficult to draw palaeoecological inferences from this Bradleya (Bradleya) praemackenziei Whatley because of the small number of specimens and Downing, 1983 in the Hamilton sample and the dif- ficulty of discriminating between partially PI. 8 figs 7, 9; PI. 13 fig. 2 aggraded specimens subject to abrasion in the Bradleya praemckenziei post-depositional environment (possibly Whatley and Downing, 1 981: even 381, pi. 7 figs 7-9. — Warne, 1987: 443. remanie specimens) and those not showin° Bradleya momingtonensis McKenzie and Peypouauet aggradation per se. 1984:301. Some specimens, only tentatively assigned to this Figured Specimens. species, have the eye tubercle lower NMV P123369 — PI 8 Tig 7- P134979 than the PI. dorsal margin in lateral - 8 fig. 9; PI 34993 — PI. 13 fig. 2. view, with a narrow rid^e above the Dimensions. (PI 23369) LV L=0.80; H=0.43. tubercle. These also show an enlarge- Material. 10 specimens. ment of alternate Muddy Creek at Clifton Bank and denticulations along the anteri- Hentys near Hamilton. B. (B.) or margin into praemackenziei also occurs in short spines. This may be more Fyansford Clay, the Sherwood Marl (M. T. Warne, pers. widespread but cannot be detected comm., in the more 1985) and the Balcombe Clay (McKenzie and Pey- abraded specimens. The dorsum of these speci- pouquet, 1984); in the Gellibrand Marl at Native Hut Creek mens is often very discontinuous in lateral view. .

MIOCENE TRACHYLEBERIDIDAE AND HEMICYTHERIDAE 21

All of these points indicate intraspecific varia- Material. 7 specimens, Hentys and Clifton Bank, near Hamil- tion only. ton, Muddy Creek Marl, early Middle Miocene.

Bradleya (Bradleya) sp. cf. B. kincaidiana Briefdescription. Differing from B. (B.) sp. cf. B. (Chapman) (B.) kincaidiana in shape of valves in lateral view, which is closer to that of B. (B.) PI. 8 figs 8, 10 praemackenziei. Differ from latter species in Cythere kincaidiana Chapman, 1926: 132-133, pi. 10 presence of a median ridge in reticulation pat- figs la-c. tern. This pattern has a longitudinal trend in the

Figured Specimens. NMV P123370 — PI. 8 fig. 10; PI34978 dorsal half of the valve. The posteroventral ter- — PI. 8 fig 8. mination of the ventral ridge is much less promi- Dimensions. (P123370) RV: L=0.84; H=0.43. nent than in either of the preceding species. The Material. 21 specimens, Hentys and Clifton Bank, on Grange material is too limited for the erection of a new Burn and Muddy Creek, Muddy Creek Marl, early Middle species, and the presence of a median ridge Miocene. makes assignment to the subgenus Bradleya ten- Brief description. Caudate species with clearly- tative. defined dorsal ridge sweeping below small eye Bradleya (Quasibradleya) Benson, 1 972 tubercle in anterior, and separate from, but par- alleled by, ridge beginning at eye tubercle and Bradleya (Quasibradleya) pyxos sp. nov. continuous with strongly developed narrow ven- PI. 9 figs 2, 3; PI. 13 fig.3; PI. 14 fig. 8 tral ridge. These ridges have a finely

punctate/reticulate surface (PI. 13 fig. 2). Poste- Quasibradleya sp. — McKenzie, 1979: 91-92, pi. 2 figs rior termination of ventral ridge a flattened spine. 6,7. This characteristic spine develops to varying Holotype. NMV P123257 — Clifton Bank — PI. 9 fig. 2, PI. degrees in this species, and also in B. (B.) 14 fig. 8. praemackenziei and is most prominently devel- Paratopes. NMV P123256, PI23258 (Not figured); P134980 oped in some specimens of Bradleya (B.) sp. A — PI. 9 fig. 3, PI. 13 fig. 3. (see below). Hence it should not be regarded as Dimensions. Holotype RV, male: L=0.76; H=0.36. Paratypc diagnostic at the species level. Ventral adductor (P123256) LV. male: L=0.73; H=0.38. Paratype (PI23258) scar apparently divided, but difficult to determine LV, female: L=0.77; H=0.42. with certainty. Material. 98 specimens, Clifton Bank and Hentys, near Hamilton, Muddy Creek Marl, early Middle Miocene. (The Remarks. The species is referred to Cythere kin- occurrence in borehole WLG38 in the South Australian

caidiana Chapman, 1926 but with reservations Willunga Embayment recorded by McKenzie [1979] is from because of the paucity of the material. The most Early Miocene, N6.) notable feature of Chapman's species is the pos- Diagnosis. Subrectangular Quasibradleya with terodorsal spine. This is missing from these spec- well-developed ventral ridge, strongly developed imens so it is appropriate to compare them with anterior ridge linking with median ridge, anteri- B. (B.) kincaidiana which they resemble in many or to subcentral tubercle, but does not continue other respects, rather than to regard them as con- towards the posterior. specific, even though there is interspecific (and intraspecific) variability of the posteroventral Description. Valve subrectangular in lateral spine. These specimens differ from Bradleya reg- view. Anterior broadly and evenly rounded. Dor- ularis McKenzie et al„ 1991 in the undulating sal and ventral margins subparallel. Dorsum sweeps of the dorsal and ventral ridges, though slightly convex in anterior half, ventral margin the poor preservation of the latter species makes slightly convex overall. Posterior with small, comparison difficult. They differ from Bradleya rounded caudal process in ventral half, smooth- dickbensoni McKenzie et al., 1991 in their more ly continuous with straight margin from pos- caudate shape and smaller reticulation pattern. terodorsal angle. Caudal process more pro- The absence of a central longitudinal ridge dis- nounced and angular in juvenile specimens. tinguishes them from Quasibradleya species. Lateral margins unbroken by projection of orna- ment or ridge. IBradleya (Bradleya) sp. A Ornamentation of lateral surface of valves a PI. 9 fig. 1 complex reticulate pattern, with tendency to lon- gitudinal rows of fossae. Strong, rounded anteri- Figured Specimen. NMV P123255 — PI. 9 fig. I Dimensions. RV: L=0.70; H=0.41. or marginal ridge. Strong ventral ridge parallel to 22 JOHN V. NEIL

ventral margin, thinner than anterior ridge, and elongate B. (Q.) pyxos shares this characteristic, more strongly developed in stratigraphically which, taken together with its partial median younger specimens. Valves strongly inflated ridge, warrants placement in the subgenus Qua- except posteriorly — caudal area compressed. sibradleya. Well-defined median ridge linking anterior ridge Quadracythere Hornibrook, 1952 with subcentral tubercle, but not continuing beyond. Dorsal ridge in anterior half of valve a Subgenus Quadracythere Hornibrook, 1952 continuation of rounded anterior ridge. From eye- tubercle to posterodorsal angle, dorsal ridge Quadracythere {Quadracythere) spica Holden developed from reticulation immediately below PI. 9 figs 4, 5, 6 eye-tubercle sinus, sweeping upward to form dor- sal margin in posterior half of valve. Quadracythere spica Holden, 1976: F24, P1.5 figs 22, 25. Greatest height through anterodorsal angle to Figured Specimens. NMV PI 34981 — PI. 9 fig. 4; PI 23263 ventral margin. Greatest length medially. Great- — PI. 9 fig. 5; PI 34982 — PI. 9 fig. 6; PI 23262, P123264 est width medially through subcentral tubercle. (Not figured). Inner lamella very broad anteriorly, with numer- Dimensions. (P123262) LV: L=0.83; H=0.50. (P123263) RV: ous straight unbranched RPCs. No vestibules. L=0.84; H=0.48. (P123264) LV, instar: L=0.63; H=0.38. Normal pores not observed. Material. 957 specimens, Hentys and Clifton Bank, Muddy Creek Marl, early Middle Miocene. Hinge strongly holamphidont, with median bar and groove smooth. Muscle scar pattern — 2 sub- Remarks. Holden (1976) tentatively linked his circular frontal scars aligned obliquely to long three species of Quadracythere from the Mid- axis of valve; 4 adductors in semicircular arc con- way Island drillholes into an evolutionary cave to anterior. Dorsal adductor large, kidney- sequence, beginning with Q. (Q.) spica, contin- shaped; dorsomedian adductor small; ventrome- uing with Q. aequabilis Holden, 1976 and end- dian adductor clearly divided; ventral adductor ing with Q. trijugis Holden, 1976. He also sug- small fig. (PI. 14 8). Eye tubercle just below gested that marked variation in the posteroventral anterodorsal angle variably in — preserved the and posterodorsal tubercles is an ecophenotypic material available for study. No LV/RV overlap. response (Holden, 1976: F24). Specimens of Q. Sexual dimorphism not established. Later (Q.) spica from the Muddy Creek Marl show evi- instars with more prominent caudal process and dence of these variations, but all are sufficiently greater angularity in ridge pattern. similar to be one species. A range of instars from A6 to A8 are present with adult forms. Q. (Q.) Affinities. McKenzie (1979) briefly referred to a spica is the most abundant species overall being Quasibradleya species from borehole WLG38 at the most abundant at Clifton Bank and the sec- depth 76.5 m conspecific with Q. pyxos. Warne ond most abundant at Hentys. It resembles Horni- ( 1 987) listed two Quasibradleya species from the brook's New Zealand Quadracythere species and Melbourne Trough. Of Hornibrook's bradleyine is closest to Q. mediaruga Hornibrook, 1952, dif- species (1952), B. cunazea and B. dictyon come fering in the absence of the median ridge. The closest morphologically to B. (Q.) pyxos but their age of the Midway Island specimens is given as reticulation patterns are quite different. Quasi- Lower Miocene, allowing time for probable bradleya janjukiana McKenzie etal., 1991 is less migration westwards across the Pacific. Quadra- caudate and quadrate in shape than Bmdleya cythere singletoni McKenzie et al., (Quasibradleya) pyxos. Quasibradleya momitea 1991 lacks the longitudinal development of ribs and the McKenzie et al., 1993 has a subrounded posteri- prominent posterodorsal 'ear' characteristic of or, and a different reticulation pattern from this spica. species. Q. (Q.)

