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We describe the first known blood fluke from a marine mammal, the dugong, Dugong dugon (Sirenia: Dugongidae), which represents a new species of aporocotylid, Cardicola dhangali n. sp. (Digenea: Aporocotylidae). Eggs presumed to be of blood flukes have been previously reported from dugongs. This exciting discovery raises questions regarding evolution and host-switching in the Aporocotylidae, which prior to this study were only known to infect actinopterygian and chondrichthyan fishes. The new species has male and female genital pores opening on the right side of the body, with the male genital pore opening posterior to the entire reproductive system and the testis is extra-caecal. The uterus is highly convoluted, and the ovary is irregularly lobate. These features, together with the size and number of the tegumental spines per row, easily distinguish the new species from the most similar congeners Cardicola aurata Holzer et al., 2008, Cardicola chaetodontis Yamaguti, 1970, Cardicola currani Bullard and Overstreet, 2004, Cardicola forsteri Cribb et al., 2000, C. jiingurru Yong et al., 2016, and Cardicola palmeri Bullard and Overstreet, 2004, all of which infect actinopterygian fishes. Given that Cardicola is the most diverse and least host-specific of the marine aporoctoylid genera, it seems credible that a successful host-switch has occurred from an actinopterygian to D. dugon. Further sampling of sirenians and other marine mammals is warranted to gain a more comprehensive understanding of the evolutionary biology and biodiversity of the blood flukes (superfamily Schistosomatoidea Stiles and Hassall, 1898), but presents a substantial challenge with respect to their conservation status and large size., Graphical abstract Image 1, Highlights • a new species of aporocotylid, Cardicola dhangali n. sp. was discovered in the heart of a dugong. • The new species is the first known blood fluke from a marine mammal. • Infection of dugong with an aporocotylid blood fluke may represent a host-switch event from a fish.

Remains of an extinct sea cow are identified on several paving stones in the city of Girona (Catalonia, NE Spain). The limestone slabs are of middle Eocene age, making the fossil one of the oldest representatives of its group in Europe. Based on macroscopic and CT scan data, our study provides first results on the individual age and taxonomic identification of the find. The sea cow remains represent a single specimen. The relative position and degree of wear of the third upper molar indicate a subadult or young adult. Analysis of basicranial sutures and of the third upper molar indicate a young adult. Morphological comparisons focusing on Eocene taxa from Europe that are considered valid and belong to the Dugongidae argue for a closer relationship of the Girona specimen with the genus Prototherium. Given the palaeobiogeographic and stratigraphic distribution of the species available for comparison, the Girona sea cow is tentatively assigned to P. ausetanum. Ongoing post-processing of the CT scans and subsequent 3D reconstruction of the preserved bones are expected to enhance the morphological and taxonomic interpretation and will provide new insights into the evolutionary history and diversity of Eocene sirenians. For this reason, the city of Girona, which already maintains a system of touristic routes for explaining the local geology and palaeontology, will include the scientifically significant site of discovery in its cultural tourism programme. The sea cow remains will be included in the “Inventory of Areas of Geological Interest”, a catalog summarizing the geological history of Catalonia.

In the transition from a terrestrial to an aquatic environment, sirenian marine mammals reduced and lost their hind limbs and developed a horizontal caudal fin, the main propulsive organ in extant sirenians. Quadrupedal forms are only known from the Eocene and are represented by three different clades: the amphibious “prorastomids,” the aquatic quadrupedal protosirenids, and Sobrarbesiren cardieli, a four-legged sirenian from the middle Eocene of Spain, considered the sister taxon of the fully aquatic Dugongidae. This ecological shift from terrestrial to an aquatic environment was naturally associated with adaptations, among others, of the skeleton. However, sirenian hind limb bones have been poorly studied because of the scarce material available in the fossil record. Here, we describe in detail the hind limb bones of Sobrarbesiren, analyzing their functional morphology and comparing them with other basal sirenians and cetaceans, and with related terrestrial mammals such as proboscideans and hyracoids. The hind limbs of Sobrarbesiren were capable of a great variety of movements. Based on the presence of a strong sacroiliac articulation, we propose that it swam by dorsoventral pelvic undulation combined with pelvic paddling analogous to extant otters and the “prorastomid” Pezosiren. We also conduct the first microanatomical analysis of hind limb bones of an Eocene sirenian. Data reveal extreme inner compactness in the Sobrarbesiren innominate and femur, with the first description of osteosclerosis in an amniote innominate combined with the highest degree of osteosclerosis observed in amniote femora. The results confirm that the microanatomical changes precede the external morphological changes in such ecological transitions. The process of adaptation of sirenians to an aquatic life was thus a more complex process than previously thought.

Syafutra R, Adi W, Iqbal M, Yustian I. 2018. Short communication: Dugong dugon Müller, 1776 (Sirenia, Dugongidae) in Bangka Island, Indonesia. Biodiversitas 19: 823-830. Dugong dugon is a marine mammal species classified as Vulnerable. It has distribution in Indonesia, especially in Bangka Island. However, only four records of dugong were reported in Bangka Island in 1976, 2006, and 2007. In addition, there is little published information about local beliefs toward dugong and awareness actions toward dugong conservation in Bangka Island. This research compiled new records of dugong, local beliefs toward dugong, and awareness actions toward dugong conservation in Bangka Island. Sixteen new records of dugong were collected in Bangka Island leading to a total of 18 records for this island. All new records of dugong were obtained entirely from the eastern waters of Bangka Island. The new records also informed that most of the dugongs were found dead and entangled in gill nets. In addition, an interesting local belief caused Kurau Village becomes the most important location for fishermen to sell dead dugongs or dugongs’ meat. Furthermore, three main awareness actions toward dugong had been implemented in Bangka Island in 2017.

A new stem dugongid species, Prototherium ausetanum sp. nov. (Dugongidae, Halitheriinae), is described based on a cranium from the middle Eocene of Mas Vilageliu (Tona, NE Iberian Peninsula). The new species displays a combination of features that enables its distinction from other halitheriines, including Prototherium veronense (type species of the genus), Prototherium ? intermedium (which likely belongs to a different genus), and Prototherium ? montserratense (here considered a nomen dubium), as well as Eotheroides spp. In overall morphology (e.g., dolichocephaly) the new species more closely resembles species previously included in Prototherium . However, a cladistic analysis based on craniodental features recovers the new species as the sister taxon of Eotheroides aegyptiacum (type species of this genus), further constituting a polytomy with P. veronense , Eotheroides lambondrano and the remaining Halitheriinae. Our analysis further indicates that P. ? intermedium is more derived than other species of Prototherium , but it does not conclusively resolve the phylogenetic relationships between the included species of Prototherium and Eotheroides . A deeper taxonomic revision of these two genera would be required in order to better resolve the phylogeny of early dugongids.

The faunal assemblage of Monteviale (Vicenza, northern Italy) represents a rare condition among the earliest Oligocene assemblages of south-eastern Europe at the ‘Grande-Coupure’. The lignitic fossiliferous strata lie above explosive basaltic breccias produced by a volcanic complex raised within a lagoon where the Calcareniti di Castelgomberto Formation (earliest Oligocene in age) was deposited. Systematic revision of the vertebrate remains from Monteviale reveals the presence of 15 taxa belonging to ?Butidae, Palaeobatrachidae, Trionychidae, Geoemydidae, Diplocynodontinae, Dugongidae, ?Pantolesta, Chiroptera, Rhinocerotidae, Anthracotheriidae and Palaeochoeridae. The fossiliferous deposit of Monteviale probably originated in a coastal lagoon characterized by salinity fluctuations, from brackish to fresh water, the latter evidenced by the presence of palaeobatrachid larvae. The terrestrial vertebrate assemblage indicates a humid forest environment with an age close to the Eocene–Oligocene boundary, lowerm...

The Steller's sea cow – Hydrodamalis gigas (Dugongidae: Sirenia) – is an extinct herbivorous marine mammal which inhabited the North Pacific Ocean during the Pleistocene and Holocene. H. gigas was the largest member of the Sirenia order and disappeared in the middle of the 18th century. Here, we present the complete sequence of the mitochondrial genome of this extinct animal. The Steller's sea cow mitochondrial DNA (mtDNA) is 16,872 base pairs (bp) in length and contains a set of mitochondrial genes typical for mammals. Phylogenetic analysis based on complete mitochondrial genomes of the sirenian species allows accurate assessment of the degree of their mitogenomic diversification during millions of years of evolution.

