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The fossil Crustacea of China: their taxonomy, palaeobiology, biogeography and phylogenetic relationships

Taylor, R.S.

Publication date 1999

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Citation for published version (APA): Taylor, R. S. (1999). The fossil Crustacea of China: their taxonomy, palaeobiology, biogeography and phylogenetic relationships. Fac. der Biologie.

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Download date:29 Sep 2021 Fossil Crustacea of China

Chapter 5

The Crustacea of China: a Palaeobiogeographical Perspective

Abstract The fossil record in China has been much discussed in the scientific literature of late with the recent discovery of new localities there with many new and informative fossil taxa. One group in particular has received attention, the Crustacea (and the Arthropoda in general). The known Crustacean fossil record of China is summarized and discussed in this paper. These Chinese fossils are compared to related taxa worldwide, in an attempt to piece together local and global biogeographic trends for these groups. The importance of the fossil record in understanding the evolutionary history of any group is a prevalent theme.

Introduction Consideration as to the true nature of fossils is a practice that has been ongoing since the early days of human civilization. The first recorded commentary on the organic origins of fossils dates back to Xanthos of Sardis in about 500 B.C.; 150 years later, Aristotle discussed how fossil fish were the remains of once living animals that had swum into cracks in rocks and had been stranded there. Palaeontology as we think of it today, however, did not truly com­ mence until the 19th century. At this time, the ichthyosaurian, plesiosaurian and pterosaurian fossil remains discovered by Mary Arming and the description of the first known dinosaur, Iguanodon, by Mantell in the early 1800s captured the attention of the media in Britain and ini­ tiated what would eventually become the modern-day worldwide fascination with fossils (McGowan, 1991). The palaeontological situation in China is perhaps one of the most exciting right now, with the recent discovery of such palaeontological treasures as the Lower Cambrian Chengjiang fauna in Yunnan, southwestern China, and new birds and dinosaurs in Liaoning province, northeastern China. Palaeontological research, however, has been slower to develop in China than in the 'western world'. Even now, much of the palaeontological work done in China is published in Chinese language journals (only sometimes with an English abstract and/or summary) that are not carried by most non-Chinese libraries. Because of this, it is often difficult for non-Chinese palaeontologists to get a true feeling for the extensive palaeon­ tological research being done there today. The intentions of this paper are twofold. One is to present a relatively up-to-date pic­ ture of China's fossil crustacean record, incorporating where possible information published in less-well-known Chinese journals. The second goal of this paper is to put the Chinese crus­ tacean fossil record in a more global framework, thus allowing for a better understanding of the palaeobiological history of China with respect to the related faunas around the world.

Palaeontological Research in China The palaeontological record in China is rich and diverse, as reflected by the enormous numbers of published studies focussing on fossils from China. Some examples demonstrating

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this diversity are the trilobite studies of Yang Jialu (e.g., Yang, 1978; Yang et al., 1984), Lin Bayou's work on corals (e.g., Lin and Chou, 1977; Lin and Wang, 1985), Wang Keliang's foraminiferan studies (e.g., Wang, 1984; Wang, 1985), Huang Wanpo's publications regarding China's mammal faunas (e.g., Huang, 1980; Huang, 1986), and the works on China's palaeoflo- ras by Xu Ren (e.g., Xu, 1982). This is hardly a comprehensive list of the studies emerging from China's palaeobiological community It does give some idea of the broad range of work occurring there today, however [for more information, see the recent volumes 'The Palaeobiogeography of China' (Yin, 1994) and The Geology of China (Yang et al., 1986)]. A good example of the depth of the long-term studies taking place in China is the Chinese literature regarding graptolites, a group of colonial hemichordates that dominated the plankton of the world's oceans during the Ordovician and Silurian. The database regarding these animals from Chinese strata is nothing short of enormous. Several authors have pub­ lished extensively on Chinese graptolites, including Mu En-zhi in the 1960s - 1980s (e.g., Mu and Chen Xu, 1962; Mu et al, 1974; Mu and Lin, 1984; and as Mu A.T. in the 1940s - 1960s), Lin Yao-kun in the 1980s (e.g., Lin Yao-kun, 1980; Lin Yao-kun and Zho Zhao-ling, 1989) and Chen Xu in the 1980s and 1990s (e.g., Chen et al., 1981; Chen, 1994). Thanks to the work of these and other authors, the biostratigraphic and palaeobiogeographic history of the Graptolithina is well understood in a global context. The appearance of recent volumes in English, such as the won­ derful book 'Graptolite Research Today' edited by Chen et al. (1994), has greatly improved the international understanding and interpretation of these Chinese graptolites (e.g., Cooper et al., 1991). The past few years in particular have seen China emerge as the source of some of the world's most significant fossil finds. Issues that have long been sources of contention within the palaeontological community (and, increasingly, the general public) have been influenced by recent finds from China. Perhaps the most widely publicized of these has been the issue of bird-dinosaur relationships and bird evolution, which has been greatly bolstered by the discov­ ery of dinosaurs with feathers (Ji Qiang et al., 1998) and early therapod dinosaurs that possess many morphological features shared with birds (Chen et al., 1998). Another widely publicized palaeontological find from China recently has been the dis­ covery of a Lower Cambrian Lagerstätte in Moatian, Yunnan Province, southwestern China. This locality has produced extensive amounts of fossiliferous material comparable in quality to (perhaps even better than) the Burgess Shale Lagerstätte fossils of western Canada. The fossils from this locality are revealing much about the early nature of life, the evolution of arthropods, the origins of major phyla, and the relationships between these phyla (e.g., Chen et ah, 1996; Chen and Zhou, 1997; Hou and Bergström, 1997; Conway Morris, 1998).

Fossil Crustacea in China and their global 'relatives' Several crustacean groups are represented in the fossil record of China, some extensive­ ly. Others are known from China through only a few occurrences (or even a single specimen in a few cases). Several factors may be responsible for the seeming irregularities in the distrib­ utions of fossil Crustacea in China. Among them are true variability in the distributions of dif­ ferent animal groups, which would naturally be reflected in their fossil record, and/or incom­ pleteness of the fossil record itself. Another reason, and perhaps the most important with

86 Fossil Crustacea of China respect to this discussion, is our relative ignorance of the geological and palaeontological sequences of China. Nevertheless, our knowledge of the palaeobiological history of China has increased tremendously in recent decades. While we are now filling in the numerous gaps in our knowledge of Chinese paleobiology, there are still considerable questions that remain to be answered. In this paper, I will briefly summarize the current state of knowledge pertaining to the fossil Crustacea of China and how they compare to related forms, both fossil and recent, around the globe. This effort cannot be a comprehensive summary of the subject - such a par­ taking would unfortunately be far beyond the scope of this paper. It is intended rather to serve as an introduction to the research occurring there today and to serve as a stimulus to delve deeper into the wealth of palaeontological information that is today emerging from Chinese strata.

Class Phyllopoda The Phyllopoda Latreille, 1825 are one of the four major crustacean classes and are characterized by the possession of leaf-shaped, polyramous limbs. They are known both from Recent taxa and the fossil record, and include both the subclass Phyllocarida Packard, 1879 and the subclass Calmanostraca Tasch, 1969. Among the calmanostracan orders of particular interest to this paper are the Kazacharthra Nozohilov, 1957 and Conchostraca Sars, 1867.

Subclass Phyllocarida A major component of the crustacean fossil record in China is the Class Phyllopoda (in the sense of Schram, 1986), which includes the subclass Phyllocarida Packard, 1879 (Figure la). Phyllocarida have long been problematic taxa in regards to their classification, and their taxonomy is currently seriously in need of revision (Dahl, in Schram, 1986). The fossil taxa (including the orders Archaeostraca, Canadaspidida, Hoplostraca, and Hymenostraca) share the same taxonomie problems, largely because many fossil forms are known from limited material such as tailfan elements or isolated carapaces. Another difficulty arises from the fact that only a single feature, the presence of a seven-segmented abdomen, unites these taxa with­ in the Phyllocarida. Fortunately, detailed morphology is preserved in some fossil taxa, such as the Middle Devonian Nahecaris stuertzi from the Hunsruck Slate of Germany (Figure la), so morphological comparisons between the extinct and recent taxa are sometimes possible. However, such 'type animal' comparisons can be flawed if taken too literally (that is, not all phyllocarid taxa should be expected to actually look like Nahecaris!). The taxonomy of the Cambrian Phyllocarida is a contentious issue. The Burgess Shale animal Canadaspis perfecta Walcott, 1912 has been considered by some (e.g. Briggs, 1978) to be a phyllocarid due to its possessing eight pairs of thoracic limbs and an abdomen with seven (limbless!) segments. Dahl (1983,1984), on the other hand, denies any phyllocaridan affinities for this genus (although he failed to provide any alternative suggestions as to the 'true' nature of Canadaspis). The author agrees with Briggs' interpretation that these animals are phyllo- carids, albeit primitive ones [see Schram and Hof (1998) for a more detailed discussion]. Species belonging to the extinct phyllocaridan orders are known from strata as early as the Cambrian and extend upwards through to the Upper Triassic. Their geographical ranges

