PROC. R. SOC. VICT. vol. 99, no. 1, 37-50, March 1987

BRACHIOPODS FROM CARBONATE SANDS OF THE AUSTRALIAN SHELF

By J. R. R ichardson

Museum of Victoria, 285 Russell Street, Melbourne, Vic. 3000.

A bstract : Three new genera, Anakinetica and Parakinetica (Terebratulida, Terebratellidae, M agadinea) and Aulites (Rhynchonellida, Cryptoporidae), and 2 new species, Parakinetica stewarti and Magadinella mineuri, are described. All 5 species are found in biogenic sands of the Australian shelf and differ in their adaptations for life in these sediments. Magadinid species use the pedicle to move individuals so that a stable position at the sediment/water interface is maintained. The rhynchonellid is a sedentary form fixed by the pedicle to the undersurfaces of free-living bryozoan species. Magadinid species are the dominan t brachiopods in Australian shelf sediments in notewo rthy contrast to their absence in New Zealand and Antarctic shelf faunas.

Living brachiopods in southern seas are not confined SYSTEMATICS to rocky coastlines and reefs. In the A ntarctic and Suban- Superfamily Terebrate llacea King 1850 tarctic (Foster 1974) and in New Zealand (Richardso n Family Terebratellidae King 1850 1981a) they are the dom inant or co-dom inant m acroin ­ Subfamily M agadinae Davidson 1886 vertebrates in a variety of depositional environm en ts. Spe­ cies within the Subfamily Terebratellinae are the D iagnosis : Differentially thickened Terebratellidae with com m onest forms in Antarctic and New Zealand waters . permesothyrid foramen; cardinalia consisting of soc ket All occupy soft substrates, som e exclusively (Gyrothyris, ridges, crural bases, and a cardinal process with trefoil Neothyris), while others {Magasella, Waltonia) are oppor­ posterior surface; loop axial to teloform . tunistic and may live as either cliff hangers or bo ttom dwellers (Richardson 1981b). G enera I ncluded : Anakinetica n.gen.: Tertiary and Re­ Brachiopods are also common on soft substrates of cent, Australia (Terebratella C um ingii Davidson 1852). the A ustralian shelf and are of interest for the fo llowing Australiarcula Elliott 1959: Cretaceous, Australia (Aus- reasons: traliarcula artesiana Elliott 1959). 1. W ith one exception, they are members of a subfam ily M agadina Thom son 1915: Tertiary, New Zealand (M aga- (M agadinae) unknown in m odern seas in any other are a; dina browni Thom son 1915). 2. The four m agadinids and one rhynchonellid described M agadinella Thom son 1915 Tertiary and Recent, A ustra­ are specific to the bryozoan sands that are continu ous lia (M agadinella Woodsiana Tate 1880). along southern Australia (Wass, Conolly & McIntyre Magas Sowerby 1816: Cretaceous Europe (M agas pum i- 1970); and lus Sowerby 1816). 3. They display a variety of adaptations of the ped icle Parakinetica n.gen.: Tertiary and Recent, Australia which is related to the occupation of a soft substr atum . (Parakinetica stewarti n.sp.). Pirothyris Thom son 1927: Recent, Australia (M agasella vercoi Blochmann 1910). SOURCES OF MATERIAL Rhizothyris Thomson 1915: Tertiary, New Zealand Living individuals of all species studied were collected (Bouchardia rhizoida H utton 1905). from Bass Strait during a cruise on Tangaroa, a res earch Tanakura H atai 1936: Tertiary, Japan (Tanakura tanakura vessel of the New Zealand O ceanographic Institute (now H atai 1936). Division of M arine Research, Departm ent of Scientif ic Only those genera with species available for study have and Industrial Research). Samples from this cruise are held been placed under the heading “Genera Included”. by the Division in W ellington (Q register) and by t he However, inclusion of the genera that Elliott and H atai M useum of Victoria, M elbourne. Locality data for th ese (1965) attributed to this subfamily in the Treatise is not and other stations sam pled in Bass Strait are liste d by W il­ disputed. son & Poore (in press) — registration num bers of M u seum of Victoria material are prefixed NMVBSS. Dried and C omments : The only living species (from four genera) preserved m aterial has also been studied from the c ollec­ described from this subfamily are benthic and confi ned tions of the M useums of Western Australia (W AM), So uth to carbonate sands. The position of individuals at the sur­ Australia (SAM), the Australian M useum (AM ) and the face of soft sediments is m aintained by the pedicle sys­ British M useum of Natural History (BMNH). tem which is distinctive in character in each genus . The sediments from which all species were collected Diagnostic features of genera are the areas used fo r at­ have been described in the publications of Wass, Co nolly tachm ent of the dorsal adjustor muscles and details of and M cIntyre (1970), M arshall and Davies (1978), Jo nes the beak—its length and curvature and whether deltidial and Davies (1983) and Quilty (1985). plates are fused or discrete and the beak ridges sh arp or