Author(s): Bauer, Gordon B; Reep, Roger L; Marshall, Christopher D | Abstract: Abstract The successful return of mammals to aquatic environments presented numerous sensory challenges to overcome. Aquatic habitats reduced the utility of vision and the type of chemoreception important in terrestrial perception. In several orders, the sense of touch assumed greater importance, especially when enhanced by the development of vibrissal (sensory hair) systems. Species of two extant orders, Sirenia and Cetacea, lost all of their hairs except for vibrissae. In the former, these hairs cover the entire bodies of the two families, Trichechidae and Dugongidae. Hairs in adult cetaceans are more constrained (e.g., some river dolphins and baleen whales) and are restricted primarily to rostral regions. Pinnipeds and sea otters retained their pelage, but in addition have elaborated their mystacial and other facial vibrissae. High numbers of vibrissal receptors, associated dense innervation, prominence of neural tracts, and hypertrophy of brain areas associated with touch suggest an importance of tactile senses for aquatic mammals. Experimental testing has demonstrated the exquisite tactile sensitivity of many marine mammal species. Sensory hairs contribute to that tactile sensitivity in both haptic and mechanosensory contexts. Several, if not most, pinniped species, seals and sea lions, can track prey based on mechanoreception alone. In this review we will discuss the neurobiological and behavioral evidence for the tactile senses of marine mammals.

Sirenians are the only extant herbivorous mammals fully adapted to an aquatic lifestyle. They originated in Africa during the Paleocene from an undetermined clade of afrotherian mammals, and by the end of the Eocene they were widely distributed across the tropical latitudes. Here we introduce Sobrarbesiren cardieli gen. et sp. nov. It is the first adequately-known quadrupedal sirenian from Eurasia and the oldest record of this clade from western Europe. Fossils have been recovered from the middle Lutetian (SBZ15) site of Castejón de Sobrarbe-41 (Huesca, Spain), and comprise many cranial and postcranial remains, including pelvic girdle and hind limb bones, from at least six sirenian individuals of different ontogenetic stages. Sobrarbesiren shows a suite of characters previously considered synapomorphies of different clades of derived sirenians, such as the presence of the processus retroversus of the squamosal and the pterygoid fossa, combined with ancestral characters such as the presence of an alisphenoid canal, a permanent P5, at least two sacral vertebrae, a primitive pelvis and functional femora and fibulae. Sobrarbesiren is recovered as the sister taxon of Dugongidae and represents a transitional stage of adaptation to aquatic life between the amphibious quadrupedal prorastomids and the aquatic quadrupedal protosirenids.

We report and describe the first sirenian endocranial casts from the West Indies based on three specimens collected from two quarries of the upper Oligocene–lower Miocene Colon Formation, in the pr...

There are three extant sirenian species of the Trichechidae family and one living Dugongidae family member. Given their close ties to coastal and often urbanized habitats, sirenians are exposed to many types of anthropogenic activities that result in challenges to their well-being, poor health, and even death. In the wild, they are exposed to direct and indirect local pressures as well as subject to large-scale stressors such as global climate change acting on regions or entire genetic stocks. In captivity, they are subject to husbandry and management practices based on our collective knowledge, or in some cases lack thereof, of their needs and welfare. It is therefore reasonable to consider that their current imperiled status is very closely linked to our actions. In this chapter, we identify and define human interactions that may impact dugongs and manatees, including hunting, fisheries, boat interactions, negative interactions with man-made structures, disease and contaminants, and global climate change. We examine techniques used to investigate these impacts and the influence of sirenian biology and of changing human behaviors on potential outcomes. We examine how this differs for dugongs and manatees in the wild and for those held in captivity. Finally, we provide possible mitigation strategies and ways to assess the efforts we are making to improve the welfare of individuals and to conserve these species. This chapter identifies how the welfare of these species is intrinsically linked to the human interactions these animals experience, and how the nature of these interactions has changed with societal shifts. We proffer suggested ways to minimize negative impacts. Current knowledge should be used to minimize negative human interactions and impacts, to promote positive impacts, and to protect these animals for the future.

The recorded history of Sirenia species in managed care is short and quite variable with many areas of early efforts poorly documented with anecdotal material. The three extant Sirenia species of the Trichechidae family and the one extant species of the Dugongidae family are all listed as threatened by the IUCN (International Union for the Conservation of Nature). Initially hunted as a source of food in many locations, our understanding of their physiology, history, and role in the environment was slow to develop. Early literature on human interaction contributed by scientists, anatomists, and the curiosity of those who wished to share their involvement with the species was fragmented but important. Managed care of Sirenia in zoos and aquariums was initially catalyzed by a desire to show these strange animals to the public, but has morphed into a developing concern for the conservation of Sirenia populations. Public and scientific concern for the species led to protective measures in some of their ecosystems with improvements in our understanding of their biology, genetics, reproduction, disease challenges, and the influence of humans on their welfare. This evolution of public involvement led to rescue and rehabilitation efforts by aquariums, zoos, state, and federal agencies to intervene in individual animal health. Research into human mortality causes also supported better documentation of natural illnesses that effect the population’s survival. The Florida manatee rehabilitation programs and Australian dugong efforts illustrate the intersection of science, medicine, and ecosystem health in advocating the needs of these unique animals and what is required to support their survival and encourage recovery. As we intersect with Sirenia in rehabilitation and exhibit exposure for encouraging public support, it is important to provide suitable habitats for health and welfare and design their environments to their special needs while increasing protection of the wild habitats.

