Kilianicaris lerichei Van Straelen, 1923

Laville, Thomas, Forel, Marie-Béatrice & Charbonnier, Sylvain, 2023, Re-appraisal of thylacocephalans (Euarthropoda, Thylacocephala) from the Jurassic La Voulte-sur-Rhône Lagerstätte, European Journal of Taxonomy 898 (1), pp. 1-61 : 15-22

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 ).

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.

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.

Figures

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 lericheiVan 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.

Fig. 7. Kilianicaris lericheiVan 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; p2–5 = 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; ra2 = raptorial appendage 2; tls = telson; tp1–11 = 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; p1–5 = podomeres of raptorial appendages; pm = posterior margin; r = rostrum; ra1–3 = 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.

Fig. 11. Ostenocaris ribeti (Secrétan, 1985) comb. nov. A. Holotype MNHN.F.R50981. B. Specimen MNHN.F.A29349. C. Specimen MNHN.F.A29368. D–E. Specimen MNHN.F.A84023. D. General view. E. Drawing. F–G. Specimen MNHN.F.A29365. F. General view. G. Drawing. Abbreviations: am = anterior margin; b = body; ce = compound eye; dlc = dorso-lateral carina; dm = dorsal midline; g = gills; mlc = medio-lateral carina; p 1–5 = podomeres of raptorial appendages; ra 2–3 = raptorial appendages; tp1–7 = pleural part of the posterior trunk; vm = ventral margin. Scale bars: 5 mm. Photos: A: J. Falconnet (RECOLNAT – MNHN); B–C, F: T. Laville; D: L. Cazes.