37 38 J. R. RICHARDSON

rounded. No living species from the same genus co-e xist, C omments : The type species of M agadina is M. browni but sufficient Tertiary species have been collected to show from Waipara, New Zealand. In this and other New the characters that differentiate species. Three sp ecies in­ Zealand species attributed to M agadina, components of cluded in Anakinetica (from Recent seas, Miocene & the cardinalia are not fused together to form a solid plat­ Oligocene deposits) differ in shell outline, in deg ree of form , the cardinal process is not swollen, and a de ep hinge convexity of the valves, and in the shape and relative size trough separates the crural bases. Thomson noted th e of the area occupied by the cardinal platform . The differ­ difference between the two groups of species — “Car dinal ences are slight but consistent and are easily iden tifiable. process in primitive species (genotype) small but c onfined O ther fossil species attributed to Anakinetica display an to the um bonal end of the hinge-trough, in advanced spe­ incurved beak and heavy posterior thickening, and s econ­ cies (M cumingi) large and swollen com pletely filling the dary loss of the pedicle may be inferred from these hinge trough” (1927, p. 275). Growth stages of A. cumingi characters. described below indicate that the crural bases also con­ Some of the genera (Australiarcula, Rhizothyris, tribute to filling the hinge trough—they fuse media lly with Tanakura) described from fossil species are similar in each other and with the anterior surface of the car dinal character to Anakinetica and Parakinetica, i.e., with a process. solid cardinal platform without a hinge trough and with Anakinetica includes one living species and three Ter­ attachm ent areas of the dorsal adjustor muscles in the tiary species form erly included in M agadina—Terebratula posterior position indicating ratchet-like movement s of compta Sowerby 1845 (Oligocene-M iocene), Terebratella a free pedicle. Australiarcula artesiana was described from tenisoni Tenison-W oods 1865 (Oligocene-M iocene), and glauconitic sands of the Great A rtesian Basin (Elliott 1959, M agasella deform is Tate 1880 (Upper Eocene). In addi­ Parkin 1969), Tanakura tanakura from coarse-grained tion, collections m ade from Beaum aris, Victoria (U. M i­ sandstones in Japanese M iocene deposits, and num ero us ocene) and from the Jandakot Bores in W estern Austr alia species of Rhizothyris occur in greensands and bryozoan (Pleistocene) show that m embers of the genus were a com ­ calcarenites of the New Zealand Tertiary (Thom son 1915, m on com ponent of Australian shelf faunas during the Ter­ Allan 1960, Bowen & Campbell 1973). tiary. Characters that separate species are adult loop stage, The non-terrigenous character of the sediments oc­ configuration of the cardinal platform , and details of the cupied by members of the subfamily is noteworthy. A ll beak. living species have been collected from bryozoan sa nds Anakinetica cumingi (Davidson 1852) while m embers of fossil genera have been described from Fig. 1 chalks, calcarenites and greensands. It is not possible to define any ancestor/descendan t Terebratella (?) Cum ingii: Davidson 1852a, p. 78, pi. 14, relationships in different genera because all are s pecia­ figs 10-16. lised for benthic life in a particular type of sediment. Com­ Terebratella (?) Cumingii: Davidson 1852b, p. 368. parison with the subfam ily Bouchardiinae illustrate s this Terebratula (Bouchardia) Cumingii: Reeve 1861a, pi. 8, point. The latter family contains four genera, thre e (Ne- fig. 30. obouchardia, Bouchardia, Bouchardiella) specialised for Terebratula (Bouchardia) Cumingii: Reeve 1861b, p. 179. life in biogenic sands, one (M alleia) with characters as­ Terebratula (Bouchardia) fibula: Reeve 1861b, p. 180. sociated with a sedentary life style (Richardson 1973) and M agasella Cumingii: Dali 1870, p. 137. so it is possible to differentiate characters assoc iated with M agasella (?) cumingi: Davidson 1880, p. 18. life style from those that suggest com m on ancestry, e.g., M agasella Cumingi: Davidson 1886, pp. 97-99, pi. 17, figs the shape of the cardinal process and the absence o f crural 23-32. bases. The trefoil shape of the cardinal process of the M agasella cumingi: Verco & Blockmann 1910, p. 97. M agadinae is probably a familial character but cann ot be M agadina cumingi: Thom son 1915, p. 400, fig. 12. confirm ed as such in the absence of genera that occ upy M agadina cumingi: Thom son 1927, pp. 275-277. different substrates and follow a different life style. M agadina cumingi: Cooper 1973, p. 30, pi. 5, figs 39-42. M agadina cumingi: Richardson & W atson 1975a, pp. 381- Genus Anakinetica gen. nov. 382, fig. 1. M agadina cumingi: Richardson & W atson 1975b, pp. 379- E tymology : From the Greek ana (up) kineticos (moving). 387, figs 1-7. IY pe S pecies : Terebratella (?) C um ingii Davidson 1852. M agadina cumingi: Richardson 1979, pp. 415-417, 424- 428, 432, figs 2, 3, 12. D iagnosis: Beak large, suberect to nearly straight; deltidial M agadina cumingi: M ineur & Richardson 1984, pp. 327- plates fused, wide, flat; cardinal m argin straight or nearly 334, figs 1-2. straight. Cardinal platform with posterior pits for attach­ ment of the dorsal adjustor muscles. Loop annular t o TVpe L oca lity : Port Jackson Heads, N.S.W. trabecular.

TYpes : Davidson Collection, British M useum (Natural G eologic O ccurrence : Eocene to Recent. History). L oca lity : Australia. O ccurrence : M edium to coarse carbonate sands, Aus­ tralian shelf, between latitudes 31° and 39°S, long itudes 113° to 154°E, depths of 22-155 m. Stations NMVBSS BRACHIOPODS FROM CARBONATE SANDS 39