Lentiarenium cristolii (Fitzinger, 1842) comb. nov. Figs 2���10, Tables 1���5 Halitherium cristolii Fitzinger, 1842: 71, pl. 1. Metaxytherium (?) pergense Toula, 1899: 459, pl. 12. Halitherium abeli Spillmann, 1959: 36, pls. 1���4, fgs 19���20, 22, 24���27, 29b, 31���32, 33b, 34. Manatus christolii ��� De Blainville 1844: 122. Metaxytherium christolii ��� Laurillard 1846: 172. Halianassa collinii ��� Meyer 1847: 189, 578 (partim). ��� Ehrlich 1850: 14���15, fgs a���c. ��� Ehrlich 1855: 3, pls. 1���2, corresponding fgs on pages 14���17. Halitherium schinzii ��� Peters 1867: 310. Halitherium schinzi ��� Lepsius 1882: 164 (partim). Halitherium christoli ��� Abel 1904: 25, pl. 1, fgs 12���13, pl. 2, fgs 4, 11, 17, pl. 5, fg. 8, fg. 1. ��� Spillmann 1959: 17, fgs 8���18, 21, 23, 28, 29a, 30, 33a; 1969: 62, pl. 8, fg. 2; 1973: 198, pl. 40, fg. 4. Halitherium pergense ��� Spillmann 1959: 11, fgs 6���7; 1969: 61, fg. 1; 1973: 197, pl. 39, fgs 1���2. Halitherium abeli ��� Spillmann 1969: 62, pl. 9, fg. 3; 1973: 205. Diagnosis As for the genus. Type Material Lectotype (present designation) A mandible (OLL 2012/1) of an adult individual (based on the presence of a large retromolar space and erupted m3 in wear) with left dp5���m2 and right m1���3, ���Sicherbauer��� sandpit, Linz. Paralectotypes Fragment of right maxilla with worn M1 crown and remnants of DP5 roots (OLL 2012/2), and an isolated crown of M3 (OLL 2012/3) from the right side, both from the ���Sicherbauer��� sandpit, Linz. Holotype (by monotypy) of Metaxytherium pergense Cast of a parietal-supraoccipital skullcap (OLL 1899/11), sandstone quarry near the town of Perg. Holotype (by original designation) of Halitherium abeli Mandible of an adult individual (based on the presence of a large retromolar space and erupted m3 in wear), fragments of basicranium, cervical and other vertebrae (OLL 1939/257), ���Limoni��� sandpit, Linz. Referred material OLL 1854/327, 1863/184, 1917/7, 1921/71, 1926/394, 1926/395, 1927/200, 1928/82, 1931/21, 1931/263, 1948/33, 2012/4, 2012/5, 2012/6, 2012/7, 2013/1. For a detailed listing of the preserved skeletal parts see Table 1. Type horizon and locality ���Sicherbauer-Sandgst��tte���, a former sandpit within the city limits of Linz (Upper Austria). Linz-Melk Formation, Linzer Sande (= Linz Sands), upper Oligocene, lower Egerian (Chattian). Range and distribution Known only from the upper Oligocene of Linz and the surrounding area. Description The following description is based on the available sirenian material housed in OLL, regardless of the different species that were proposed in the past. It will be outlined in detail in the Discussion why the respective skeletal material represents a single species. Lentiarenium cristolii is known from cranial and postcranial elements. However, the premaxilla and lacrimal are unknown as are the pelvis, zeugopod and autopod. The following description is mainly based on a partial skull (OLL 1926/394) and two mandibles (OLL 1939/257 and OLL 2012/1). PREMAXILLA. The premaxilla is not preserved in any specimen but some morphological characters can be indirectly determined. The external nares are retracted and enlarged (Fig. 2), as in all sirenians, and reach beyond the anterior margin of the orbit. Judging from the recesses in the anterior margin of the frontal, the nasal processes are not broadened and bulbous at their posterior ends but taper, having lengthy overlap with the frontals. The angle of the rostrum most likely exceeds 50�� considering the defection of the mandibular symphysis of about 60�� (Fig. 7). NASAL. The exact status of the nasals cannot be determined without doubt due to the poor preservation of the nasal area in specimen OLL 1926/394 (Fig. 2). Judging from the right anteromedial margin of the frontals, which is not damaged, but smooth without an attachment area for the nasals, these elements are at least considered to have been small without meeting in the midline. A nasal incisure is present at the posterior end of the mesorostral fossa, but unlike in Metaxytherium albifontanum (Velez-Juarbe & Domning, 2014a) and Priscosiren atlantica (Velez-Juarbe & Domning, 2014b) it is deep, extending posterior to the supraorbital processes of the frontals, though not to the extent seen in dugongines like Crenatosiren olseni (Domning 1997). It is uncertain whether the nasals were fused or coalesced with the frontals. ETHMOIDAL REGION. The ethmoid is incompletely preserved and not easily observable in all aspects. A prominent perpendicular plate of the mesethmoid is visible in dorsal and anterior views of the skull OLL 1926/394 (Fig. 2). This vertical wall measures 10 mm to 15 mm in width, is narrower dorsally and ventrally, and apparently also becomes thinner posteriorly. Ventrally, the perpendicular plate is fused with the likewise distinctly developed vomer. On the right side of the skull, and medial to the frontal (Fig. 2), the almost complete large ethmoturbinal (concha maxima ethmoidalis (Kaiser 1974)) extends nearly parallel to the mesethmoid. Its left counterpart is only fragmentarily preserved. The crista galli and lamina papyracea are either not preserved or not visible. VOMER. The vomer is exposed on the ventral side of the skull OLL 1926/394 but broken anteriorly (Fig. 3). It is fused with the presphenoid posteriorly and forms the cranial extension of its median crest. The vomer is triangular in cross section, frmly fused with the ethmoid via its fat dorsal surface, and contacts the maxilla laterally. In lateral view (Fig. 4B), the vomer is also visible through the orbit due to the incomplete preservation of the skull. FRONTAL. In dorsal view (Fig. 2), the frontal roof is fat between the temporal crests, and bears no knoblike bosses as present in some dugongines (e.g., Crenatosiren olseni (Domning 1997)). The straight to slightly concave anterior margin of the frontal has no internasal process. The temporal crests form distinct keels (morphotype B; Domning 1988) and are as prominent on the frontal as on the parietal. In lateral view (Fig. 4B), the supraorbital process is dorsoventrally fattened with its dorsal surface inclined gently ventrolaterad. Its lateral margin is not divided, and it has a prominent posterolateral corner that projects posteriorly. An orbitotemporal crest is distinct relative to what is observed in Metaxytherium albifontanum (Velez-Juarbe & Domning 2014a), and forms a craniocaudally-extending ridge. The lamina orbitalis is signifcantly less than 10 mm thick. PARIETAL. The parietal roof (Fig. 2) is fat between the temporal crests and characterised by a strong intertemporal constriction that reaches its maximum behind the centre of the skull roof with the parietal bulging laterally. An external sagittal crest is not developed. The frontal processes of the parietal are short and do not exceed half the length of the frontal in the midline, a condition similar to that in Priscosiren atlantica (Velez-Juarbe & Domning 2014b). The parietal is longer than the frontal, and the overall proportions of the cranial roof indicate a slight brachycephaly when the value of the frontal length is divided by the width of the supraoccipital, i.e., the ratio l FP/w SO, which is below 2. In endocranial view (Fig. 3), the bony falx cerebri extends from a prominent tentoric process and fattens out anteriorly before reaching the frontoparietal suture. The tentorium osseum is well developed and an internal parietal spine (or tentorial process as illustrated in Voss (2008: Fig. 4B)) is missing. On both sides of the bony falx, the fat internal parietal surface shows the depressions for the superior parts of the brain hemispheres. SUPRAOCCIPITAL. This element is widest dorsally rather than ventrally (Fig. 4A), relative to what is observed in Metaxytherium spp. (e.g., M. albifontanum (Velez-Juarbe & Domning 2014a)). The supraoccipital is only slightly wider than high (width to height ratio Crenatosiren olseni (Domning 1997). Dorsally, the nuchal crest is constantly narrow along its transversal length and relatively sharp-edged. It makes up the dorsolateral margin of the supraoccipital. The external occipital protuberance rises above the parietal roof and is also prominent posteriorly. Ventrad, the protuberance continues as the external occipital crest that forms a distinct ridge, which slightly fattens out after one third of the supraoccipital���s height, almost reaching its ventral margin. Dorsolateral to this median ridge the deep and large insertions for the semispinalis capitis muscle occupy about the upper third of the external lamina. The area of the muscle insertion is triangular and defned by distinct ridges medioventrally and the nuchal crest dorsolaterally. The ventral margin of the supraoccipital forms an angle of approximately 135�� in specimen OLL 1926/394. Specimen OLL 1899/11 (Fig. 5), formerly designated as the holotype of ��� Halitherium ��� pergense but now referred to Lentiarenium cristolii, also shows a distinct nuchal crest. However, the protuberance, median ridge and defnitions of the muscle insertions are less prominently developed than in OLL 1926/394, indicating its juvenile status. In interior view (Fig. 3), the supraoccipital is fat with the exception of longitudinal bulges dorsolaterally that are merged in the median plane and separated by a deep transverse sulcus from the tentorium osseum. Posterolaterally, the parietals extend between the supraoccipital and squamosal, forming a short fange. EXOCCIPITAL. The dorsal parts of these paired elements are not preserved in any specimen. However, the total length of the ventral margin of the supraoccipital in OLL 1926/394 (Figs 3, 4A) reveals the articulation surface for the exoccipitals, indicating that these bones evidently meet in a suture dorsal to the foramen magnum. Additionally, specimen OLL 1939/257 preserves the ventralmost parts of the exoccipitals, which Spillmann (1959: fg. 19) illustrated in ventral view. During the personal examinations, the paroccipital processes were detected to be long, projecting as far ventrally as the occipital condyles, which is similar to what can be observed in some dugongines (e.g., Nanosiren garciae Domning & Aguilera, 2008 and N. sanchezi Domning & Aguilera, 2008 (Domning & Aguilera 2008: fg. 3, 11)). Medioventral to the paroccipital processes, the hypoglossal foramen is not opened to form a notch or incisure but is well surrounded by bone. The supracondylar fossae are distinct and defne the occipital condyles across their entire width. BASIOCCIPITAL. An isolated basioccipital fused with the lower parts of the exoccipitals is preserved in specimen OLL 1939/257 (Spillmann 1959: fg. 19). It contributes to the occipital condyles ventrolaterally and extends craniad as a short, columnar bone. On its ventral side, the sphenooccipital eminences for the longus capitis muscles are concave and separated by a short but distinct ridge. Specimens OLL 1939/257 and 1926/394 (Fig. 3), in which either the basioccipital or basisphenoid is preserved, show smoothed attachment areas for the adjacent bone, indicating that the basioccipital and basisphenoid were not fused. On that basis, both specimens can be determined as subadults. BASISPHENOID, PRESPHENOID, ORBITOSPHENOID. In specimen OLL 1926/394, the sphenoidal region is clearly observable (Fig. 3). The basisphenoid has a fat ventral surface that is defned laterally by antero posteriorly-broad pterygoid processes. Cranially, the basisphenoid continues with a slight anterodorsal slope into the presphenoid. Both bones are frmly fused with each other and with the orbitosphenoid anterolaterally, the alisphenoid dorsolaterally, and the pterygoid posterolaterally. The median crest of the presphenoid is not prominently developed, which might be related to the state of preservation of the skull in this area, and only becomes distinct at the level of the adjacent vomer. On the lateral side of the skull (Fig. 4B), the orbitosphenoid is exposed and contributes to the anteromedial wall of the temporal fossa. The orbitosphenoid is defned by the frontal dorsally, the alisphenoid posterodorsally, and apparently by the maxilla ventrally. Its sutures with the palatine are not detectable. ALISPHENOID. The alisphenoid is visible in the lateral view of the skull (Fig. 4B). Its sutural contacts with the frontal, parietal and squamosal can be clearly determined. Furthermore, the alisphenoid forms the slightly uneven posterolateral side of the pterygoid process. An alisphenoid canal is absent, and the foramen ovale is opened to form a notch or incisure. PTERYGOID. As in other sirenians, the pterygoid is present on the posteromedial side of the pterygoid process but fully fused