Re-appraisal of thylacocephalans (Euarthropoda, Thylacocephala) from the Jurassic La Voulte-sur-Rhône Lagerstätte Author Laville, Thomas EDDB1B51-2017-405B-9A92-52EA900A13CA Muséum national d’Histoire naturelle, Centre de Recherche en Paléontologie - Paris (CR 2 P, UMR 7207), Sorbonne Université-MNHN-CNRS, 57 rue Cuvier, 75005 Paris, France. & Biogéosciences, UMR 6282 CNRS, Université de Bourgogne, 6 boulevard Gabriel, 2100 Dijon, France. thomas.laville2@mnhn.fr Author Forel, Marie-Béatrice 063C1F7E-6D26-48F9-A8B1-2AFA496B5FB8 Muséum national d’Histoire naturelle, Centre de Recherche en Paléontologie - Paris (CR 2 P, UMR 7207), Sorbonne Université-MNHN-CNRS, 57 rue Cuvier, 75005 Paris, France. marie-beatrice.forel@mnhn.fr Author Charbonnier, Sylvain 2B4CC15F-FB7A-4AAF-8CB5-365E976850FA Muséum national d’Histoire naturelle, Centre de Recherche en Paléontologie - Paris (CR 2 P, UMR 7207), Sorbonne Université-MNHN-CNRS, 57 rue Cuvier, 75005 Paris, France. sylvain.charbonnier@mnhn.fr text European Journal of Taxonomy 2023 2023-10-05 898 1 1 61 https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/2295/9941 journal article 10.5852/ejt.2023.898.2295 2118-9773 8413500 87EE2C76-1DDC-40DE-87E7-4D0E11A312DC Kilianicaris lerichei Van Straelen, 1923 Figs 5B , 6–9 Kilianicaris lerichei Van Straelen, 1923a: 434–435 , pl. XIV figs 4–5. Kilianicaris lerichei – Secrétan & Riou 1983: 84 , pl. III figs 1–4. — Secrétan 1985: 386–387 , fig. 2e. — Schram et al . 1999: 772 . — Charbonnier 2009: 205–206 , figs 249, 337, 367, tab. 14. — Charbonnier et al . 2010: 115 , 117, 121, fig. 5c, tabs 1–2; 2014: 375, fig. 4b, tab. 1. — Schram 2014: 353 . — Ji et al . 2017: 174 . — Rak et al . 2018: 268 . — Van Roy et al . 2021: 1737 . — Schram & Koenemann 2022 : tab. 41.2. Material examined Holotype FRANCE • La Boissine , La Voulte-sur-Rhône , Ardèche , France; Callovian, Middle Jurassic ; OSUG-UJF-ID.11545 . Paratype FRANCE • same collection data as for holotype; OSUG-UJF-ID.1752 . Additional material FRANCE • 48 specs ; same collection data as for holotype; MNHN .F. A29246 , A29253 , A29301 to A293016 , A29318 , A29374 , A29375 , A53334 , A53335 , A53338 , A53339 , A53342 , A83991 to A85013 , A84073 , R50942 , R50961 , R50967 , R50969 , R50972 , R50973 , R50975 , R50976 • 1 spec. ; same collection data as for holotype; OSUG-UJF-ID.1751 • 3 specs ; same collection data as for holotype; MSNM i7593 , i7596 , i20704 . Measurements See Table 2 . Description Shield morphology Rounded shield in lateral view with a straight and sub-vertical anterior margin, an antero-dorsal corner expressed as a large, rounded and horizontal rostrum, a slightly convex dorsal midline bearing a dorsal carina in its posterior third ( Fig. 6 ). Presence of serrations along the first two thirds of the dorsal midline, until the dorsal carina ( Fig. 6H–I ). Postero-dorsal corner expressed as a small spine; straight and vertical posterior margin ending in a rounded postero-ventral corner; ventral margin divided into a posterior half steeply descending antero-ventrally and an anterior one ascending antero-dorsally; both parts merged approximately at mid-length; rounded antero-ventral corner. Rim of all free margins forming a marginal fold. Shield macro-ornamentation Dorso-lateral carina protruding from the posterior margin, running straight until the anterior third of the shield and forming a depression ( Figs 6–7 ); carina then ascending to the dorsal midline and merging with the dorso-lateral carina from the other side of the shield; carina associated