^ p UCLA Typs Collection RHPRiNT , ~ Do K'ot Remove From This Room TRILOBITE AND STAR-LIKE TRACE FOSSILS FROM THE WHITE-INYO MOUNTAINS, CALIFORNIA STEPHEN P. ALPERT Reprinted from JOURNAL OF PALKONTOLOGY Vol. 50, No. 2, March 1976 a pp. 226-239 Made in United, States of America Copyright © 1976, The Society of Economic Paleontologists and Mineralogists JOURNAL OF PALEONTOLOGY, V. 50, NO. 2, p. 226-239, 3 PLS., 1 TEXT-FIG., MARCH 1976 Copyright © 1976, The Society of Economic Paleontologists and Mineralogists TRILOBITE AND STAR-LIKE TRACE FOSSILS FROM THE WHITE-INYO MOUNTAINS, CALIFORNIA STEPHEN P. ALPERT Department of Geology, University of California, Los Angeles, 90024 ABSTRACT—The trilohite trace fossils present in the Lower Cambrian rocks of the White- Inyo Mountains, California belong to the genera Cruziana d'Orbigny (crawling furrows), Rusophycus Hall (resting burrows), Diplichnites Dawson (walking trackways), and Monomorphichnus Crimes (parallel scratchmarks). New species described are Rusophycus radivanskii and Monomorphichnus multilineatus. Three star-like trace fossils, comparable to Astcriacitcs Schlotheim, Astro politlwn Dawson, and Dactyloiditcs Hall, are described from the Lower Cambrian rocks. Dacty- loiditcs is interpreted as lobate feeditig burrows. INTRODUCTION Genus CRUZIANA d'Orbigny, 1842 USOPHYCUS Hall, the resting- burrows of tri- For synonymy before 1842, see Seilacher, R lobites, is the most abundant trilobite trace 1953b, p. 107. fossil in the White-Inyo Mountains, California Cruziana D'ORHIGNY, 1842, p. 30 (not seen) ; SALTER, (see Alpert, 1975, for locality map). The other 1861, p. 70; SALTER, 1866, p. 291; TROMELIN & genera present, Cruziana d'Orbigny, Diplich- LEBESCONTE, 1876, p. 626; SALTER, 1881, p. 482; nitcs Dawson, and Monomorphichnus Crimes, LEBESCONTE, 1883, p. 466^*72; DF.LGADO, 1885 (not seen); LEBESCONTE, 1887, p. 810-811; MIL- are uncommon. The fossils are generally pre- LER, 1889, p. 115; WALCOTT, 1890a, p. 35-36; served as casts on the underside of beds. WALCOTT, 1890b (partint), p. 604; FRITEL, 1925 The oldest trilobite trace fossils in the White- p. 34-35; YIN, 1932, p. 75-80; PICARD, 1942, p. 9; Inyo Mountains (Rusophycus, Diplichnites) oc- SAMPELAYO, 1950, p. 151-168; SEILACHER, 1953b (partim), p. 107-108; LESSERTISSEUR, 1955, p. cur in the basal quartzite unit of the upper 44-47; HANTZSCHEL, 1962, p. W189; RADWANSKI member of the Deep Spring Formation, about & RON IEWICZ, 1963, p. 267—269; HANTZSCHEL 1,500 feet stratigraphically below the lowest 1965, p. 27-28; GUBLER, 1966, p. 153; CRIMES^ 1968, p. 360-364; SEILACHER & CRIMES, 1969, p. trilobite (Text-fig. 1). I consider these trilobite 145-148; CRIMES, 1970a, p. 49; CRIMES, 1970b, p. trace fossils to be Early Cambrian in age. 111-112, 119-124; ORLOWSKI, RADWANSKI, & Trilobites of the White-Inyo Mountains are RONIEWICZ, 1970, p. 350-356; SEILACHER, 1970 illustrated in Nelson & Durham (1966). (partim), p. 454-456; ANDREWS, 1970, p. 62; RIRKE.VMAJER & BRUTON, 1971, p. 303-310, 313- The trilobite and star-like trace fossils of 318; nan BROMLEY & ASGAARIJ, 1972, p. 7-13; the White-Inyo Mountains are described herein. CRIMES, 1975a, p. 36-37; CRIMES, 