Santonian Sea Cucumbers (Echinodermata: Holothuroidea) from Sierra Del Montsec, Spain
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Santonian sea cucumbers (Echinodermata: Holothuroidea) from Sierra del Montsec, Spain Mike Reich1,2 * & Jörg Ansorge3 1Geoscience Museum, Georg-August University Göttingen, Goldschmidtstr. 1-5, 37077 Göttingen, Germany; Email: [email protected] 2Department of Geobiology, Geoscience Centre, Georg-August University Göttingen, Goldschmidtstr. 3, 37077 Göttingen, Germany 3Institute for Geography and Geology, Ernst-Moritz-Arndt University Greifswald, F.-L.-Jahn-Str. 17a, 17489 Greifswald, Germany; Email: [email protected] * corresponding author 77: 147-160, 8 figs. 2014 Recent discovery of disarticulated sea cucumber material from Font de la Plata (Sierra del Montsec, Lleida, Catalonia, Spain) resulted in the identification of at least six holothurian taxa, belonging to the Apodida (Synaptidae, Chiridotidae), Molpadiida (?stem group Molpadiidae), and Aspidochirotida (Holothuriidae). Three new genera (Cruxopadia, Eolepto- synapta, Eorynkatorpa) and four new species (Cruxopadia mesozoica, C. reitneri, Eoleptosynapta jaumei, Eorynkatorpa catalonica) are described from Late Cretaceous sediments of Spain, and in part from the Late Jurassic of France. The new fauna increases our knowledge of holothuroid echinoderms from Santonian strata worldwide. Received: 12 June 2013 Subject Areas: Palaeontology, Zoology Accepted: 01 August 2013 Keywords: Echinodermata, Holothuroidea, Jurassic, Oxfordian, France, Normandy, Cretaceous, Santonian, Spain, Catalonia, systematics, phylogeny LSID: urn:lsid:zoobank.org:pub:9C2E58EE-77E4-44F1-9511-4337496D7823 Introduction The Sierra del Montsec, situated in the southern marginal Santonian holothurians have so far been recorded only zone of Pyrenees, presents classical outcrops and excellent from Germany and the U.K. Lommerzheim (1976, 1991) preserved fossils of early and late Cretaceous age. Among reported their occurrence from Westphalia (Germany), them are also members of eleutherozoan echinoderms, but, unfortunately, without any descriptions. Upton (1917) such as echinoids, asteroids, and ophiuroids; only holo- mentioned a chiridotid wheel (Apodida) from the “Upper thurians were missing up to now. Chalk” of Purley (Surrey, England). Recently, a nearly ar- Holothuroid echinoderms are not common as fossils ticulated find from the “Upper Chalk” of England, be- in general (e.g., Frizzell & Exline 1956, 1966; Gilliland longing to the Holothuriidae (Aspidochirotida), was pre- 1993), the skeleton is rarely robust and consists of micro- sented by Reich (2008, 2013b) and is currently under de- scopic ossicles embedded in the body wall as well as of scription by Reich & Gale. larger calcareous ring elements, encircling the pharynx at the inner side of the mouth. Consequently they disarticu- late rapidly after death and have left a rather poor fossil record (e.g., Reich 2013a). 148 Mike Reich & Jörg Ansorge Fig. 1: Location of the sampled outcrop at Font de la Plata, east of Rúbies, Sierra del Montsec, Catalonia, Spain. Geological map from Ansorge (1991, modified). Geological setting and material The studied microfossil material from the late Santonian (1966: 84) are biostratigraphically useful and are consid- (“Santon E” of Krusat 1966) of the Font de la Plata ered to be late Santonian in age, which is in agreement (Montsec de Rúbies; Figs. 1–2) was sampled by JA in Sep- with other fossils (see Llompart 1979; Caus et al. 1999). tember 1996 and includes around 50 isolated holothurian This Santonian environment corresponds to an open shal- ossicles. This formation (> 100 m) contains grey and/or low-water platform (e.g., Llompart 1979). yellowish calcareous marls and marly limestones interbed- ded by limestones and sandstones (Krusat 1966: 60f.). It The studied samples include besides the isolated holothu- can be correlated with the “Unit 5” of Caus & Cornella rian ossicles also typical other calcareous microfossils, (1983) or with the “Montsec marls” of Caus & Gómez- such as foraminifera and ostracods, as well as microscopic Garrido (1989). remains of macrofossils, like octocoral scleres (Alcyo- The rich associated fauna (e.g., Krusat 1966) compris- nacea), echinoid spines, and ophiuroid ossicles (lateral side es abundant scleractinian corals and rudist bivalves, cal- shields, vertebrae etc.). careous algae, chaetetid sponges, decapod crustaceans, bivalves, gastropods, cephalopods, articulate brachiopods, In the systematic description we also introduce a new larger foraminifera and teleost fishes (e.g., Bataller 1937a, molpadiid genus (Cruxopadia Reich gen. nov.) with its 1953; Hottinger 1966; Cornella 1977; Caus et al. 1978; genotype C. mesozoica Reich sp. nov. from the early Ox- Hottinger et al. 1989; Nolf 2003; Garassino et al. 