53, 59, 80-1, 118, 120, 161-2, 164, 166, 171, 173, 179, 183, the crural bases are fused medially and with the an terior 185-6, 189, 192-3, 199-206, 220; SAM 4862; W AM 19-71, (sm ooth) surface of the cardinal process. Two pits are thus 74-71, 77-71, 88-72, 272-86, 273-86, 274-86, 291-86 , 306- cut off on either side of the cardinal process; the y are 86, 317-86, 346-86. bounded posteriorly by the m edian borders of the so cket ridges and anteriorly by the posterior borders of the crural C omments : Davidson (1852a) described Terebratella (?) bases. Between the cardinal platform and the elevated me­ Cumingii from two specimens which were believed to have dian septum, the m edian region of the valve floor is thick­ been collected in New Zealand waters. In the Challe nger ened as a rounded elevation. Crural processes exten d from Reports (1880) Davidson recorded M agasella (?) cum ingi the crura and rudim ents of the descending branches from from Port Jackson Heads, New South Wales, and in 1886 the septum. he confirm ed its occurrence in Port Jackson and sta ted At 4.5 mm dorsal valve length, the crural bases are that when first described “only two dead specimens were fused medially, the m edian line of fusion being vis ible an­ known in this country (England) and their habitat w as teriorly but not posteriorly. The shallow grooves w hich uncertain.” (p. 98). Davidson (1886) also considere d m arked the lines of fusion of the socket ridges and crural Terebratula (Bouchardia) fibula o f Reeve, collected in Bass bases are no longer visible but a new pair of groov es is Strait, to be synonymous with A. cumingi. Reeve (1861) evident on the surface of the now solid cardinal pl atform . stated that Terebratula (Bouchardia) fibula differed from These grooves run from the anterior borders of the pits A. cumingi in possessing a flat deltidium whereas the del- flanking the cardinal process and converge slightly anteri­ tidium of A. cumingi is excavately grooved. As Davidson orly. The descending branches are complete, and the (1886, p. 98) points o u t-“The area in M. Cumingi is, it lamellae extending from the crest of the septum are is true, usually excavated or concave, but in some exam­ discrete. ples it is alm ost flat, and upon that slight appare nt differ­ The adult form results from further fusion and thic k­ ence it would not be right, I think, to record it a s a separate ening of the cardinalia so that the anterior border of the species.” platform is straight and not indented. The median s ep­ Specimens collected in Bass Strait, Victoria were u sed tum has merged indistinguishably with the m edian th ick­ for the photographs in Fig. 1. This material has be en com­ ening of the valve floor, and has grown in an anter ior and pared with Davidson’s specimens (in the British M us eum, ventral direction so that the lam ellae lie not on t he septal N atural History), and other specimens collected in Port crest but on its posteriorly facing slope. The adul t loop Jackson, N.S.W., and they are considered to be con- of A. cumingi is characteristically annular but in old speci­ specific. The illustrations of the loop (pi. 17, figs. 30 and mens the lines of attachm ent of the descending bran ches 31) in Davidson’s paper of 1886 are inaccurate. The two may coalesce giving the haptoid type of loop. curved lam ellae (which fuse to form the ring) are d epicted with their lines of attachm ent on the sides of the septum Genus Parakinetica gen. nov. a short distance below its crest. In all specim ens observed by the author, both the lamellae and the ring lie f lush with E tymology : From the Greek para (sideways) kineticos the crest of the septum, a condition also illustrated by (moving). D avidson (1852, pi. 14, fig. 15) in his original de scription Type S pecies : Parakinetica steward, new species. of the species. This difference in Davidson’s two p apers may be accounted for by the fact that Davidson hims elf D iagnosis : Beak small, straight; deltidial plates disjunct. was the lithographer of the illustrations in his pa per of Cardinal platform with posterior pits for the attac hm ent 1852, but not in the paper of 1886 that was publish ed of dorsal adjustor muscles. Loop annular. posthum ously. G eologic O ccurrence : Recent. The lophophore, pedicle, muscles and other soft str uc­ tures and their relationship to hard parts are desc ribed L oca lity : Australia. in detail in Richardson and W atson (1975b) and M ine ur C omments : The characters separating Parakinetica from and Richardson (1984). The distinctive cardinal pla tform other members of the subfamily are beak form and sh ell of adults of A. cumingi (Fig. 1G, J) is derived from the shape. The beck is short with disjunct deltidial plates and fusion of socket ridges, crural bases, and the post erior the shell is plano-convex. D eltidial plates are fus ed in all surface of the cardinal process and stages in this process other genera attributed to this subfamily. are described below. Similarities in the cardinalia of Anakinetica and

G rowth S equence : A t 3 m m dorsal valve length the Parakinetica show that, in each genus, dorsal adjustor various com ponents of the cardinalia can be disting uished muscles are used to push the pedicle into the surro und­ on the thickened posterior region of the valve (Fig . 1H). ing sediments. However, although the same movements The socket ridges converge posteriorly to fuse with the enable individuals to surface in carbonate sands, d iffer­ lateral borders of a bowl-shaped cardinal process. The ences in the grades of sands they occupy are eviden t from crura are visible and their swollen bases are disti nguisha­ the processes of the pedicle; in Anakinetica they are short, ble from the socket ridges by shallow grooves. Medially, stout and term inal, in Parakinetica relatively long and a deep hinge trough extends for alm ost the full len gth of slender and scattered along the distal portion of the shaft. the cardinal platform . A high median septum bearing two Differences in the disposition of the processes are evident curved lamellae is restricted to the m id-region of the valve. in the fused deltidial plates of Anakinetica and the dis­ A t 3.5 mm dorsal valve length, the posterior lim its of junct plates of Parakinetica. 40 J. R. RICHARDSON

A number of collections from Australian Janjukian Genus Magadinella Thomson, 1915 (Late Oligocene) deposits include individuals with the di­ TYpe S pecies : M agasella Woodsiana Tate 1880. agnostic characters of this genus. D ia gnosis : Beak erect to nearly straight; deltidial plates Parakinetica stewarti sp. nov. fused, wide; cardinal platform with posterior hinge trough Figs. 2, 3 bordered anteriorly by short, solid hinge plates. L oop hap- toid to teloform . The species is nam ed after Mr. Ian Stewart in recog ­ nition of his assistance in num erous brachiopod pro jects. G eologic O ccurrence : Tertiary and Recent.