1975b, p. 34- Previously I have described the sea anemone 39; HANTZSCHEL, 1975, p. W55; OSGOOD & DREN- NEN, 1975, p. 317. burrows, Bcrgaucria (Alpert, 1973), and Plano- Crysiana GIEBEL, 1851, p. 115 (misspelling). litcs and Skolithos (Alpert, 1975) from this Crusiana DAWSON, 1880, p. 46 (misspelling). California section. Cruciana and Crucianas SAMPELAYO, 1915, p. 279 (misspellings). All specimens with UCLA numbers are de- Cruzianas SAMPELAYO, 1950, p. 148, 149 (misspell- posited in the invertebrate paleontology collec- ing). tion of the Department of Geology, University Fracna ROUAULT, 1850 (partim), p. 729. of California, Los Angeles. Type species.—Cruziana rugosa d'Orbigny, 1842. SYSTEMATIC PALEONTOLOGY Description.—Elongate furrows generally pre- TRILOBITE TRACE FOSSILS served as hypichnial casts. Cast consists of The generic synonymies of Cruziana, Ruso- two parallel ridges with transverse, oblique, or phycus, and Diplichnites contain the major and longitudinal striae or scratchmarks, and a me- important references only. Numerous refer- dian groove or space between the ridges. Exo- ences, treating one or two particular species podal, genal, and pleural markings may be or specimens, and not generic concepts, are present in addition to the central endopodal omitted. ridges (Seilacher, 1970, text-fig. 3), but do CAMBRIAN TRACE FOSSILS 22 7 not occur in the White-Inyo Mountains speci- ber of the Campito Formation (PI. 1, fig. 5; mens. only specimen), in quartzite of the upper Remarks.—The genus Rusophycus, trilobite member of the Poleta Formation (one speci- resting traces, was put into synonymy with men), in quartzite of the basal Harkless For- Cruziana by Seilacher (1970). The two genera mation (two specimens,) and in siltstone of are here recognized as morphologically distinct, the upper member of the Saline Valley For- but related, genera, as is done in other recent mation (one specimen). works (Crimes, 1975a, b; Hantzschel, 1975; The above Cruziana sp. and cruzianid forms Osgood & Drennen, 1975). of R. didymus probably represent "head down Cruziana in the White-Inyo Mountains.— plowing" movement of the trilobites (Seil- Cruziana is uncommon in the White-Inyo acher, 1970, text-fig. 4). Mountains. It occurs in the Andrews Moun- A single specimen of Cruziana (PI. 1, fig. tain and Montenegro Members of the Campito 4), comparable with Cruziana rugosa d'Or- Formation, in the quartzite of the Poleta For- bigny, 1842, was collected by Lee Early of mation, in the lowTer Plarkless Formation, and Bishop, California, from quartzitic siltstone in the upper member of the Saline Valley For- float of the Andrews Mountain Member of mation. the Campito Formation, in Payson Canyon. The most common form of Cruziana consists The specimen is about 30 to 35 mm wide and of two parallel hypichnial ridges, in contact or 120 mm long. The two low, broad, hypichnial slightly separated, with closely spaced, fine, ridges possess strong transverse ridges, 1 to transverse or slightly oblique scratchmarks (PI. 3 mm wide and 2 to 4 mm apart. The trans- 1, figs. 6,9,12). The specimens are about 8 to verse ridges contain series of fine, parallel, 15 mm wide, and 15 to 35 mm