View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by ESC Publications - Cambridge Univesity The Earliest Tegulorhynchia (Brachiopoda: Rhynchonellida) and Its Evolutionary Significance Author(s): Kenneth J. McNamara Source: Journal of Paleontology, Vol. 57, No. 3 (May, 1983), pp. 461-473 Published by: SEPM Society for Sedimentary Geology Stable URL: http://www.jstor.org/stable/1304689 Accessed: 16-07-2018 10:49 UTC REFERENCES Linked references are available on JSTOR for this article: http://www.jstor.org/stable/1304689?seq=1&cid=pdf-reference#references_tab_contents You may need to log in to JSTOR to access the linked references. JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected]. Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at http://about.jstor.org/terms SEPM Society for Sedimentary Geology is collaborating with JSTOR to digitize, preserve and extend access to Journal of Paleontology This content downloaded from 131.111.64.116 on Mon, 16 Jul 2018 10:49:02 UTC All use subject to http://about.jstor.org/terms JOURNAL OF PALEONTOLOGY, V. 57, NO. 3, P. 461-473, 3 FIGS., MAY 1983 THE EARLIEST TEGULORHYNCHIA (BRACHIOPODA: RHYNCHONELLIDA) AND ITS EVOLUTIONARY SIGNIFICANCE KENNETH J. McNAMARA Western Australian Museum, Francis Street, Perth, Western Australia 6000 ABSTRACT- Tegulorhynchia boongeroodaensis n. sp. is described from the Early Paleocene-Early Eocene Cardabia Group in the Cararvon Basin of Western Australia. This is the earliest known occurrence of the genus. Changes in frequency of occurrence of this species correspond with changes in the nature of the sediment: highest frequency of occurrence is in greensands; upward stratigraphic change to calcarenites and ultimately to calcilutites is associated with diminution in frequency of occurrence of the brachiopod and is thought to relate to reduction in suitable sites of attachment. Like descendant species, T. boongeroodaensis underwent no morphological change during the course of its time range. Evidence is presented to indicate that evolution of later species of Tegu- lorhynchia and the closely related Notosaria proceeded by paedomorphosis. The result of this was attainment of a morphology adapted to regimes of higher hydrodynamic activity. INTRODUCTION tions of the Western Australian Museum THE CARDABIA GROUP, which occurs (WAM). in All the Grid References (G.R.) refer to northern Carnarvon Basin of Western Aus- the KV section of the Giralia 1:100,000 map tralia, outcrops mainly on the flanks of sheet. the Giralia Range, south of Exmouth Gulf. This One new term is introduced: 'paedomor- largely carbonate sequence ranges in age phocline.' This may be defined as a stepped (McGowran, 1968, 1978) from the Early morphological gradient of paedomorphic Paleocene (planktonic foraminiferal Zone P.2) forms, extending from an ancestral apaedo- to the Early Eocene (p.f. Zone P.8) and prob- morph to an 'extreme' paedomorph which ably represents the most fossiliferous unit ofpossesses adult characteristics found only in this age in Australia. the earliest juveniles of the ancestor. The pae- The aim of this paper is to describe the domorphocline is an evolutionary gradient only species of rhynchonellide brachiopod which may extend through time and/or space. which occurs in the Cardabia Group; to dis- Examples, apart from that described herein, cuss the relationship between its stratigraphic are the Scottish olenellid trilobite paedo- distribution and sediment type; and to reap- morphocline through space (McNamara, praise the evolution of the genus Tegulo- 1978) and the Cretaceous ammonite genus rhynchia (within which the species is placed) Protacanthoceras (Wright and Kennedy, and the closely related Notosaria. 1980), a paedomorphocline through time. Little work has been carried out on the rich The counterpart of paedomorphocline will macrofossil fauna of the Cardabia Group be a 'peramorphocline' (for definition of per- which, dominated by echinoids, also com- amorphosis see Alberch et al., 1979). An monly contains brachiopods, corals, bryo- example is the morphological gradient zoans, bivalves and gastropods, as well as through space and time in the lineage of the occasional crabs. Cockbain (1967) has heart urchin Schizaster (McNamara and described the craniid brachiopod Westrali- Philip, 1980). The concepts of the paedo- crania alleni from borehole material, while morphocline and the peramorphocline are Foster and Philip (1978) described two newdiscussed more fully in McNamara (1982). genera and three new species of holasteroid echinoids and McNamara and Philip (1980) STRATIGRAPHY OF THE CARDABIA GROUP have described the echinoid Schizaster (Par- The oldest unit in the Cardabia Group is aster) carinatus. the Boongerooda Greensand which reaches a All specimens of the newly described maximum thickness of only 3.3 m in its type species of Tegulorhynchia are in the collec- section in Toothawarra Creek (Condon et al., Copyright ? 