D escr iption : Pale grey to white. M aximum observed L oca lity : Australia. length 6.5 mm, breadth 6.0 mm, depth 3.0 mm. Dorsal C omments : The genus M agadinella was erected by Thom ­ outline broadly ovate; plano-convex, dorsal valve w ith pair son (1915) for M. woodsiana on the basis of differences of posterior ridges converging at the um bo, ventral valve in outline, cardinal margin, and stage of loop deve lop­ carinate. A nterior com missure sulcate; lateral comm issures m ent from those species attributed by him to M agadina. sinuate; cardinal m argin slightly curved, tapering to a m e­ The hinge trough, used for attachm ent of dorsal adj us­ dian point. Beak straight, deltidial plates disjunc t. tor muscles, distinguishes M agadinella from Anakinet­ D orsal valve interior with well-m arked pallial sinu ses ica and Parakinetica. Size, shape and folding differentiate and adductor muscle impressions; lateral transverse ridges M agadinella from Pirothyris, the only other Recent Aus­ separating posterior thickened area containing sock ets and tralian genus with a hinge trough. cardinal platform. Cardinalia with thick, posterior ly- The type species was described from Janjukian- convergent, socket ridges, fused medially with crur al bases; Batesfordian (L. Oligocene-M iocene) calcarenites, a nd crural bases occupying central area of platform , fu sed other collections from sim ilar deposits show that t he ge­ posteriorly with anterior surface of cardinal proce ss, form ­ nus is well represented in the Tertiary. ing anterior borders of deep circular pits for atta chm ent to dorsal adjustor muscles; cardinal process with p osterior Magadinella mineuri sp. nov. surface, striated, triple-faceted with lateral wing s diverg­ Fig. 4 ing from flat dorsal base. M edian septum high anter iorly, alm ost touching ventral valve, gradually tapering p osteri­ The species is nam ed after M r. Rudi M ineur in recog ­ orly to term inate as low ridge at anterior border o f cardi­ nition of his assistance in num erous brachiopod pro jects. nal platform . Loop annular. D escr iption : Shell white to salm on-pink to red, rarely Ventral valve slightly thickened posteriorly. H inge teeth white with longitudinal red stripes. M aximum observ ed thick, with subquadrate outline overhanging grooves for length 21 mm, width 15 m m , depth 10 mm. Outline nar ­ socket ridges. M edian ridge low, running from point just rowly ovate to ovate; biconvex, the ventral valve d eeper anterior of cardinal margin to anterior margin of v alve. and carinate. A nterior commissure sulcate; lateral com­ M uscle scars not impressed. missures sinuate; cardinal m argin strongly curved. Beak Pedicle inert, total length approximately half shell erect to nearly straight; deltidial plates fused; b eak ridges length, with slender processes extending from dorsa l sur­ rounded. face of posterior one third of length of shaft, pro xim al Dorsal valve interior with prom inent adductor m us­ process occupying gap separating deltidial plates w hen cle impressions extending from cardinal platform to an­ pedicle retracted. Pedicle muscles as for Anakinetica terior tip of septum. Cardinalia with posteriorly- cumingi. convergent socket ridges, not projecting beyond valve m ar­

TYpe L oca lity : NM VBSS 81-HKI-121, latitude 39° 01.0'S, gin, their anterior segments fused medially with cr ural longitude 143° 15.4'E, 82 m, fine sand. bases; hinge trough wide posteriorly in area border ed by socket ridges, narrow and shallow in anterior area bor­ TYpes : Holotype NMVF52910; paratypes NMVF dered by crural bases; cardinal process variable in size. 52911-19 M edian septum blade-like, slightly higher anteriorly than

O ccurrence : Fine carbonate sands of western Bass posteriorly. Loop trabecular. Strait, between latitudes, 38°48' to 39°26'S, longitudes Ventral valve interior thickened posteriorly; beak cavity 143 °06' to 143°49'E, depths 77 to 115 m. Stations - filled except for tunnel leading to foramen. Hinge teeth NMVBSS 48, 49, 55, 80, 119, 162, 184, 194. long, extending full widths of margins of palintrop es.

Fig. 1— Anakinetica cumingi: A-G, ventral interior, ventral, lateral, dorsal, p osterior, anterior and dorsal interior views of the shell. H, dorsal interior of posterior region of juvenile shell before fustion o f the crural bases with the anterior surface of the cardinal process (scanning electron micrograph). I, diag ram­ matic longitudinal section to show pedicle system a nd adductor and diductor muscles. J, outline diagram of cardinalia showing areas of muscle attachment of diductors (horizontal stipple) to the posterior su rface of the cardinal process and of the dorsal adjustors (diagonal stipple) to areas flanking the anterior surface of the cardinal process. K, reconstruction of a liv ing individual in medium bryozoan sands. Bar scale = 1 mm BRACHIOPODS FROM CARBONATE SANDS

BRACHIOPODS FROM CARBONATE SANDS 43

Fig. 3 — Parakinetica stewarti: Distal ends of pedicles of 2 individuals illustrating in A the grain of sedi­ ment used for larval bonding at the end of one proc ess and B a later stage of development in which the processes are free of substrate. Growth lines are v isible at regular intervals along the lengths of th e processes. C, scanning electron micrograph of the loop and lop hophore. Bar scale =1 mm

Socket ridge articulating surfaces, shallow grooves under­ shell. Sedentary populations of L. neozealanica differ lying hinge teeth. D iductor muscle scars well-marke d, ex­ from the terebratellid and rhynchonellid species ob served tending anteriorly to at least half the length of v alve. in the same area (Richardson 1981a) in that individ uals are suspended by the pedicle. Thus they can occupy only TYpe L oca lity : NMVBSS175, 39°06'S, 147°26'E, 63 m, the under-surfaces of rocks not their vertical or u pper sandy shell. faces as do the terebratellids that lie on these su rfaces.

