A new genus for Indo-Pacific fossil strombids, and two new species from the Miocene of Java and Borneo (Caenogastropoda, Strombidae) Aart M. Dekkers* Oasestraat 79, 1448 nr Purmerend, The Netherlands; [email protected] Virgilio Liverani* Via Batticuccolo 45, 48018 Faenza, Italy; [email protected] Stjepan Ćorić Geologische Bundesanstalt, Fachabteilung Sedimentgeologie, Neulinggasse 38, 1030 Vienna, Austria; [email protected] Stephen J. Maxwell College of Science and Engineering, James Cook University, Cairns Qld 4870; [email protected] Bernard M. Landau Naturalis Biodiversity Center, P.O. Box 9517, 2300 ra Leiden, The Netherlands; Instituto Dom Luiz, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisbon, Portugal; International Health Centres, Av. Infante de Henrique 7, Areias São João, P-8200 Albufeira, Portugal [email protected] [corresponding author]. * These authors are joint first author Dekkers, A.M., Liverani, V., Ćorić, S., Max- INTRODUCTION well, S.J. & Landau, B.M., 2020. A new genus for Indo-Pacific fossil strombids, and two new species The Neogene fossil assemblages of Indonesia are known from the Miocene of Java and Borneo (Caenogas- mainly from the work of Dutch geologists working in tropoda, Strombidae). – Basteria 84 (1-3): 1-9. Leiden. the area at the end of the 19th century and beginning of Published 11 July 2020 the 20th century. The pioneer in Indonesia fossil mollusc research was Martin, who published numerous papers (1879-1932), work continued by Tesch (1915-1920), Oostingh A new strombid genus (Spinatus gen. nov.) is described (1923-1941), Koperberg (1931), Haanstra & Spiker (1932), from the Miocene of Indonesia. Two new species of Spina­ Pannekoek (1936), van Regteren Altena (1938-1972) and tus from the middle and upper Miocene of Indonesia are Beets (1941-1986). These works are supplemented by a hand- described: S. echinatus spec. nov. and S. wonosariensis spec. ful of works by non-Dutch researchers (Wanner & Hahn, nov. The former is selected as the type species ofSpinatus . 1935; Cox, 1948; Nuttall, 1961-1965). For a full bibliography A third species, Strombus (Strombus) tjilonganensis Mar- of the above mentioned authors see Leloux & Wesselingh tin, 1899, is here assigned to the new genus. Notes are given (2009). For the most part, material amassed by the Dutch on the genus Persististrombus Kronenberg & Lee, 2007 as workers is housed in the Naturalis Biodiversity Center, Lei- its species show the highest similarity with Spinatus. Fur- den (The Netherlands), which has the most important col- thermore, a characterization is given of the fossil-rich, but lection of Indonesian fossils known. Martin’s type material previously unknown, Miocene assemblage from the area of from this collection was recently catalogued, photographed Wonosari (Java). and updated by Leloux & Wesselingh (2009). Since then, sporadic papers have added to our knowledge Key words: Strombidae, Spinatus, new genus, new species, of these rich Neogene assemblages (i.e. Vermeij & Raven, Miocene, Langhian, Wonosari, Indonesia. 2009; Raven, 2016; Harzhauser et al., 2018). Photographs of undescribed fossil shells in popular books, such as Dharma (2005), hint at a much greater diversity than so far known. basteria 84 (1-3): 1 A.M. Dekkers, V. Liverani et al. – Indo-Pacific fossil strombids Major family-level revisions on the assemblages are so far of a river or stream. The collection was donated to the Nat- lacking, with the notable exception of Beu’s (2005) work of ural History Museum Vienna (nhmw) in the framework the tonnoidean gastropods of Indonesia and Robba’s (2013) of an exchange with K. Martin. Although this situation revision on the pyramidelloidean gastropods. is far from ideal, the collection deposited represents the In this work we focus on an as yet unpublished fos- best-preserved middle Miocene Indonesian assemblage we sil assemblage from the area of Wonosari, Gunung Kidul have seen, with many species that remain undescribed. The Regency, Special Region of Yogyakarta, Java, Indonesia. preservation of the fossils, and the attached matrix, is simi- This locality might have been mentioned in the literature lar for the whole collection. Matrix was removed from three before, spelled ‘Wirosari’ (Martin, 1881: 123; Leloux & Wes- specimens and examined for microfossils. All three sam- selingh, 2009: 172) and three species were described from ples were identical in their microfossil content, and we are these deposits including Strombus (Strombus) preoccupatus therefore quite certain they all come from the same locality. Finlay, 1927 (see Leloux & Wesselingh, 2009). However, all Miocene calcareous nannofossils were investigated by three species are represented by ‘steinkerns’, whereas the Renema