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Thursday, April 25th, 2024
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| 2:08a | [Crustacea • 2024] Wollastenothoe minuta • “Hidden” Biodiversity: A New amphipod Genus (Amphipoda: Stenothoidae) dominates Epifauna in Association with a mesophotic Black Coral Forest
Abstract Black corals are important components of mesophotic and deep-water marine habitats. Their presence at great depths (e.g., 50 to 200 m) makes accessibility difficult, limiting our understanding of the associated biodiversity. Amphipods dominate vagile epifauna in marine habitats around the world, fulfilling important ecosystem functions. However, there are no studies on amphipods exclusively associated with black corals, including relationships between their ecological patterns (e.g., abundances) and the size of coral colonies. We investigated the epifaunal composition and abundance associated with black coral colonies of Antipathella wollastoni in the subtropical eastern Atlantic Ocean. In total, 1,736 epifaunal individuals were identified, of which 1,706 (98.27%) were amphipods, belonging to 6 taxa. We identified and described a new amphipod genus and species within the Stenothoidae family, Wollastenothoe minuta gen. nov., sp. nov., which outnumbered the amphipod assemblage (86.15%) and provided a complete taxonomic key of Stenothoidae family including this new finding. For the first time, the association between an amphipod species and a black coral was described, including a strong correlation between coral colony size and amphipod abundances. This study demonstrates that epifauna associated with mesophotic black corals remains largely undescribed. Keywords: Stenothoidae, Key to species, Antipathella wollastoni, Epifauna, Marine animal forests
Taxonomy Class Malacostraca Latreille 1806 Order Amphipoda Latreille 1816 Suborder Senticaudata Lowry & Myers 2013 Family Stenothoidae Boeck 1871 Genus Wollastenothoe Gouillieux & Navarro-Mayoral gen. nov. Diagnosis of the new genus: Body dorsally smooth. Head without rostrum. Antenna 1 article 1 not nasiform; accessory flagellum with 1 article. Mandible palp with 1 article, molar process conical. Maxilla 1 palp with 2 articles. Gnathopod 1 and 2 subchelate, subequal. P5 basis rectolinear without posterodistal lobe. P6-7 basis widened. Etymology: The genus name, Wollastenothoe, refers the combination of host name corresponding to the species of black coral (i.e., Antipathella wollastoni) with the genus name Stenothoe belonging to the Stenothoidae family. Wollastenothoe minuta Gouillieux & Navarro-Mayoral gen. nov., sp. nov., Diagnosis: Body length less than 1.5 mm. Antenna subequal, shorter than half length of body. Antenna 1 accessory flagellum with 1 small article. Gnathopod 1 and 2 subchelate, subequal. Pereonite 4 slightly longer than pereonite 3. Coxa 4 ventral margin concave. Coxae 5–7 posterior margin with a notch. P5 basis rectolinear without posterodistal lobe. P6-7 basis widened with posterodistal lobe reaching along half of ischium, merus posterodistal lobe reaching more than half length of carpus. Telson with dorsal spines. Etymology. The epithet specific of the species, minuta, refers to its small size. Type locality. Puerto del Carmen, Lanzarote, Canary Islands, Spain. Sandra Navarro-Mayoral, Benoit Gouillieux, Victoria Fernandez-Gonzalez, Fernando Tuya, Ninon Lecoquierre, Lorenzo Bramanti, Lucas Terrana, Fernando Espino, Jean-François Flot, Ricardo Haroun and Francisco Otero-Ferrer. 2024. “Hidden” Biodiversity: A New amphipod Genus dominates Epifauna in Association with a mesophotic Black Coral Forest. Coral Reefs. DOI: 10.1007/s00338-024-02491-y | ||||
| 3:26a | [PaleoIchthyology • 2024] Exceptionally preserved Shark Fossils from Mexico elucidate the Long-standing Enigma of the Cretaceous Elasmobranch Ptychodus (Lamniformes: Ptychodontidae)
Abstract The fossil fish Ptychodus Agassiz, 1834, characterized by a highly distinctive grinding dentition and an estimated gigantic body size (up to around 10 m), has remained one of the most enigmatic extinct elasmobranchs (i.e. sharks, skates and rays) for nearly two centuries. This widespread Cretaceous taxon is common in Albian to Campanian deposits from almost all continents. However, specimens mostly consist of isolated teeth or more or less complete dentitions, whereas cranial and post-cranial skeletal elements are very rare. Here we describe newly discovered material from the early Late Cretaceous of Mexico, including complete articulated specimens with preserved body outline, which reveals crucial information on the anatomy and systematic position of Ptychodus. Our phylogenetic and ecomorphological analyses indicate that ptychodontids were high-speed (tachypelagic) durophagous lamniforms (mackerel sharks), which occupied a specialized predatory niche previously unknown in fossil and extant elasmobranchs. Our results support the view that lamniforms were ecomorphologically highly diverse and represented the dominant group of sharks in Cretaceous marine ecosystems. Ptychodus may have fed predominantly on nektonic hard-shelled prey items such as ammonites and sea turtles rather than on benthic invertebrates, and its extinction during the Campanian, well before the end-Cretaceous crisis, might have been related to competition with emerging blunt-toothed globidensine and prognathodontine mosasaurs. Keywords: Chondrichthyes, Lamniformes, Ptychodontidae, ecomorphology, Late Cretaceous, Vallecillo fossil Lagerstätte    Romain Vullo, Eduardo Villalobos-Segura, Manuel Amadori, Jürgen Kriwet, Eberhard Frey, Margarito A. González González, José M. Padilla Gutiérrez, Christina Ifrim, Eva S. Stinnesbeck and Wolfgang Stinnesbeck. 2024. Exceptionally preserved Shark Fossils from Mexico elucidate the Long-standing Enigma of the Cretaceous Elasmobranch Ptychodus. Proc. R. Soc. B. 291: 20240262. DOI: 10.1098/rspb.2024.0262   | ||||
