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Moulting in phacopid trilobites

Published online by Cambridge University Press:  03 November 2011

Stephen E. Speyer
Affiliation:
Department of Geological Sciences, University of Rochester, Rochester, New York 14627, U.S.A.

Abstract

Phacopid trilobites, unlike most trilobites, lack functionally articulated libregenae. This distinction presumably dictated ecdysial strategies which were fundamentally different from those forms with sutured cephala. Phacops rana (Green) and Greenops boothi (Green) from the Middle Devonian Hamilton Group (New York) are preserved in circumstances which illustrate certain aspects of their moulting behaviour. Undisturbed exuviae display five different moult patterns; these suggest two basic modes of exuviation in phacopid trilobites (Body-upright and Body Inversion Moult Procedures).

Certain Hamilton beds yield clusters of Phacops comprising complete and/or moulted remains. Complete trilobites in body clusters display varied orientations which, when considered in conjunction with exuvial patterns in moult clusters, suggest ecdysial procedures that involved body inversion and erratic tergal contractions (Body Inversion Moult Procedures). Ensembles where in thoracopygidia are upright and outstretched indicate hyperextension of the thorax and disarticulation of the cephalo-thoracic suture (Body-upright Moult Procedures). Phacops moult ensembles are characterised by inverted and tightly recurved thoracopygidia, whereas Greenops ensembles comprise outstretched, usually upright thoracopygidia with cephala that are frequently upright. Classic ‘Salterian’ patterns are uncommon in Phacops rana and have not been recognised in Greenops boothi. Variations in moult procedure are attributed to differences in functional morphology and substrate consistency.

Type
Life and environment of fossil forms
Copyright
Copyright © Royal Society of Edinburgh 1985