TYpes : Holotype NMVF52920; paratypes 52921-4. Pirothyris differs from other living m agadinids in that adults display a variety of substrate relationships as a result O ccurrence : Bass Strait, V ictoria (BSS 154, 173, 174, of variability in the length of the pedicle and the size of 175, 186, 199, 203, 204) between latitudes 38° to 4 0°S, substrates used for settlement. Differences in pedicle longitudes 143-148°E, depth 49 to 82 m. length are not evident in hard structures. In both M agadinella and Pirothyris the dorsal adjus­ Genus Pirothyris Thomson, 1927 tor muscles are attached to a hinge trough which is bor­

TYpe Species: M agasella vercoi Blochmann, 1910. dered anteriorly by solid hinge plates. These two g enera are also sim ilar in the absence of well-defined pal intropes D ia gnosis : Uniplicate. Beak suberect; deltidial plates and of beak ridges and in the strong convexity of t he fused. Cardinal platform with a posterior hinge tro ugh valves. However, the fact that depth is greater tha n width and solid anterior hinge plates. Loop haptoid. in P. vercoi m eans that the shell of this species rests on

G eologic O ccurrence : Recent. its side whereas that of M. mineuri rests on either valve.

L oca lity : Australia. Pirothyris vercoi Blochmann 1910 Com m ents: Pirothyris is the only terebratellid genus Fig. 5 known with uniplicate folding and a shell in which depth is greater than width. In other genera, width is gr eater M agasella vercoi: Blochm ann 1910, pp. 91, 92, 98, pi. 27, than depth so that a shell rests on the dorsal or v entral figs 1-5. valve in contrast with shells of P. vercoi that lie on either Pirothyris vercoi: Thom son 1927, pp. 280-1, figs 94 a-c. side. O ther living brachiopods with a similar depth /w idth Pirothyris vercoi: Richardson 1975, pp. 197-205, pi. 15, relationship are members of the Terebratulacea. One ex­ figs 1-7. am ple is Liothyrella neozealanica which is also uniplicate TYpe L oca lity : Backstairs Passage, S.A. in folding. At present, this association of charact ers ap­ pears to be related to different orientations of th e resting TYpes : South Australian M useum, Adelaide, S.A.

Fig. 2 -Parakinetica stewarti: A, outline diagram of cardinalia showing areas of muscle attachm ent of the diductors (horizontal stipple) to the posterior surface of the cardinal process and of the dorsal adjus­ tors (diagonal stipple) to areas flanking the anter ior surface of the cardinal process. B, diagram m ati c lon­ gitudinal section to show pedicle system and adduct or and diductor muscles. C-I, dorsal, ventral, dors al interior, ventral interior, lateral, anterior and p osterior views of the shell (scanning electron m icr ographs). J, reconstruction of living individuals in fine bry ozoan sands —inset diagram s showing pedicle movemen t. Bar scale = 1 mm 44 J. R. RICHARDSON BRACHIOPODS FROM CARBONATE SANDS 45

O ccurrence : Verco’s (1910) records give a num ber of lo­ The species has been re-described because previous ac­ calities in South A ustralian waters at depths of 22 to 300 counts do not include diagnostic characters or desc rip­ m with the observation that the largest collections were tions of soft parts. m ade in Backstairs Passage at depths of 30 to 44 m. Col­ lections identified by the author from Bass Strait (BSS Aulites brazieri (Crane, 1886) 120, 183, 188, 192, 200, 203), and South Australia (Port Fig. 6 Sinclair and Pearson Island), represent a range of latitudes Atretia brazieri: Crane 1886, pp. 183-4. 32° to 40°S, longitudes 133° to 144°E, depths of 48 to Cryptopora brazieri: Hedley 1906, p. 467, pi. 36, figs 1-2. 85 m, on medium sand. Cryptopora brazieri: Cooper 1959, p. 18.

Superfam ily R hynchonellacea Gray 1848 D escr iption : Shell im punctate, white, sm ooth, delicate, Family C ryptoporidae M uir-W ood 1955 translucent, with faint radial lines. M aximum obser ved Genus Aulites gen. nov. length 2.9 mm, breadth 1.95 mm, depth 1.0 mm. Dorsa l outline pyriform with pointed apex. Unequally bicon vex, E tymology : Aulites Gk. m .=tent dweller. the ventral valve deeper, dorsal valve with two rid ges con­

Ty pe S pecies : Atretia brazieri Crane 1886. verging at umbo. Anterior commissure rectimarginate ; lateral commissures straight; cardinal margin sligh tly D iagnosis : Rectimarginate to uniplicate Cryptoporidae curved. Beak erect; deltidial plates discrete, narr ow, m ar­ with outer hinge plates and without dental plates. ginal; foram en subapical, triangular; beak ridges s harp.