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Figure 1. Fossil Crustacea, a: Nahecaris stuertzi, a phyllocarid from the Lower Devonian of Germany (x0.55; from Brooks et al., 1969). b: Panacanthocaris ketmenia, a kazacharthran from the Lower Jurassic of Kazakhstan (x0.8; from Tasch, 1969). c: Massagetes karagandensis, a conchostracan from the Upper Carboniferous of Kazakhstan (xl0.5; from Tasch, 1969). d: Beyrichia salteriana, an ostracode from Upper Silurian of Europe (x25; from Tasch, 1961). e: Tylocaris asiaticus, a pygocephalomorph from the Permian of China (x3.1; from Taylor et al., 1998). f: Schimperella beneckii, a lophogastrid from the Triassic of France (x3.2; from Schram, 1986). g: Liaoningogriphus quadripartites, a spelaeogriphacean from the Upper Jurassic of China (x5.5; from Shen et al, 1998). h: Cricoidoscelosus aethus, a crayfish from the Upper Jurassic of China (x0.7; from Taylor et al, in press). Fossil Crustacea of China and taxonomie richness were widely varied: for example, the two taxa making up the dis­ cussed above Cambrian Order Canadaspidida, Canadaspis and Perspicaris, are found to date only in North America and southwestern China. The Cambrian/Ordovician Hymenostraca, known only from the single species Hymenocaris vermicauda Salter, 1853, is found in strata from western Europe, North America, Australia, and New Zealand. Thirdly, the Order Hoplostraca is known from three Carboniferous species, Sairocaris elongata Peach 1882 from the UK, S. centurion Schram and Horner, 1978 and Kellibrooksia macrogaster Schram, 1973 from the USA. These phyllocaridan taxa appear to be limited in number, highly endemic and endured for only short periods of geological time. The Order Archaeostraca, on the other hand, is considerably more diverse taxonomical- ly than the Phyllocarida, with numerous genera and species subdivided over two suborders and seven families. They range temporally from the Lower Ordovician to the Upper Triassic, with the majority of taxa occurring during the Devonian in North America and/or Europe. Archaeostracan taxa, like the three extinct phyllocaridan orders, usually show restricted geo­ graphical ranges. A few taxa, however, such as Ceratiocaris solenoides M'Coy, 1849 (from the Upper (Middle?) Ordovician - Lower Devonian (?Permian)), Echinocaris sublevis Whitfield, 1880 (Middle Devonian), and Caryocaris wrightii Salter, 1863 (Upper Ordovician), demonstrate cosmopolitan distributions. The fossil Phyllocarida thus appeared to reach a peak in biodiver­ sity during the Upper Ordovician/Devonian. Recent Phyllocarida belonging to the Order Leptostraca are not a major component of the ocean's faunas today. Martin et al. (1996) listed a total of seven leptostracan genera, with at least 19 species currently known [or a minimum of 28 species, according to Dahl's (1990) review and subdivision of the genus Nebalia longicornis]. These are distributed over three families (one of which is monotypic with the sole known leptostracan fossil, the Upper Jurassic Rhabdouraea bentzi Schram and Malzahn 1984, from the Permian of Germany). Despite this relative taxonomie paucity, they appear to be relatively widespread geographically at the generic level: Nebalia, with its six species, possesses a worldwide distribution. The Chinese fossil record for the extinct Phyllocarida ranges from the Lower Cambrian to the Middle Triassic, closely reflecting that of the rest of the world. The Chinese phyllocarid taxa subdivide into two main groups: those belonging to the Cambrian Order Canadaspidida (Perspicaris sp., from the Chiungchussu Formation of Yunnan Province and Canadaspis eucal- lus, from the Maotianshan Formation, also from Yunnan) and those from the Order Archaeostraca. These archaeostracan forms include Yangzicaris xiangxiensis (Middle Triassic, Hubei/Nanjing), Echinocaris hunanensis (Late Devonian Xikuangshan Formation, Hunan), Ceratiocaris pierloti (Lower Silurian, Yunnan) and Caryocaris zhejiangensis and C. wrightii (Lower Ordovician Ningkuo Formation, Zhejiang). There are also a few problematic taxa that have been tentatively assigned to the Phyllocarida, but with little certainty as to their true tax­ onomie position: these include the Lower Silurian forms Tuzoia retifera, Sinocaris asiaticus and S. barbagei. It must again be stressed that there is still considerable confusion as to the taxonomie placement of many phyllocarid taxa, both in China and around the globe. Rolfe (1969) lists 25 fossil genera belonging tentatively to the Order Phyllocarida, many from the Cambrian of North America, which were not then well enough understood to place in any lower-level taxo-

89 Chapter 5 nomic rank with any certainty. Many of these have since been placed in their 'proper' orders and families, thanks to the collection of new material and/or our coming to better understand the available material (e.g. Sairocaris and Anomalocaris), but the problem still persists for many taxa. As stated so succinctly by Schram (1986: p. 326): "...although it is convenient to group all these orders together in the Phyllocarida some of these groups may have noth­ ing to do with each other".

Subclass Calmanostraca The Calmanostraca are a group of crustaceans characterized by carapace features such as its presence/absence, its shape if present (bivalved/bilobed) and/or the presence of a head- shield if the carapace is absent. Of interest to us here are the orders Kazacharthra Nozohilov, 1957 and Conchostraca Sars, 1867.

Order Kazacharthra The Kazacharthra Nozohilov, 1957 are a group of very distinctive crustaceans. They are characterized by a heavily sclerotized, shield-like carapace (often decorated with spines of varying size and shape and optical tubercles), highly elongate abdomens with anywhere from 32 to 40 segments, and a club-like telson (sometimes with a pair of terminal rami; Figure lb). They are known from Eurasian Late Middle to Late Triassic deposits only (most were until recently considered to be Jurassic in age), from Kazakhstan, southwestern Mongolia, and sev­ eral basins in western Xinjiang Province, China. The sole kazacharthran family, Family Ketmeniidae, contains nine genera with a total of twenty-five species (McKenzie and Chen, 1999). The Kazacharthra are currently recognized as a sister group to the Order Notostraca, a taxonomie placement that is far from universally accepted. As argued by Sharov [and summa­ rized by Schram (1986)], the general form of the appendages and the presence of caudal rami may warrant nothing more than familial status within the Notostraca as opposed to the cur­ rent ordinal level the Kazacharthra enjoy (see McKenzie and Chen, 1999 for an extended dis­ cussion of these unusual animals).

Order Conchostraca Summarizing the current state of our knowledge of conchostracans is a daunting task. The best known volume summarizing the palaeontological record of the Conchostraca Sars, 1867 (Figure lc) is Tasch's chapter on the Branchipoda in the Treatise of Invertebrate Palaeontology (1969). Unfortunately, this contribution was already considered by many scien­ tists to be largely out of date by the time it went through the editorial process and was finally published. A more recent offering was Tasch's 1987 volume 'Fossil Conchostraca of the Southern Hemisphere and Continental Drift'; but as it focuses strictly on Southern Hemisphere taxa, it is not of direct relevance to this discussion. Other potentially useful volumes are pub­ lished in languages other than English, such as Chernysheva's 'Fundamentals of Paleontology Volume 8: Arthropoda - Trilobita and Crustacea' (1960), currently available only in Russian. Another relevant factor is the general alpha-taxonomic nature of papers dealing with this group: few studies dealing with other aspects of their natural history of evolution have been

90 Fossil Crustacea of China published. Due to these difficulties, this summary of the Conchostraca will be relatively brief. The Conchostraca (Figure lc) are characterized by the body being enclosed in a lateral­ ly compressed bivalved carapace and the presence of 10 to 32 pairs of phyllopodous trunk limbs. They range in time from the Devonian to the Recent, with approximately 200 species currently known. These species are distributed over two suborders and 12 families, five of which are now extinct. The suborder Laevicaudata Linder, 1945 possesses only one family, the Lynceidae, which is known from the Lower Cretaceous to the Recent. This Family is unusual among the Conchostraca in that it possesses no growth lines on the carapace (key features used in the taxonomy of fossil Conchostraca), caudal furcae or dorsal abdominal spines. They are also unique in that they are one of the few conchostracan groups that are currently being studied from a more broad biological perspective than just alpha-taxonomy (e.g., Martin, Felgenhauer and Abele, 1986, Martin and Belk, 1988, and Martin, 1989). The second conchostracan suborder, Spinicaudata Linder, 1945, is host to the remaining 11 families. Two of these, the families Cyclestheriidae Sars, 1899 and Leptestheriidae Daday, 1923 are known only from Recent forms. Of the remaining nine families, only three have Recent representatives: the Limnadiidae Baird, 1849 from the Carboniferous to the Recent; Cyzicidae Stebbing, 1910 from the Lower Devonian to the Recent; and Limnadopsidae Tasch, 1969 from the Lower Carboniferous to the Recent. The remaining six families contain fossil- only taxa: the Lower Devonian - Upper Cretaceous Asmussiidae Kobayashi, 1954; Middle Carboniferous - Lower Cretaceous Estheriellidae Kobayashi, 1954; Middle Devonian - Lower Cretaceous Leaiidae Raymond, 1946; Lower Carboniferous - Upper Triassic Kobayashi, 1954; Pennsylvanian Pemphilimnadiopsidae Tasch, 1961; and Devonian - Lower Cretaceous Ipsiloniidae Novozhilov, 1958 (Schram, 1986; Benton, 1993). The Recent Conchostraca are cosmopolitan in their distribution with the exception of Antarctica (Martin, 1989) and are found in temporary and/or permanent pools at all altitudes. Their production of dessication-resistant eggs, which can be distributed by water or wind, explains their cosmopolitan distribution and their occurrence in highly isolated temporary pools. Most Recent forms occupy freshwater habitats only, but some are also capable of with­ standing brackish-water environments. Many fossil forms, however, are found in association with both fresh-water and marine faunas. This may be due to this tolerance of some taxa to brackish water, or it may truly reflect a wider range of environmental tolerance limits for the fossil Conchostraca (Tasch, 1969; Schram, 1986). Shen and Tong (1990), for example, suggest that some Permian Conchostraca may have been adapted to living in seashore or marsh envi­ ronments. These freshwater and marine associations for fossil Conchostraca may also reflect convergent morphological features in different taxa (see below). As so little is understood of the natural history of conchostracans, Schram (1986) sug­ gests that some of the features on which their taxonomy is based may reflect convergent fea­ tures and not true homologies. Also problematic is the fact that many of the characters used to distinguish among the Lynceidae (and among the Conchostraca in general) are "variable and taxonomically unreliable" (Martin and Belk, 1988: p. 453). Such is probably particularly true for the taxonomy of the fossil taxa, which is almost exclusively based on carapace features (Tasch, 1969). The paucity of soft part anatomy in fossil forms makes it very difficult to make interpretations as to the evolutionary history of the group (Schram, 1986). One suggestion is