Hornibrookellina subgen. nov. Etymology. From the Greek pyxos, a box.

Type species. Hornibrookellina hentyensis sp. Remarks. This species is placed in Benson's sub- nov. genus Quasibradleya even though the diagnostic median ridge does not continue from the anteri- Diagnosis. Quadracythere with subrectangular or beyond the subcentral tubercle. Benson's illus- valves in lateral view; posterodorsal margin not trated species (B. dictyonites, (Q.) B. (Q.)prod- markedly caudate; shell surface strongly reticu- ictyonites B. and (Q.) paradictyonites) are all late with no median ridge, but dorsal and ventral noticeably more elongate than Bradleya s.s. The ribs developed to a greater or lesser extent. MIOCENE TRACHYLEBERIDIDAE AND HEMICYTHER1DAE 23

Muscle scar pattern variable, but upper adductor quadracytherid. Both Al-Furaih and Siddiqui scars undivided, and 2 frontal scars subcircular in failed to describe muscle scar patterns of the form. species they included in Hornibrookella because of poor preservation or because they made only Remarks. This subgenus has been erected general statements (Al-Furaih, 1983). However, because of disparities between Hornibrookella because the material fits Al-Furaih's group and (sensu Al-Furaih, 1977) and Quadracythere because its muscle scar pattern is distinct from (Hornibrookella) Moos, 1965 s.s. The latter was those of the Moos group and is consistent in erected on the basis of differences of the LV, occurrence, a separate subgenus can be erected hinge features and muscle scars from the origi- for them. This leaves Q. (Hornibrookella) as nal genus. Quadracythere s.s. has been used less originally diagnosed by Moos (1965) for at least than it might had not Hornibrook's (1952) inclu- Q. (H.) anna (Lienenklaus, 1 894) (type species), 1 1 widely different species extend- sion of rather Q. (H.) macropora macropora (Bosquet 1894), variability present taxonomic ed its beyond Q. (H.) macropora gamma Moos, 1965 and Q. acceptability. Material of Quadracythere s.s. in (H.) vahrenkampi Moos, 1965. this fauna provides scope for a resolution of the The following species are referred to the new problems associated with diagnosis and place- subgenus: ment of Hornibrookella and other quadracytherid Q. (Hornibrookellina) cyclifossata, Q. (H.) species which do not fit readily into the existing cvclopea, Q. (H.) cuspidata, Q. (H.) divergens, taxonomy. Q. (H.) epicelis, Q. (H.) posterisella (All Al- The subgenus Q. (Hornibrookella) was erect- Furaih, 1977); ed to include distinctly quadracytherid species, Q. (Hornibrookellina) abdulrazzaqi Al-Furaih, including Q. anna (Lienenklaus, 1894) as type 1983; species. Subsequently Al-Furaih (1975, 1977) Q. (Hornibrookellina) platybomus, Q. (H.) features rejected Moos' s diagnostic muscle scar directa, Q. (H.) subcpiadra, sp. A. (All Siddiqui, because he was able to show that intraspecific 1971); and (and even RV and LV) variation occurred. Q. (Hornibrookellina) hentyensis sp. nov. Instead, Al-Furaih (1977) elevated Horni- The other species listed by Siddiqui Q. (Horni- to genus level with a diagnosis brookella brookella) arcana (Lubimova and Guha, 1 960) is focussed on shape, ridge and reticulation pattern, retained in the Moos subgenus because of its eye- and subcentral-tubercles and hinge. The last shape. Hornibrookella (?) currimundria McKen- but are three characteristics are not diagnostic zie et al., 1993 is also retained in Hornibrookel- shared with Quadracythere s.s. To establish a la because its shape and reticulation are allied to genus (as distinct from a subgenus) on the basis those of the type species. of valve shape and a single characteristic of the reticulation pattern is debatable. Quadracythere (Hornibrookellina) hentyensis Furthermore, Al-Furaih' s concept of Horni- sp. nov. brookella, thus defined, does not clearly accom- PI. 9 figs 7, 8, 10; PI. 10 fig. 1; PI. 13 fig. 4; PI. modate its type species which has a definite pos- 14 fig. 9 terodorsal extension with evidence of relatively In fact, all the large denticulate projections. Holotype. NMV P123260 — Hentys — PI. 9 fig. 7, PI. 14 fig. species figured by Moos (1965) — Q. (H.) anna, 9. Q. (H.) macropora gamma, and Q. (H.) Paratypes. NMV P123259 — PI. 9 fig. 10; P134983 — PI. 9 vahrenkampi — share this shape, whereas the fig. 8; P134985 — PI. 10 fig. I, PI. 13 fig. 4; P123261 (Not species figured by Al-Furaih (1975, 1977, 1980) figured). Dimensions. Holotypc LV: L=0.95; H=0.53. Paratypc and by Siddiqui (1971) have a less well-defined (PI23259) LV: L=0.90; 11=0.48. (PI2326I) Paratypc RV, posterodorsal extension. If one were to look for instar: L=0.73; H=0.40. confirmation of Al-Furaih's concept of Horni- Material. 185 specimens, Hentys on Grange Burn, at Yule- subcentral-tubercles and brookella in eye- and cart, near Hamilton, Muddy Creek Marl, early Middle hinge, one would find it difficult to differentiate Miocene. between Hornibrookella and Quadracythere s.s. It is clear that Moos's (1965) subgenus Q. Diagnosis. Thick-shelled subrectangular Q. (Hornibrookella) and Al-Furaih's (1977) con- (Hornibrookellina) having subpolygonal semi-

cept of it differ, if not on muscle scar patterns, regular reticulation with narrow muri covering then on shape, since species of the latter are lateral surface of valves. Large depression pos- longer and less high than the characteristic terior to the eye tubercle. 24 JOHN V. NEIL

Description. Valves subrectangular in lateral nov., and Omaniella nomen nudum are transi- view, with dorsal and ventral margins virtually tional forms with shared morphology. Further parallel. Dorsal margin in LV straight; in RV investigations of the phylogeny of Quadra- with slight anterodorsal hinge-ear (van Mork- cythere s.s., its subgenera, and these other gen- hoven, 1962). Anterior broadly rounded, with era will be necessary to distinguish clearly narrow flange. Posterior margin with weakly between them. developed process, caudal more evident in LV Of the 1 8 species of Q. (Hornibrookella) and than RV. Anterior and posterior cardinal angles Q. (Hornibrookellina) described and figured up rounded. Carapace inflated posteriorly in dorsal to 1989, only Q. (Hornibrookella) rnacropora and ventral views. No marginal denticulations. (Bosquet, 1984) ranges above the Oligocene. Ornament a cellular reticulation of subpolyg- Most are confined to the Palaeogene. In terms of onal, flat-surfaced narrow muri defining deep valve shape in lateral view and general pattern fossae. Dorsal ridge less prominent than ventral of ornamentation, Q. (Hornibrookellina) hen- ridge. Ventral ridge marked posteriorly by nar- tyensis sp. nov. comes closest to Q. (H.) pos- row rib. Subcentral tubercle covered by reticula- terisella (Al-Furaih, 1977) from which it differs tion pattern. Little suggestion of longitudinal or in having a much less pronounced cardinal angle lateral ridges. Fossae posterior to eye-tubercle and a reticulation pattern which docs not extend fused into large depression. In ventral view, cel- to the posteroventral margin. Q. (H.) hentyensis lular pattern of reticulation well-developed. sp. nov. resembles through its cellular ornamen- Inner lamella moderately broad in anterior and tation the seven species described by Al-Furaih posteroventral sections. No vestibules. Numer- (1977, 1983) sp. and Q. (H.) A of Siddiqui (197 1) ous simple, unbranched RPCs, concentrated in butdiffers in valve shape, in details of ornamen- anterior and posteroventral sections. Hinge tation, and in having undivided adductor muscle strongly holamphidont, with smooth anterior and scars and distinctive frontal scars. posterior teeth in RV; median element crenulate, Moos (1965), in diagnosing the subgenus Q. with anterior end having a large, rounded tooth (Hornibrookella), and Al-Furaih (1975), in in and LV, with posterior end of median element redescribing the type species Q. (H.)anna, drew flared into small rounded lobe. Normal pores not attention to the variable muscle scar pattern, even identifiable on exterior surface because of adher- within one species, so that it is unwise to use it ent matrix. as a diagnostic feature unless its consistency can Muscle scars a subvertical row of 4 undivided be established with a hypodigm (Simpson, 1940) adductors; 2 subcircular or slightly elongate of at least 20 specimens. In the case of Q. (H.) frontal scars, and 2 small mandibular scars. Dor- hentyensis sp. nov. no such variation was evident sal and dorsomedian adductor scars elongate; in a hypodigm of 24 adult specimens (in the orig- ventral and ventromedian adductor scars com- inal collection — 20 more specimens added since pressed, giving the appearance of a single, but then), or in a possibly conspecific population divided, larger scar. (PI. 14 fig. 9 and discussion from the Wuk Wuk Marl of Gippsland (own above). Lye tubercle distinct and rounded. No unpublished data). To establish the phylogenel- conspicuous overlap of valves; line of valve clo- ic relationships of these species, and of the gen- sure in dorsal view straight. Sexual dimorphism era and subgenera Quadracythere s.s., Q. (Horni- evident males — longer and less high than brookella), Q. (Hornibrookellina) and Omaniella females. Specimens of the 7th and 8th instars nomen nudum, it is likely that classification by occur with adults. No distinctive juvenile fea- ornamentation pattern proposed by Liebau tures. (1971 ) and Neale (1975) with modifications sug- gested by Al-Furaih Affinities. Alocopocythere Siddiqni, 1971 and (1977) will be valuable. OmanicUa Zawawi, 1985 nomen nudum share Etymology. From the locality 'Hentys' on Grange some characteristics with this subgenus, but the Burn, near Hamilton. single v- or j-shaped frontal scar removes them from Hemicytheridae using conservative criteri- Remarks. This is the first record of the subgenus on. Howe and McKenzie (1989) suggested that Q. (Hornibrookellina) in Australia. An unde- Alocopocythere, which has been reassigned from scribed species of the related subgenus [ ?Q. Echinocytherideinae to Cylhereltidae, may be (Hornibrookella)] of Janjukian age, from Castle transitional to some Neocytheretta. It seems like- Cove (Upper Glen Aire Clays) also exists ly, however, that Quadracythere (Hornibrookel- (McKenzie, 1985, pers. comm.). Similar forms la) Moos, 1965, Q. (Hornibrookellina) (Hornibrookella subgen. sp. I Warne, 1987 and Horni- MIOCENE TRACHYLEBERIDIDAE AND HEMICYTHERIDAE 25