G eologic O ccurrence : Late Oligocene and Recent. D orsal interior with socket ridges, short, widely s epa­ rated. O uter hinge plates shelf-like, extending fro m dorso- L oca lity : A ustralia. medial borders of socket ridges, anteriorly continu ous C omments : W ith the transference of A ulites brazieri from with crura. Paired thickenings, semi-circular in ou tline, Cryptopora, the Family Cryptoporidae now contains two occupying shell border between posterior extremitie s of genera. They differ from all other Recent rhynchone llids socket ridges. A dductor muscle impressions wide, al m ost in beak characters (narrow, m arginal deltidial plates bor­ circular, area with anterior border just posterior to an­ dering the delthyrium), crura (maniculifer), cardin al terior limit of septum. process (bilobate thickening), and in the median se ptum Ventral interior with low m edian ridge in central r egion (high). M embers of the family in which soft parts a re of valve. Pedicle collar incomplete, lining apex of valve known possess two pairs of adductor muscles and one pair interior, merging walls just posterior borders of h inge of m etanephridia, while one pair of adductors and two teeth. M uscle impressions not visible. pairs of m etanephridia characterise the m embers of other Lophophore spirolophous. Intestine straight, withou t rhynchonellid families. distal enlargement. M etanephridia one pair. Gonads Aulites brazieri is distinguished from species attributed reticulate. to Cryptopora by the absence of dental plates and the A dductor muscles two pairs, each with paired attach ­ presence of hinge plates. O ther consistent differen ces are ments to dorsal valve and single attachm ent to ventral the larger foram en and narrower palintropes of the Aus­ valve; posterior adductors attached to area of dors al valve tralian species — external features associated inte rnally with between bases of socket ridges and posterior limit of sep­ widely separated socket ridges and curved, not stra ight, tum , ventrally to mid-region of ventral valve in an area crura. Since Aulites is a m onotypic genus, the features at the level of the hinge teeth; anterior adductors with that discriminate between species and genera are broadly ovate attachm ents flanking median septum an d unknown. However, it is probable that the presence or ab­ term inating ventrally in m id-line of ventral valve anterior sence of structures is m ore likely to separate gene ra than to posterior adductors. D iductor muscles paired, ex tend­ differences in the relative proportions of structur es such ing anteriorly to mid-region of valve; posteriorly the ter­ as foramen and socket ridges which are likely species minations of the paired muscles united by connectiv e differentiators. tissue with the muscular tissue attached to paired thick­ Species of Cryptopora are found in m ost seas and at enings on the valve’s posterior border and connective tis­ m ost depths —in abyssal as well as shallow waters. Au­ sue to the area between the thickenings. lites brazieri is the only living species found in A ustralia Pedicle short with chitinous coat, attached to subs trate and is also the only species within the family in w hich close to foramen. Dorsal adjustor muscles thin, rib bon­ distribution in relation to sediment is known. Living in­ like bands, running from lateral faces of the pedic le to dividuals are sedentary in habit and have been foun d only junctions of the outer hinge plates and socket ridg es; ven­ on the under-surfaces of species of free-living Bry ozoa. tral adjustors extending from proximal end of pedic le

Fig. 4 —Magadinella mineuri: A-E, lateral, anterior, posterior, dorsal, and ven tral views of a shell. F, dor­ sal view of a shell with colour markings. G, ventral interior. H, diagrammatic longitudinal section to show pedicle system and adductor and diductor muscles. I, dorsal interior. J, outline diagram of cardinalia showing areas of muscle attachment of the diductors (horizo ntal stipple) to the posterior surface of the cardinal process (diagonal stipple) and of the dorsal adjustors (diagonal stipple) to the hinge trough underlying the anterior surface of the cardinal process. K, reconstruction of living individuals in coarse bryozoan sands. Bar scale = 1 mm 46 J. R. RICHARDSON flanking adductor muscles, with attachm ents posteri or to P edicles : O f the soft parts, only the pedicle system differs diductor muscles. in each of the four species, in the form of the ped icle and in the position of the muscles. In all species it is defined Type Loca lity : Port Stephens, N.S.W., at 25 fathoms, as “inert” (Richardson 1979), i.e., com posed of a thick sandy mud. chitinous coat enclosing a fibrous core. Adults of two of TVpes : Davidson Collection, BM NH. the species (Pirothyris vercoi and M agadinella mineuri) studied retain the substrate used for larval settle m ent. In O ccurrence : Janjukian (late Oligocene) M allee Bore II, two others (Anakinetica cumingi and Parakinetica 430' to 432'. Recent —NM VBSS 121, 194, both fine sa nd. stewarti) it is outgrow n at an early stage of developm ent, WAM 290-86, 292-86, 293-86, 299-86, 301-86, 306-86. and the pedicle is free with chitinous processes fr inging Queensland —M ast Head Island. its distal end. Either three (in P. vercoi and M. mineuri) The shells of Aulites brazieri have been collected from or four (in A. cumingi and P. stewarti) pairs of pedicle depths of 34 to 228 m off the eastern, southern, an d muscles connect the head of the pedicle with the sh ell. western Australian coasts, i.e. between latitudes o f approx­ The position of the ventral adjustors is sim ilar in all spe­ im ately 23° & 39°S and longitudes of 113° to 154°E. Col­ cies, and their contractions pull the pedicle into the shell. lections from Bass Strait, Victoria, have shown tha t living The action of the dorsal adjustor muscles differs a ccord­ individuals are found only on free-living bryozoans which ing to the areas of the cardinalia used for their a ttach­ are the dom inant living organisms in sands collecte d from m ent. A posterior position, in pits flanking the ca rdinal the Bass Strait stations listed above. Samples from these process as in A. cumingi, means that these muscles are stations contain at least fifteen free-living bryoz oan spe­ more or less parallel to the pedicle and so contrac tions cies (P. Bock, pers. comm.) and A . brazieri was found will extrude the pedicle. In these species the m edian pedicle attached to Selenaria maculata and Lunulites capulus. The muscles are long, thin, and contractile and their c ontrac­ only other record of living specimens by Hedley (19 06), tions assist in the extrusion of the pedicle. Contr actions also notes their presence on the undersurfaces of of dorsal adjustor muscles that are attached to reg ions bryozoans but with no record of the sediment sample d. of the cardinalia anterior to the cardinal process (the hinge C omments : Cooper (1959) suggested that the M iocene spe­ trough or plates) result in rotation of the pedicle . W ith cies Terebratella acutirostra Chapm an may be a synonym adjustors in this position, the m edian pedicle musc les are of Aulites brazieri and study of the holotype, the only short and fibrous and they hold the pedicle in posi tion specimen, confirm s that, in external features at le ast, it during contraction of the dorsal adjustors. is indistinguishable from A ulites brazieri. M ovement : Parakinetica stewarti moves in similar fashion to Anakinetica cumingi by the ratchet-like action of a free FUNCTIONAL MORPHOLOGY pedicle (Figs 1, 2). However, although the muscles, their All the species described were collected live, but from position, and their actions are sim ilar in each spe cies the depths (55-120 m) that prevented in situ studies. Conse­ direction of movement of individuals differs in eac h be­ quently, the behaviour of individuals was observed in cause they also differ in shell shape. P. stew arti is subcir­ aquaria in the sediments in which they were collected. It cular in outline with a flat dorsal valve and a sho rt beak is assumed that the movements of individuals would be and contractions of the muscles result in movements that similar in laboratory conditions to those in natura l sur­ are roughly parallel with the surface of the sedim e nt. The roundings although their am plitude and frequency wo uld same movements in A. cumingi, which is biconvex and probably differ. ovate, result in movement of the shell in an upward and Com parative anatomical studies of the four m agadinid forward direction. In P. stewarti, the pedicle processes are species showed that no differences are apparent in the long and slender and extend from the lateral and do rsal form and disposition of nephridia, gonads, gut, dig estive surfaces of the distal portion of the pedicle. Diff erences diverticula, or of the circulatory system as described in in the length and position of the processes in thes e two detail for one species, Anakinetica cumingi, by Richard­ species are linked with activity in sediments of different son & W atson (1975b). The lophophore is plectolopho us grain size. The short, thick, closely-spaced proces ses of in all and differences in the extent of coiling of the spiral A. cumingi are associated with movement in m edium to arm can be related to size, relative to total shell space, of coarse bryozoan sands, the long, thin processes of P. the m antle cavity (Richardson & W atson 1975b). A ddu c­ stewarti with that in fine sands. tor and diductor muscles are inserted on the same s ur­ Collections of young individuals of Parakinetica faces and occupy the same position relative to othe r stewarti show that larvae settle on fragments that com ­ structures. prise the sands occupied by adults. The pedicles of in-