91 Chapter 5 that the Conchostraca appear to have come upon hard times during the Cretaceous, when four of the six extinct families apparently vanished. Of these four, three have not been recorded after the Lower Cretaceous, suggesting that their demise may not have been due to the so- called 'end-Cretaceous mass extinction'. This is not particularly surprising, as many other ani­ mal and plant groups appear to have experienced declines through the Cretaceous (e.g. Surlyk 1990; Halstead, 1990). The Chinese palaeontological record for the Conchostraca is extensive. They were widely distributed over the whole of China during and since the unification of its constituent landmasses through the Mesozoic, occupying tropical, temperate and arctic regions. Their fre­ quency of occurrence seems to decline the further backwards in time we go, such that they are seen only on some of the pre-Chinese land masses during the Permian. They were even more geographically restricted (but already considerably diverse taxonomically) by the Middle Devonian, on what was then the equatorial Indochinese and South China plates, with Shen (1978) reporting six genera and twelve species from two localities in what is now Hunan province. Shen (1978) has also suggested that the leaid conchostracans may have originated in South China and later radiated outwards, eventually colonizing Australia, Africa, Antarctica, South America, Europe, and North America. Most of the current palaeontological literature from China deals with the more recent geological epochs. Thus, our understanding of the Conchostraca from such periods as the Cretaceous and Jurassic is far superior to our knowledge of these groups from earlier ages (e.g. Chen, 1996; Chen, et al. 1982; Chen and Chang, 1994; Shen and Mateer, 1988). Of considerable interest is the reference of Yang (1986) to unidentified Conchostraca and 'palaeoconchostraca' from Cambrian deposits in the Tarim, Yangzi, and Jiangnan regions in northwest, central and southeast China, respectively. If accurate, this would considerably extend the temporal range for this group of Crustacea.

Subclass Ostracoda Schram (1986: p. 414) stated that "the magnitude of the fossil record of ostracodes is almost to a point beyond the comprehension of any one person". Just a few years later, Whatley, Siveter and Boomer (in Benton, 1993; p. 343) stated in a somewhat more reserved tone that "the classification of the Ostracoda is in a state of flux", and that classification schemes used by different research schools today are "radically different". As a result, approaching the field of ostracod biology can be a daunting task. The Ostracoda (Figure Id) are characterized by their possession of a bivalved carapace that is hinged along its dorsal margin [unlike the dorsal 'hinge' of the Conchostracan carapace, which may be merely a flexible portion of an otherwise continuous carapace (Schram, 1986)]. Ostracodes today are found in freshwater, brackish or marine habitats worldwide. Marine forms range from near the shoreline to waters three km deep, while other aquatic forms live in such inhospitable habitats as sulpher springs, swamps, and salt marshes. There are also terres­ trial species, as well as taxa that are parasitic on fish, amphibians, or other crustaceans (Benson, 1961; Moore et al, 1961). In other words, the Recent Ostracoda live in practically any imaginable aquatic (as well as some terrestrial) habitats. The fossil ostracode are also difficult to summarize briefly. For example, Schram (1986)

92 Fossil Crustacea of China records 11 Ostracod families in the Cambrian (from a total of 137 families [in six orders]) while Whatley, Siveter and Boomer (in Benton, 1993) list 12 Cambrian ostracode families (from a total of 118 families [in 10 orders]). Despite the short period of time separating these two publica­ tions, there are tremendous differences in their taxonomie schemes. Of the 11 Cambrian fami­ lies reported by Schram and the 12 reported by Whatley et ah, only nine are reported by both authors - another good indication of how confused the taxonomy for this group is. Another perspective on Ostracode classification is that of Kempf (1980,1986), who reports approximately 50 000 species of ostracodes from eight orders: Archaeocopida (includ­ ing the Bradoriina and Phosphatocopina), Cladocopida, Halocyprida, Leperditicopida, Myodocopida, Palaeocopida, Platycopida, and Podocopida. This taxonomie scheme is built upon by McKenzie et al. (1999) in their recent discussion of the functional morphology of the Ostracoda. They re-assert that the Bradoriida are "true and primitive ostracods" (p. 507), despite the recent arguments of Hou et al. (1986) to the contrary (see below). They also raise the Bradoriida and Phosphatocopina to ordinal level taxa, as well as recognizing the new order Reticulocopida Kozur, 1993; this brings the current number of ostracodan orders to 10, four of which have no living members. Cambrian Ostracoda are recorded from areas as geographically widespread as Canada, Siberia, China, Kazakhstan, England, Australia, Germany, and Sweden. Most of these areas were equatorial during the Cambrian (Figure 2), but others were near the southern polar region. Thus, they appear to have been widely distributed not only in space but had probably developed a wide range of environmental tolerances already by the Cambrian. Ostracodes are subject to study from a number of fronts today. For example, an entire volume of the Treatise on Invertebrate Palaeontology is dedicated solely to the Ostracoda (Moore, 1961), suggesting just how immense the palaeontological database for these animals is. De Decker, Colin and Peypouquet (1988) edited a volume entitled 'Ostracoda in the Earth Sciences', a collection of articles largely oriented towards the use of ostracodes as palaeoenvi- ronmental indicators. The British Micropalaeontological Society has recently published a vol­ ume entitled 'Ostracoda and Global Events' (Whatley and Maybury 1990), containing 47 con­ tributions; while a third recent volume, 'Evolutionary Biology of Ostracoda' (Hanai, Ikeya and Ishizaki, eds., 1988) is made up of a truly staggering 91 contributions. The bulk of the papers making up these last two volumes are taxonomie or stratigraphie in nature (reflecting the great importance of ostracodes in biostratigraphy today), although palaeoecological studies are becoming more common in the recent literature. A rapidly growing field of relevance is the study of complete specimens of animals pre­ served in three dimensions. The small size of ostracodes, most being considerably less than one cm in length, makes them among the best candidates for 3-D preservation through phos- phatization. Specimens of 'ostracods' with most (if not all) of soft parts preserved are known from deposits as old as the Cambrian (e.g., Müller, 1979; Hou et al, 1996), with localities con­ taining phosphatized fossils known from most epochs. Ostracodes are, for example, the most abundant fossils found in the Lower Cretaceous Santana Formation Lagerstätte, northeastern Brazil (see Martill, 1999 for further discussion on phosphatization and in particular the Santana formation). The fossil record for the Ostracoda in China is similar to that worldwide: they are

93 Chapter 5

Late Cambrian 514 Ma

Ancient Landmass "England Modem Umtitnas* &J and Wales Subduction Zone (triangles point in the^""*"" New England direction ot subduction)

Sea Floor Spreading Ridg|>

Figure 2. Palaeogeographic map of the Late Cambrian Earth (from Scotese 1997). abundant there both in terms of absolute numbers and collection localities. As stated above, the Ostracoda are known in China from as early as the Cambrian; and they are extremely com­ mon throughout the Chinese fossil record and up to Recent times. Important fossil ostracodes finds are not uncommon in China. Zhang and Pratt (1993) reported the discovery of univalved bradoriid ostracode larvae from the Early Cambrian of China. More recently Hou et al. (1996) have described specimens of Kunmingella with pre­ served appendages, long reported as being bradoriid ostracodes. Their findings suggested that these animals are not truly ostracodes, and also that most (if not all) of the known Cambrian ostracodes are not in fact true Ostracoda, nor perhaps even true Crustacea! (see the discussion on the Burgess-type faunas below for more on Cambrian 'arthropod' relationships.) The amazing abundance of Ostracoda in the fossil record (of China in particular; worldwide in general) coupled with the instability in ostracodan taxonomy makes it very diffi­ cult to draw conclusions regarding biogeographic trends through the history of this group. Their rapid (in geological terms) speciation coupled with their ubiquitous occurrences to make them tremendously useful biostratigraphic tools (e.g., Colin and Lethiers, 1988). However, it also results in high enough numbers of species and genera to make higher-level taxonomy extremely difficult.

Class Malacostraca, Subclass Eumalacostraca Until recently, the record of Eumalacostraca Grobben, 1892 in China was restricted to just a few occurrences (e.g., Shen, 1983; van Straelen, 1928). These fossils have recently proven to be considerably more abundant than previously thought, with the discovery of new forms from the Late Permian to the Cretaceous (e.g., Taylor et al, 1998; Shen et al., 1998; Taylor

94 Fossil Crustacea of China et al, in press). The Eumalacostraca are characterized among the Malacostraca by the presence of a single antennal scale and a heavily muscled abdomen.