1983, The Society of Economic 461 0022-3360/83/0057-0461$03.00 Paleontologists and Mineralogists and The Paleontological Society This content downloaded from 131.111.64.116 on Mon, 16 Jul 2018 10:49:02 UTC All use subject to http://about.jstor.org/terms 462 KENNETH J. McNAMARA 1956). The formation is composed entirely upward development of finer-grained car- of green glauconitic sand apart from bonate minor sediments through the Cardabia phosphatic nodules and reworked phospha- Group. This change is accompanied by an tized ammonites derived from the underlying alteration in the aspect of the fauna. Maastrichtian Miria Marl, which it discon- formably overlies. Although Brunnschweiler SYSTEMATIC PALEONTOLOGY (1966) favored a Late Cretaceous age for Order the RHYNCHONELLIDA Kuhn, 1949 Boongerooda Greensand, Edgell (1952) and Family HEMITHYRIDIDAE McGowran (1968, 1978) have suggested an Rzhonsnitskaya, 1956 Early Paleocene (p.f. Zone P.2) age on the Genus TEGULORHYNCHIA Chapman and basis of the foraminifers. Brunnschweiler Crespin, 1923 (1966, p. 12) based his conclusion for a Late Type species.-Rhynchonella squamosa Cretaceous age, in part, on the occurrence of Hutton, 1873, p. 37. "brachiopods of the Cyclothyris group in great numbers." The youngest known cyclothyrids TEGULORHYNCHIA BOONGEROODAENSIS are Late Cretaceous (Ager, 1965). However, n. sp. the foraminiferal evidence and the descrip- Figures 1A-Y tion of the brachiopod herein as a member of the Tertiary to Recent genus Tegulorhyn- Cyclothyris spp. nov. BRUNNSCHWEILER. In CONDON ET AL., 1956, p. 30. chia suggest an early Tertiary age. The Boongerooda Greensand is conform- Holotype. -WAM 80.1523 from the Boon- ably overlain by the 25-30 m thick Wadera gerooda Greensand, 3.6 km NNW of Whit- Calcarenite. The formation consists almost lock Dam, Giralia Station, from head and left entirely of glauconitic calcarenite (Condon bank et of gully, Grid Reference Giralia al., 1956). The overlying Pirie Calcarenite KV115820; collected by G. W. Kendrick reaches a thickness of 33 m and is composed 26.8.79. Dimensions of the holotype and largely of bryozoal calcarenite with minor paratypes given in Table 1. intercalations of calcilutite. The uppermost Material, localities and horizons.-In member of the Cardabia Group, the 10 m addition to the holotype, 158 specimens have thick Cashin Calcarenite, differs from the been collected from the Cardabia Group. underlying Pirie Calcarenite in the greater From the Boongerooda Greensand: 44 spec- proportion of calcilutite and fine-grained cal- imens (including the paratypes WAM carenite. Thus, there is a general progressive 71.161a, b, d, e, 80.1499-80.1502) from the FIGURE 1- Tegulorhynchia boongeroodaensis n. sp. All specimens are from the Early Paleocene Boon- gerooda Greensand, except for WAM 80.1508 (A, F, G, K) which is from the Late Paleocene Pirie Calcarenite. All magnifications are X2. A, F, G, K, WAM 80.1508, paratype, from the southern tributary of Toothawarra Creek, about 350 m S of junction with northern tributary, G.R. 070720. Note relatively large foramen, low beak angle, narrow shell, lenticular profile and rectimarginate commissure. B, L, WAM 80.1492, paratype, from the base of Section Hill, G.R. 017543. C, H, WAM 80.146, paratype, from same locality as 80.1492. D, I, WAM 71.148b, paratype, from same locality as 80.1508, but lower in section. Note increasing development of uniplicate commissure through Figures K, L, I. E, WAM 80.1501, paratype, from same locality as 71.148b. Note small foramen. J, WAM 80.1500, paratype, from same locality as 71.148b. M, WAM 71.148c, paratype, from same locality as 71.148b. Development of strong uniplicate commissure initiated at earlier stage of growth than normal in this individual. N, R, WAM 71.16 la, paratype, from same locality as 71.178b. Gerontic individual with excess shell growth occurring dorso-ventrally about commissure. P, WAM 71.161e, paratype, from same locality as 71.148b. Individual with narrow profile, but uniplication still very pronounced. Q, WAM 80.1497, paratype, from same locality as 80.1492, showing lemniscate type of pallial sinus pattern in pedicle valve. S, WAM 71.148a, paratype, from Toothawarra Creek, G.R. 070725, showing internal features of brachial valve. T, W, X, Y, WAM 80.1523, holotype, from 3.6 km NNW of Whitlock Dam, Giralia Station, G.R. 115820. U, V, WAM 80.1499, paratype, from same locality as 71.148b. This content downloaded from 131.111.64.116 on Mon, 16 Jul 2018 10:49:02 UTC All use subject to http://about.jstor.org/terms PALEOCENE A USTRALIAN BRA CHIOPODS 463 ,f A At'1 E F Gi is- ..;1. H 1 I K L ,,? X %:!li 7 ?I rid) M ZP;. ?r ,? P , / , .' Q 9" *^ ?M\^ W ^ I R T U y This content downloaded from 131.111.64.116 on Mon, 16 Jul 2018 10:49:02 UTC All use subject to http://about.jstor.org/terms 464 KENNETH J.