et al. (2015) from the Kutai Basin and Marshall plentiful material we have seen is all well preserved, the et al. (2015) from the Mahakam Delta. Sediments from shells filled with soft matrix. Therefore, although the his- Mahakam Delta contains a nannofossil assemblage identi- torical material figured by Leloux & Wesselingh might be cal to that seen in the assemblages from the three samples from the same area, they are certainly not from the same investigated in our study. This section was dated as Lang- beds. hian (nn4/nn5) based on planktic foraminifera, larger ben- This assemblage shows remarkable diversity of fossil thic foraminifera and calcareous nannofossils. gastropods and the preservation is unusually good. Here, All three investigated samples contain rare, moder- we concentrate on two new strombid species. We hope to ately preserved calcareous nannofossils accompanied by follow this with a series of systematic taxonomic papers common ascidian spicules. The nannofossil assemblages describing the rest of this assemblage. are dominated by Reticulofenestra minuta Roth, 1970 and Umbilicosphaera jafari Muller, 1974. Also occurring are: Calcidiscus leptoporus (Murray & Blackman, 1898) Loeb- MATERIAL AND METHODS lich & Tappan, 1978, Calciosolenia fossilis (Deflandre in Deflandre & Fert, 1954) Bown, in Kennedy et al., 2000, The material described here is deposited in the Natural His- Coronosphaera mediterranea (Lohmann, 1902) Gaarder, in tory Museum Vienna (nhmw). The Beets (1941) material is Gaarder & Heimdal, 1977, Cyclicargolithus floridanus(Roth deposited in the Naturalis Biodiversity Center, Leiden, The & Hay, in Hay et al., 1967) Bukry, 1971, Discoaster deflandrei Netherlands (rgm coll.). The systematics follow Bouchet et Bramlette & Riedel, 1954, Discoaster exilis Martini & Bram- al. (2017). lette, 1963, Discoaster variabilis Martini & Bramlette, 1963, Matrix for geological dating was taken from three sam- Helicosphaera carteri (Wallich, 1877) Kamptner, 1954 and ples at random. Preparation for smear slides followed the Umbilicosphaera rotula (Kamptner, 1956) Varol, 1982. The standard method described by Perch-Nielsen (1985a, b). stratigraphic important zone marker Sphenolithus hete­ Nannofossil identifications were made using light-micros- romorphus Deflandre 1953 occurs frequently in all three copy (Leica dmlp). All samples were investigated under samples. Reworked fossils from older sediments were not 1000× magnification with parallel and crossed nicols. observed. Biostratigraphic assignments were made in accordance Based on the presence of S. heteromorphus, and the with the nannoplankton zonation of Martini (1971). absence of Helicosphaera ampliaperta Bramlette & Wil- Abbreviations. — nhmw = Natural History Museum coxon, 1967 all three investigated samples can be attributed Vienna (Vienna, Austria); rgm = Rijksmuseum voor Geol- to the nn5 zone (Martini, 1971), which comprises the upper ogie en Mineralogie, now part of Naturalis Biodiversity Langhian and the lowermost Serravallian. Although the Center, Leiden, The Netherlands;vl = Virgilio Liverani absence of H. ampliaperta can be caused by paleoenviron- private collection. mental conditions, based on the similarity with the nann- ofossils association described by Marshall et al. (2015) our assemblages can be dated as Langhian (upper nn4/nn5). GEOLOGICAL SETTING Common occurrences of small reticulofenestrids (Re ­ ticulofenestra minuta) and ascidian spicules together with The material originates from the area around the village of discoasters point to shallow, well stratified, warm marine Wonosari, Gunung Kidul Regency, Special Region of Yog- water. yakarta, 40 km se of Yogyakarta, Java, Indonesia. The exact locality is unknown, but the deposits outcrop on the banks basteria 84 (1-3): 2 A.M. Dekkers, V. Liverani et al. – Indo-Pacific fossil strombids SYSTEMATIC PART bus Linnaeus, 1758 or Persististrombus, but we currently exclude them from the new genus, awaiting further studies. Subclass Caenogastropoda Cox, 1960 Following this generic revision, the oldest record of Per­ Order Littorinimorpha Golikov & Starobogatov, 1975 sististrombus is P. radix (Brongniart, 1823), from the Atlantic Superfamily Stromboidea Rafinesque, 1815 Oligocene of France (Lozouet & Maestrati, 1986). During the Family Strombidae Rafinesque, 1815 lower Miocene P. nodosus (Borson, 1820) (Strombus bonellii Brongniart, 1823 is a synonym) is the most widespread mem- ber of the genus, recorded from Italy, France and Greece Genus Spinatus gen. nov. (Borson, 1820; Lozouet et al., 2001; Harzhauser & Kronen- berg, 2013), but other forms like P. praecedens (Schaffer, Type species (by original designation). — Spinatus echina­ 1912) described from Austria (Schaffer,