with the surrounding bones (Fig. 3). Though not well preserved in OLL 1926/394, the wing-shaped pterygoid processes each bear a dorsoventrally elongated pterygoid fossa posteriorly that extends above the level of the roof of the internal nares, relative to the condition observed in some dugongines like Dioplotherium manigaulti (Domning 1989). The distal ends of both pterygoid processes are somewhat damaged, although the distomedial angle of the right pterygoid process is still distinct and indicates a hamula process. PALATINE. Only the posteriormost parts of the palatines are preserved in OLL 1926/394, and are best observable on the right side (Fig. 3). There the palatine forms the anteromedial margin of the pterygoid process. Its sutures with the surrounding bones are only barely visible on the distal and medial sides of the pterygoid process and on the posterior side of the maxillary alveolar margin. MAXILLA. The zygomatic-orbital bridge (Fig. 3) is not completely preserved in any of the specimens. However, in the maxillary fragment of OLL 1939/257 its dimensions are 47 mm in minimum length and 17.5 mm in nearly original height (Spillmann 1959: fg. 20). On the basis of these data, the zygomaticorbital bridge can be clearly determined to be long anteroposteriorly, relative to what is observed in the genus Hydrodamalis (Domning 1978; Velez-Juarbe & Domning 2014a). Additionally, and in contrast to some hydrodamalines, e.g., Dusisiren jordani Kellogg, 1925 and Hydrodamalis cuestae Domning, 1978 (Domning 1978; Velez-Juarbe & Domning 2014a), it is only slightly elevated above the alveolar margin, and its posterior edge is thickened. Remnants of the infraorbital canal reveal no obstruction. SQUAMOSAL. The cranial part of the squamosal (Figs 2, 4B) extends up to the temporal crests but does not interrupt the course of the temporal crests, so that these reach the occipital nuchal crest. The posttympanic process is not club like distally (Fig. 4B), but concave anteroventrally for the attachment of the sternomastoid muscle. In the posterior view of the skull (Fig. 4A), a prominent sigmoid ridge is visible forming the laterocaudal margin of the squamosal. Posterolaterally, the mastoid foramen is present, flled by the periotic, and enclosed by the squamosal anteriorly, the exoccipital posteriorly, and the supraoccipital dorsally. Lateral to the braincase (Figs 2, 4B), each of the zygomatic processes projects from a zygomatic root that, though partially broken, is characterised by a distinct notch posteriorly. The zygomatic process is triangular in shape, tapering anteriorly. Its lateral and medial sides are fat to concave with the dorsal margin distinctly inclined inwards to form a sigmoid ridge. The posterodorsal end of the zygomatic process is straight to concave. The external auditory meatus is short mediolaterally and about as wide as high anteroposteriorly. Ventrally (Fig. 3), the elements of the mandibular articulation surface are elongated transversely. The mandibular fossa forms a distinct depression relative to the slightly convex tuberculum anteriorly. Posterior to the mandibular fossa, the postglenoid process forms a rounded and longitudinal knob, which rises above the level of the tuberculum. The posterior end of the zygomatic process, the processus retroversus, shows a moderate inward-directed infection in contrast to what is observed in the living dugong (e.g., Domning & Aguilera 2008; Velez-Juarbe & Domning 2014a). JUGAL. Only a fragmentarily preserved middle part of the right jugal is known from specimen OLL 1926/394 (Fig. 4B), indicating that a postorbital process is probably present. Considering the position and shape of the supraorbital processes of the frontal, the development of a postorbital bar can be excluded. The zygomatic process of the jugal is not preserved but according to its imprint on the ventral side of the zygomatic process of the squamosal it reaches the tuberculum, exceeding the diameter of the orbit. EAR REGION. In specimen OLL 1926/394, the right periotic is poorly preserved (Figs 3, 4A). It is not fused with the adjacent skull bones, and is set in a closely-ftting socket in the squamosal. The tegmen tympani is only indicated by its imprints on the dorsolateral side of the squamosal. It was most likely about as big as the mastoid or slightly smaller. The petrosal is fragmentarily preserved medioventrally, with the perilymphatic foramen apparently not separated into a fenestra rotunda and cochlea canaliculus. The processus fonticulus flls the mastoid foramen posteriorly (Fig. 4A). MANDIBLE (Table 3). The mandibular symphysis is broad, as is the masticating surface that is lacking a median furrow and houses four large and shallow alveoli for vestigial incisors and canines. This is best visible in OLL 1939/257 (Fig. 6A), which exhibits a completely preserved masticating surface, whereas in OLL 2012/1 (Figs 6B, 7A) the ventralmost end is broken. In lateral view (Fig. 7), the symphysis is higher than long and bears the mental foramen laterally, which is joined dorsoposteriorly by two accessory mental foramina on each side in specimen OLL 1939/257 (Fig. 7B). The accessory mental foramina are large relative to what is observed in more plesiomorph dugongid taxa, e.g., ��� Halitherium ��� taulannense (Sagne 2001a), but they are still smaller than the principal foramen. This observation is interpreted here in analogy with Trichechus (Domning 1982, 1994, and personal observations), as ���true��� accessory mental foramina, which are present in addition to and usually posterior to the large principal foramen. In the lectotype (OLL 2012/1; Fig. 7A), the mental foramen is broken off dorsoposteriorly, and therefore the accessory mental foramina are not identifable, but their open canals are merged with the main foramen. The overall build of the horizontal mandibular ramus appears to be broad dorsoventrally, but it is evaluated to be slender on the basis of its minimum dorsoventral height, which is smaller than 0.25 �� the length of the mandible. The ventral border, Published as part of Manja Voss, Bj��rn Berning & Erich Reiter, 2016, A taxonomic and morphological re-evaluation of " Halitherium " cristolii Fitzinger, 1842 (Mammalia, Sirenia) from the late Oligocene of Austria, with the description of a new genus, pp. 1-32 in European Journal of Taxonomy 256 on pages 7-24, DOI: 10.5852/ejt.2016.256, http://zenodo.org/record/889326, {"references":["Fitzinger L. J. 1842. Bericht uber die in den Sandlagern von Linz aufgefundenen fossilen Reste eines urweltlichen Saugers (Halitherium cristolii). Bericht uber das Museum Francisco-Carolinum Linz 6: 61 - 72.","Toula F. 1899. Zwei Saugetierreste aus dem \" kristallisierten Sandstein \" von Wallsee in Nieder- und Perg in Oberosterreich. Neues Jahrbuch fur Mineralogie, Geologie und Palaeontologie, Beilagen 12: 447 - 476.","Spillmann F. 1959. Die Sirenen aus dem Oligozan des Linzer Beckens (Oberosterreich) mit Ausfuhrungen uber \" Osteosklerose \" und \" Pachyostose \". Denkschriften der mathematisch-naturwissenschaftlichen Klasse der Osterreichischen Akademie der Wissenschaften 110: 1 - 68.","De Blainville H. M. D. 1844. Osteographie ou Description iconographique comparee du Squelette et du Systeme dentaire des Mammiferes recents et fossiles pour servir de Base a la Zoologie et a la Geologie. Des Lamantins (Buffon), (Manatus, Scopoli), ou gravigrades aquatiques. Vol. 3. Bailliere et Fils, Paris","Laurillard C. L. 1846. Metaxytherium. Dictionnaire de l'Universite d'Histoire Naturelle 8: 171 - 172.","Meyer H. von. 1847. Mittheilungen an Prof. Bronn, Frankfurt a. M., 4. Januar 1847. Neues Jahrbuch fur Mineralogie, Geognosie, Geologie und Petrefaktenkunde 1847: 181 - 196.","Ehrlich C. 1850. Uber die nordostlichen Alpen. Ein Beitrag zur naheren Kenntnis des Gebietes von Osterreich ob der Enns und Salzburg in geognostisch-mineralogisch-montanistischer Beziehung. Jos. Wimmer, Linz.","Ehrlich C. 1855. Beitrage zur Palaeontologie und Geognosie von Oberosterreich und Salzburg. I. Die fossilen Cetaceen-Reste aus den Tertiar-Ablagerungen bei Linz, mit besonderer Berucksichtigung jener der Halianassa collinii H. v. M., und des dazu gehorigen, im August des Jahres 1854 aufgefundenen Rumpfskelettes. Bericht uber das Museum Francisco-Carolinum Linz 15: 3 - 21.","Peters K. F. 1867. Das Halitheriumskelet von Hainburg: Halitherium cordieri, Christol sp. (Manatus cuvieri ou fossilis, Blainv.; Hippopotamus medius cuvieri var). Jahrbuch der Kaiserlich-Koniglichen Geologischen Reichsanstalt 17: 309 - 341.","Lepsius G. R. 1882. Halitherium Schinzi, die fossile Sirene des Mainzer Beckens. Abhandlungen des Mittelrheinischen geologischen Vereins 1, Bergstrasser, Darmstadt. http: // dx. doi. org / 10.5962 / bhl .title. 25531","Abel O. 1904. Die Sirenen der mediterranen Tertiarbildungen Osterreichs. Abhandlungen der Kaiserlich- Koniglichen Geologischen Reichsanstalt 19: 1 - 223.","Spillmann F. 1969. Die fossilen Saugetierfaunen des Linzer Raumes. In: Podzeit W. & Steininger F. (eds) Geologie und Palaontologie des Linzer Raumes. Kataloge des Oberosterreichischen Landesmuseums 64: 55 - 66, Oberosterreichischen Landesmuseum, Linz.","Velez-Juarbe J. & Domning D. P. 2014 a. Fossil Sirenia of the West Atlantic and Caribbean region. IX. Metaxytherium albifontanum, sp. nov. Journal of Vertebrate Paleontology 34 (2): 444 - 464. http: //dx. doi. org / 10.1080 / 02724634.2013.799072","Velez-Juarbe J. & Domning D. P. 2014 b. Fossil Sirenia of the West Atlantic and Caribbean region. X. Priscosiren atlantica, gen. et sp. nov. Journal of Vertebrate Paleontology 34 (4): 951 - 964. http: // dx. doi .org / 10.1080 / 02724634.2013.815192","Domning D. P. 1997. Fossil Sirenia of the West Atlantic and Caribbean region. VI. Crenatosiren olseni (Reinhart, 1976). Journal of Vertebrate Paleontology 17 (2): 397 - 412. http: // dx. doi. org / 10.1080 / 027246 34.1997. 10010984","Kaiser H. E. 1974. Morphology of the Sirenia: a Macroscopic and X-Ray Atlas of the Osteology of Recent Species. S. Karger AG, Basel.","Domning D. P. 1988. Fossil Sirenia of the West Atlantic and Caribbean region. I. Metaxytherium Foridanum Hay, 1922. Journal of Vertebrate Paleontology 8 (4): 395 - 426. http: //dx. doi. org/10.1080/02724634.1988.10011728","Voss M. 2008. New fnds of Halitherium (Sirenia, Mammalia) from the lower Oligocene of the Rhine area, Germany. Neues Jahrbuch fur Geologie und Palaontologie - Abhandlungen 249 (3): 257 - 269. http: // dx. doi. org / 10.1127 / 0077 - 7749 / 2008 / 0249 - 0257","Domning D. P. & Aguilera O. A. 2008. Fossil Sirenia of the West Atlantic and Caribbean Region. VIII. Nanosiren garciae, gen. et sp. nov. and Nanosiren sanchezi, sp. nov. Journal of Vertebrate Paleontology 28 (2): 479 - 500. http: // dx. doi. org / 10.1671 / 0272 - 4634 (2008) 28 [479: FSOTWA] 2.0. CO; 2","Domning D. P. 1989. Fossil Sirenia of the West Atlantic and Caribbean region. II. Dioplotherium manigaulti Cope, 1883. Journal of Vertebrate Paleontology 9 (4): 415 - 428. http: // dx. doi. org / 10.1080 / 02 724634.1989. 10011774","Domning D. P. 1978. Sirenian evolution in the North Pacifc Ocean. University of California Publications in Geological Sciences 118: 1 - 177.","Sagne C. 2001 a. Halitherium taulannense, nouveau sirenian (Sirenia, Mammalia) de l'Eocene superieur provenant du domaine Nord-Tethysien (Alpes-de-Haute-Provence, France). Comptes rendus de l'Academie des Sciences de la Terre et des Planetes 333 (8): 471 - 476. http: // dx. doi. org / 10.1016 / S 1251 - 8050 (01) 01661 - 5","Domning D. P. 1982. Evolution of manatees: a speculative history. Journal of Paleontology 56: 599 - 619.","Domning D. P. 1994. A phylogenetic analysis of the Sirenia. In: Berta A. & Demere T. (eds) Contributions in marine mammal paleontology honoring Frank C. Whitmore Jr. Proceedings of the San Diego Society of Natural History 29: 177 - 189, San Diego Society of Natural History, San Diego","Sagne C. 2001 b. La DiversiFcation des Sireniens a l'Eocene (Sirenia, Mammalia). Etude morphologique et Analyse phylogenetique du Sirenian de Taulanne, Halitherium taulannense. PhD thesis, Museum National d'Histoire Naturelle, Paris.","Pia J. & Sickenberg O. 1934. Katalog der in den osterreichischen Sammlungen befndlichen Saugetierreste des Jungtertiars Osterreichs und der Randgebiete. Denkschriften des Naturhistorischen Museums in Wien, Geologisch-Palaontologische Reihe 4: 1 - 544.","ICZN 1999. International Code of Zoological Nomenclature. 4 th Edition. The International Trust for Zoological Nomenclature, London.","Berning B. 2013. Typen in der Palaontologischen Sammlung des Biologiezentrums Linz. Teil I. Beitrage zur Naturkunde Oberosterreichs 23: 73 - 75."]}