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References

Agassiz, A. 1878. Note on the habits of young Limulus. AM J SCI (SER 3) 15, 75–6.Google Scholar
Atema, J. & Engstrom, D. 1971. Sex pheromones in the lobster Homarus americanus. NATURE 232, 261–3.CrossRefGoogle Scholar
Baird, G. & Brett, C. E. 1983. Regional variation and paleontology of two coral beds in the Middle Devonian Hamilton Group of western New York. J PALEONTOL 57, 417–6.Google Scholar
Baird, G., Brett, C. E., Gray, L. & Kloc, G. in preparation. Stratigraphy, lithofacies and paleontology of the middle Devonian Ludlowville Formation in central and western New York State. NEW YORK STATE MUS BULL, to be submitted.Google Scholar
Bergström, J. 1973. Organisation, life and systematics of trilobites. FOSSILS STRATA 2, 169.CrossRefGoogle Scholar
Bishop, G. A. 1972. Moults of Dakoticancer overanus, an Upper Cretaceous crab from the Pierre Shale of South Dakota. PALAEONTOLOGY 15, 631–6.Google Scholar
Borowsky, B. 1980. The physiological control of reproduction in Microdeutopus gryllotalpa (Crustacea, Amphipoda); 1: the effects of exogenous ecdysterone on the female molt and behavioural cycles. J EXP ZOOL 213, 399404.CrossRefGoogle Scholar
Boucot, A. J. 1953. Life and death assemblages among fossils. AM J SCI 251, 2540.CrossRefGoogle Scholar
Brett, C. E. & Baird, G. 1982. The Genesee-Moscow contact in western New York: evidence for regional erosive beveling during the late Middle Devonian. NEW YORK STATE GEOL ASSOC GUIDEB 54, 1963.Google Scholar
Brett, C. E., Speyer, S. E. & Baird, G. in press. Storm generated sedimentary units: tempestite proximality and event stratification in the middle Devonian Hamilton Group of New York. NEW YORK STATE MUS BULL.Google Scholar
Campbell, K. S. W. 1975. The functional anatomy of phacopid trilobites; musculature and eyes. J R SOC NEW SOUTH WALES 108, 168–88.Google Scholar
Case, G. 1982. A Pictorial Guide to Fossils. New York: Van Nostrand.Google Scholar
Charnaiux-Cotton, H. 1960. Sex determination. In Waterman, T. (ed.). The Physiology of Crustacea (vol. 1) Metabolism and Growth, 411–41. New York: Academic Press.Google Scholar
Christy, J. 1978. Adaptive significance of reproduction in the fiddler crab Uca pugilator: an hypothesis. SCIENCE 199, 153–5.CrossRefGoogle ScholarPubMed
Cisne, J. 1973. Beecher's trilobite bed revisited: ecology of an Ordovician deep water fauna. POSTILLA 160, 125.Google Scholar
Clarkson, E. N. K. 1966. The life attitude of the Silurian trilobite Phacops musheni Salter 1864. SCOTT J GEOL 2, 7683.CrossRefGoogle Scholar
Clarkson, E. N. K. & Henry, J.-L. 1973. Structures coaptatives et enroulement chez quelques Trilobites ordoviciens et siluriens. LETHAIA 6, 105–32.CrossRefGoogle Scholar
Darby, H. H. 1938. Moulting in the crustacean, Crangon armillatus. ANAT REC 72 (Supplement), 78.Google Scholar
Fortey, R. A. 1975. The Ordovician trilobites of Spitsbergen II. Asaphidae, Nileidae, Raphiophoridae, Telephinidae of the Valhallfonna Formation. SKR NOR POLARINST 162, 1125.Google Scholar
Ginatzy, W. & Romer, F. 1984. Cuticle: formation, moulting and control. In Berelter-Hahn, J., Mataltsky, A. & Richards, K. (eds.) Biology of the Integument, 638–84. Berlin: Springer.CrossRefGoogle Scholar
Grabau, A. 18981899. Geology and Paleontology of Eighteen-mile Creek and the lake shore sections of Erie County, New York. BUFFALO SOC NAT SCI BULL 6(1, 2), 1403.Google Scholar
Harrington, H. 1959. Treatise on Invertebrate Paleontology, Part 0: Arthropoda 1. Lawrence: Geological Society of America and University of Kansas.Google Scholar
Hartnoll, R. 1969. Mating in Brachyura. CRUSTACEANA 16, 161–81.CrossRefGoogle Scholar
Henningsmoen, G. 1957. The trilobite family Olenidae. SKR NOR VIDENSK AKAD OSLO MAT-NAT 1, 1303.Google Scholar
Henningsmoen, G. 1975. Moulting in trilobites. FOSSILS STRATA 4, 179200.CrossRefGoogle Scholar
Jaanusson, V. 1975. Evolutionary processes leading to the trilobite suborder Phacopina. FOSSILS STRATA 4, 209–18.CrossRefGoogle Scholar
Jegla, T. 1982. A Review of the Molting Physiology of the Trilobite Larva of Limulus. In Bonaventura, J., Bonaventura, C. & Tesh, S. (eds) Physiology and Biology of Horshoe Crabs, 83101. New York: Alan R. Liss.Google Scholar
Johnson, S. & Attramadal, Y. 1982. Reproductive behaviour and larval development of Tanais cavolini (Crustacea, Tanaidacea). MAR BIOL 71, 11–6.CrossRefGoogle Scholar
Laverock, W. 1927. On the casting of the shell in Limulus. PROC TRANS BIOL SOC LIVERPOOL 41, 13–6.Google Scholar
Liddell, W. D. 1975. Recent crinoid biostratinomy. GEOL SOC AM ABSTR PROGRAMS 7 (7), 1169.Google Scholar
Lipcius, R. N. & Herrnkind, W. F. 1982. Molt cycle alterations in behavior, feeding and diel rhythms of a Decapod crustacean, the spiny lobster Panulirus argus. MAR BIOL 68, 241–52.CrossRefGoogle Scholar
Lockwood, A. P. M. 1967. Aspects of the Physiology of Crustacea. San Francisco: W. H. Freeman.Google Scholar