Order Pygocephalomorpha The Pygocephalomorpha (Figure le) were a group of Permian/Carboniferous Crustacea that were one of the dominant elements of nearshore marine and freshwater com­ munities in North America and Europe (Schram, 1979). They were also a component of com­ munities elsewhere, such as China and South America, but seem to have been less common numerically and less rich taxonomically (perhaps an artifact of less comprehensive collection in these areas). Some five families of Pygocephalomorpha have been recognized: the Carboniferous/Permian Tealliocarididae Brooks, 1962 from Europe and China, the Carboniferous/Permian Pygocephalidae Brooks, 1962 from North America, Russia and Europe, the Lower Permian Jerometichenoriidae Schram, 1978 from Russia, the Permian Notocarididae Brooks, 1962 from South America and South Africa, and the Tylocarididae Taylor et al, 1998 from China. As a group, they are characterized by two main morphological traits: the presence of a triangular- or quadrangular-shaped field of ventral thoracic sternites, and a broad, well-devel­ oped tailfan including one or two sets of lobate caudal lobes. They are closely related to the eumalacostracan orders Lophogastrida and Mysida, but there has been much disagreement as to the relationships among these three orders. Schram (1986), for example, considered the three to be sister orders, and Brusca and Brusca (1990) treat the Lophogastrida and Mysidacea as sister orders (they neglect to mention the extinct Pygocephalomorpha). Some authors, how­ ever, (e.g. Casanova et al, 1998) still refer to the Lophogastrida as a sub-order within the Mysidacea (see below). I will follow with Schram's taxonomie arrangement of the three repre­ senting distinct orders. Relationships within the Order Pygocephalomorpha are also in something of a state of flux. After several decades of relative inactivity, two papers dealing with relationships within this group have recently been published. Pinto and Adami-Rodriguez (1996) have focused on the Brazilian and South African taxa, including a general historical discussion of relationships between the pygocephalomorphs. They suggested that much of the current taxonomy for the group is erroneous, based on morphological features that the authors consider more likely be taphonomic and not morphologic. For example, they suggest that the presence of a reflexed abdomen is a valid feature in distinguishing between the genera Anthrapalaeomon (generally considered a junior synonym for Pygocephalus) and Pygocephalus. However, abdominal flex­ ure in crustacean corpses is a phenomenon easily affected by such taphonomic influences as orientation and/or degree of biological decomposition of the specimen in question immediate­ ly prior to and during preservation (e.g., Hof and Briggs, 1997). Taylor et al. (1998) have recently described two new monospecific genera of pygo­ cephalomorphs and placed them into a new family, the Tylocarididae (Figure le). They also performed a cladistic analysis of the entire known pygocephalomorph group, based on 33 morphological characters and utilizing several recent and fossil Mysida and Lophogastrida as out-group taxa. Many aspects of Brooks' (1962) taxonomy for the Pygocephalomorpha were

95 Chapter 5 supported by this analysis, such as the union of the genera Pygocephalus, Anthracaris, and Mamayocaris in the Family Pygocephalidae. Their analysis also suggested a union of taxa that Brooks had originally placed in separate families (e.g., Tealliocaris and Pseudotealliocaris, which Brooks had placed within the Tealliocarididae and Pygocephalidae, respectively). The basal polytomy in their tree suggested that a better understanding of the poorly understood Southern Hemisphere taxa such as Liocaris, Notocaris, and Pygaspis is required to finally erect an effective taxonomie scheme for this group. The pygocephalomorphs show a shift in their biogeographic distributions over time. The Carboniferous taxa were all found in the Laurentian realm, while most of the taxa living in the Permian (four of the five species known, the exception being Mamayocaris jepseni) occurred in Gondwanan waters. There was thus an evident shift in their distribution from the northern Laurentian realm to the southern Gondwanan 'sub-continent' around the time of the Permo-Carboniferous transition. The Permian occurrence of M. jepseni probably represents a relict of the earlier Laurentian distribution. Despite the apparent simplicity of this biogeographical pattern, the issue of rela­ tionships within the group and how they achieved their distributions is a complicated one. For example, Chaocaris chinensis (unfortunately based only on a single carapace) was original­ ly placed within the Tealliocarididae by Shen (1983). It appears, however, to be more closely related to the more recently described Chinese taxa. The subsequent description of 'new' pygocephalomorph taxa from China and the phylogenetic analysis of the group by Taylor et al. (1998) suggest that the Chinese taxa belong to a separate family of their own, the Tylocarididae. This certainly helps to clear up the problematic issue of the Tealliocarididae being distributed in such disparate areas as Europe and China; but other issues remain to be resolved. The Chinese pygocephalomorphs cannot easily be correlated biogeographically to the others. All non-Chinese pygocephalomorphs (as well as the known fossil lophogastrid and mysid taxa), from such diverse areas as North America, West Europe, South America, and South Africa, are physically far removed from China during the Permo-Carboniferous. The phylogenetic analysis of Taylor et al. (1998) suggests that the closest 'relative' to the Chinese pygocephalomorphs is Pseudogalathea macconochiei Etheridge, 1879, a form known to date only from the UK. China and the UK occupied very similar equatorial latitudes during the Permo-Carboniferous (Scotese, 1997), so it is perhaps not surprising that they possessed forms with similar adaptive morphologies; but whether these similarities are phylogenetic or merely convergent is impossible to determine with the current state of knowledge. It is thus very dif­ ficult as of now to place the Chinese forms into any easily understandable historical continu­ um.

Order Mysida Fossil mysids are rare. Schram (1986: p. 124) refers to the problematic taxa Elder ungulatus Munster, 1839 and Francocaris grimmi Borili, 1917, from the Jurassic Solnhofen limestones of Bavaria, as being "too poorly understood to permit an unqualified assignment". Secretan and Riou (1986) describe two species of mysids from the Upper Middle Jurassic deposits of la Voulte-sur-Rhône, Ardeche, France. These taxa, Siriella antiqua and S. carinata, are perhaps the only valid fossil mysids known to date.

96 Fossil Crustacea of China

Mysids today are cosmopolitan in the truest sense of the word, occupying marine, brackish, and fresh waters worldwide. Due to their restricted fossil record, it is impossible to draw any palaeobiogeographic conclusions regarding this group. Secretan and Riou (1986: p. 22) state, however, that based on their fossils, "the evolutionary stage reached by [the] Jurassic has not appreciably improved later on". Thus, it appears that the bauplan seen in the extant (and Jurassic) Mysidacea had developed well before any of the currently known forms. With luck, earlier members of this Order will eventually be discovered which may shed some light as to their biogeographic history and perhaps on their area(s) of origin. It is important to mention here that the status of the group generally referred to as the 'mysidacea' is not perceived as a monophyletic taxon. The 'mysidacea' refers to a para- phyletic group of taxa, including the members of the closely related Orders Mysida, Lophogastrida and Pygocephalomorpha, all relatively primitive, carapaced peracarids.

Order Lophogastrida The Lophogastrida (Figure If) are not so rare as the Mysidacea in the fossil record (perhaps reflecting the exoskeleton of early lophogastrids being more heavily sclerotized than those of the early mysids, as seen in many Recent forms). Three families of lophogastrids are currently recognized. The extant Family Lophogastridae is represented in the fossil record by Lophogaster volutensis Secretan and Riou, 1986 from the Upper Middle Jurassic Voulte-sur- Rhône, Ardeche, France. Two supposed lophogastrid taxa, Dollocaris ingens van Straelen, 1923 and Kilianicaris lerichei van Straelen, 1923 (both from the Upper Jurassic of France), have recently been identified as belonging not to the Mysidacea but to the Thylacocephala (Arduini and Pinna, 1989; in Benton, 1993). The Family Peachocarididae is represented solely by Peachocaris strongii Brooks, 1962 from the Middle Carboniferous Mazon Creek beds, USA. The extant Family Eucopiidae is represented in the fossil record by Schimperella beneckei Bill, 1914 (Figure If) and S. kessleri Bill, 1914, both from the Triassic exposures of Grès à Voltzia, Alsace, France. A 'new' form of lophogastrid from Middle Triassic sediments in Guizhou Province, China, will be placed in the Family Eucopiidae (in preparation) based on its striking overall similarity to S. beneckei. As with the fossil Mysidacea, the known fossil forms of lophogastrids are very simi­ lar to extant forms. The 'early' Lophogastrida demonstrate a wide dispersal pattern already by the Triassic, occurring in areas that today make up France and China. These countries were at distant ends of the Palaeo-Tethys Ocean during the Triassic, suggesting that the Triassic distrib­ ution of the Lophogastrida may be the product of an earlier time when these landmasses were closer together. As these animals were already so well developed morphologically, it is likely that their Triassic distribution is the by-product of an earlier fauna.