| 2:03p | [PaleoIchthyology • 2024] From Sabers to Spikes: A newfangled Reconstruction of the Ancient, Giant, sexually dimorphic Pacific Salmon, Oncorhynchus rastrosus (Salmoniformes: Salmoninae: Salmonini)
Abstract The impressive †Oncorhynchus rastrosus of the Pacific Northwest’s Miocene and Pliocene eras was the largest salmonid ever to live. It sported a hypertrophied premaxilla with a pair of enlarged teeth which the original describers reconstructed as projecting ventrally into the mouth, leading them to assign the species to “Smilodonichthys,” a genus now in synonymy. Through CT reconstruction of the holotype and newly collected specimens, we demonstrate that the famed teeth projected laterally like tusks, not ventrally like sabers or fangs. We also expand the original description to characterize sexual dimorphism in mature, breeding individuals. Male and female †Oncorhynchus rastrosus differ in the form of the vomer, rostro-dermethmoid-supraethmoid, and dentary, much as do other extant species of Oncorhynchus. Male specimens possess a more elongate vomer than do females, and female vomers have concave ventral surfaces and prominent median dorsal keels. The dentary of females has no evidence of a kype, though some specimens of †O. rastrosus have a non-uniform density mesial to the tooth bed, which we interpret as a male kype. Unlike extant Oncorhynchus, male and female †O. rastrosus do not differ in premaxilla shape. Because male and females possess hypertrophied premaxillae and lateral premaxillary spikes, the former common name “Sabertoothed Salmon” no longer reflects our understanding of the species’ morphology. Accordingly, we redub †O. rastrosus the Spike-Toothed Salmon and postulate that its spikes were multifunctional, serving as defense against predators, in agonism against conspecifics, and as a practical aid to nest construction.
 Conclusion: Extant Pacific salmon are sexually dimorphic, anadromous fishes navigating complex terrains to successfully breed. They undergo impressive physiological and morphological transformations prior to and during migration inland to spawn. †Oncorhynchus rastrosus was no exception, despite its huge size and unusual filter feeding ecology. The newly recovered specimens from the Gateway Locality of Oregon represent mature individuals with subtle dimorphism in the vomer, rostro-dermethmoid-supraethmoid, and dentary. Male specimens possess a more elongate vomer than do females and do not have a dorsal keel as in females. The female dentary has no evidence of a kype and possesses two mesial teeth. Male specimens of †O. rastrosus have a non-uniform density deep to the tooth bed and edentulous portion of the dentary, which we interpret as evidence of a kype. Finally, the rds is blunt in females and pointed in males. Unlike extant Oncorhynchus, male and female specimens of †O. rastrosus do not differ in premaxilla shape and both sexes possess prominent, laterally-directed premaxillary teeth. These spikes on the hypertrophied premaxilla could have defended against predators, enhanced agonism against conspecific individuals, and/or aided nest construction. Kerin M. Claeson, Brian L. Sidlauskas, Ray Troll, Zabrina M. Prescott and Edward B. Davis. 2024. From Sabers to Spikes: A newfangled Reconstruction of the Ancient, Giant, sexually dimorphic Pacific Salmon, †Oncorhynchus rastrosus (SALMONINAE: SALMONINI). PLoS ONE. 19(4): e0300252. DOI: 10.1371/journal.pone.0300252 | ||||
| 2:24p | [Botany • 2024] Leopoldia oztasii (Asparagaceae: Scilloideae) • A New Species from South Anatolia-Türkiye
Abstract Leopoldia oztasii sp. nov. (Asparagaceae, Scilloideae) is described as a new species in this study. It spreads on the stony slopes of Konya province in the south of Türkiye. Leopoldia oztasii is similar to L. tenuiflora, but it is easily distinguished from it, by having larger bulbs, falcate leaves, shorter scape, conical inflorescence, longer pedicels, and larger capsules. In this study, the morphology, seed surface characteristics and ecology of L. oztasii were studied. A detailed description of the new species, a comparison table between the two species, and detailed photographs showing their differences are provided. The distribution areas of L. oztasii and L. tenuiflora in Türkiye are also presented on the map. Asparagaceae, Leopoldia, morphology, new species, seed, taxonomy, Türkiye, Monocots   “Leopoldia oztasii Eker, Eroğlu & Pınar” “Konya Morbaşı” Hüseyin Eroğlu, Süleyman Mesut Pinar, İsmail Eker. 2024. A New Leopoldia (Asparagaceae, Scilloideae) Species from South Anatolia-Türkiye: Leopoldia oztasii. Phytotaxa. 633(1); 17-28. DOI: 10.11646/phytotaxa.633.1.3  |
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