brookella sp. 2 Warne, 1987) also occur in the terodorsally as slight arch beyond otherwise Melbourne Trough in the Fyansford Clay at the straight line of margin. Posterior marked by sub- Batesford Quarry, a formation of equivalent age acuminate cauda in ventral half. Ventral margin to the Muddy Creek Marl. McKenzie et al., almost straight. Ornamentation — noded rib (1991) described and figured three species of oblique to dorsal margin from below eye tuber- Hornibrookella. Of these, H.flexicostata is dealt cle to posterodorsal angle; narrow anterior ridge; with under Chapmanella gen. nov. below; H. concentric noded anterior and anteroventral rib; aggradata is not a Hornibrookellina because of discontinuous noded ventral rib; sharply-edged its arched dorsum, caudate posterior and thick- wedge-shaped termination to posterodorsal lat- ened ribs and Hornibrookella sp. (McKenzie et eral surface. Subcentral tubercle not strongly al., 1991: PI. 6 fig. 7, PI. 10 fig. 15) is possibly a developed. Eye spots below anterodorsal angle of Hornibrookellina, which differs from H. hen- valve. Margins without denticulations except for tyensis in its anterior 'hinge ear' and its caudate 2 small denticles on posteroventral margin. posterior, especially marked in the specimen fig- Hinge strongly holamphidont. LV median bar ured in PI. 10 fig. 15. slightly crenulate on margin. Teeth on RV Q. (Hornibrookellina) hentyensis sp. nov. smooth. Posterior tooth and socket at pos- occurs only at Hentys on Grange Burn and is not terodorsal angle and extended linearly around found in any of the samples from Clifton Bank. that angle. Muscle scar pattern of 3 frontal scars,

The species is part of the biocoenose, as juve- 1 small and anterior to 2 larger ones; adductor niles of at least three instars occur with the adults. scars subdivided in a distinctive array (text-fig. The juveniles tend to be a little less rectangular 3). Inner lamella moderately broad anteriorly; and more tapered posteriorly. Whatley and narrower posteroventrally. RPCs numerous, sim- Downing (1983) did not record Quadracythere ple and straight. Normal pores not observed. s.s. or its subgenera from their Balcombian local- Etymology. From the L. rectus, right, perpendic- ity, probably because deeper water conditions ular to the base, straight — a reference to the prevailed, as indicated by a fauna in which Krithe unusually quadrate appearance of this species. nitida was the most abundant species. Q. (Horni- brookellina) cf. hentyensis was also recorded Remarks. The species is only tentatively assigned from the Wuk Wuk Marl on the Mitchell River, to Ambostracon because of the absence of ribbed, Gippsland (Neil, 1985; unpublished data — reticulated ornamentation. McKenzie (1967) Geol. Surv. Vic. Locality No. GSV-F31). referred to Ambostracon species as "character- ized externally by an ornament of heavy ribs and Urocythereidinae Hartmann and Puri, 1974 intermediate reticulations". However, its muscle Ambostracon Hazel, 1962 scars, eye spot and hingement fall within the genus. It differs from A. pumila (Brady, 1 866) in 'Ambostracon' recta sp. nov. its more elongate shape and absence of orna- mentation referred to above. Some figured PI. 5 figs 7, 8, 9, 10; text-fig. 3 species of Ambostracon (A. ? fredbrooki Milhau, Hololype. NMV PI 23270 — Clifton Bank — PI 5 fig. 10, 1993; A. cf. A. pumila (Brady, 1866) in Swanson text-fig. 3. (1979) show little of the pattern of ornamenta- PI. fig. PI34962 PI. 5 Paratypes. NMV P123271 — 5 9; — tion referred to in Hazel's (1962) diagnosis but I PI. 5 fig. 8. fig. 7;P134963 — stress its significance by only tentatively referring Dimensions. Holotype LV: L=0.54; H=0.28. Paratype this relatively unornamented species to the genus. (P12327I) RV: L=0.52; H=0.29. I agree with Dingle (1992), who regarded Material. 89 specimens, Clifton Bank only, (not present at Ambostracon as a senior synonym of Patagona- Hentys), Muddy Creek Marl, early Middle Miocene. cythere Hartmann, 1962, some characteristics of

Diagnosis. Small, subquadrate Awbavfracwi-like which are shared by 'A. ' recta. The absence of species with noded dorsal ridge having promi- the diagnostic areas of attachment of the inner nent posterodorsal termination. lamella ('pillar structures') rules out assignment

of 'A. ' recta to Caudites. Description. Valves subquadrate in outline; slightly tapered. Anterior broadly rounded; dor- Chapmanella gen. nov. with anterodorsal hinge ear, and sal margin Type species. Cythere flexicostata Chapman, dorsal margin of LV with slightly arched in RV; 1914. greatest height at anterodorsal cardinal angle; ridged section of valve surface projects pos- Diagnosis. Urocythereinid usually with 3 frontal 26 JOHN V. NEIL

scars; a thick, rounded, marginal anterior ridge; al ribs, more or less continuous from anterior to ornamentation of longitudinal, celated, coarse posterior; generally sinuous and flat-surfaced. ribs, and distinct caudal process in ventral half (Specimens show a wide range of rib types from of the posterior. sharp-edged and narrow, through rounded, to broad and flat-surfaced — PL 13 figs 5, 6). Dor- Etymology. For Frederick Chapman who sal ribs sharply angled below eye tubercle; ribs described the type species. slightly subparallel from subcentral tubercle in Remarks. Chapmanella shares some characteris- posterior half of valve; rib pattern variable tics with Urocythereis Rugpieri, 1950, namely between specimens. Valve surface between ribs its muscle scar pattern, heavily calcified valves not visible because of adherent matrix. Short rib and strong and celated pattern of ornamentation. on venter not continuous with lateral ribs. Eye tubercle However, it differs in its longitudinal ribbing and present in both valves; prominent, glassy its more distinct cauda. and slightly below dorsal margin. Hinge strongly holamphidont; RV anterior Chapmanella jlexicostata (Chapman, 1914) tooth rounded; posterior tooth lobed; median bar smooth. LV socket deep and rounded. Inner mar- PI. 10 figs 2, 3, 4, 5, 6, 7, 8; PI. 13 figs 5, 6 gin and line of concrescence coincident; fused Cythere Jlexicostata Chapman, 1914: 35-36, pi. 7 figs zone broad anteriorly, less so posteriorly. RPCs 14a, 14b. — McKenzie, 1974: 160. numerous, simple and unbranched on anterior (?Bradleyini) gen. C, jlexicostata (Chapman). — Warne, margin; less numerous on cauda and ventral mar- 1987:443. gin. Normal pores visible in valve interior; Hornibrooketla flexicostata — McKenzie et a!., 1991: numerous and aligned in channels between ribs; 1 59-160, pi. 10 fig. II. not observed externally; type unknown. Figured specimens. NMV PI2337I — PI. 10 fig. 7, P134986 Muscle scars visible on subcentral tubercle — PI. I0fig.2;PI34987 — PI. 10 fig. 3; P134988 — PI. 10 externally (in some specimens). Internally, mus- fig. 4, PI. 13 fig. 6; PI 34989 PI. lOfig. PI34990 — PI, — 5; cle scar pattern of 3 small, subcircular frontal 10 fig. 6; P134991 — PI. 10 fig. 8; PI34994 — PI. 13 fig. 5. scars in a triangular configuration; an oblique Nominate Specimens. NMV P123232; PI23233; P123234. row of 4 adductors — dorsal subrounded, dorso- Dimensions. (PI 23371) Male LV instar: L=0.41; H=0.22. median clearly divided, (P123232) RV: L=0.76; H=0.42. (P123233) LV: L=0.74; ventromedian elongate, 6=041. ventral ovate to subrounded. (Some intraspecif- Material. 236 specimens, Clifton Bank and Hentys. Muddy ic variation occurs but the pattern described is by Creek Marl, early Middle Miocene. Also recorded by far the most common.) McKenzie et al., 1991 from Late Oligocene to Middle Sexual dimorphism not established with the Miocene, and by Wanic, 1987, Early Middle to Late Miocene. specimens from any one sample; intraspecific variation in length/height ratios within the total Description. In lateral view, subquadrate valves, population may be due to sexual dimorphs. tapered posteriorly. Dorsal and ventral margins Juve- niles — A7 and A8 instars; rib pattern estab- straight in LV; dorsal margin slightly convex in lished, but ribs fine and threadlike RV. (Some specimens show a slight 'hinge-ear' (PI. 1 3 fig. 6); normal pores more evident externally. at the anterodorsal cardinal angle in LV.) Cara- Hinge merodont. pace blunt arrow shape in dorsal view. Blunt cau- dal process in ventral half of posterior, with 3 or Remarks. In view of the inadequacy of Chap- 4 short, peg-like spines. (Two rows of spines man's description I give a full description includ- superimposed in some specimens.) Anterior ing the muscle scar pattern which was not known broadly rounded, with greatest lateral extension to Chapman. in ventral half; numerous small denticulations — The characteristics referred to above constitute usually very abraded in the population studied. a clearly differentiated set which cannot readily Anterior bounded by rounded, substantial ridge, be incorporated in any other genus of the sub- continuous along ventral margin, but tapered family. off If the celation of the ribbing (which is the at anterodorsal angle. Dorsal and ventral ridges most distinctive feature) is due to an ecological terminated posteriorly by blunt, rounded spines. response a population without such celation may (This condition may be due to abrasion in the be discovered. In that event, Chapmanella might Muddy Creek Marl specimens; Chapman's holo- have to be synonymised with Urocythereis. type is well-preserved.) Posterodorsal margin McKenzie et al. (1991) figured a specimen (PI. 10 concave. fig. 11) which is very similar to that figured in Ornamentation a series of 6 or 7 distinct later- PI. 10 fig. 7, and assigned it to Homibrookella MIOCENE TRACHYLEBERIDIDAE AND HEMICYTHERIDAE 27