Order Hemicaridea, Suborder Spelaeogriphacea The Spelaeogriphacea (Figure lg) are a group of Crustacea that are rare both in the fossil record and in the modern biosphere. A total of three extant species are currently known. Spelaeogriphus lepidops was described by Gordon in 1957, based on material collected from the underground water pools in Bat Cave, Table Mountain, South Africa. The second recent species is Potiicoara brasiliensis, collected from a lake within the Gruta do Laga Azul cave in

97 Chapter 5

Late Permian 255 Ma

Figure 3. Palaeogeographic map of the Late Permian Earth (from Scotese 1997).

the Bodoquena Mountains, Mato Grosso do Sul, Brazil and described by Peres in 1986. The third and most recently described species is Mangkurtu mityula, described by Poore and Humphries (1998). It is the first spelaeogriphacean reported from Australia, and has been col­ lected from the Western Australia Pilbara region, Millstream aquifer. All three recent taxa belong to the Family Spelaeogriphidae Gordon, 1957. The fossil record for the Spelaeogriphacea is, sadly, as sparse as that of the known recent taxa. They are divided over two families, the Spelaeogriphidae and the Acadiocarididae Schram, 1974. The earliest known fossil form, Acadiocaris novascotica, was described by Copeland (1957) and later re-described by Schram (1974). It is found in Carboniferous strata in the Maritime Provinces, eastern Canada, and is the sole member of the Family Acadiocarididae. Shen et al. (1998) have recently described a second fossil spelaeogriphacean - Liaoningogriphus quadripartitus (Figure lg) - from the Upper Jurassic of northeastern China, and placed it in the Spelaeogriphacea. A third fossil form has been discovered from Upper Jurassic strata in Las Hoyas, Spain, and will be described in an upcoming publication (E. Pinardo Moya, personal commun., 1997). Despite the fact that the number of known spelaeogriphacean taxa may be few, they still manage to paint an interesting biogeographic picture. The fossil forms (A. novascotica, L. quadripartitus and the as-yet-unpublished species from Las Hoyas) all share a Laurentia/Angara, northern hemisphere distribution, with their respective collection localities of Canada, China and Spain. The recent taxa, on the other hand, are all from areas derived from a Gondwanan distribution: S. lepidops from South Africa, P. brasiliensis from South America, and M. mityula from Australia. One possible explanation for this distribution is a shift in spelaeogriphacean distributions sometime between the Jurassic and today: a Laurentian origin/dispersal followed by a migration to (and subsequent secondary dispersal in) the southern hemisphere Gondwanan regions.

98 Fossil Crustacea of China

A more likely explanation, however, is an earlier origin with a Permian distribution throughout Pangea (Figure 3), with the Recent cavernicolous forms known today representing the relics of this earlier and more widespread distribution. The occurrence of the Carboniferous spelaeogriphacean A. novascotica in a marine habitat (Schram, 1974) supports this notion of their once having broader habitat ranges. The recent discovery of the Jurassic form in Spain and M. mityula in Australia agree with Schram's (1977,1982) prediction that liv­ ing Spelaeogriphacea would be found in Gondwanan areas. It is anticipated that as explo­ ration of the little-known groundwater systems of the world continues, more of these enigmat­ ic creatures will be discovered. We also expect that further exploration will unveil more fos­ silized Spelaeogriphacea, in both the southern and northern hemispheres.

Order Decapoda, Suborder Reptantia [Fractosternalia.Astacida (sensu Scholts & Richter, 199511 The group known generally known as the 'reptantian' Decapoda has recently undergone some serious taxonomie revision. The traditional perspective (e.g., Glaessner, 1969; Hobbs Jr., 1988) has been a sister-group relationship between the crayfish and the lobsters within the infraorder Astacidea Latreille, 1803. The crayfish (Superfamilies Astacoidea and Parastacoidea; Figure lh) occur naturally on all continents with the exception of Africa, and have been introduced (either intentionally or accidentally) to many new localities worldwide (Hobbs, Jr., 1988). There are three extant families of crayfish, the northern hemisphere Astacidae (from western North America and western Europe) and Cambaridae (east North America and East Asia) as well as the Southern Hemisphere Parastacidae. The lobsters have traditionally been placed in the Family Nephropidae, which includes the true lobsters such as Homarus americanus and H. gammarus, the lobsters commonly served at dinner tables in North America and Europe, respectively. Recent work by Scholtz and Richter (1995) suggests a different taxonomie scheme for these taxa. They carried out a phylogenetic analysis using the method of Hennig on the reptantian Decapoda (using a wide suite of features, including morphological, developmental, behavioral, reproductive, and neural characters), and came to some rather different conclu­ sions than those traditionally accepted. Most relevant here was their result that indicated the crayfish are not the sister group to the Nephropidae (as perhaps expected) but are closer to the 'higher' decapods in a clade they named the Fractosternalia. I will follow the taxonomie scheme of Schultz and Richter in this discussion, while using the traditional superfamily and family names. Extinct astacidean families include the Protastacidae Albrecht, 1983 and the Platychelidae Glaessner, 1969. The Platychelidae are found only in Triassic strata, Platypleon van Straelen, 1936 in the USA and Glaessnericaris Garassino and Teruzzi, 1993 in Italy. The Jurassic/Cretaceous Family Protastacidae is also made up of two genera (both monotypic), Pseudastacus Oppel, 1861 and Protastacus Albrecht, 1983 (but see below). Both forms are known only from German strata, and are considered to be an intermediate form between the extinct Erymidae and the 'true' crayfishes making up the remaining astacidean families. Tshudy and Babcock (1997) also included Pseudastacus Oppel, 1861 in their new Family Chilenophoberidae (as well as three fossil genera: the Middle Jurassic Palaeophoberus Glaessner, 1932, Late Jurassic Chilenophoberus Chong & Förster, 1976, and Early Cretaceous

99 Chapter 5

Tillocheles Woods, 1957). They suggest this family is the sister group to the Nephropidae, a more traditional ('pre-Scholtz and Richter') perspective. There is, clearly, still much confusion regarding the taxonomy of many of the decapods. The three crayfish families are the Astacidae and the Cambaridae, making up the Astacoidea, and the Parastacidae, sole family of the Parastacoidea. The Astacidae and Cambaridae are known today from Northern Hemisphere localities, the Astacidae being found in western North America and western Asia and the Cambaridae in western Asia and eastern North America. The Parastacidea occur only in the Southern Hemisphere, with native taxa reported from Australia, Indonesia, New Zealand, South America and Madagascar. These areas reflect their natural distributions only: several taxa from all three families have been introduced into numerous other regions, both intentionally and accidentally. The earliest recorded fossil cambarid is Cambarus primaevus Packard, 1880, from the Tertiary of North America. Undescribed Upper Triassic material from the Colorado Plateau, North America, may also be cambarid in affinity (Hasiotis and Mitchell, 1989; in Benton, 1993). Fossil members of the Parastacidae are rare, with the oldest known to date being the Pleistocene ?Astacopsis (Glaessner, 1969). The earliest reported fossil astacids are from the Jurassic of China, and are discussed in detail immediately below. Well-developed fossil crayfish, resembling modern forms closely, have been report­ ed from Liaoning Province, northeastern China. Van Straelen (1928) provided the first report of fossil crayfish in China, with his description of the freshwater species Astacus licenti from Upper Jurassic strata "south-west of Moukden, in Eastern Mongolia" (in actuality, northeastern Liaoning Province; p. 134). He was uncertain as to the true generic identity of this material, as he was working from little (and mostly poorly preserved) material, although he felt it belonged "undoubtedly to the family of the Astacidae". Imaizumi (1938) provided further insight into the astacidean fauna of the region, with his erection of the new taxon Astacus spinirostrius based on two new specimens collected (along with three new specimens of A. licenti) at Niehhutzekow, near Lingyuan, northeastern China. He also showed some trepida­ tion in assigning this species to the genus Astacus, due to its similarities to Pseudastacus. The recent collection of several new specimens from the region has lead to a re­ examination of the Jurassic crayfish of Liaoning. After studying this new material (as well as the type specimens used by Imaizumi (1938); Van Straelen's (1928) types are unfortunately lost), Taylor et al. (in press) suggested that the differences between the two Chinese Jurassic crayfish taxa are not sufficient to maintain them as separate species, and synonomysed A. spinirostrius with A. licenti. However, they also erected a new taxon, Cricoidoscelosus aethus (Figure lh), based on several specimens with annulate, antennae-like pleopods, a feature not seen in any other crayfish taxa (extinct or extant). They erected a new family, the Cricoidoscelosidae, to house this unusual species. Scholtz (1995) has considered the distribution of fossil and recent crayfishes, and has suggested that there must have been a single invasion by the crayfish to freshwater, with the ur-crayfish moving from the marine realm to freshwater systems during the Triassic [prior to the break-up of Pangea (Figure 3)]. Thus, a common ancestor would have provided the ori­ gins for the Laurentian Cambaridae and Astacidae and the Gondwanan Parastacidae. The wide distributions of each of these three families today supports the notion that they must

100 Fossil Crustacea of China have originated well before the division of the Gondwanan and Laurentian landmasses. The presence of highly developed freshwater crayfish in Jurassic strata in China also agrees with this idea of their probably Triassic origins. If the undescribed Triassic specimens mentioned by Hasiotis and Mitchell (1989; in Benton, 1993) are in fact cambarid, this would lend even more support to this Pangean origin of the freshwater crayfish as suggested by Schultz.