with a row of at least 19 pores (d = ~ 0.5 mm ) in its posterior part ( Fig. 8H–K ). Marginal fold delimited by a ventro-lateral groove ( Fig. 6C–D ). Sensory structures Oval, stalked compound eyes protruding from the anterior margin and occupying the entire margin ( Figs 7F–G , 9E, G ). Cephalic appendages Cephalic appendages not preserved. Raptorial appendages Presence of three pairs of raptorial appendages recognised by preservation of muscles, protruding from the ventral margin ( Figs 9H–I , 11 ). Raptorial appendages consisting of two parts: a proximal postero-ventrally oriented and a distal one, antero-ventrally oriented. Articulation between both parts forming an elbow. First pair of raptorial appendages ( Fig. 9A–D ), the shortest, consisting of a proximal part with two podomeres: a rectangular podomere 1 being 3.4 times as long as wide; a stout podomere 2 being 5.9 times as long as wide. Distal part of the appendages formed by three podomeres: podomere 3 being 4 times as long as wide; podomere 4 being 5.6 times as long as wide and bearing two medial spines; podomere 5, the most distal and shortest one, being 4.8 times as long as wide. Second pair of raptorial appendages consisting of a proximal part with two podomeres ( Fig. 9 ): podomere 1 not well preserved; podomere 2 being 4.7 times as long as wide ( Fig. 9A–B, D ). Distal part of the appendage consisting of three podomeres: podomere 3, the longest, being 5.2 times as long as wide and bearing two medial spines; podomere 4 being 5.3 times as long as wide and bearing four medial spines; podomere 5 being 3.5 times as long as wide and ending distally in a cluster of five long spines, the medial one being the smallest. Third pair of raptorial appendages, the longest, consisting of a proximal part with two poorly preserved rectangular podomeres ( Fig. 9 ). Distal part consisting of three podomeres: podomeres 3 being 4.8 times as long as wide; podomere 4 being 6.1 times as long as wide; podomere 5 being 5.3 times as long as wide and ending in a cluster of two spines. Oval structure Long oval structure, protruding from the anterior part of the ventral margin, between raptorial and trunk appendages ( Fig. 9E–F ). Fig. 5. Scatter plots of length of the shield against maximal height of the shield. A . Kilianicaris lerichei Van Straelen, 1923 . B . Ostenocaris ribeti ( Secrétan, 1985 ) comb. nov. C . Paraclausocaris harpa gen. et sp. nov. D . Paraostenia voultensis Secrétan, 1985 . Abbreviations: Hmax = maximal shield height; Ls = length of the shield. Fig. 6. Kilianicaris lerichei Van Straelen, 1923 . A,B, E . Holotype OSUG-UJF-ID.11545. A . General view. B . Drawing. E . Close-up of posterior trunk appendages. C–D . Specimen MNHN.F.R50973. C . General view. D . Drawing. F–G . Specimen MNHN.F.A29315. F . General view. G . Drawing. H–I . Specimen MNHN.F.A29304. H . General view. I . Drawing. J . Specimen MSNM i7593. Abbreviations: am = anterior margin; cs = circular structure; dc = dorsal carina; dlc = dorso-lateral carina; dm = dorsal midline; pm = posterior margin; r = rostrum; ra 2, 3 = raptorial appendages; t = trunk; ta 1-7 = posterior trunk appendages; tls = telson; tp 1–11 = pleural part of posterior trunk; vm = ventral margin; vlg = ventro-lateral groove. Scale bars: A–B, E, I = 5 mm; C–D, F–H, J = 10 mm. Photos: A, E: S. Charbonnier; C: L. Cazes; F–J: T. Laville. Posterior trunk Eleven, elongate rectangular structures (i.e., pleural part of posterior trunk segments) surrounding a long rectangular structure (i.e., possible tergal