without discussion. For the reasons set out above, no major morphological differences between the their specimens would have to be included in the specimens from the Miocene deposits and the new genus Chapmanella. Recent species. The only differences could be attributed to effects of differential preservation Hemicytheridae incertae sedis of the fossil specimens (e.g. foveolation of the Neobuntonia Hartmann, 1981 surface was sometimes obscured). Consequent- ly, Hartmann's species has been placed in syn- Emended diagnosis. In addition to the characters onymy with the Miocene species. The species is listed by Hartmann, a muscle scar pattern (PI. 14 placed in Neobuntonia, although there are no fig. 5) of 4 adductors, subrounded or elongate; records from the intervening period. the central 2 adductors alongside each other, rather than in a subvertical alignment. Two sub- Neobuntonia sp. indet. rounded frontal scars, the dorsal larger — verti- PI. 6 fig. 5 cally aligned. In some cases, dorsomedian adduc- tor elongate, ventromedian rounded, with Figured Specimen. NMV PI 2323 8 — PI. 6 fig. 5. alignment tending to oblique rather than hori- Dimensions. RV: L=0.90, H=0.58. zontal. Juvenile forms show considerable varia- Material. 1 specimen, Clifton Bank on Muddy Creek, Muddy tion. Creek Marl, early Middle Miocene.

Remarks. Since the muscle scars were not diag- Brief description. Neobuntonia somewhat more nosed by Hartmann, conspecific Recent speci- elongate than N. batesfordiense. Posterior acute- mens from beach sand at Robe, SA, were exam- ly rounded without caudal process. No marginal ined. Characteristic hemicytherid scars were denticulations. Surface clearly foveolate, as dis- found and they formed essentially the same pat- tinct from fossil specimens of N. batesfordiense tern as in the fossil population from Hentys and where foveolation is weak, and sometimes not Clifton Bank. By the criteria discussed in con- evident in poorly preserved material. nection with 'Hermanites' lungulata (McKenzie Notocarinovalva gen. nov. et al., 1991) the two median scars would be clas- sified as divided scar were it not for their sub- a Type species. Notocarinovalva yulecartensis sp. rounded, and hence quite separate, configuration. nov. Consequently, Hartmann's diagnosis has been amended to include the muscle scar pattern, and Other species. Neobuntonia airella McKenzie et the genus is assigned to the tribe Hemicytherini. al., 1991.

Neobuntonia batesfordiense (Chapman, 1910) Diagnosis. Carinate hemicytherid with marked posterodorsal cardinal angle, and flat venter. PL 6 figs 2, 3, 4; PI. 14 fig. 5 Etymology. Greek, notos, south, and Carinovalva. Cytheropteron batesfordiense Chapman. 1910: 300-301,

PI. 2 figs 7a-c. — Chapman 1914: 45, PI. 8 fig. 36. Remarks. The type species is similar in external Cytheropteron batesfordiense var. aculeata Chapman, appearance to the type species of Carinovalava 1914:46, PI. 8 fig. 37. Sissingh, 1973 (C. keiji [Sissingh, 1973]), hence Neobuntonia siebertorum Hartmann, 1981: 115, text figs the generic name Notocarinovalva. However, 38-46, PI. 8 figs 6-9. significant differences between Carinovalva and Figured Specimens. NMV P123366 — PI. 6 fig. 2, PI. 14 fig. Notocarinovalva include frontal muscle scars and 5; NMV P123367 — PI. 6 fig. 3; PI 34964 — PI. 6 fig. 4. hinge structure and lead me to assign the genus

(PI RV: L=0.92; H=0.59 ; (PI 23367) Dimensions. 23366) to Hemicytheridae rather than to Trachyleberidi- RV L=0.90; H=0.60. dae in which Sissingh placed Carinovalva. The Material. 130 specimens, Hentys and Clifton Bank, near only other related species is N. airella (McKen- Hamilton, Muddy Creek Marl, early Middle Miocene. zie et al., 1991). Remarks. Examination of Chapman's types of Malz (1981a) suggested that the acceptance of Cytheropteron batesfordiense Chapman, 1910 a world-wide distribution of particular species and C. batesfordiense aculeata Chapman, 1914 and genera on the basis of external similarities is indicated that the subspecies is not warranted. frequently in error, because separate evolutionary Spines in some specimens is considered intraspe- lines of development can be proved. It is possi- cific variation. Examination of paratypes of ble that the external similarities between Cari- Neobuntonia siebertorumUartmann, 1981 found novalva Sissingh and Notocarinovalva gen. nov. 28 JOHN V. NEIL

Text-figure 3. 'Ambostracon' recta sp. nov. NMV PI23270 RV int. and muscle scars, x 100

may be due to convergent evolution, since the olate in all but anterior and venter. Marginal retic- muscle scar patterns place the genera in different ulation ventrally and posteroventrally. No sub- families. I believe that the external similarities central tubercle. Hinge strongly holamphidont in of Notocarinovalva and Carinovalva, coupled adult specimens; lophodont in juveniles. RV with their basic difference in muscle scar pattern anterior tooth smooth; RV posterior tooth elon- at the family level lend weight to this hypothesis. gate; median element smooth. LV complemen- tary. Notocarinovalva yulecartensis sp. nov. Adductors a subvertical row of 4 individual scars — dorsomedian elongate; lower 2 scars PI. 6 figs 6, 7, 8 closely associated. Two (or rarely 3) subcircular

Holotype. NMV PI23240 — Hentys — PI. 6 fig. 6. and subequal frontal scars. Muscle scars visible Paratopes, NMV P123239 — PI. 6 fig. 8; PI2324I (Not fig- on exterior of valves. Small anterior vestibule. ured); PI34965 — PI. 6 fig. 7. Fused zone relatively narrow. RPCs straight, Dimensions. Holotype RV: L=0.71; 11=0.39. Paralype unbranched and numerous only in anterior. Few (PI23239) LV: L=0.71; H=0.39. Paratype (PI 23241) Cara- thick, unbranched RPCs along ventral carina. pace: L=0.73; H=0.43; W=0.45. Normal pores not observed. Sexual dimorphism Material 73 specimens, Hentys and Clifion Bank (rare), near not observed. Hamilton, Muddy Creek Marl, early Middle Miocene.

Etymology. From Yulecart, the locality in which Diagnosis. Notocarinovalva with foveolate sur- Hentys and Clifton Bank are situated. face, small blunt ventral caudal process and small anterior vestibule. Affinities. Neobuntonia airella McKenzie et al., 1991 is similar to Notocarinovalva yulecarten- Description. Valves tending to hemi-elliptical in sis gen. et sp. nov. and should be placed in Noto- lateral view and subequal in size. Dorsal and ven- carinovalva because it has both the marked pos- tral margins straight. Anterior broadly rounded. terodorsal cardinal angle and the flat venter Posterior margin slightly concave, with ventral diagnostic of the genus. N. airella, however, dif- termination marked by slight, subrounded cau- fers from N. yulecartensis in its large shallow dal extension in line with ventral margin, and punctations, and its less elongate shape. bearing some small dcnticulations in well-pre- served specimens. Valves inflated ventrally in Remarks. The main reason for placing Notocari- characteristic hemicytherid form, but bounded novalva in the Hemicytheridae is the double by rounded carinate ridge. Venter flat and broad frontal scar. The holamphidont hinge, which with greatest width medially. Small anteroventral lacks the special features in the hingement of dcnticulations (visible only in well-preserved Yajimaina, is similar to that of Carinovalva as specimens). Small eye tubercle below valve mar- figured in Sissingh (1973). See also comments gin at anterodorsal angle. Surface of valves fove- on the genus. MIOCENE TRACHYLEBERIDIDAE AND HEMICYTHERIDAE 29

Conclusion Arabia. University Libraries, University of Riyadh: Riyadh, Saudi Arabia. 211 pp.