'Burgess Shale-type'faunas This is a truly fascinating time of discovery for Cambrian palaeontology, with sev­ eral research groups publishing on Cambrian soft-part preservation around the world. Examples include G. Budd, who has recently published a series of papers dealing with fossil arthropods from the Lower Cambrian Sirius Passet fauna of North Greenland (i.e., Budd 1997, 1999). A second source of extensive information on Cambrian arthropods has been the work of D. Walossek and K. Müller, who have published extensively on the Upper Cambrian Orsten fauna from Sweden. Their research has dealt in particular with stem-lineage crustaceans and early 'true' crustaceans (i.e., Müller and Walossek, 1985; Walossek, 1993; Walossek and Müller, 1997). The most widely known Cambrian fossils, both in the scientific literature and to the general public, are those from the Burgess Shale of British Columbia, western Canada. They have been immortalized in the public eye by the publication of such 'popular' volumes as Simon Conway-Morris' 'The Crucible of Creation' (1998) and Stephen Gould's 'Wonderful Life' (1989), two highly educational and entertaining volumes, if somewhat disparate in viewpoint. Through these books and the publications of Harry Whittington, Derek E. G. Briggs, Simon Conway-Morris and Desmond Collins (i.e., Briggs, 1983; Collins, 1996; Conway-Morris, 1986; Whittington, 1980; Whittington and Conway-Morris, 1985), the Burgess Shale has become per­ haps the best understood and best known fossiliferous fauna in the world. Also relevant to this paper are the works emerging today from the Lower Cambrian Chengjiang fauna of southwestern China. This locality has been the focus of intensive research since only the 1980s, although it was first discovered - and subsequently forgotten, it seems - in the first decade of this century (Mansuy, 1912; in Conway-Morris, 1998). In just a few years, it has revealed an enormous amount of new information about life (and the Arthropoda in par­ ticular) during the Early Cambrian (i.e., Chen, et al, 1995; Hou et al, 1996; Hou and Bergström, 1997). Dealing with the Cambrian Lagerstätte in the context of this paper, or in any paper dealing with the Crustacea, touches on vexing issues. Interpretations as to the nature of the Burgess-type faunas are rarely in agreement. There are several separate schools of thought as to the true nature of these Cambrian animals, which sometimes represent apparently closely related taxa despite the geographical separation of China and Canada during the Cambrian and the 15 million years separating them (Figure 2). Gould (1988) has suggested that many of the Burgess Shale oddities, the animals that cannot readily be 'fit' into existing taxa, are in fact the remnants of a time when the range of existing animal types was much greater than during any other time period. By this reasoning, many more phyla would have existed in the Cambrian world than the 35 or so we recognize today. Hou and Bergström (1997) have sug­ gested just this for many of the Chengjiang animals, if on a lower taxonomie scale. For exam-

101 Chapter 5 pie, the Order Canadaspidida had been previously placed within the crustacean subclass Phyllocarida, as discussed previously. Hou and Bergström, however, erected the new Class Paracrustacea to house this order (including the Canadian species Canadaspis perfecta and the new Chinese form C. laevigata) as well as other orders. They suggest, in fact, that there may be no true Crustacea at all in the Chengjiang fauna. Another perspective is the more conservative notion that many Cambrian animals can be fit into existing taxonomie categories, while others may represent primitive or early forms of modern taxa. Perhaps the best-known example of this is the work of Walossek and Müller on the Upper Cambrian Orsten fauna of Sweden (i.e., Walossek and Müller, 1990), which they interpret as representing early or 'stem-group' crustaceans. These animals possess only a few features in common with the 'true' Crustacea, but other unique features that they suggest are derived from a common ancestor shared with the Crustacea. Such animals as those from the Orsten faunas may eventually shed much light on the early evolution of the Arthopoda and in particular the Crustacea. Other approaches to these Cambrian faunas result in varying interpretations. Schram and Hof (1998) found that in a cladistic analysis including the Burgess/Orsten 'arthro­ pods' and all major 'crown group' ('true') crustacean taxa, the Burgess and Orsten fossils could emerge as a separate clade in an intermediate position between the out-group taxa (three uni- ramians) and the 'crown-group' Crustacea. Wills et al. (1998), using a similar cladistic approach, achieved a different result in their analysis. They found that the while the 'true' Crustacea did end up in their own monophyletic clade (including several Cambrian taxa), many Cambrian forms were widely dispersed throughout their tree. Most (mainly the non- bivalved problematica) were closely associated with the Arachnomorpha (including the Chelicerata and Trilobita), sister clade to the Crustacea. Others were closer to the Marrellomorpha, the group of distinctive Cambrian - Devonian animals found basally in the schizoramian clade. Clearly, the final word on the taxonomie position of the Cambrian 'arthropods' has not yet been written. The new material coming out of the Chengjiang deposits will hopefully help to clarify some of these issues of arthropod and crustacean origins. Cladistic methods are another likely candidate to help in the final understanding of the Cambrian fossil record, but much yet needs to be done before cladistic analyses utilizing fossil and modern taxa are universally accepted.

Conclusions Over the course of this paper, one theme has recurred more often than most: the importance of understanding the deep history of taxa. In order to accurately piece together the biogeographic history of a group, it is usually not enough to look at trends shown by modern representatives. To understand the evolutionary history of a group, it is not sufficient to sim­ ply compare it to other living taxa, be it through morphological, genetic or cladistic techniques. The durations of many taxa extend back in time for several hundred million years. It is unlike­ ly that any such taxonomie group can be properly understood today without some apprecia­ tion of where they lived, what they looked like, and what mode of life they lived in the past. Several groups discussed in this paper demonstrate 'early' representatives that are

102 Fossil Crustacea of China strikingly similar to their modern-day descendants, such as the Triassic Lophogastrida and the Jurassic Spelaeogriphacea. Other fossil taxa, such as the Early Cambrian 'stem-group' Crustacea of the Sirius Passet fauna and the Middle/Late Cambrian arthropods of Canada and China, tell us much about the early evolution of the Arthropoda, one of the major invertebrate groups evident in today's biosphere. Only through a better understanding of the fossil records of these and other taxa will we have any chance of understanding their evolutionary history and the history of life on the Earth.

Acknowledgments Thanks go out to ER. Schram for his suggestions and comments during the prepa­ ration of this manuscript. This research has been made possible by a grant (no. 750.195.17) from 'de Stichting Geologisch, Oceanografisch en Atmosferisch Onderzoek', Nederlandse Organisatie voor Wetenschappelijk Onderzoek (the Foundation for Geological, Océanographie and Atmospheric Research, the Dutch Organization for Scientific Research).

REFERENCES

Benson, R.H., 1961. Ecology of Ostracode assemblages, p. Q56-63. In R.C. Moore (ed.), Treatise on Invertebrate Paleontology, Part Q, Arthopoda 3: Crustacea: Ostracoda. Geological Society of America and University of Kansas Press, Lawrence. Benton, M.J., 1993. The Fossil Record 2. Chapman and Hall, London, 845 pp. Briggs, D.E.G., 1978. The morphology, mode of life, and affinities of Canadaspis perfecta (Crustacea: Phyllocarida), Middle Cambrian, Burgess Shale, British Columbia. Philosophical Transactions of the Royal Society, London B, 281: 439-487. Briggs, D.E.G., 1983. Affinities and early evolution of the Crustacea: the evidence of the Cambrian fossils, p. 1-22.. In FR. Schram (ed.), Crustacean Phytogeny. A.A. Balkema, Rotterdam. Brooks, H. K., 1962. The Palaeozoic Eumalacostraca of North America. Bulletins of American Paleontology, 44: 163-338. Brusca, R.C. and G.J. Brusca., 1990. Invertebrates. Sinauer Associates, Inc., Sunderland. 922 pp. Budd, G.E., 1997. Stem group arthropods from the Lower Cambrian Sirius Passet fauna of North Greenland, p. 125-138. In R.A. Fortey and R.H. Thomas (eds.), Arthropod Relationships. Systematics Association Special Volume Series 55. Chapman & Hall, London. Budd, G.E., 1999. A nektaspid arthropod from the Early Cambrian Sirius Passet fauna, with a description of retrodeformation based on functional morphology Palaeontology, 42: 99- 122. Casanova, J.-P, L. De Jong and E. Faure, 1998. Interrelationships of the two families constitut­ ing the Lophpgastrida (Crustacea: Mysidacea) inferred from morphological and molec­ ular data. Marine Biology, 132: 59-65.