long; they are nearly longitudinal ridges (casts of scratch- the furrowing form of the species Rusophycus marks), up to 8 on each side; these fine ridges didymus (Salter, 1856). The cruzianid form are 0.5 to 1 mm wide and 3 to 6 mm long. of R. didymus occurs with and grades into the The transverse constrictions and the approxi- more common resting form of R. didymus (PI. mately longitudinal, sharp, multi-clawed endo- 1, figs. 9,12). Similar examples are illustrated podal markings ally this specimen to the "ru- by Seilacher (1955, p. 358-362, pi. 19, fig. 1) gosa group" of Cruziana (Seilacher, 1970, p. and Lessertisseur (1955, p. 44, text-fig. 25H). 462-464), previously known only from Or- The resting forms are shorter, generally deeper, dovician rocks. and the two lobes may be parallel or form a V (PI. 1, figs. 9-13). Genus RUSOPHYCUS Hall, 1852 If Cruziana and Rusophycus are to be con- For synonymy before 1852, see Osgood, 1970, sidered as separate genera not in synonymy, p. 301. then the morphologic variation within Ruso- phycus didymus warrants placing the cruzianid Rusophxcus HALL, 1852 (partim), p. 23, PI. 8, figs. forms in Cruziana and the resting forms in 1,6, PI. 9, figs. 1-3; DAWSON, 1864, p. 363-367; JAMES, 1885 (partim), p. 153-155; MILLER, 1889, Rusophycus. Thus two species are necesssary. p. 138; SEILACHER, 1959, p. 292-293, text-fig. 4; An additional nomenclatural problem arises in HANTZSCHEL, 1962, p. W212-W214; RADWANSKI that Salter's Arenicola didyma may not be a & RONIEWICZ, 1963, p. 265-267; HANTZSCHEL, true Rusophycus. Salter (1856, p. 248-249) 1965, p. 80; KEGEL, 1965, p. 1-11; OSGOOD, 1970, p. 301-305; CRIMES, 1970a, p. 53-57; CRIMES, interpreted A. didyma as small U-shaped bur- 1970b, p. 114-116, 119-124; ORLOWSKI, RAD- rows; Arenicola didyma was designated as WANSKI, & RONIEWICZ, 1970, p. 350-356; AN- genotype of Arenicolites by Bassler (1915, p. DREWS, 1970, p. 187; SANTOS & CAMPANHA, 1970, p. 742; ORLOWSKI, RADWANSKI, & RONIEWICZ, 67; this designation not noted in Hantzschel, 1971, p. 343-346; BIRKENMATER & BRUTON, 1971, 1975, p. W38). p. 303-313, 318; YOUNG, 1972, p. 14; CRIMES, About six good specimens of the cruzianid 1975a, p. 37-41; CRIMES, 1975b, p. 34-35; HANTZ- form of R. didymus were collected or observed, SCHEL, 1975, p. W101-W102; OSGOOD & DRENNEN, 1975, p. 311-312. in siltstones of the upper Andrews Mountain Rhysophycus EICHWALD, 1860, p. 54 (not seen) ; Member of the Campito Formation and silt- LINNARSSON, 1869, p. 403-405; SCHIMPER & stones of the lower Harkless Formation. SCHENK, 1885, p. 54; LESSERTISSEUR, 1955, p. 44-47; HANTZSCHEL, 1965, p. 79; GUBLER, 1966, Larger but similar forms of Cruziana, 12 to p. 155. 40 mm wide, occur in quartzitic siltstone of Rhyssophycus GOEPPERT, 1860, p. 434; HANTZSCHEL, the upper Andrews Mountain Member of the 1965, p. 79; ANDREWS, 1970, p. 186. Campito Formation (two specimens observed), Rusiclinites DAWSON, 1864, p. 367; DAWSON, 1873, in quartzite of the middle Montenegro Mem- p. 18; MILLER, 1889, p. 566; DAWSON, 1890, p. 595-596; HANTZSCHEL, 1965, p. 80. 228 STEPHEN P. ALPERT Clossopleura Ogygopsis, Alokisfocare Alokisfocare Syspacepha/us, Oryctocephalus Olenellus,