part; Fig. 8A–D ). Pleural parts slightly curved downward at their distal end ( Fig. 8D ). Last pleura thinner than the others. Posterior extremity of the trunk expressed as a rhomboidal element (i.e., telson) bearing a rounded structure, formed by two circular parts ( Fig. 6C– D ): an outer one, delimiting the entire feature, and an inner smaller one. Fig. 7. Kilianicaris lerichei Van Straelen, 1923 preserved dorso-ventrally. A . Specimen MNHN.F.A83998 (sliced after the photograph). B . Specimen MNHN.F.A84012. C . Specimen MNHN.F.A29307. D–E . Specimen MNHN.F.R50969. D . Counter-part. E . Part. F–G . Specimen MNHN.F.A84009. F . General view. G . Drawing. H–I . Specimen MNHN.F.R50975. H . General view. I . Drawing. Abbreviations: b = body; ce = compound eye; dlc = dorso-lateral carina; dm = dorsal midline; p 2–5 = podomeres of raptorial appendages; ra 1, 2 = raptorial appendages. Scale bars = 10 mm. Photos: A–C: L. Cazes; D–E: Elise Porez (RECOLNAT – MNHN); F: T. Laville; H: Jocelyn Falconnet (RECOLNAT – MNHN). Fig. 8. Kilianicaris lerichei Van Straelen, 1923 . A–B . Specimen MNHN.F.A29375. A . General view. B . Drawing. C–D . Specimen MNHN.F.A29309. C . General view. D . Close-up of posterior trunk. E–G . Specimen MNHN.F.A29246. E . General view. F . Close-up of oval structure. G . Close-up of posterior trunk. H–K . Specimen MNHN.F.A29374. H . General view. I . Drawing. J . Close-up of dorsolateral carina. K . Close-up of pores. Abbreviations: am = anterior margin; b = body; dlc = dorso-lateral carina; dm = dorsal midline; pm = posterior margin; ra 2 = raptorial appendage 2; tls = telson; tp 1–11 = pleural part of posterior trunk segments; tta = terminal trunk appendages; ttaen = endopod of terminal trunk appendages; ttaex = exopod of terminal trunk appendages; vlg = ventro-lateral groove; vm = ventral margin. Scale bars: A–C, E, H–I = 10 mm; D, G = 5 mm; F, J = 4 mm; K = 1 mm. Photos: T. Laville. Fig. 9. Kilianicaris lerichei Van Straelen, 1923 . A–D . Specimen MNHN.F.A53342. A . General view (natural light). B . Drawing. C . General view (green fluorescence; band-pass width: 532–554 nm, with a maximal excitation wavelength of 543 nm; detection ranges: 570–613 nm). D . General view (green fluorescence; colour marked). E–G . Specimen MNHN.F.R50972. E . General view. F . Close-up of raptorial appendages. G . Drawing. H–I . Specimen MNHN.F.A29253. H . General view. I . Close-up of raptorial appendages. Abbreviations: ce = compound eye; dc = dorsal carina; dlc = dorso-lateral carina; dm = dorsal midline; p 1–5 = podomeres of raptorial appendages; pm = posterior margin; r = rostrum; ra 1–3 = raptorial appendages; sp = spines; st = stalk; t = posterior trunk; ta 8, 10 = posterior trunk appendages; tp 1–11 = pleural part of posterior trunk segments; vlg = ventro-lateral groove; vm = ventral margin. Scale bars:A–E, G–H = 10 mm; F, I = 5 mm. Photos: A–D, H–I: T. Laville; E–F: Carolin Haug & Joachim T. Haug. Posterior trunk appendages Eleven pairs of trunk appendages, postero-dorsally oriented, protruding from the posterior part of the ventral margin ( Fig. 8 ). First ten appendages formed by two parts: a square-shaped proximal one with a rounded distal margin and a styliform distal one ( Fig. 6E ). Last pair of trunk appendages formed by two paddle-like parts and being longer than the rest ( Fig. 8A–B ). Gills Eight long lamellar gills preserved under the central part of the shield below the dorso-lateral carina ( Fig. 6H–I ). Gills with an elliptic shape, becoming arcuate near the dorsal midline.