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Chen PJ, ZM Dong and SN Zhen, 1998. An exceptionally well-preserved Theropod dinosaur from the Yixian Formation of China. Nature, 391: 147-152. Chen Peiji, 1996. Nonmarine Jurassic strata of China, p. 395-412. In Michael Morales (ed.), The Continental Jurassic. Museum of Northern Arizona Bulletin 60. Chen Peiji, Li Wenben, Chen Jinhua, Ye Chunhui, Wang Zhen, Shem Yanbin and Sun Donglu, 1982. Statigraphical classification of Jurassic and Cretaceous in China. Scientia Sinica, 25:1227-1248. Chen Peiji and Chang Zhenlu, 1994. Nonmarine Cretaceous stratigraphy of eastern China. Cretaceous Research, 15: 245-257. Chen Junyuan, Zhou Guiqing and L.Ramsköld, 1995. The Cambrian lobopodian Microdictyon sinicum. Bulletin of the National Museum of Natural Science, 5: 1-93. Chen Junyuan, Zhou Guiqing, Zhu Maoyan and Yeh Y.K., 1996. The Chengjiang Biota. A Unique Window of the Cambrian Explosion. National Museum of Natural Sciences, Taichung, Taiwan, China. Chen Junyuan and Zhou Guiqing, 1997. Biology of the Chengjiang Fauna. In Chen Junyuan, Cheng Yennien and H.V. Iten (eds.), The Cambrian Explosion and the Fossil Record. Bulletin of the National Museum of Natural Science Number 10, Taichung, Taiwan, China. Chen Xu, 1994. "Arenig" to Llanvirn" graptolite provincialism of South China, p. 223-239. In Chen Xu, B.-D. Erdtmann & Ni Yu-nan (eds.), Graptolite Research Today. Nanjing University Press, Nanjing. Chen Xu, B.-D. Erdtmann & Ni Yu-nan (eds.), 1994. Graptolite Research Today. Nanjing University Press, Nanjing, 223-239 p. Chen Xu, Yang Wang-rong, He Zi-qiang and Wang Sheng-hui, 1981. Ordovician graptolite- bearing beds of Xingian, Guangxi. Journal of Stratigraphy, 5: 36-45. Chernysheva, N.E. (ed.), 1960. Fundamentals of Paleontology Vol. 8: Arthropoda - Trilobita and Crustacea. Akademiya Nauk SSSR, Moscow, 515 p. Colin, J.-P and F. Lethiers, 1988. The importance of ostracods in biostratigraphic analysis, p. 27-46. In P. De Deckker, J.-P Colin and J.-P. Peypouquet (eds.), Ostracoda in the Earth Sciences. Elsevier, Amsterdam. Collins, D. 1996, The "evolution" of Anomalocaris and its classification in the arthropod Class Dinocarida (nov.) and Order Radiodonta (nov). Journal of Paleontology, 70: 280-293. Conway Morris, S., 1986. The community structure of the Middle Cambrian phyllopod bed (Burgess Shale). Palaeontology, 29: 423-467. Conway Morris, S., 1998. Tlie Crucible of Creation. Vie Burgess Shale and the Rise of Animals. Oxford University Press, Oxford. 242 pp. Cooper, RA., RA. Fortey and K. Lindholm, 1991. Latitudinal and depth zonation of early Ordovician graptolites. Lethaia, 24: 199-218. Copeland, M.J., 1957. The Carboniferous genera Palaeocaris and Euproops in the Canadian Maratime Provinces. Journal of Paleontology, 31: 595-599. Dahl, E., 1983. Phylogenetic systematics and the Crustacea malacostraca: a problem of prereq­ uisites. Abhandlungen des naturwissenschaftlichen Vereins in Hamburgs (NF) 26: 355-371. Dahl, E., 1984. The subclass Phyllocarida (Crustacea) and the status of some early fossils: a

104 Fossil Crustacea of China

neontologist's view. Videnskabelige Meddelelser fra dansk naturhistorisk Forening, 145: 61- 76. Dahl, E., 1990. Records of Nebalia (Crustacea Leptostraca) from the southern hemisphere - a critical review. Bulletin of the British Museum of Natural History, 56: 73-91. De Deckker, P., J.-R Colin and J.-P Peypouquet (eds.), 1988. Ostracoda in the Earth Sciences. Elsevier, Amsterdam, 302 p. Glaessner, M.F., 1969. Decapoda, p. R399-651. In Raymond C. Moore (ed.), Treatise on Invertebrate Paleontology, Part R, Arthropoda 4(2). Geological Society of America and University of Kansas, Lawerence. Gould, S.J., 1989. Wonderful Life. The Burgess Shale and the Nature of History. WW. Norton & Co., New York, 347 p. Hanai, T., N. Ikeya and K. Ishizaki (eds.), 1988. Evolutionary Biology of Ostracoda (its fundamen­ tals and applications). Developments in Palaeontology and Stratigraphy 11. Proceedings of the Ninth International Symposium on Ostracoda, Shizuoka, Japan, 29 July - 2 August 1985. Elsevier, Amsterdam, 1356 p. Halstead, L.B., 1990. Cretaceous - Tertiary (Terrestrial), p. 203-207. In D.E.G. Briggs and PC Crowther (eds.), Palaeobiology: A Synthesis. Blackwell Scientific Publications, Oxford. Hobbs Jr., H.H., 1988. Crayfish distribution, adaptive radiation and evolution, p. 52-82. In D.M. Holdich & R.S. Lowery (eds.), Freshwater Crayfish: Biology, Management and Exploitation. Croom Helm, London. Hof, Cees and D.E.G. Briggs, 1997. Decay and mineralization of mantis shrimps (Stomatopoda: Crustacea) - a key to their fossil record. Palaios, 12: 420-438. Hou, Xianguang, D.J. Siveter, M. Williams, D. Walossek and J. Bergstrom, 1996. Appendages of the arthropod Kunmingella from the early Cambrian of China: its bearing on the sys­ tematic position of the Bradoriida and the fossil record of the Ostracoda. Philosophical Transactions of the Royal Society, London B, 351:1131-1145. Hou Xianguang and J. Bergström, 1997. Arthropods of the Lower Cambrian Chengjiang fauna, southwest China. Fosils & Strata Number 45. Scandinavian University Press, Oslo, 116 pp. Huang Wanpo, 1980. The sites of Quaternary mammal faunas in Xizang, p. 35-41. In: Paleontology of Xizang Vol. 1. Geological Publishing House, Beijing. Huang Wanpo, 1986. Quaternary mammalian faunas and climate variations in East China. Quaternaria Sinica, 7: 54-60. Imaizumi, R, 1938. Fossil crayfishes from Jehol, p. 173-178. The Science Reports of the Tohoku Imperial University (Sendai, Japan). Ser. 2 (Geology), vol. 19. Ji Qiang, P.J. Currie, M.A. Norell and Ji Shuan, 1998. Two feathered dinosaurs from northeast­ ern China. Nature, 393: 753-761. Kempf, E.K., 1980. Index and bibliography of nonmarine Ostracoda, 1, Index A. Geologisches Institut der Universität zu Köln Sonderveroffentlichungen no. 35. Kempf, E.K., 1986. Index and bibliography of marine Ostracoda, 1, Index A. Geologisches Institut der Universität zu Köln Sonderveroffentlichungen no. 50. Lin Bayou and Chou Xinghu, 1977. Tabulata and Heliolitida of the Upper Ordovician of the Chejiang and Jiangxi provinces. Professional Papers of Stratigraphy and Palaeontology, 3:

105 Chapter 5

108-208. Lin Bayou and Wang Bayou, 1985. Some Ordovician heliolitid corals from Jiabosar Formation of Jiabosar district, Xinjiang. Acta Palaeontologica Sinica, 24: 351-356. Lin Yaokun, 1980. Cambrian graptolites of China and their sequence. Journal of Stratigraphy, 4: 129-135. Lin Yaokun and Zhu Zhaoling, 1989. New investigation of the Cambrian-Ordovician bound­ ary in the Shansonggang-Xangxishao region, Huinan, Jilin. Journal of Stratigraphy, 13: 138-143. McGowan, C, 1991. Dinosaurs, Spitfires, and Sea Dragons. Harvard University Press, Cambridge, 365 pp. McKenzie, K.G., M.V. Angel, G. Becker, I. Hinz-Schallreuter, M. Kontrovitz, A.R Parker, R.E. Schallreuter and K.M. Swanson, 1999. Ostradocs, p. 459-507. In E. Savazzi (ed.), Functional Morphology of the Invertebrate Skeleton. John Wiley & Sons, Chichester. McKenzie, K.G. and Chen Peiji, 1999. Kazacharthra, p. 443-458. In E. Savazzi (ed.), Functional Morphology of the Invertebrate Skeleton. John Wiley & Sons, Chichester. Martill, D.M., 1999. Resolution of the fossil record: the fidelity of preservation, p. 55-74. In S.K. Donovan and C.R.C. Paul (eds.), The Adequacy of the Fossil Record. John Wiley & Sons, Chichester. Martin, J.M., 1989. Morphology of feeding structures in the Conchostraca with special refer­ ence to Lynceus, p. 123-136. In B.E. Felgenhauer, L. Watling and A.B. Thistle (eds.), ER. Schram, series ed., Functional Morphology of Feeding and Grooming in Crustacea. Crustacean Issues 6, A.A. Balkema, Rotterdam. Martin, J.M. and D. Belk, 1988. Review of the clam shrimp Family Lynceidae Stebbing, 1902 (Branchiopoda: Conchostraca) in the Americas. Journal of Crustacean Biology, 8: 451-482. Martin, J.M., B.E. Felgenhauer and L.G. Abele, 1986. Redescription of the clam shrimp Lynceus gracilicornis (Packard) (Branchiopoda, Conchostraca, Lynceidae) from Florida, with notes on its biology. Zoologica Scripta, 15: 221-232. Martin, J.M., E.W. Vetter and CE. Cash-Clark, 1996. Description, external morphology, and natural history observations of Nebalia hessleri, new species (Phyllocarida: Leptostraca), from southern California, with a key to the extant families and genera of the leptostraca. Journal of Crustacean Biology, 16: 347-372. Moore, R.C. (ed.), 1961. Treatise on Invertebrate Paleontology, Part Q, Arthopoda 3: Crustacea: Ostracoda. Geological Society of America and University of Kansas Press, Lawrence. Moore, R.C., H.W Scott and P.C. Sylvester-Bradley, 1961. Introduction, p. Q2-3. In Moore, R.C. (ed.), Treatise on Invertebrate Paleontology, Part Q, Arthopoda 3: Crustacea: Ostracoda. Geological Society of America and University of Kansas Press, Lawrence. Mu Enzhi and Chen Xu, 1962. Graptolites in China. Science Press, Beijing. Mu Enzhi, Li Jilin, Ge Meiyu, Chen Xu, Ni Yunan, Lin Yaokum and Mu Xinan, 1974. Ordovician graptolites, p. 154-164. In The Nanjing Institute of Geology and Palaeontology, Academia Sinica (ed.), A Handbook of the Stratigraphy and Palaeontology in Southwest China. Science Press, Beijing. Mu Enzhi and Lin Yaokun, 1984. The Xingangian graptolites from western Zhejiang, p. 162- 182. In: Stratigraphy and Palaeontology of Systemic Boundaries in China, Cambrian-