The ostracode faunas of which these species form Al-Furaih, A.A.F., 1 983. Paleocene and Lower Eocene Ostra- a part are dominated by the hemicytherids, coda from the Umm er Radhuma Formation of Saudi Paleontological Contri- though there is also a substantial representation Arabia. University of Kansas, of xestoleberids, loxoconchids, cytherurids and butions 107: 1-10. Benson, R.H., 1972. The Bradleya problem, with descrip- bairdiids. The trachyleberids and bythocytherids tions of two new psychrospheric ostracode genera, form a smaller proportion of the total. The prime Agrenocythere and Poseidonamicus (Ostracoda, Crus- purpose of this monograph is taxonomic, since it tacea). Smithsonian Contributions to Paleobiology 12: is on the basis of an adequate taxonomy that stud- 1-138.

ies of palaeoecology and evolutionary develop- Berggren, W.A., Kent, D.V. and Flynn. J.J., 1985. Paleogene ment must be based. Other taxonomic papers are geochronology and chronostratigraphy. Pp. 21 1-260 in: planned, to be followed by palaeoecological Snelling, N.J. (ed.) Geochronology and the Geological Geological Society of London. studies. Record. Special Papers,

Bhatia, S.B. and Kumar, S., 1 979. Recent Ostracoda from off Acknowledgments Karwar, west coast of India. Pp. 173-178 in: Krstic, N. (ed.) Proceedings of the VII International Symposium on This work has been carried out as part of a Ostracodes — Taxonomy, Biostratigraphy and Distri- study of the ostracode fauna of the Muddy Creek bution of Ostracodes. The Serbian Geological Society: Marl for the degree of M.Sc. of the University of Beograd. Carter, A.N., 1978. Phosphatic nodule beds in Victoria and Melbourne. I wish to thank my supervisors, Drs the late Miocene-Pliocene eustatic event. Nature 276: McKenzie and George Thomas for their Ken 258-259. encouragement and help over many years, as this Chapman, F., 1910. A study of the Batesford limestone. Pro- to work was done part-time. Ken introduced me ceedings of the Royal Society of Victoria, n.s. 22(2): the Ostracoda and his enthusiasm and friendship 264-314. have provided me with a rewarding interest dur- Chapman, F., 1914. Description of new and rare fossils Malice. Part III: Ostra- ing my retirement. I would also like to thank Dr obtained by deep boring in the David Sewell and Mr Pat Kelly for help with coda to fishes. With a complete list found in the borings. Royal Society Victoria, n.s. 27(1): SEM work, Dr Mark Warne and Mr Kerry Swan- Proceedings of the of 28-71. son for advice and encouragement and Mr Ken Chapman, F„ 1926. Geological notes on Neumerella, and the Bell for stimulating discussions and help in the section from Bairnsdale to Orbost. Proceedings of the Bowles gave invaluable guid- field. Mrs Jean Royal Society of Victoria, n.s. 38: 125-142. process- ance and assistance with photographic Chapman, F. and Crespin, I., 1928. The Sorrento Bore, Morn- ing. The Clifton Bank samples were collected ington Peninsula, with a description of new or little by Messrs Hutchinson, Aslin and party and made known fossils. Records of the Geological Survey of Vic- available to me through the good offices of Mr toria 5(1): 1-195. Cytheracea (Ostracodes) du Maastrichtien Ken Bell and Mr Bob Burn of Geelong. Deroo, G., 1966. de Maastricht (Pays-Bas) et des regions voisincs; resul- My thanks are extended to Dr David Holloway tats stratigraphiques et paleontologiques de leur etude. for access to collections in the Museum of Vic- Mededelingen van de Geologische Stickling C, 2(2) for providing com- toria; to Prof. Gerd Hartmann [Uilgevers Maatschappij 'Ernest van Aelsl', Maas- Prof. Chris Wilson parative material; to Assoc. tricht.] extended and Prof. Ian Plimer for giving me Douglas, J. A. and Ferguson, J. A. (eds), 1988. Geology of Vic- access to facilities in the Department of Geolo- toria. Victorian Division, Geological Society of Aus- tralia. 664 gy, University of Melbourne and to the Museum pp. stratigraphical occurrence and palaeoe- of Victoria for continuing support and research Gill, E.D., 1957. The cology of some Australian marsupials. Memoirs oj the assistance. An Edmund Gill Memorial Research National Museum of Victoria 21:1 35-203. Grant from the Royal Society of Victoria is also Hartmann. G., 1978. Die Ostracoden der Ordnung Podocop- gratefully acknowledged. ida G.W. Mueller, 1894 der tropisch-subtropischen Westkuste Australicns (zwischen Derby im Norden und References Perth im Suden). Mitleilungen aus dem Hamburgischen Zoologischen Museum und Inslitut 75: 64-219. Al-Furaih, A.A.F., 1975. On Hornibrookella anna (Lienen- 1-214. Hartmann, G„ 1979. Die Ostracoden der Ordnung Podocop- klaus). A Stereo-Atlas of Ostracod Shells 2(3): 21 ida G.W. Mueller, 1894 der warm-temperierten (anti- Al-Furaih, A.A.F., 1977. Cretaceous and Palacocene species borealcn) West- und Sudwestekuste Australicns (zwis- of the ostracod Hornibrookella from Saudi Arabia. chen Perth im Norden und Eucla im Suden). Palaeontology 20(3): 483-502. Mitteilungen aus dem Hamburgischen Zoologischen Al-Furaih, A.A.F., 1980. Upper Cretaceous and Lower Ter- Saudi Museum und Institut 76: 219-301. tiary Ostracoda (Superfamily Cytheracea) from 30 JOHN V.NEIL

In : Cooper, B . J . (ed ), Eocene and Miocene stratigraphy . Fodocop- Hartinann, C, 1 98 1 Die Oslracoden dor Ordnung . ida G.W. Mueller, 1894 dcr sublropisch-tropischen of the Willunga Embaymenl. Geological Survey ofSouth Ostkustc Australicns (zwischen Eden itn Suclen und Australia, Reports of Investigations 50: 90-101.

Heron Island im Norden). MUleilungen aus dem Ham- McKenzie, KG, 1981 . Chapman's 'Mallee Bores' and 'Sor- burgischen '/.oologischen Museum und Inslilul 78: rento Bore' Ostracoda in the National Museum of Vic- 97-149. toria, with the description of Maddocksella new genus. Ilurtniann, G and Puri, U.S., 1974. Summary of neonlolog Proceedings of the Royal Society of Victoria, n.s. 93: ical and paleontologioal classification ofOstracoda. Mit- 105-107. teilungen aus dem Hamburgischen Zoologischen Muse- McKenzie, KG. and Bonaduce, G., 1991. Partial redescrip- um und Inslilut 70: 7-73. tions of some Trachyleberididae and Hcmicythcridae Hazel, J.E., 1967. Classification and distribution of the Recent from the Bay of Naples: comparisons, and a re-appraisal Hcinieylheridae and Trachyleberididae (Ostracoda) off of trachylcbcridid — hemicythcrid classification. Pro- northeastern North America. United Stales Geological gram and Abstracts: Eleventh International Symposium Survey, Professional Paper 564: 1-49. on Ostracoda. Wurrnambool: p. 60 Ilolden, J.C., 1967. Late Cenozoic Ostracodes from the McKenzie, K.G. and Pcypouquet, J. -P., 1984. Oceanic drowned terraces in the Hawaiian Islands. Pacific Sci- palaeoenvironment of the Miocene Fyansford Forma- ence 21(1): 1-50. tion from Fossil Beach, Mornington, Victoria, inter- Ilolden, J.C., 1976. Late Cenozoic Ostracoda from Midway preted on the basis of Ostracoda. Alcheringa 8(4); Island drill holes. United States Geidngiau'Survey, Pro- 291 303. fessional Paper 680-F: Fl -F40, 17 pis. McKenzie, K.G. and Warne, M.T., 1986. Alataleberis new Hornibrook, N. dc B., 1952. Tertiary and Kecent Marine genus (Crustacea, Ostracoda) from the Tertiary of Vic- Ostracoda of New Zealand. New Zealand Geological toria and South Australia. Proceedings of the Royal

Survey, Palaeontologtcal Bulletin 18: 1-82. Society of Victoria 98( I ): 3 1 -40. Howe. H.V. and McKenzie, KG., 1989. Recent marine McKenzie, KG, Reyment, R.A. and Reyment, E.R., 1990. Ostracoda (Crustacea) from Darwin and northwestern Pleistocene and Recent Ostracoda from Goose Lagoon Australia. Northern Territory Museum ofArts and Sci- Drain, Victoria and Kingston, South Australia. Bulletin ences. Monograph Series 3: 1-50. of the Geological Institutions of the University of Upp- Howe, II. V., Sylvester-Bradley, P., van den Bold, X. and sala n.s. 16: 1-46. ReyiiK'nt, K.A., 1961. Family Trachyleberididae. In McKenzie, K.G., Reyment, R.A. and Reyment, E.R., 1991. Moore, R.C. (ed.), Treatise on Invertebrate I'aleontol Eoccnc-Oligocene Ostracoda from South Australia and ogy. Fart 0. Arthropoda 3, Crustacea — Ostracoda. Victoria, Australia. Revista Espanola de Paleontologia Geological Society of America and University of 6(2): 135-175. Kansas Press: New York and Lawrence. McKenzie, KG., Reyment, R.A. and Reyment, E.R., 1993. Liebau, A „ 1975. Comment on the suprageneric laxa of the Eocene Ostracoda from (he Browns Creek Clays at Trachyleberididae s.n. (Ostracoda, Cytheracea). Neues Browns Creek and Castle Cove, Victoria, Australia. Jahrbitch Geologic Palaeontidogie Abhandlungen Revista Espanola de Paleontologia 8(1): 75-1 16. 148(3): 353-379. Moos, B., 1965. Die Ostracoden-Fauna des Unteroligoziins Lindsay, J.M., 1985. Aspects of South Australian Tertiary von Bunde (Bl. Hcrford-West, 3817) und einigc vcr- foraminilcral biostratigraphy, with emphasis on studies wandte jiingcre Arten (Ostr., Cmsl.) I. Quadracythere of Massilina and Suhbolinu. Special Publications, South (Hornibrookella) n. subg., Pokornyella, Hemicythere, Australian Department of Mines and Energy 5: llermanites. Geologisches Jahrbuch 82: 593-630. 187 231. Morkhoven, F.P.C.M. van, 1962. Post-Palaeozoic Ostraco- Mailed, C.W., 1977. Studies in Victorian Tertiary da: Their Morphology, 'Taxonomy and Economic Use. foruniinijera: planktonic Neogene faunas. Parts I and Part I: General. Elsevier: Amsterdam. 204 pp. 2. Unpublished PhD. thesis, University of Melbourne. Morkhoven, F.P.C.M. van, 1963. Post-Palaeozoic Ostraco- Malz, II., 1980. Clctocythereis Swain, 1963 (Ostracoda); da: Their Morphology, Taxonomy and Economic Use. besondere Merkmale und gcographische Verbreitung Pari 2: Generic Descriptions. Elsevier: Amsterdam. ihrcr Arlung. Senckenbergiana Lelhaca 60(4/6): 478 pp. 381-397. Neale, J.W., 1959. Normanicythere gen. nov. (Pleistocene Malz, II., 1981. Yajimaina n. gen., eine fernoestliche Cari- and Recent) and the division of the ostracod family Tra- novalva — Verwandle (Ostracoda; Traehyleberidinae). chyleberididae. Palaeontology 2(1): 72-93. Mittcilungen Bayerischen Staalssammlttngfiir Palaeon- Neale, J.W., 1975. The ostracod fauna of the Santonian Chalk tologie und historische Geologic 2 1 : 65-72. (Upper Cretaceous) of Gingin, Western Australia. Spe- McKenzie, K.G.. 1967. Recent Ostracoda from Poll Phillip cial Papers in Palaeontology 16: 1-81. Bay. Victoria. Proceedings of the Royal Society of Vic- Neil, J. V., 1992. Taxonomy and palaeoecology of the ostra- toria, n.s. 80(1): 61-106. cude fauna of the Middle Miocene Muddy Creek Marl, McKenzie, 1974. Cenozoic KG., Ostracoda of southeastern southwestern Victoria. Unpublished M.Sc. thesis, Uni- Australia, with the description of Hanaiceratina new versity of Melbourne. 267 pp., 22 pis, 9 tables, 6 text- genus Gcoscience and Man(r. 153-182. figs. McKenzie, K.G., 1979. Notes on Ostracoda from Willunga Pokorny, VI., 1955. Contribution to the morphology and lax- Embaymenl boreholes WLG38. WLG40. and VVLG42. ionomy of the subfamily Hcmicytherinae Puri, 1953 .

