Belaústegui et al.—Echinoderm ichnology and other related processes
respective synonyms Fossichnus and Balticapunctum Rozhnov, 1989. Wisshak et al. (2015; see emended and differential diagnoses) differentiated Oichnus from Tremichnus because this latter is restricted to echinoderm host substrates and does not penetrate through the substrate. Two names, Myzostomites and Schizoproboscina, were
653
(Richard, 1907; Jangoux, 1987). They have, however, not yet been recognized in the fossil record. Finally, the ichnogenus Ostiocavichnus was erected by
firstly and respectively proposed by Clarke (1921) and Yakolev (1939) to designate swelling- or cyst-like structures produced by parasites on echinoderms, mainly crinoids and echinoids. Radwańska and Radwański (2005), studying the myzostomid and copepod infestation of Jurassic echinoderms, revised the taxonomic validity of these names and highlighted that: (1) Myzostomites has been treated both as a body fossil (the worm M. clarkei Howell, 1962) and a trace fossil (Häntzschel, 1975), (2) Schizoproboscina (with its species S. ivanovi Yakolev, 1939) was accepted as a worm body fossil by Howell (1962), and (3) the Schizoproboscina material described by Yakolev (1939) and revised by Arendt (1961) shares many similarities with the Myzostomites type material of Clarke (1921). Radwańska and Radwański (2005) regarded Schizoproboscina as a junior synonym of Myzostomites,and consequently, M. ivanovi (Yakovlev, 1939) as the valid name for the type material of Clarke (1921). Additionally, Brett (1985) proposed to replace M. clarkei with Tremichnus cysticus Brett, 1985; however, Radwańska and Radwański (2005) considered this modification invalid according to the ICZN rules. Following Radwańska and Radwański (2005), the ichnogenus Myzostomites (Yakolev, 1939) should comprise paired round borings connected by an internal U-shaped canal produced on echinoderms (mainly crinoids), which inmost cases promotes an overgrowth (swelling-like or cyst) of their stereom. Castexia Mercier, 1936 includes spherical endocysts,
convexly elevated upon the echinoid test, with a pentagonal or subdecagonal outline, and five to 16 teardrop-shaped, periph- erally dispersed orifices (occasionally, a subcentral orifice may occur). The wall of these endocysts is constructed by the stereom overgrowth of the host echinoderm (exclusively echinoids) that reacts to the activity of the producer, thus embedding it. Copepods (Crustacea) have been proposed as probable tracemaker from the Ordovician onward (see extensive review in Klompmaker and Boxshall, 2015). These endocysts are especially prevalent in the Middle to Late Jurassic (Mercier, 1939; Radwańska and Radwański, 2005 and references therein). In addition, Radwańska and Radwański (2005) regarded the ichnotaxon Canceripustula nocens Solovyev, 1961 as a junior synonim of Castexia douvillei Mercier, 1939. Radwańska and Radwański (2005) also described
‘Halloween pumpkin-mask’ cysts consisting of bulbous exo- cysts with numerous circular orifices, recorded on Late Jurassic echinoid tests and more rarely on Early Jurassic crinoid stems. As in the case of Castexia, these exocysts have been interpreted as the result of stereom overgrowth promote by copepod parasitism. Similar fossil exocysts or swelling structures have described by Franzen (1974), Smith (1988), Mehl et al. (1991), Radwańska and Poirot (2010) and Klompmaker and Boxshall (2015). It is also known that the modern copepod Pionodesmotes Bonnier, 1898 inhabits the internal test surface of live echinoids within galls, which are connected to the exterior by an irregular opening bored through the stereom
Bohatý et al. (2012) from Devonian crinoids of Germany and Poland. It comprises gall-like swellings produced on crinoid pluricolumnals by epizoozoan rugose corals. These traces consist of elliptical or subcircular concavities resulting from the encasing of the coral by stereomic coating (Bohatý et al., 2012).
Swelling structures comparable to the ichnogenera cited in
this subsection but not ascribed to any of them, and produced by diverse parasites (e.g., myzostomid worms, copepods) on different kinds of echinoderms (mainly crinoids and echinoids, Fig. 6.1, and their spines), have also been described (e.g., Franzen, 1974; Welch, 1976; Werle et al., 1984; Abdelhamid, 1999; Radwańska and Radwański, 2005; Hess, 2010; Thomka et al., 2014; Wilson et al., 2014 and references therein).