Genus Lentiarenium Voss gen. nov. urn:lsid:zoobank.org:act:A67C71FB-CBC3-460E-953C-5774A3EA9939 Type species Halitherium cristolii Fitzinger, 1842 Diagnosis Dugongid based on the following combination of synapomorphies: absence of alisphenoid canal, open foramen ovale, loss of permanent ffth premolar, and squamosal reaching temporal crest. Differs from the Dugonginae (Crenatosiren Domning, 1991, Nanosiren Domning & Aguilera, 2008, Dugong Lac��p��de, 1799, Rytiodus Lartet, 1866, Corystosiren Domning, 1990, Callistosiren V��lez-Juarbe & Domning, 2015, Bharatisiren Bajpai & Domning, 1997, Domningia Thewissen & Bajpai, 2009, Kutchisiren Bajpai, Domning, Das, V��lez-Juarbe & Mishra, 2010, Dioplotherium Cope, 1883 and Xenosiren Domning, 1989), the Hydrodamalinae Simpson, 1932 (Dusisiren Domning, 1978 and Hydrodamalis Retzius, 1794), and other dugongid genera (Eotheroides Palmer, 1899, Prototherium De Zigno, 1887, Eosiren Andrews, 1902, Caribosiren Reinhart, 1959, Priscosiren V��lez-Juarbe & Domning, 2014b, Metaxytherium De Christol, 1840, and other species formerly lumped under ��� Halitherium ���) by displaying the following unique combination of plesiomorphies: frontal roof fat; supraorbital process of the frontal dorsoventrally fattened with well-developed, prominent posterolateral corner; supraoccipital wider dorsally than ventrally; exoccipitals meet in a suture dorsal to the foramen magnum; posttympanic process with a prominent anteroventral process for attachment of m. sternomastoideus; paroccipital process of exoccipital long, reaching as far ventrally as occipital condyles; accessory mental foramina present; horizontal ramus of mandible slender dorsoventrally; permanent premolars (P2/p2 ��� P4/p4) present. Synapomorphies: nasals reduced and not meeting in midline (shared with Eosiren imenti Domning et al., 1994, Caribosiren, Priscosiren, and all later dugongid taxa), nasal incisure at posterior end of the mesorostral fossa deep, extending posterior to the supraorbital processes of the frontals (shared with some Metaxytherium spp., dugongines, and Hydrodamalis); strongly concave ventral border of the horizontal mandibular ramus (shared with Priscosiren, Metaxytherium spp., and dugongines), masticating surface of mandible broad (shared with Metaxytherium ssp., dugongines, and hydrodamalines). In contrast to the similar species Priscosiren atlantica it has a supraorbital process with the posterolateral corner projecting posteriorly; prominent temporal crests on frontal and parietal; supraoccipital distinct in height, only slightly wider than high. Etymology A combination of the Latin terms for the Linz Sands (Lentia and arenium), the informal name for the upper Oligocene sediments in which the species was found., Published as part of Manja Voss, Bj��rn Berning & Erich Reiter, 2016, A taxonomic and morphological re-evaluation of " Halitherium " cristolii Fitzinger, 1842 (Mammalia, Sirenia) from the late Oligocene of Austria, with the description of a new genus, pp. 1-32 in European Journal of Taxonomy 256 on pages 6-7, DOI: 10.5852/ejt.2016.256, http://zenodo.org/record/889326, {"references":["Fitzinger L. J. 1842. Bericht uber die in den Sandlagern von Linz aufgefundenen fossilen Reste eines urweltlichen Saugers (Halitherium cristolii). Bericht uber das Museum Francisco-Carolinum Linz 6: 61 - 72.","Domning D. P. & Aguilera O. A. 2008. Fossil Sirenia of the West Atlantic and Caribbean Region. VIII. Nanosiren garciae, gen. et sp. nov. and Nanosiren sanchezi, sp. nov. Journal of Vertebrate Paleontology 28 (2): 479 - 500. http: // dx. doi. org / 10.1671 / 0272 - 4634 (2008) 28 [479: FSOTWA] 2.0. CO; 2","Springer M. S., Signore A. V., Paijmans J. L. A., Velez-Juarbe J., Domning D. P., Bauer C. E., He K., Crerar L., Campos P. F., Murphy W. J., Meredith R. W., Gatesy J., Willerslev E., MacPhee R. D. E., Hofreiter M. & Campbell K. L. 2015. Interordinal gene capture, the phylogenetic position of Steller's sea cow based on molecular and morphological data, and the macroevolutionary history of Sirenia. Molecular Phylogenetics and Evolution 91: 178 - 193. http: // dx. doi. org / 10.1016 / j. ympev. 2015.05.022","Domning D. P. 1997. Fossil Sirenia of the West Atlantic and Caribbean region. VI. Crenatosiren olseni (Reinhart, 1976). Journal of Vertebrate Paleontology 17 (2): 397 - 412. http: // dx. doi. org / 10.1080 / 027246 34.1997. 10010984","Domning D. P. 1989. Fossil Sirenia of the West Atlantic and Caribbean region. II. Dioplotherium manigaulti Cope, 1883. Journal of Vertebrate Paleontology 9 (4): 415 - 428. http: // dx. doi. org / 10.1080 / 02 724634.1989. 10011774","Simpson G. G. 1932. Fossil Sirenia of Florida and the evolution of the Sirenia. Bulletin of the American Museum of Natural History 59: 419 - 503.","Domning D. P. 1978. Sirenian evolution in the North Pacifc Ocean. University of California Publications in Geological Sciences 118: 1 - 177.","Reinhart R. H. 1959. A review of the Sirenia and Desmostylia. University of California Publications in Geological Sciences 36: 1 - 146.","Velez-Juarbe J. & Domning D. P. 2014 b. Fossil Sirenia of the West Atlantic and Caribbean region. X. Priscosiren atlantica, gen. et sp. nov. Journal of Vertebrate Paleontology 34 (4): 951 - 964. http: // dx. doi .org / 10.1080 / 02724634.2013.815192","Domning D. P. 1994. A phylogenetic analysis of the Sirenia. In: Berta A. & Demere T. (eds) Contributions in marine mammal paleontology honoring Frank C. Whitmore Jr. Proceedings of the San Diego Society of Natural History 29: 177 - 189, San Diego Society of Natural History, San Diego"]}