MIOCENE TRACHYLEBERIDIDAE AND IIEMICYTHERIDAE 31

(Crustacea: Ostraeoda). Acta Universitas Carolinae, Australia. Pp. 435-445 in: McKen/ie, KG. (ed.), ShaU Geologica 111: 3-34. low Tethys 2. Balkema: Rotterdam. Pokorny. VI., 1957. The phylomorphogeny of the hinge in Whalley, R., Harlow, C.J., Downing. S.E. and Kcsler, K.J., Podocopida (Ostraeoda: Crustacea) and its bearing on 1983. Observations on the origin, evolution, dispersion the taxionomy. Acta Universitas Carolinae, Geologica and ecology of the genera Poseidonamicus Benson and III: 3-22. Bradleya Hornibrook. Pp. 492-509 in: Maddocks. R.F. Pokorny, VI., 1964. The taxonomic delimitation of the sub- (ed.), Applications of Ostraeoda. University of I louston families Trachyleberidinae and Hemicylherinae (Ostra- Geoscicnces. eoda, Crustacea). Acta Universitas Carolinae, Geolog- Whalley, R. and Downing, S.E., 1983. Middle Miocene ica 111: 275-284. Ostraeoda from Victoria, Australia. Revista Espanolu Puri. H.S.. 1957. Stratigraphy and donation of the Ocala de Micropaleonlologia 15(3): 347-407. Group. Florida Geological Survey Bulletin 38: 1-248. Whalley, R., Downing, S.E., Kcsler, K. and Harlow. C.J., Puri, H.S. and Hulings. N.C.. 1976. Designation of leclotypes 1984. New species of the ostracod genus Bradleya from of some ostracods from the Challenger Expedition. Bul- the Tertiary and Quaternary of DSDP sites in the south letin of the British Museum (Natural History) Zoology west Pacific. Revista Espanola de Micropaleonlologia 29: 249-315, 27 pis. 14 text-figs. 16:265-298.

Reeckmann, S.A., 1974. The geology and environmental Whatley, R.C. and Titlerton, R., 1981. Some new Recent analysis oj the Tertiary sequence at Muddy Creek, and podocopid Ostraeoda from the Solomon Islands south- Grange Burn, Hamilton, Victoria. Unpublished west Pacific. Revista Espanola de Micropaleonlologia B.Sc.(Hons.) thesis. University of Melbourne. 13: 157-170. Roer, R. and Dillaman, R., 1984. The structure and calcifi- Y.ijima, M., 1978. Quaternary Ostraeoda from Kisara/u near cation of the crustacean cuticle. American Zoologist 24: Tokyo. Transactions and Proceedings of the Paleonlo-

893-909. logical Society of Japan n.s. 1 12: 371-409.

Ruggieri, G., 1962. Gli oslracodi marini del Tortoniano. Sicil- Yassini. 1. and Jones, B.G., 1 987. Ostraeoda in Lake lllawar

ia Centrale. Palaeontographia Italica 56 (n.s. 26) Mem- ra: Environmental factors, assemblages and systematica. oir!: 1-68. Australian Journal ofMarine and I'reshwater Research Scott. M., 1974. Ornate Ostraeoda from the Victorian Ter- 38: 795-843.

tiary. Unpublished M.Sc. thesis, Macquarie University. Yassini, I. and Wright, A. J., 1988. Distribution and ecology Siddiqui, Q.A., 1971. Early Tertiary Ostraeoda of the fami- of Recent oslraeodes (Crustacea) from Port Hacking, ly Trachyleberididae from West Pakistan. Bulletin of New South Wales. Proceedings of the Linnaean Soci- the British Museum (Natural History), Geological Sup- ety of New South Wales NO: 159-174. plement 9: 1-98. Zawawi, T., 19867 Ostraeoda from Oman. Unpublished Simpson, G.G., 1940. Types in modem taxonomy. American M.Sc. thesis. Macquarie University, Sydney.

Journal ofScience 238: 4 13—43 1 Sissingh, W., 1972. Laic Cenozoic Ostraeoda of the South Plate captions Aegean Island Arc. Utrecht Micropaleontologica! Bul- The specimens are housed in the invertebrate letins 6: 1-187. palaeontology collections ot the Museum of Vic- Sissingh, W., 1973. Carinovalva new genus (Ostraeoda), and toria, and are identified by numbers prefixed bv comments on the ostracode genus l.ixouria Ulic/.ny the letters NMV P. ( 1 969). Proceedings Koninklijke Nederlandse Akademie van Wetenschappen (B) 76: 143-147. The following abbreviations are used: RV, Swain, F.M., 1963. Pleistocene Ostraeoda from the Gubik right valve; LV, left valve; C, carapace; F, Formation, Arctic Coastal Plain, Alaska. Journal of female; M, male; J, juvenile; ext., external; int., Paleontology 37(4): 798-834. internal. Sample numbers for Clifton Bank are Swanson, 1969 Some Lower Miocene Ostraeoda from KM, referred to in the introduction. 'Hentys' is the the Middle Waipara district, New Zealand. Transac- locality name for the bulk sample from Grange tions of the Royal Society of New Zealand. Earth Sci- Burn (Fig. 1). Localities for the specimens are ences 7(3): 33-48. given as either Clifton Bank or 'Hentys'. The Sylvester-Bradley, P. and Benson, R.H., 1971. Terminology stratigraphic level of samples from Clifton Bank for surface features in ornate oslraeodes. Lethaia 4: 249-286. is given in Fig. 2. The Early - Middle Miocene

Triebel, E., 1958 Zwei neue Ostracoden-Gatlungen aus dent boundary is between planktonic t'oram in i feral Lulet des Pariser Beckcns. Senckenbergiana Lethaea zones N8 and N9. In some cases, the stratigraphic 39: 105-117. level of specimens from the Clifton Bank sam- Oberoligo/iin und Uffenorde, H., 1 98 1 . Ostracodcn aus dem ples is not known. (Nicdersaehsen und Miozan des unteren Elbe-Gcbictes Magnifications are given for each photograph. Hamburg, NW-Deulsches Tcrtiarbecken). Palaeonto- graphica(A) \12: 103-198. Plate 1 Warne, MX, 1987. Lilhostratigraphical associations of the ostracode fauna in the marine Neogene of the Port 1. ?Trachyleberis robuslus (Yassini and Jones. Phillip and Western Port Basins, Victoria, southeastern 1987) RV ext. NMV PI23216 Clifton Bank, . . .