Fig. 5 — Pirothyris vercoi: A-F, ventral, dorsal, ventral interior, posterior, lateral, anterior views of shells. G, scanning electron micrograph of dorsal interior. H-J, 3 individuals with pedicles of different leng ths, each bonded with fragments of bryozoan colonies. K, outline diagram of cardinalia showing area of mus­ cle attachment of the diductors (horizontal stipple) to the posterior surface of the cardinal process and of the dorsal adjustors (diagonal stipple) to the h inge trough underlying the anterior surface of the cardi­ nal process. L, diagrammatic longitudinal section to show pedicle system and adductor and diductor mus ­ cles. M, reconstruction of living individuals in me dium bryozoan sands. Bar scale = 1 mm BRACHIOPODS FROM CARBONATE SANDS 47 48 J. R. RICHARDSON BRACHIOPODS FROM CARBONATE SANDS 49 dividuals with a shell length of 1.5 mm display only two in the movements of individuals. Three pairs of mus cles or three processes (Fig. 3A) with a fragment bonded to extend from the head of the pedicle—ventral adjusto rs the tip of the pedicle’s central shaft. That is, th e tip of and m edian pedicles to the ventral valve, dorsal ad justors the pedicle retains the fragm ent used for larval se ttlem ent. to the hinge trough in the dorsal valve. Contractio ns of Fragm ents have not been observed on the pedicles of m ost the dorsal adjustor muscles together with the shell shape individuals larger than 1.5 mm. However, in those i n­ characteristic of this species (depth greater than width) stances in which the fragm ent is retained, it is no t fixed result in rolling m ovem ents irrespective of pedicle length. to the pedicle tip but appears as a ring around its shaft. A short stalk combined with substrate of mass equal to The pedicle tip has apparently grown through and be yond or less than the organism results in alternate or s equen­ the original site of bonding and disintegration and loss tial movements of the shell and stalk that are also charac­ of the fragm ent occurs with growth. It is presumed that, teristic of M agadinella mineuri. Individuals with long as soon as the pedicle muscles operate as observed in pedicles have been observed to be bonded only with rela­ adults, the larval substrate is not needed and coul d be an tively large masses. In these individuals contracti ons of encumbrance to movements of the pedicle. It is em­ the dorsal adjustor muscles cause the shell to roll from phasised that the bonded substrate is not lost by a ccident side to side in response to sediment or water movem ents. but by active growth, i.e., by progressive chitinis ation visi­ C haracters associated w ith habitat and l ife ble as growth rings on the shaft and its processes (Fig. 3b). style : The movements that characterise the magadinid M agadinella mineuri appears to be confined to coarse species result from differences in the position of the dor­ bryozoan sands in which larger fragments may approx i­ sal adjustor muscles, in the form of the pedicle an d its m ate the mass of adult organisms (Fig. 4). The subs trate processes, and in shell shape. Differences in muscle posi­ is fixed perm anently to the tip of the pedicle whic h is in­ tion and pedicle type are clearly reflected in the cardina­ variably short. Three pairs of muscles extend from the lia and beak. The position of the dorsal adjustor m uscles head of the pedicle—ventral and dorsal adjustors an d ven­ determ ines types of movement — attachm ent to pits in the tral m edian pedicle muscles. The dorsal adjustors a re at­ posterior region of the platform shows that contrac tions tached to the floor of the hinge trough. extrude the pedicle, while insertions to the floor of the The living individuals displayed little m ovem ent wh en hinge trough indicate twisting movements. The posit ion placed on the surface of sediments in aquaria. Howe ver, of the shell in relation to the sedim ent is evident from the if they were covered with loose sediment, movements of beak ridges —sharp ridges show that the posterior e nd of either or both the shell and the pedicle with its b onded the shell is the leading edge in movements within t he sedi­ substrate would work the organism to the surface. S edi­ m ent, while rotating or rolling movements are chara cteris­ m ent on the shell results in contractions of the pe dicle tic of species with rounded beak ridges. Deltidial plates muscles, which connect the shell with the pedicle a nd its are fused in species in which pedicle processes are restricted substrate, and contractions of these muscles will twist the to the tip of the pedicle (whether free or bonded), del­ lighter of the two bodies (shell or substrate). In an inert tidial plates are discrete in those in which proces ses are m edium (sediment) alternate or successive movements of distributed along the shaft. either shell or substrate give the organism a surfa cing ac­ O ther characters that may be associated with habita t tion. The capacity to twist appears to be an im port ant and life style are size and the absence of ornam ent or attribute in this species with its short pedicle an d consis­ epibionts. Occupation of shifting sediments (Richar dson tently close connection with bonded substrates. As a con­ & W atson 1975a) requires continual adjustm ent so th at sequence, the dorsal adjustor muscles are strong bu t the individuals occupy a stable position to feed at the sedi­ size of all muscles indicates a high level of activ ity. The m ent/w ater interface. The mobility of these forms a ppar­ m edian pedicle muscles in sedentary or opportunisti c spe­ ently inhibits the growth of epibionts that are so common cies consist of fibrous, non-contractile tissue whe reas pink, on the shells of members of sedentary populations ( Do­ contractile tissue is a m ajor com ponent in M . mineuri. herty 1979). M embers of sedentary populations also form Pirothyris vercoi occupies m edium to coarse bryozoan the principal settling surfaces for larvae (W isely 1969). sands and individuals are bonded throughout life with However, no m em ber of any m agadinid species has bee n fragments of varied mass and shape (Fig. 5). The processes collected with any brachiopod attached to the shell. The that bond the pedicle to carbonate surfaces are not visi­ pedicles of the smallest shells collected are invar iably ble to the naked eye. The flexible pedicle also var ies in bonded with grains of sediment. The larvae may thus ex­ length, it may be very short or approxim ately half the to­ hibit preferential settlem ent, or they m ay settle a t random tal length of the shell. Variation in both pedicle length but fail to survive on surfaces other than the roug hened and the mass of bonded substrate results in differe nces grains that predominate in the sediments they occup y.