2009; fordian of Villers-sur-Mer (Calvados, France). Early Ox- Hottinger & Caus 2009). Echinoderms are also reported fordian mudstones of the Quenstedtoceras mariae Zone are with representatives of the Echinoidea and Asteroidea exposed at longer cliff sections of the English Channel (e.g., Bataller 1937b: 590, 1953: 57ff.; Krusat 1966: 58; coast between Houlgate and Villers-sur-Mer, Normandy Neumann & Hess 2001: 7ff.). (e.g., Dugué et al. 1998; Merle 2011). Holothurians from The pachydont bivalves Hippuritella maestrei (Vidal), the Oxfordian marls of Villers-sur-Mer are known for a Hippuritella sulcatissima (Douvillé), and Vaccinites galloprovin- long time (e.g., Deflandre-Rigaud 1946, 1962). Samples cialis (Matheron) (systematics updated after Vicens 1992, were taken by MR in 1999 and 2012. Vicens et al. 1998 and Steuber 2002) reported by Krusat Santonian sea cucumbers (Echinodermata: Holothuroidea) from Spain 149 Methods The microscopic fossils from clayey and calcareous marls were isolated using hot water and/or hydrogen peroxide (10 %). After washing (sieve sizes: >0.063 mm, 0.1 mm and 1 mm), the residues were dehydrated at a temperature of ~70°C (cf. Wissing & Herrig 1999). All specimens were studied under a binocular microscope first and later mounted on stubs and coated with Au/Pd or Au for in- vestigation and documentation using scanning electron microscopy (SEM). All figured specimens are deposited at the Geoscience Centre of the Georg-August University Göttingen, Ger- many (GZG). Fig. 2: Outcrop at Font de la Plata, east of Rúbies, showing the interbedded strata of calcareous marls and limestones (September 1996). Systematic palaeontology Phylum Echinodermata Bruguière, 1791 [ex Klein, 1734] Subphylum Eleutherozoa Bell, 1891 Class Holothuroidea de Blainville, 1834 Type locality. – Villers-sur-Mer, Normandy, France. Subclass Holothuriacea Smirnov, 2012 Order Molpadiida Haeckel, 1896 Type horizon. – “Marnes de Villers”, Quenstedtoceras mariae Zone (late Jurassic: early Oxfordian). Family (?stem group) Molpadiidae J. Müller, 1850 Etymology. – Species name refers to the “Mesozoic” era. Diagnosis. – A species of Cruxopadia with the following char- Genus Cruxopadia Reich gen. nov. acteristics: ossicle in one plane, four solid radiating arms at (nearly) right angles, medium-sized in length and tapering Type species. – Cruxopadia mesozoica Reich sp. nov. from the distally. All arms are more or less of equal length. Four early Oxfordian of Normandy, France. central perforations are cross-shaped arranged, and medi- Etymology. – Named after Latin crux, crŭcis = cross, and in um-sized in diameter. remembrance of the modern holothurian genus Molpadia. Description. – The ossicles of C. mesozoica are cross-shaped The generic name is of feminine gender. (Fig. 3A; diameter ~250–260 µm) and in one plane with Diagnosis. – Solid cross-shaped plates with four central per- four solid radiating arms at nearly right angles (±90°) or forations. so with respect to each other. These arms are medium- sized (~100–110 µm) and more or less of equal length and Comparison. – The new genus differs from the related Pris- tapering distally. Four central perforations with a medium- colongatus Górka & Luszczewska, 1969 (syn. Fletcherina sized diameter (~16–17 µm) are cross-shaped arranged Soodan, 1975; Brianella Huddleston, 1982; Hannaina Soo- and circular to suboval in outline. The square of these per- dan, 1975; Koteshwaria Tandon & Saxena, 1983) in being forations is covering approx. 20 % of the whole central not table-like and therefore in having no spire or stirrup. portion of the ossicle. The central portion takes approx. The synonymy of genera/paragenera within this ‘Priscolon- 60 % of the total ossicle area (diameter). No spire or stir- gatus group’ was briefly discussed by Gilliland (1993: 81– rup is present. The surface is fine-grained (Fig. 3A). 82). Comparison. – C. mesozoica differs from C. reitneri Reich Occurrence. – Hitherto known only from the late Jurassic sp. nov. in having shorter and more robust arms as well as (Oxfordian) to the late Cretaceous (Santonian) of Europe in having much larger central perforations. Also the cen- (France, Spain). tral portion is much larger, by covering more than 60 % of the total ossicle area (diameter). Cruxopadia mesozoica Reich sp. nov. Remarks. – The new material extends the fossil record of the Figs. 3A–B ‘fusiform rod’ molpadiid morphotype back to the Meso- zoic, and furthermore shows that Cenozoic and modern Material. – One cross-shaped ossicle (GZG.INV.91405; ‘fusiform rods’ probably evolved from primarily cross- holotype; Fig. 3A); two further (broken) ossicles shaped ossicles with an evolutionary trend to decrease the (GZG.INV.91406–91407; paratypes). number of central perforations (4 to 3) and the formation 150 Mike Reich & Jörg Ansorge of arms