32 JOHN V. NEIL

Sample 5 (Middle Miocene) x 65 'Hentys' (early Middle Miocene) x 80 2. ?trachyleberis robustus (Yassini and Jones, 1987) RV ext. NMV PI 34937 Clifton Bank, Plate 3

Sample 8 (late Early Miocene) x 90 1. Deltaleberis warnei sp. nov. RV int. NMV 3. ?Trachyleberis robustus (Yassini and Jones, PI 34950 Clifton Bank, Sample 10 (late Early 1987) C dorsal NMV PI 34938 Clifton Bank, Miocene) x 90 Sample unknown (Middle Miocene) x 60 2. Deltaleberis warnei sp. nov. MRV ext. Holo- 4. ?Actinocythereis sp. A LV ext. NMV P123221 type NMV P123224 Clifton Bank, Sample 10 Clifton Bank, Sample 3 (Middle Miocene) x 65 (late Early Miocene) x 90 5. ?Actinocythereis sp. A JRV ext. NMV 3. Deltaleberis warnei sp. nov. FRV ext. NMV PI 34939 "Hentys" (early Middle Miocene) x 80 PI 34951 Clifton Bank, Sample 8 (late Early 6. Cletocythereis caudispinosa (Chapman and Miocene) x 100 Crespin, 1928) RV ext. NMV PI 34939 'Hentys' 4. ?Alatahermanites septarca sp. nov. RV ext. (early Middle Miocene) x 90 Holotype NMV PI 23221 'Hentys' (early Mid- 7. Cletocythereis caudispinosa (Chapman and dle Miocene) x 65 ext. Crespin, 1928) RV NMV PI 34940 Clifton 5. Idiocythere sp. aff. /. thalassea McKenzie, Bank, Sample 10 (late Early Miocene) x 90 Reyment and Reyment, 1991 LV ext. NMV 8. Cletocythereis caudispinosa (Chapman and PI 23361 Clifton Bank, Sample 9 (late Early Crespin, 1928) RV ext. NMV PI 34941 'Hentys' Miocene) x 85 (early Middle Miocene) x 90 6. ?Alatahermanites septarca sp. nov. JRV ext. 9. Cletocythereis caudispinosa (Chapman and NMV PI 34952 Clifton Bank, Sample unknown Crespin, 1928) LV ext. NMV PI 23327 'Hentys' (Middle Miocene) x 100 (early Middle Miocene) x 90 7. Mackencythere sp. A RV ext. NMV PI 23360 10. Cletocythereis sp. cf. C. rastromarginata 'Hentys' (early Middle Miocene) x 120 (Brady, 1880) LV ext. NMV PI 34942 Clifton 8. ?Arculacythereis postdeclivis (Chapman, Bank, Sample 10 (late Early Miocene) x 90 1914) LV ext. NMV P123225 Clifton Bank, Sample 10 (late Early Miocene) x 50 Plate 2 9. ?Arculacythereis postdeclivis (Chapman, 1 Cletocythereis sp. cf. C. rastromarginata 1914) JRV ext. NMV PI 34953 'Hentys' (early (Brady, 1880) C ventral NMV P134943 Clifton Middle Miocene) x 100 Bank, Sample 5 (Middle Miocene) x 90 10. ?'Arculacythereis postdeclivis (Chapman, 2. Cletocythereis sp. cf. C. rastromarginata 1914) RV ext. NMV P134954 Clifton Bank, (Brady, 1880) LV int. NMV PI 34944 'Hentys' Sample 1 (late Early Miocene) x 55 (early Middle Miocene) x 90 1 1 Arculacythereis tatei sp. nov. RV ext. Holo- 3. PPonticocythereis sp. aff. P. manis Whatley type NMVP 123266 Clifton Bank, Sample 2 and Titterton, 1981 RV ext. NMV PI 34945 (Middle Miocene) x 75 'Hentys' (early Middle Miocene) x 75 12. Arculacythereis tatei sp. nov. LV ext. NMV 4. ?Ponticocythereis sp. aff. P. manis Whatley PI 34955 'Hentys' (early Middle Miocene) x 80 and Titterton, 1981 RV ext. NMV PI 34946 Clifton Bank, Sample 9 (late Early Miocene) x 75 Plate 4 5. ?Ponticocythereis sp. aff. P. manis Whatley 1 Arculacythereis sp. aff. A. thomasi McKenzie, and Titterton, 1981 RV ext. PI 232 17 NMV Reyment and Reyment, 1991 RV ext. NMV 'Hentys' (early Middle Miocene) x 75 PI 34956 'Hentys' (early Middle Miocene) x 80 6. ?Dumontina cratis sp. nov. RV int. NMV 2. Arculacythereis sp. aff. A. thomasi McKenzie, PI 34947 Clifton Bank, sample unknown Middle Reyment and Reyment, 1991 LV ext. NMV Miocene) x 90 PI 23265 Clifton Bank, Sample 10 (late Early 7. '/Dumontina cratis sp. nov. JMRV ext. NMV Miocene) x 85 PI 34948 Clifton Bank, Sample 4 (Middle 3. Arculacythereinid gen. indet. sp. A LV ext. Miocene) x 90 NMV PI 23268 'Hentys' (early Middle Miocene) 8. ?Dumontina cratis sp. nov. LV ext. Holotype x 65 NMVP123218 'Hentys' (early Middle Miocene) 4. Alataleberis miocenica McKenzie and Warne, x65 1986 JRV int. NMV PI 34957 Clifton Bank, 9. ?Dumontina sp. A JLV ext. PI 34949 NMV Sample 4 (early Middle Miocene) x 80 'Hentys' (early Middle Miocene) x 120 5. Alataleberis miocenica McKenzie and Warne, 10. ?Dumontina sp. A RV ext. PI NMV 23220 1986 JRV ext. NMV PI 34958 Clifton Bank, .

MIOCENE TRACHYLEBERIDIDAE AND HEMICYTHERIDAE 33

Sample 4 (early Middle Miocene) x 80 3 (Middle Miocene) x 60 6. Alataleberis miocenica McKenzie and Warne 3. Neobuntonia batesfordiense (Chapman, 1914) 1986 C from LV side NMV P123363 Clifton MRV ext. NMV PI 23367 Clifton Bank, Sample Bank, Sample 5 (Middle Miocene) x 75 10 (late Early Miocene) x 60 7. 'Hemicythere' lubrica sp. nov. RV ext. Holo- 4. Neobuntonia batesfordiense (Chapman, 1914) type NMV P123226 Clifton Bank, Sample 10 JRV ext. NMV PI 34964 'Hentys' (early Middle (late Early Miocene) x 75 Miocene) x 80 8. 'Hemicythere' lubrica sp. nov. LV int. NMV 5. Neobuntonia sp. indet. RV ext. NMV P123238 P123227 Clifton Bank, Sample 10 (late Early Clifton Bank, Sample 9 (late Early Miocene) x 60 Miocene) x 75 6. Notocarinovalva yulecartensis gen. et sp. nov.

9. 'Hemicythere ' tenuicostata sp. nov. MRV ext RV ext. Holotype NMV PI 23240 'Hentys' (early NMV P134959 Clifton Bank, Sample 8 (late Middle Miocene) x 85 Early Miocene) x 90 7. Notocarinovalva yulecartensis gen. et sp. nov. 10. 'Hemicythere' tenuicostata sp. nov. LV ext. JRV ext. NMV PI 34965 'Hentys' (early Middle Holotype NMV PI 23230 Clifton Bank, Sample Miocene) x 90 8 (late Early Miocene) x 85 8. Notocarinovalva yulecartensis gen.et sp. nov. LV int. NMV P123239 'Hentys' (early Middle Plate 5 Miocene) x 75 1. 'Hemicythere' tenuicostata sp. nov. RV int 9. 'Hermanites' lungulata (McKenzie, Reyment NMV PI 34960 Clifton Bank, Sample 4 (early and Reyment, 1991) JMLV ext. NMV PI 34966 Middle Miocene) x 90 Clifton Bank, Sample 3 (Middle Miocene) x 80

2. 1 'Hemicythere' sp. cf. 'H. ' tenuicostata sp. nov. 0. 'Hermanites' lungulata (McKenzie, Reyment LV ext. NMV P 123364 Clifton Bank, Sample 10 and Reyment, 1991) RV ext. NMV PI 23245 (late Early Miocene) x 90 'Hentys' (early Middle Miocene) x 65 3. Mackenzine foveolata gen. et sp. nov. RV ext. Holotype NMV P123235 'Hentys' (early Mid- Plate 7 dle Miocene) x 90 1. 'Hermanites' lungulata (McKenzie, Reyment 4. Mackenzinafoveolata gen. et sp. nov. LV ext. and Reyment, 1991) C dorsal NMV PI 23247 NMV P123236 'Hentys' (early Middle Miocene) 'Hentys' (early Middle Miocene) x 50 x90 2. 'Hermanites' lungulata (McKenzie, Reyment 5. Mackenzinafoveolata gen. et sp. nov. JLV ext. and Reyment, 1991) LV int. NMV PI 34967 NMV PI 34961 'Hentys' (early Middle Miocene) Clifton Bank, Sample 8 (early Middle Miocene) x 100 x65 6. Mackenzinafoveolata gen. et sp. nov. JRV int. 3. Hermanites glyphica sp. nov. LV ext. Holo- NMV PI 23237 'Hentys' (early Middle Miocene) type NMV P123249 'Hentys' (early Middle xlOO Miocene) x 65

7. 'Ambostracon ' recta sp. nov. FRV ext. NMV 4. Hermanites glyphica sp. nov. FRV ext. NMV P134962 Clifton Bank, Sample 10 (late Early PI 34968 Clifton Bank, Sample 4 (early Middle Miocene) x 120 Miocene) x 70

8. 'Ambostracon ' recta sp. nov. MRV int. NMV 5. Hermanites glyphica sp. nov. JRV ext. NMV PI 34963 Clifton Bank, Sample 9 (late Early PI 23251 'Hentys' (early Middle Miocene) x 75 Miocene) x 120 6. Hermanites glyphica sp. nov. C ventral NMV 9. 'Ambostracon' recta sp. nov. FRV ext. NMV PI 34969 Clifton Bank, Sample 10 (late Early PI 23271 Clifton Bank, Sample 10 (late Early Miocene) x 70 Miocene) x 75 7. Hermanites glyphica sp. nov. RV int. NMV

10. 'Ambostracon ' recta sp. nov. MLV ext. Holo- PI 34970 Clifton Bank, sample unknown (Mid- type NMV P123270 Clifton Bank, Sample 10 dle Miocene) x 70 (late Early Miocene) x 100 8. Hermanites glyphica sp. nov. JLV ext. NMV P134971 'Hentys' (early Middle Miocene) x 80 Plate 6 9. 'Hermanites' thomasi sp. nov. FLV ext. Holo-