Fig. 6 —Aulites brazieri: A-G, scanning electron micrographs of dorsal, ventral, ventral interior, dorsal in­ terior, posterior, anterior, lateral views. H, small individual fixed to the undersurface of the free living bryozoan colony, Seienaria maculata. I, cardinalia showing areas for the attachment of diductors on the posterior margin and hinge plates for the attachmen t of dorsal adjustor muscles. J, cardinalia showing complete maniculifer crura. K, diagrammatic longitu dinal section showing adductors (2 pairs), diductors and pedicle system. L, reconstruction of individual fixed to the undersurface of living Seienaria maculata. Bar scale = 1 mm. 50 J. R. RICHARDSON

Various m odifications of the pedicle and its muscle s J ones , H. A. & D avies, P. J., 1983. Superficial sediments of the have been described which give m agadinids the capac ity Tasmanian continental shelf and part o f Bass Strait. Bull. to m aintain a position at or near the sediment surf ace. Bur. Miner. Resour. Geol. Geophys. Aust. 218: 1-25. In contrast, the surface position of the sedentary rhyn- M arsha ll , J. F. & D avies, P. J., 1978. Skeletal carbonate varia­ tion on the continental shelf of eastern Australia. J. Aust. chonellid, A ulites brazieri, is m aintained by using free- Geol. Geophys. 3: 85-92. living bryozoans as sites of attachm ent. M ineur , R. J. & R ichardson , J. R. 1984. Free and mobile brachiopods from New Zealand Oligocene deposits and ACKNOWLEDGEMENTS Australian waters. Alcheringa 8 : 327-334. P arkin , L. W., 1969. Handbook of South Australian Geology. I acknowledge the assistance of Frank Coffa, David Geological Survey of South Australia, 268 pp. Holloway, Rudi M ineur and Ian Stewart in production of Q u ilty , P., 1985. M iocene and Pliocene sediments dredged from the figures. The work was undertaken with the suppo rt the sea floor off St. Helens, northeastern Tasmania. Pap. of the Australian Biological Resources Study. Proc. R. Soc. Tasm. 119: 93-101. R eeve , L., 1861a. Monograph of Terebratula. Conch. Icon. 13: REFERENCES 11 pis. R eeve , L., 1861b. Monograph of Terebratula. Ann. Mag. Nat. A llan , R. S., 1960. The succession of Tertiary brachiopod faunas Hist. Ser. 3. 7: 1-180. in New Zealand. Rec. Canterbury Mus. 1: 233-268. R ichardson , J. R., 1973. Studies on Australian Cainozoic B lochmann , F., 1910. The brachiopods of South Australia. Trans. brachiopods 3. The subfamily Bouchardiinae (Terebratel- R. Soc. S. Aust. 34: 90-99. lidae). Proc. R. Soc. Viet. 8 6 : 127-132. B owen , Z. & C ampbe ll , J. D., 1973. Systematics and evolution R ichardson , J. R ., 1979. Pedicle structure of articulate brachio­ of the brachiopod genus Rhizothyris in the Oligocene- pods. JR. Soc. N.Z. 9: 415-436.

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