Genus Lentiarenium Voss gen. nov. urn:lsid:zoobank.org:act:A67C71FB-CBC3-460E-953C-5774A3EA9939 Type species Halitherium cristolii Fitzinger, 1842 Diagnosis Dugongid based on the following combination of synapomorphies: absence of alisphenoid canal, open foramen ovale, loss of permanent ffth premolar, and squamosal reaching temporal crest. Differs from the Dugonginae (Crenatosiren Domning, 1991, Nanosiren Domning & Aguilera, 2008, Dugong Lacépède, 1799, Rytiodus Lartet, 1866, Corystosiren Domning, 1990, Callistosiren Vélez-Juarbe & Domning, 2015, Bharatisiren Bajpai & Domning, 1997, Domningia Thewissen & Bajpai, 2009, Kutchisiren Bajpai, Domning, Das, Vélez-Juarbe & Mishra, 2010, Dioplotherium Cope, 1883 and Xenosiren Domning, 1989), the Hydrodamalinae Simpson, 1932 (Dusisiren Domning, 1978 and Hydrodamalis Retzius, 1794), and other dugongid genera (Eotheroides Palmer, 1899, Prototherium De Zigno, 1887, Eosiren Andrews, 1902, Caribosiren Reinhart, 1959, Priscosiren Vélez-Juarbe & Domning, 2014b, Metaxytherium De Christol, 1840, and other species formerly lumped under “ Halitherium ”) by displaying the following unique combination of plesiomorphies: frontal roof fat; supraorbital process of the frontal dorsoventrally fattened with well-developed, prominent posterolateral corner; supraoccipital wider dorsally than ventrally; exoccipitals meet in a suture dorsal to the foramen magnum; posttympanic process with a prominent anteroventral process for attachment of m. sternomastoideus; paroccipital process of exoccipital long, reaching as far ventrally as occipital condyles; accessory mental foramina present; horizontal ramus of mandible slender dorsoventrally; permanent premolars (P2/p2 – P4/p4) present. Synapomorphies: nasals reduced and not meeting in midline (shared with Eosiren imenti Domning et al., 1994, Caribosiren, Priscosiren, and all later dugongid taxa), nasal incisure at posterior end of the mesorostral fossa deep, extending posterior to the supraorbital processes of the frontals (shared with some Metaxytherium spp., dugongines, and Hydrodamalis); strongly concave ventral border of the horizontal mandibular ramus (shared with Priscosiren, Metaxytherium spp., and dugongines), masticating surface of mandible broad (shared with Metaxytherium ssp., dugongines, and hydrodamalines). In contrast to the similar species Priscosiren atlantica it has a supraorbital process with the posterolateral corner projecting posteriorly; prominent temporal crests on frontal and parietal; supraoccipital distinct in height, only slightly wider than high. Etymology A combination of the Latin terms for the Linz Sands (Lentia and arenium), the informal name for the upper Oligocene sediments in which the species was found.