1 Pokornyella sp. indet. RV ext. NMV P123368 type NMV PI 23242 Clifton Bank, Sample 10 Clifton Bank, Sample 10 (late Early Miocene) x (late Early Miocene) x 80 85 10. 'Hermanites' thomasi sp. nov. MRV ext 2. Neobuntonia batesfordiense (Chapman, 1914) NMV P134972 Clifton Bank, Sample 5 (Middle FRV ext. NMV PI 23366 Clifton Bank, Sample Miocene) x 90 . V . 4

34 JOHN V.NEIL

Plate 8 subgen. et sp. nov. RV ext. NMV PI 34983 'Hen-

1 tys' (early Middle 'Hcrmanitcs ' ihoinasi sp. nov. FRV cxt. NM Miocene) x 80 PI 34973 Clifton Bank, Sample 5 (Middle 9. Quadracylhere (Hornibrookellina) hentyensis Miocene) x 90 subgen. et sp. nov. JRV int. NMV PI 34984 2. 'Hermanites' ihoinasi sp. nov. LV int. NMV 'Hentys' (early Middle Miocene) x 100 10. PI 34974 CI i Hon Bank, Sample 10 (late early Quadracylhere (Hornibrookellina) hentyen- Miocene) x90 sis subgen. et sp. nov. MLV ext. NMV PI 23259 3. Spinobradleya nodosa sp. nov. LV ext. Holo- 'Hentys' (early Middle Miocene) x 65 type NMV PI23252 Clifton Bank, Sample 10 (late Early Miocene) x 65 Plate 10 4. Spinobradleya nodosa sp. nov. MRV ext. 1 Quadracylhere (Hornibrookellina) hentyensis NMV PI 34975 Clifton Bank, Sample 3 (Middle subgen. et sp. nov. JRV ext. NMV PI 34985 Miocene) x 80 'Hentys' (early Middle Miocene) x 90 5. Spinobradleya nodosa sp. nov. JRV ext. NMV 2. Chapmanella flexicostata (Chapman, 1914) C P134976 Clifton Bank, Sample 10 (late Early ventral NMV PI 34986 Clifton Bank, Sample 4 Miocene) x 90 (Middle Miocene) x 80 6. Spinobradleya nodosa sp. nov. JRV ext. NMV 3. Chapmanella flexicoslata (Chapman, 1914) PI34977 Clifton Bank, int. Sample 10 (lale Early MRV NMV P 1 34987 Clifton Bank, Sample Miocene) x 120 4 (Middle Miocene) x 80 7. Bradleya (Bmdleya) praemackenziei Whatley 4. Chapmanella flexicostata (Chapman, 1914) and Downing, 1983 LV ext. NMV PI23369 JRV ext. NMV PI34988 'Hentys' (early Middle 'Hentys' (early Middle Miocene) x 75 Miocene) x 100 8. Bradleya (Bradleya) sp. cf. B. kineaidiana 5. Chapmanella flexicostata (Chapman, 1914) (Chapman, 1926) JRV ext. PI 34978 ext. NMV 'Hen- MRV NMV P 1 34989 Clifton Bank, Sample tys' (early Middle Miocene) x 90 tO (late Early Miocene) x 80 9. Bradleya (Bradleya) praemackenziei What ley 6. Chapmanella flexicostata (Chapman, 1914) and Downing, 1983 JLV cxt. NMV PI 34979 RV ext. NMV PI 34990 'Hentys' (early Middle Clifton Bank, Sample 7 (Early Middle Miocene) Miocene) x 80 x 65 7. Chapmanella flexicostata (Chapman, 1914) 10. Bradleya (Bradleya) sp. el". B. kineaidiana JMLV ext. NMV P12337I 'Hentys' (early Mid- (Chapman, 1926) RV ext NMV PI 23370 Clifton dle Miocene) x 130 Bank, Sample 10 (late Early Miocene) x 75 8. Chapmanella flexicostata (Chapman, 1914) RV ext. NMV PI3499I Clifton Bank, Sample Plate 9 (Middle Miocene) x 80 1. Bradleya (Bradleya) 9. 'Hcrmanitcs' sp. A MRV cxt. NMV thomasi sp. nov. FLV ext. NMV PI 23255 'Mentys' PI (early Middle Miocene) x 85 34992 Clifton Bank, Sample 10 (late Early 2. Bradleya (Quasihradleya) pyxos sp. nov Miocene) x 100 MRV ext. Holotype NMV PI 23257 Clifton 10. Spinobradleya nodosa sp. nov JLV ext Bank, Sample 10 (late Early Miocene) x 75 NMV PI 34993 Clifton Bank, Sample 4 (Middle 3. Bradleya (Quasibradleya) pyxos sp nov II V Miocene) x 100 ext. NMV PI 34980 'Hentys' (early Middle- Miocene) x 80 Plate 11 4. Quadraeydiere (Quadracylhere) spiea Hold- All figures I show detail of surface ornament at en, 1976 RLV ext. NMV PI3498I Clifton Bank, higher magnification.] Sample 3 (Middle Miocene) x 70 5. Quadraeydiere (Quadracylhere) spiea Hold- 1. Cletocythereis caudispinosa (Chapman and en, 1976 RV ext. NMV PI 23263 'Hentys' Crespin, (early 1928) NMV PI23327 'Hentys' (early Middle Miocene) x 65 Middle Miocene) x 400 6. Quadracxdiere (Quadracylhere) spiea 2. Hold .'Ponticocythereis sp. aff. P. nianis Whatley en, 1976 JLV ext. NMV PI 34982 Clifton Bank, and Titterton, 1981 NMV PI 232 17 'Hentys' Sample 10 (lale Early Miocene) x 80 (early Middle Miocene) x 375 7. Quadracylhere (Hornibrookellina) hentyensis 3. '/Dumontina cratis sp. nov. JMRV NMV subgen. el sp. nov. PLV ext. Holotype NMV PI 34948 Clifton Bank, Sample 4 (Middle P123260 'Hentys' (early Middle Miocene) x 65 Miocene) x 220 8. Quadracylhere (Hornibrookellina) hentvensis 4. Deltaleberis wamei sp. nov. NMV PI 23224 MIOCENE TRACHYLEBERIDIDAE AND HEMICYTHERIDAE 35

Clifton Bank, Sample 10 (late Early Miocene) x Bank, Sample 4 (Middle Miocene) x 675 400 3. Bradleya (Quasibradleya) pyxos sp. nov. 5. Idiocythere sp. cf. /. thalassea Detail of sub- NMV PI 34980 'Hentys' (early Middle Miocene) central tubercle area NMV P123361 Clifton x350 Bank, Sample 9 (late Early Miocene) x 250 4. Quadracythere (Hornibrookellina) hentyensis 6. ?Arculacythereis tatei sp. nov. NMV P 123266 subgen. et sp. nov. NMV P134985 'Hentys' Clifton Bank, Sample 10 (late Early Miocene) x (early Middle Miocene) x 350 800 5. Chapmanella flexicostata (Chapman, 1914) 7. ?Arculacythereis tatei sp. nov. NMV PI 34994 NMV PI 34994 'Hentys' (early Middle Miocene) Clifton Bank, Sample 10 (late Early Miocene) x x350 450 6. Chapmanella flexicostata (Chapman, 1914) 8. Alataleberis miocenica McKenzie and Warne, NMV PI 34988 Clifton Bank, Sample 4 (Middle 1986 NMV PI 34995 Clifton Bank, Sample 4 Miocene) x 350 (Middle Miocene) x 800 7. IPteroygocythereis sp. indet. LV ext. NMV P123362 'Hentys' (early Middle Miocene) x 120 Plate 12 8. Hemicytherid gen. et sp. indet. ?JLV ext.

1. Mackenzina foveolata gen. et sp. nov. NMV NMV PI 23365 Clifton Bank, Sample 7A (early PI 34961 'Hentys' (early Middle Miocene) x 350 Middle Miocene) x 160 2. Mackenzina foveolata gen. et sp. nov. JLV Plate 14 NMV PI 34961 'Hentys' (early Middle Miocene) xllOO Figures show muscle scar patterns, except where 3. Neobuntonia batesfordiense (Chapman, 1914) otherwise noted. NMV P123366 Clifton Bank, Sample 10 (late Early Miocene) x 350 1. ?Trachyleberis robustus (Yassini and Jones, 4. Hermanites glyphica sp. nov. NMV PI 23251 1987) NMV P123216x 160 'Hentys' (early Middle Miocene) x 225 2. 'Hemicxthere' lubrica sp. nov. NMV PI 23226 5. Hermanites glyphica sp. nov. NMV PI 34996 x300 'Hentys' (early Middle Miocene) x 600 3. 'Hemicythere' lubrica sp. nov. NMV PI 23227 6. Hermanites glyphica sp. nov. NMV PI 34997 x300 'Hentys' (early Middle Miocene) x 675 4. 'Hemicythere' tenuicostata sp. nov. NMV 7. 'Hermanites' thomasi sp. nov. NMV PI 34973 P123229x400 Clifton Bank, Sample 4 (Middle Miocene) x 800 5. Neobuntonia batesfordiense (Chapman, 1910) 8. 'Hermanites' thomasi sp. nov. NMV P134992 x200 Clifton Bank, Sample 4 (Middle Miocene) x 350 6. 'Hermanites' thomasi sp. nov. NMV PI 23242 x250 Plate 13 7. 'Hermanites' lungulata (McKenzie, Reyment and Reyment, 1991) NMV P123245 x 225 1 . 'Hermanites' thomasi sp. nov. Detail of sub- central tubercle NMV PI 34992 Clifton Bank, 8. Bradleya (Quasibradleya) pyxos sp. nov. Sample 4 (Middle Miocene) x 350 NMVP123257x275 9. Quadracythere (Hornibrookellina) hentyensis 2. Bradleya (Bradleya) praemackenziei Whatley ' and Downing, 1983 NMV PI 34993 Clifton subgen. et sp. nov. NMV PI 23260 x 200 36 JOHN V. NED-

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