Ludvigsen, R. 1979. The Ordovician trilobite Pseudogygites Koybayashi in eastern and Arctic North America. LIFE SCI CONTRIB R ONTARIO MUS 120.Google Scholar
Maksimova, Z. A. 1955. [Trilobity srednego i verchnego devona Urala i severnych Mugodzar.] VSEGEI (N.S.) 3, 1263.Google Scholar
Mauchline, J. 1980. Advances in Marine Biology (vol. 18) The Biology of Mysids and Euphausids. New York: Academic Press.Google Scholar
McNamara, K. & Rudkin, D. 1984. Techniques of trilobite exuviation. LETHAIA 17, 153–73.CrossRefGoogle Scholar
Meyer, D. L. 1971. Post-mortem disarticulation of Recent crinoids and ophiuroids under natural conditions. GEOL SOC AM ABSTR PROGRAMS 3 (7), 645.Google Scholar
Miller, J. 1976. The sensory fields and life modes of Phacops rana (Green, 1832 (Trilobita). TRANS R SOC EDINBURGH 69, 337–67.Google Scholar
Miller, J. in press. Taphonomic approaches to trilobite palaeoecology. PALAEONTOLOGY.Google Scholar
Miller, J. & Clarkson, E. N. K. 1980. The post-ecdysial development of the cuticle and the eye of the Devonian trilobite Phacops rana milleri Stewart, 1927. PHILOS TRANS R SOC LONDON 288, 461–80.Google Scholar
Neville, A. 1975. Biology of Arthropod Cuticle. Berlin: Springer.CrossRefGoogle Scholar
Plotnick, R. E. 1984. Biostratinomy and early diagenesis of modern arthropods. GEOL SOC AM ABSTR PROGRAMS 16 (3), 186.Google Scholar
Powell, G. & Nickerson, R. 1965. Aggregation amongst juvenile king crabs (Paralithodes camtschatica, Tilesius), Kodiak, Alaska. ANIM BEHAV 13, 374–80.CrossRefGoogle Scholar
Raymond, P. E. 1920. The appendages, anatomy and relationships of trilobites. CONNECTICUTT ACAD ARTS SCI MEM 7.Google Scholar
Rhoads, D. C. 1970. Mass properties, stability and ecology of marine muds related to burrowing activity. In Crimes, T. P. & Harper, J. C. (eds.) Trace Fossils, 391406. Liverpool: Steele House.Google Scholar
Richards, A. 1951. The Integument of Arthropods. Minneapolis: University of Minnesota.Google Scholar
Richter, R. 1937. Vom Bau and Leben der Trilobiten, 8. Die “Salter'sche Einbettung” als Folge und Kennzeichen des Hautungs-Vorgangs. SENCKENBERGIANA 19, 413–1.Google Scholar
Rudloe, A. 1980. The breeding behavior and patterns of movement of horseshoe crabs, Limulus polyphemus, in the vicinity of breeding beaches in Apalachee Bay, Florida. ESTUARIES 3, 177–83.CrossRefGoogle Scholar
Salter, J. 1864. Figures and descriptions illustrative of British organic remains. MEM GEOL SURV U K, Dec. XI.Google Scholar
Schäfer, W. 1951. Fosilisation-bedingungen brachyurer Krebse. ABH SENKENB NATURFORSCH GES 485, 221–38.Google Scholar
Schäfer, W. 1972. Ecology and Palaeoecology of Marine Environments. Edinburgh: Oliver & Boyd.Google Scholar
Sheader, M. 1981. Development and growth in laboratory maintained and field populations of Parathemisto gaudichaudi (Hyperiidea, Amphipoda). J MAR BIOL ASSOC U K 61, 769–88.CrossRefGoogle Scholar
Speyer, S. E. 1984. Moulting in phacopid trilobites; a reconsideration of Salter's configuration. GEOL SOC AM ABSTR PROGRAMS 16 (6), 664–65.Google Scholar
Speyer, S. E. in preparation. Taphonomy and palaeoecology of trilobite moult accumulations.Google Scholar
Speyer, S. E. & Brett, C. E. 1982. Intraspecific clustering in Middle Devonian trilobites; the ‘coterie phenomenon’. GEOL SOC AM ABSTR PROGRAMS 14(7), 623.Google Scholar
Speyer, S. E. & Brett, C. E. 1983. Storm generated “event horizons” in the Middle Devonian Hamilton Group of western New York. GEOL SOC AM ABSTR PROGRAMS 15(2), 171.Google Scholar
Speyer, S. E. & Brett, C. E. 1984. Comparative taphonomy of Middle Devonian trilobite beds. GEOL SOC AM ABSTR PROGRAMS 16 (3), 198.Google Scholar
Speyer, S. E. & Brett, C. E. 1985. Clustered trilobite assemblages in the Middle Devonian Hamilton Group. LETHAIA 18, 85103.CrossRefGoogle Scholar
Speyer, S. E. & Brett, C. E. in preparation. Trilobite taphonomy and Hamilton Group “taphofacies.”Google Scholar
Stevčić, Z. 1971. Laboratory observations on the aggregations of the spiny spider crab (Maia squinado, Herbst). ANIM BEHAV 19, 1825.CrossRefGoogle Scholar
Thayer, C. W. 1975. Morphologic adaptations of benthic invertebrates to soft substrata. J MAR RES 33, 177–89.Google Scholar
Travis, D. 1954. The molting cycle of the spiny lobster, Panuliris argus Latreille. I. Molting and growth in laboratory-maintained individuals. BIOL BULL 107, 433–50.CrossRefGoogle Scholar
Valentin, C. & Anger, K. 1977. In situ studies of the life cycle of Diastylis rathkei. MAR BIOL 39, 71–6.CrossRefGoogle Scholar
Veuille, M. 1980. Sexual behavior and evolution of sexual dimorphism in body size of Jaera Isopoda, Asellota. BIOL J LINN SOC 13, 89100.CrossRefGoogle Scholar
Walcott, C. 1875. Notes on Ceraurus pleurexanthemus, Green. ANN LYCEUM NAT HIST 11, 155–9.CrossRefGoogle Scholar
Watson, J. 1971. Ecdysis of the snow crab Chionoecetes opilio. CAN J ZOOL 49, 1025–7.CrossRefGoogle Scholar