Lentiarenium cristolii (Fitzinger, 1842) comb. nov. Figs 2–10, Tables 1–5 Halitherium cristolii Fitzinger, 1842: 71, pl. 1. Metaxytherium (?) pergense Toula, 1899: 459, pl. 12. Halitherium abeli Spillmann, 1959: 36, pls. 1–4, fgs 19–20, 22, 24–27, 29b, 31–32, 33b, 34. Manatus christolii – De Blainville 1844: 122. Metaxytherium christolii – Laurillard 1846: 172. Halianassa collinii – Meyer 1847: 189, 578 (partim). — Ehrlich 1850: 14–15, fgs a–c. — Ehrlich 1855: 3, pls. 1–2, corresponding fgs on pages 14–17. Halitherium schinzii – Peters 1867: 310. Halitherium schinzi – Lepsius 1882: 164 (partim). Halitherium christoli – Abel 1904: 25, pl. 1, fgs 12–13, pl. 2, fgs 4, 11, 17, pl. 5, fg. 8, fg. 1. — Spillmann 1959: 17, fgs 8–18, 21, 23, 28, 29a, 30, 33a; 1969: 62, pl. 8, fg. 2; 1973: 198, pl. 40, fg. 4. Halitherium pergense – Spillmann 1959: 11, fgs 6–7; 1969: 61, fg. 1; 1973: 197, pl. 39, fgs 1–2. Halitherium abeli – Spillmann 1969: 62, pl. 9, fg. 3; 1973: 205. Diagnosis As for the genus. Type Material Lectotype (present designation) A mandible (OLL 2012/1) of an adult individual (based on the presence of a large retromolar space and erupted m3 in wear) with left dp5–m2 and right m1–3, “Sicherbauer” sandpit, Linz. Paralectotypes Fragment of right maxilla with worn M1 crown and remnants of DP5 roots (OLL 2012/2), and an isolated crown of M3 (OLL 2012/3) from the right side, both from the “Sicherbauer” sandpit, Linz. Holotype (by monotypy) of Metaxytherium pergense Cast of a parietal-supraoccipital skullcap (OLL 1899/11), sandstone quarry near the town of Perg. Holotype (by original designation) of Halitherium abeli Mandible of an adult individual (based on the presence of a large retromolar space and erupted m3 in wear), fragments of basicranium, cervical and other vertebrae (OLL 1939/257), “Limoni” sandpit, Linz. Referred material OLL 1854/327, 1863/184, 1917/7, 1921/71, 1926/394, 1926/395, 1927/200, 1928/82, 1931/21, 1931/263, 1948/33, 2012/4, 2012/5, 2012/6, 2012/7, 2013/1. For a detailed listing of the preserved skeletal parts see Table 1. Type horizon and locality “Sicherbauer-Sandgstätte”, a former sandpit within the city limits of Linz (Upper Austria). Linz-Melk Formation, Linzer Sande (= Linz Sands), upper Oligocene, lower Egerian (Chattian). Range and distribution Known only from the upper Oligocene of Linz and the surrounding area. Description The following description is based on the available sirenian material housed in OLL, regardless of the different species that were proposed in the past. It will be outlined in detail in the Discussion why the respective skeletal material represents a single species. Lentiarenium cristolii is known from cranial and postcranial elements. However, the premaxilla and lacrimal are unknown as are the pelvis, zeugopod and autopod. The following description is mainly based on a partial skull (OLL 1926/394) and two mandibles (OLL 1939/257 and OLL 2012/1). PREMAXILLA. The premaxilla is not preserved in any specimen but some morphological characters can be indirectly determined. The external nares are retracted and enlarged (Fig. 2), as in all sirenians, and reach beyond the anterior margin of the orbit. Judging from the recesses in the anterior margin of the frontal, the nasal processes are not broadened and bulbous at their posterior ends but taper, having lengthy overlap with the frontals. The angle of the rostrum most likely exceeds 50° considering the defection of the mandibular symphysis of about 60° (Fig. 7). NASAL. The exact status of the nasals cannot be determined without doubt due to the poor preservation of the nasal area in specimen OLL 1926/394 (Fig. 2). Judging from the right anteromedial margin of the frontals, which is not damaged, but smooth without an attachment area for the nasals, these elements are at least considered to have been small without meeting in the midline. A nasal incisure is present at the posterior end of the mesorostral fossa, but unlike in Metaxytherium albifontanum (Velez-Juarbe & Domning, 2014a) and Priscosiren atlantica (Velez-Juarbe & Domning, 2014b) it is deep, extending posterior to the supraorbital processes of the frontals, though not to the extent seen in dugongines like Crenatosiren olseni (Domning 1997). It is uncertain whether the nasals were fused or coalesced with the frontals. ETHMOIDAL REGION. The ethmoid is incompletely preserved and not easily observable in all aspects. A prominent perpendicular plate of the mesethmoid is visible in dorsal and anterior views of the skull OLL 1926/394 (Fig. 2). This vertical wall measures 10 mm to 15 mm in width, is narrower dorsally and ventrally, and apparently also becomes thinner posteriorly. Ventrally, the perpendicular plate is fused with the likewise distinctly developed vomer. On the right side of the skull, and medial to the frontal (Fig. 2), the almost complete large ethmoturbinal (concha maxima ethmoidalis (Kaiser 1974)) extends nearly parallel to the mesethmoid. Its left counterpart is only fragmentarily preserved. The crista galli and lamina papyracea are either not preserved or not visible. VOMER. The vomer is exposed on the ventral side of the skull OLL 1926/394 but broken anteriorly (Fig. 3). It is fused with the presphenoid posteriorly and forms the cranial extension of its median crest. The vomer is triangular in cross section, frmly fused with the ethmoid via its fat dorsal surface, and contacts the maxilla laterally. In lateral view (Fig. 4B), the vomer is also visible through the orbit due to the incomplete preservation of the skull. FRONTAL. In dorsal view (Fig. 2), the frontal roof is fat between the temporal crests, and bears no knoblike bosses as present in some dugongines (e.g., Crenatosiren olseni (Domning 1997)). The straight to slightly concave anterior margin of the frontal has no internasal process. The temporal crests form distinct keels (morphotype B; Domning 1988) and are as prominent on the frontal as on the parietal. In lateral view (Fig. 4B), the supraorbital process is dorsoventrally fattened with its dorsal surface inclined gently ventrolaterad. Its lateral margin is not divided, and it has a prominent posterolateral corner that projects posteriorly. An orbitotemporal crest is distinct relative to what is observed in Metaxytherium albifontanum (Velez-Juarbe & Domning 2014a), and forms a craniocaudally-extending ridge. The lamina orbitalis is signifcantly less than 10 mm thick. PARIETAL. The parietal roof (Fig. 2) is fat between the temporal crests and characterised by a strong intertemporal constriction that reaches its maximum behind the centre of the skull roof with the parietal bulging laterally. An external sagittal crest is not developed. The frontal processes of the parietal are short and do not exceed half the length of the frontal in the midline, a condition similar to that in Priscosiren atlantica (Velez-Juarbe & Domning 2014b). The parietal is longer than the frontal, and the overall proportions of the cranial roof indicate a slight brachycephaly when the value of the frontal length is divided by the width of the supraoccipital, i.e., the ratio l FP/w SO, which is below 2. In endocranial view (Fig. 3), the bony falx cerebri extends from a prominent tentoric process and fattens out anteriorly before reaching the frontoparietal suture. The tentorium osseum is well developed and an internal parietal spine (or tentorial process as illustrated in Voss (2008: Fig. 4B)) is missing. On both sides of the bony falx, the fat internal parietal surface shows the depressions for the superior parts of the brain hemispheres. SUPRAOCCIPITAL. This element is widest dorsally rather than ventrally (Fig. 4A), relative to what is observed in Metaxytherium spp. (e.g., M. albifontanum (Velez-Juarbe & Domning 2014a)). The supraoccipital is only slightly wider than high (width to height ratio Crenatosiren olseni (Domning 1997). Dorsally, the nuchal crest is constantly narrow along its transversal length and relatively sharp-edged. It makes up the dorsolateral margin of the supraoccipital. The external occipital protuberance rises above the parietal roof and is also prominent posteriorly. Ventrad, the protuberance continues as the external occipital crest that forms a distinct ridge, which slightly fattens out after one third of the supraoccipital’s height, almost reaching its ventral margin. Dorsolateral to this median ridge the deep and large insertions for the semispinalis capitis muscle occupy about the upper third of the external lamina. The area of the muscle insertion is triangular and defned by distinct ridges medioventrally and the nuchal crest dorsolaterally. The ventral margin of the supraoccipital forms an angle of approximately 135° in specimen OLL 1926/394. Specimen OLL 1899/11 (Fig. 5), formerly designated as the holotype of “ Halitherium ” pergense but now referred to Lentiarenium cristolii, also shows a distinct nuchal crest. However, the protuberance, median ridge and defnitions of the muscle insertions are less prominently developed than in OLL 1926/394, indicating its juvenile status. In interior view (Fig. 3), the supraoccipital is fat with the exception of longitudinal bulges dorsolaterally that are merged in the median plane and separated by a deep transverse sulcus from the tentorium osseum. Posterolaterally, the parietals extend between the supraoccipital and squamosal, forming a short fange. EXOCCIPITAL. The dorsal parts of these paired elements are not preserved in any specimen. However, the total length of the ventral margin of the supraoccipital in OLL 1926/394 (Figs 3, 4A) reveals the articulation surface for the exoccipitals, indicating that these bones evidently meet in a suture dorsal to the foramen magnum. Additionally, specimen OLL 1939/257 preserves the ventralmost parts of the exoccipitals, which Spillmann (1959: fg. 19) illustrated in ventral view. During the personal examinations, the paroccipital processes were detected to be long, projecting as far ventrally as the occipital condyles, which is similar to what can be observed in some dugongines (e.g., Nanosiren garciae Domning & Aguilera, 2008 and N. sanchezi Domning & Aguilera, 2008 (Domning & Aguilera 2008: fg. 3, 11)). Medioventral to the paroccipital processes, the hypoglossal foramen is not opened to form a notch or incisure but is well surrounded by bone. The supracondylar fossae are distinct and defne the occipital condyles across their entire width. BASIOCCIPITAL. An isolated basioccipital fused with the lower parts of the exoccipitals is preserved in specimen OLL 1939/257 (Spillmann 1959: fg. 19). It contributes to the occipital condyles ventrolaterally and extends craniad as a short, columnar bone. On its ventral side, the sphenooccipital eminences for the longus capitis muscles are concave and separated by a short but distinct ridge. Specimens OLL 1939/257 and 1926/394 (Fig. 3), in which either the basioccipital or basisphenoid is preserved, show smoothed attachment areas for the adjacent bone, indicating that the basioccipital and basisphenoid were not fused. On that basis, both specimens can be determined as subadults. BASISPHENOID, PRESPHENOID, ORBITOSPHENOID. In specimen OLL 1926/394, the sphenoidal region is clearly observable (Fig. 3). The basisphenoid has a fat ventral surface that is defned laterally by antero posteriorly-broad pterygoid processes. Cranially, the basisphenoid continues with a slight anterodorsal slope into the presphenoid. Both bones are frmly fused with each other and with the orbitosphenoid anterolaterally, the alisphenoid dorsolaterally, and the pterygoid posterolaterally. The median crest of the presphenoid is not prominently developed, which might be related to the state of preservation of the skull in this area, and only becomes distinct at the level of the adjacent vomer. On the lateral side of the skull (Fig. 4B), the orbitosphenoid is exposed and contributes to the anteromedial wall of the temporal fossa. The orbitosphenoid is defned by the frontal dorsally, the alisphenoid posterodorsally, and apparently by the maxilla ventrally. Its sutures with the palatine are not detectable. ALISPHENOID. The alisphenoid is visible in the lateral view of the skull (Fig. 4B). Its sutural contacts with the frontal, parietal and squamosal can be clearly determined. Furthermore, the alisphenoid forms the slightly uneven posterolateral side of the pterygoid process. An alisphenoid canal is absent, and the foramen ovale is opened to form a notch or incisure. PTERYGOID. As in other sirenians, the pterygoid is present on the posteromedial side of the pterygoid process but fully fused with the surrounding bones (Fig. 3). Though not well preserved in OLL 1926/394, the wing-shaped pterygoid processes each bear a dorsoventrally elongated pterygoid fossa posteriorly that extends above the level of the roof of the internal nares, relative to the condition observed in some dugongines like Dioplotherium manigaulti (Domning 1989). The distal ends of both pterygoid processes are somewhat damaged, although the distomedial angle of the right pterygoid process is still distinct and indicates a hamula process. PALATINE. Only the posteriormost parts of the palatines are preserved in OLL 1926/394, and are best observable on the right side (Fig. 3). There the palatine forms the anteromedial margin of the pterygoid process. Its sutures with the surrounding bones are only barely visible on the distal and medial sides of the pterygoid process and on the posterior side of the maxillary alveolar margin. MAXILLA. The zygomatic-orbital bridge (Fig. 3) is not completely preserved in any of the specimens. However, in the maxillary fragment of OLL 1939/257 its dimensions are 47 mm in minimum length and 17.5 mm in nearly original height (Spillmann 1959: fg. 20). On the basis of these data, the zygomaticorbital bridge can be clearly determined to be long anteroposteriorly, relative to what is observed in the genus Hydrodamalis (Domning 1978; Velez-Juarbe & Domning 2014a). Additionally, and in contrast to some hydrodamalines, e.g., Dusisiren jordani Kellogg, 1925 and Hydrodamalis cuestae Domning, 1978 (Domning 1978; Velez-Juarbe & Domning 2014a), it is only slightly elevated above the alveolar margin, and its posterior edge is thickened. Remnants of the infraorbital canal reveal no obstruction. SQUAMOSAL. The cranial part of the squamosal (Figs 2, 4B) extends up to the temporal crests but does not interrupt the course of the temporal crests, so that these reach the occipital nuchal crest. The posttympanic process is not club like distally (Fig. 4B), but concave anteroventrally for the attachment of the sternomastoid muscle. In the posterior view of the skull (Fig. 4A), a prominent sigmoid ridge is visible forming the laterocaudal margin of the squamosal. Posterolaterally, the mastoid foramen is present, flled by the periotic, and enclosed by the squamosal anteriorly, the exoccipital posteriorly, and the supraoccipital dorsally. Lateral to the braincase (Figs 2, 4B), each of the zygomatic processes projects from a zygomatic root that, though partially broken, is characterised by a distinct notch posteriorly. The zygomatic process is triangular in shape, tapering anteriorly. Its lateral and medial sides are fat to concave with the dorsal margin distinctly inclined inwards to form a sigmoid ridge. The posterodorsal end of the zygomatic process is straight to concave. The external auditory meatus is short mediolaterally and about as wide as high anteroposteriorly. Ventrally (Fig. 3), the elements of the mandibular articulation surface are elongated transversely. The mandibular fossa forms a distinct depression relative to the slightly convex tuberculum anteriorly. Posterior to the mandibular fossa, the postglenoid process forms a rounded and longitudinal knob, which rises above the level of the tuberculum. The posterior end of the zygomatic process, the processus retroversus, shows a moderate inward-directed infection in contrast to what is observed in the living dugong (e.g., Domning & Aguilera 2008; Velez-Juarbe & Domning 2014a). JUGAL. Only a fragmentarily preserved middle part of the right jugal is known from specimen OLL 1926/394 (Fig. 4B), indicating that a postorbital process is probably present. Considering the position and shape of the supraorbital processes of the frontal, the development of a postorbital bar can be excluded. The zygomatic process of the jugal is not preserved but according to its imprint on the ventral side of the zygomatic process of the squamosal it reaches the tuberculum, exceeding the diameter of the orbit. EAR REGION. In specimen OLL 1926/394, the right periotic is poorly preserved (Figs 3, 4A). It is not fused with the adjacent skull bones, and is set in a closely-ftting socket in the squamosal. The tegmen tympani is only indicated by its imprints on the dorsolateral side of the squamosal. It was most likely about as big as the mastoid or slightly smaller. The petrosal is fragmentarily preserved medioventrally, with the perilymphatic foramen apparently not separated into a fenestra rotunda and cochlea canaliculus. The processus fonticulus flls the mastoid foramen posteriorly (Fig. 4A). MANDIBLE (Table 3). The mandibular symphysis is broad, as is the masticating surface that is lacking a median furrow and houses four large and shallow alveoli for vestigial incisors and canines. This is best visible in OLL 1939/257 (Fig. 6A), which exhibits a completely preserved masticating surface, whereas in OLL 2012/1 (Figs 6B, 7A) the ventralmost end is broken. In lateral view (Fig. 7), the symphysis is higher than long and bears the mental foramen laterally, which is joined dorsoposteriorly by two accessory mental foramina on each side in specimen OLL 1939/257 (Fig. 7B). The accessory mental foramina are large relative to what is observed in more plesiomorph dugongid taxa, e.g., “ Halitherium ” taulannense (Sagne 2001a), but they are still smaller than the principal foramen. This observation is interpreted here in analogy with Trichechus (Domning 1982, 1994, and personal observations), as “true” accessory mental foramina, which are present in addition to and usually posterior to the large principal foramen. In the lectotype (OLL 2012/1; Fig. 7A), the mental foramen is broken off dorsoposteriorly, and therefore the accessory mental foramina are not identifable, but their open canals are merged with the main foramen. The overall build of the horizontal mandibular ramus appears to be broad dorsoventrally, but it is evaluated to be slender on the basis of its minimum dorsoventral height, which is smaller than 0.25 × the length of the mandible. The ventral border