Traces produced by symbiosis (mainly parasitism) on echinoderms.—The existence of diverse symbiotic relations between echinoderms and various kinds of organisms have been recorded both in the fossil record and in the Recent (e.g., Tapanila, 2008; Boucot and Poinar, 2010); subsequently, some of these relations may generate an ichnological record. The parasitism of platyceratid gastropods on crinoids
(Fig. 6.9), more rarely on blastoids, is well known and documented in the fossil record (e.g., Baumiller, 1990, 2002, 2003; Baumiller and Gahn, 2002, 2003; Gahn and Baumiller, 2003; Baumiller et al., 2004; Donovan, 2015). Baumiller (1990) described the presence of drill-holes (Oichnus-like) on Mississippian crinoids, which are interpreted as the non- predatory drilling activity of platyceratid gastropods. This interpretation is based on the occurrence of a platyceratid shell located just above a conical hole present on the tegmen of one of these Mississippian crinoids. Similar drill holes, also attributed to parasitic platyceratids, have also been documented on Devonian blastoids and crinoids (Baumiller, 1996 and Gahn et al., 2003, respectively). Circular to subcircular traces, produced on the surface of an
early Maastrichtian holasteroid echinoid test (northern Germany), and consisting of a more or less pronounced rim surrounding a central depression, were interpreted by Neumann and Wisshak (2006) as the attachment scars produced by probable parasitic foraminifera during a syn-vivo infestation; since the characteristic rim of these traces would be the result of the host-skeletal overgrowth around the attached parasite as defense mechanism. Wisshak and Neumann (2006) described 27 U-shaped
borings (Caulostrepsis isp.) produced on the test of a Late Cretaceous holasteroid echinoid of Germany. Since stereom regeneration is observed in the walls of these borings, these authors interpreted the trace as the result of a symbiotic association (syn-vivo infestation) between boring polychaetes (probably spionids) and the echinoid. Donovan et al. (2010) interpreted a non-penetrative
shallow scar (rounded to pentagonal in outline) present on the test of a Late Cretaceous holasteroid echinoid from the Maastrichtian type area (the Netherlands, Belgium), as the
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96 |
Page 97 |
Page 98 |
Page 99 |
Page 100 |
Page 101 |
Page 102 |
Page 103 |
Page 104 |
Page 105 |
Page 106 |
Page 107 |
Page 108 |
Page 109 |
Page 110 |
Page 111 |
Page 112 |
Page 113 |
Page 114 |
Page 115 |
Page 116 |
Page 117 |
Page 118 |
Page 119 |
Page 120 |
Page 121 |
Page 122 |
Page 123 |
Page 124 |
Page 125 |
Page 126 |
Page 127 |
Page 128 |
Page 129 |
Page 130 |
Page 131 |
Page 132 |
Page 133 |
Page 134 |
Page 135 |
Page 136 |
Page 137 |
Page 138 |
Page 139 |
Page 140 |
Page 141 |
Page 142 |
Page 143 |
Page 144 |
Page 145 |
Page 146 |
Page 147 |
Page 148 |
Page 149 |
Page 150 |
Page 151 |
Page 152 |
Page 153 |
Page 154 |
Page 155 |
Page 156 |
Page 157 |
Page 158 |
Page 159 |
Page 160 |
Page 161 |
Page 162 |
Page 163 |
Page 164 |
Page 165 |
Page 166 |
Page 167 |
Page 168 |
Page 169 |
Page 170 |
Page 171 |
Page 172 |
Page 173 |
Page 174 |
Page 175 |
Page 176 |
Page 177 |
Page 178 |
Page 179 |
Page 180 |
Page 181 |
Page 182 |
Page 183 |
Page 184 |
Page 185 |
Page 186 |
Page 187 |
Page 188 |
Page 189 |
Page 190 |
Page 191 |
Page 192 |
Page 193 |
Page 194 |
Page 195 |
Page 196 |
Page 197 |
Page 198 |
Page 199 |
Page 200 |
Page 201 |
Page 202 |
Page 203 |
Page 204 |
Page 205 |
Page 206 |
Page 207 |
Page 208 |
Page 209 |
Page 210 |
Page 211 |
Page 212 |
Page 213 |
Page 214 |
Page 215 |
Page 216 |
Page 217 |
Page 218 |
Page 219 |
Page 220 |
Page 221 |
Page 222 |
Page 223 |
Page 224 |
Page 225 |
Page 226 |
Page 227 |
Page 228 |
Page 229 |
Page 230 |
Page 231 |
Page 232 |
Page 233 |
Page 234 |
Page 235 |
Page 236 |
Page 237 |
Page 238 |
Page 239 |
Page 240 |
Page 241 |
Page 242 |
Page 243 |
Page 244 |
Page 245 |
Page 246 |
Page 247 |
Page 248 |
Page 249 |
Page 250 |
Page 251 |
Page 252 |
Page 253 |
Page 254 |
Page 255 |
Page 256 |
Page 257 |
Page 258 |
Page 259 |
Page 260 |
Page 261 |
Page 262 |
Page 263 |
Page 264 |
Page 265 |
Page 266 |
Page 267 |
Page 268 |
Page 269 |
Page 270 |
Page 271 |
Page 272 |
Page 273 |
Page 274 |
Page 275 |
Page 276 |
Page 277 |
Page 278 |
Page 279 |
Page 280 |
Page 281 |
Page 282 |
Page 283 |
Page 284 |
Page 285 |
Page 286 |
Page 287 |
Page 288