106 Fossil Crustacea of China

Ordovician Boundary (1). Anhui Science and Technology Publishing House, Hefei. Müller, K.J., 1979. Phosphatocopine ostracodes with preserved appendages from the Upper Cambrian of Sweden. Lethaia, 12: 1-27. Müller, K.J. and D. Walossek, 1985. Skaracarida, a new order of Crustacea from the Upper Cambrian of Västergötland, Sweden. Fossils and Strata, No. 17. 1-65. Pinto, I.D. and K. Adami-Rodrigues, 1996. Pygocephalomorph Crustacea. New data and interpretations, with emphasis on Brazilian and South African forms. Pesquisas, 23: 41- 50. Poore, G.C. and W.F. Humphries, 1998. First record of Spelaeogriphacea from Australasia: a new genus and species from an aquifer in the arid Pilbara of western Australia. Crustaceana, 71: 721-742. Rolfe, I.W.D., 1969. Phyllocarida, p. 296-331.. In Raymond C. Moore (ed.), Treatise on Invertebrate Paleontology, Part R, Arthropoda 4(1). Geological Society of America and University of Kansas Press, Lawrence. Scholtz, G., 1995. Ursprung und evolution der Flubkrebse (Crustacea, Astacida). Sitzungsberichte der Geselleshaft Naturforschender Freunde zu Berlin, 34: 93-115. Scholtz, G. and S. Richter, 1995. Phylogenetic systematics of the reptantian Decapoda (Crustacea, Malacostraca). Zoological Journal of the Linnean Society 113: 289-328. Schram, ER., 1974. Paleozoic Peracarida of North America. Fieldiana Geology, 33: 95-124. Schram, F.R, 1977. Paleozoogegraphy of Late Paleozoic and Triassic Malacostraca. Systematic Zoology, 26: 367-379. Schram, FR, 1979. The Mazon Creek biotas in the context of a Carboniferous faunal continuum, p. 159-190. In: M.H. Nitecki (ed.), Mazon Creek Fossils, Academic Press, Inc., New York. Schram, FR, 1982. The Fossil Record and Evolution of Crustacea, p. 93-147. In L.G. Abele (ed.), The Biology of Crustacea, Vol. 1. Academic Press, Inc., New York. Schram, ER, 1986. Crustacea. Oxford University Press, Oxford, 606 pp. Schram, F.R. and C.H.J. Hof, 1998. Fossils and the interrelationshyips of major crustacean groups, p. 233-302. Jn G.D. Edgecombe (ed.), Arthropod Fossils and Phytogeny. Columbia University Press, New York. Scotese, C. R, 1997. Paleogeographic Atlas. PALEOMAP Progress Report 90-0497, Department of Geology, University of Texas at Arlington, Arlington, Texas, 37 pp. Secretan, S. and B.Riou, 1986. Les Mysidacés (Crustacea, Peracarida) du Callovien de la Voulte-sur- Rhône. Annales de Paléontologie (Vert. - Invert.), 72: 295-323. Shen, Yanbin, 1978. Leaid Conchostracans from the Middle Devonian of South China with notes on their origin, classification and evolution, p. 1-15. In: Papers for the International Symposium on the Devonian System. Nanking Institute of Geoilogy and Palaeontology, Academia Sinica, Nanjing. Shen, Yanbin, 1983. A new pygocephalomorph genus (Eumalacostraca) of Lower Carboniferous from Anhui. Acta Palaeontologica Sinica, 22: 663-668. Shen, Yanbin and N.J. Mateer, 1988. An outline of the Cretaceous System in northern Xinjiang, western China, p. 49-77. Aspects ofNonmarine Cretaceous Geology. First International Symposium on Nonmarine Cretaceous Correlations, 1987.

107 Chapter 5

Shen, Yanbin and Zhu Tong, 1990. A new conchostracan genus from Lower Permian Tongziyan Formation, Fujian. Acta Palaeontologica Sinica, 29: 309-314. Shen, Yanbin, RS. Taylor and FR. Schram, 1998. A new spelaeogriphacean (Crustacea: Peracarida) from the Upper Jurassic of China. Contributions to Zoology, 68:19-35. Surlyk, F. 1990, Cretaceous - Tertiary (Marine), p. 198-203. In: D.E.G. Briggs and PC. Crowther (eds.), Palaeobiology: A Synthesis. Blackwell Scientific Publications, Oxford. Tasch, P., 1969. Branchiopoda, p. 128-191. In: Raymond C. Moore (ed.), Treatise on Invertebrate Paleontology, Part R, Arthropoda 4(1). Geological Society of America and University of Kansas Press, Lawrence. Tasch, P., 1987. Fossil Conchostraca of the Southern Hemisphere and Continental Drift. Paleontology, Biostratigraphy, and Dispersal. Geological Society of America Memoir 165. 290 pp. Taylor, R.S., Shen Yanbin and FR. Schram, 1998. New pygocephalomorph crustaceans from the Permian of China and their phylogenetic relationships. Palaeontology, 41: 815-834. Taylor, R.S., FR. Schram and Shen Yanbin, In press. A new crayfish Family (Decapoda: Astacidae) from the Upper Jurassic of China, with a reinterpretation of other Chinese crayfish taxa. Palaeontological Research. Tshudy, D. and L.E. Babcock, 1997. Morphology-based phylogenetic analysis of the clawed lobsters (Family Nephropidae and the new Family Chilenophoberidae). Journal of Crustacean Biology, 17: 253-263. Van Straelen, V., 1928. On a fossil freshwater Crayfish from eastern Mongolia. Bulletin of the Geological Society of China, 7:133-138. Walossek, D., 1993. The Upper Cambrian Rehbachiella and the phylogeny of Branchiopoda and Crustacea. Fossils and Stratra, No. 32,1-202. Walossek, D. and K.J. Müller, 1990. Upper Cambrian stem-lineage crustaceans and their bear­ ing upon the monophyletic origin of Crustacea and the position of Agnostus. Lethaia, 23: 409-427. Walossek, D. and K.J. Müller, 1997. Cambrian 'Orsten'-type arthropods and the phylogeny of Crustacea, p. 139-153. In: RA. Fortey and R.H. Thomas (eds.), Arthropod Relationships. Systematics Association Special Volume Series 55. Chapman & Hall, London. Wang Keliang, 1984. Early Carboniferous Foraminifera from Shaoyang are of Hunan province and their stratigraphie cignificance. Bulletin of Nanjing Institute of Geology and Palaeontology Academia Sinica, 6: 209-224. Wang Keliang, 1985. Fossils in the south of Tuomuer region, p. 137-140. In: Geology and Palaeontology of Tuomuer Region, Tianshan. Xinjiang People's Publishing House, Urumqi. Whatley, R. and C. Maybury (eds.), 1990. Ostracoda and Global Events. Austin, R.L. (series ed.), British Micropalaeontological Society Publication Series. Chapman and Hall, London. Whittington, H.B., 1980. The significance of the fauna of the Burgess Shale, Middle Cambrian, British Columbia. Proceedings of the Geologists' Association, 91:127-148. Whittington, H.B. and S. Conway-Morris, 1985. Extraordinary fossil biotas: their ecological and evolutionary significance. Philosophical Transactions of the Royal Society, London B, 311: 1-192. Wills, M.A., D.E.G. Briggs, RA. Fortey, M. Wilkinson and P.H.A. Sneath, 1998. An arthropod phylogeny based on fossil and recent taxa, p. 33-106. In: G.D. Edgecombe (ed.),

108 Fossil Crustacea of China

Arthropod Fossils and Phytogeny. Columbia University Press, New York. Xu Ren, 1982. Reconstructions of fossil floral communities. Science Press, Beijing. Yang Jialu, 1978. Middle and Upper Cambrian trilobites of western Hunan and eastern Guizhou. Professional papers of Stratigraphy and Palaeontology, 4: 1-82. Yang Jialu, Hu Chunsheng, Jiang Xinsheng, 1984. On new trilobite zones of the early Late Cambrian Laochatian Formation. Earth Science-Journal of Wuhan College of Geology, 25: 23-31. Yang Zunyi, 1986. The Cambrian system, p. 64-72. In: Yang Zunyi, Cheng Yuqi and Wang Hongzhen 1986. The Geology of China. Oxford Monographs on Geology and Geophysics No. 3, P. Allen, E.R. Oxburgh and B.J. Skinner (eds.). Clarendon Press, Oxford. Yang Zunyi, Cheng Yuqi and Wang Hongzhen, 1986. The Geology of China. Oxford Monographs on Geology and Geophysics No. 3, P. Allen, E.R. Oxburgh and B.J. Skinner (series eds.). Clarendon Press, Oxford, 303 pp. Yin Hongfu (ed.), 1994. The Palaeobiogeography of China. Oxford Biogeography Series No. 8, A. Hallam, B.R. Rosen and T.C. Whitmore (series eds.). Clarendon Press, Oxford, 370 pp. Zhang Xiguang and Pratt, B.R., 1993. Early Cambrian Ostracode larvae with a univalved cara­ pace. Science, 262: 93-94.

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