The fossil sirenian material from the upper Oligocene Linz Sands of Upper Austria is reviewed and re-described in detail following a recent approach on the invalidity of the genus Halitherium Kaup, 1838. This morphological study provides the first evidence for the synonymy of “Halitherium” cristolii Fitzinger 1842, “H.” abeli Spillmann, 1959 and “H.” pergense (Toula, 1899), supporting the hypothesis that only a single species inhabited the late Oligocene shores of present-day Upper Austria. In the course of the taxonomic revision of the “Halitherium” species-complex, this taxon is now assigned to the new genus Lentiarenium Voss gen. nov. It represents a more derived sirenian compared to Eocene and early Oligocene taxa distributed across Central Europe and North Africa, which is in accordance with the stratigraphical data. An updated inventory list of all identifiable and referable skeletal material is provided, including a detailed synonymy list for the new taxonomic combination.

In Sri Lanka over the past 30 years Dugong Dugong dugon numbers have declined dramatically and sightings are now very rare for this species, currently listed as a globally vulnerable. Dugongs are social animals that are broadly coincident with the sea grasses they prefer for forage, primarily the genera Halodule and Halophila. This study was conducted to determine threats, conservation, populations, habitat selection and habitat availability of dugongs in the Kalpitiya and Puttalama areas. The small resident population is known to exist in just two remaining areas in Kalpitiya and Uchchamunei. Our survey indicated that dugongs were being killed at the rate of one every four months. A systematic research on this vulnerable marine mammal should be initiated to document its current distribution in the area, habitat status, breeding and migration patterns, if any. Also there is a strong potential for declaring a marine and coastal Ramsar site for dugongs.

Herein, we describe a new early Miocene dugongine from marine deposits of the Culebra Cut (Gaillard Cut) of the Panama Canal. The new taxon, Culebratherium alemani, gen. et sp. nov., represents one...