Diverse Late Jurassic Anomuran Assemblages from the Swabian Alb and Evolutionary History of Paguroids Based on Carapace Morphology

Diverse Late Jurassic Anomuran Assemblages from the Swabian Alb and Evolutionary History of Paguroids Based on Carapace Morphology

132 R.H.B. Fraaije et al. Pilgrimcheles vonmeyeri n. sp. Material: Holotype (MAB k.3253), a near-complete shield Fig. 7A-C (total length 1.5 mm, max. width 1.5 mm). Etymology: Named in honour of christian erich her- Locality and horizon: Small local quarry at the Wester- Mann von Meyer (1801-1869), a well-known German pa- berg, with well-bedded sponge-microbial limestones and laeontologist. marls of the Aulacostephanus pseudomutabilis Zone of late Kimmeridgian (= ‘Malm delta 3-4’) age. Material: Holotype MAB k.3235, a near-complete shield with a maximum length and width of 4.0 mm and 4.0 mm, Diagnosis: Shield well calcified, of near-equal length and respectively; paratypes MAB k.3334 and MAB k.3335 with width, well areolated, with distinct regions, including an- a maximum length and width of 4.5, 5.0 mm and 4.5, 5.0 gular massetic region. Small triangular rostrum and about mm, respectively. similarly sized post-ocular spines. Post-antennal projections less distinct. Anterior portion of gastric region delimited by Locality and horizon: Small local quarry at the Wester- post-rostral ridge with central gastric groove. Long central berg, with well-bedded sponge-microbial limestones and gastric groove fading into median gastric rim posteriorly. marls of the Aulacostephanus pseudomutabilis Zone of late Typically reniform keraial regions. Kimmeridgian (= ‘Malm delta 3-4’) age. Description: Well-calcified and clearly areolated shield, of Diagnosis: Shield well calcified, length slightly exceeding about equal length and width, convex transversely, slightly width, well areolated, with many distinct regions, including convex longitudinally. Small short triangular rostrum and a massetic region. Rimmed, broad-based, triangular ros- about equally sized post-ocular spines. Post-antennal pro- trum and smaller triangular, post-ocular projections. Post- jections less distinct. Ocular-frontal area equalling about 57 antennal projections less distinct and not rimmed. Anterior per cent of total maximum width. Gastric region, bounded portion of gastric region delimited by post-rostral ridge posteriorly by cervical groove; anterior part delimited by with central gastric groove. Large globose massetic region post-rostral ridge. Post-rostral ridge centrally indented by bordered posterocentrally by smaller, yet distinct globose relatively long gastric groove fading posteriorly into central submassetic region. Typically reniform keraial regions. No rim, anteriorly a broad frontal ridge extending to rostrum. posterior parts of the carapace preserved. Prominent, angular and elongated massetic region about 140 per cent of length of narrow anterior branchial area. Description: Well-calcified and clearly areolated shield, Cervical groove anteriorly curving around reniform keraial length slightly exceeding width, convex transversely, slight- region and laterally incising lateral margin below anterior ly convex longitudinally. Rimmed, broad-based, triangular branchial area. Anterior of keraial region and bordering an- rostrum and post-ocular projections. Post-antennal pro- terior massetic region distinct oval submassetic region. No jections less distinct and not rimmed. Ocular-frontal area posterior parts of carapace preserved. equaling about 55 per cent of total maximum width. Pos- teriorly pointed, bluntly arrowhead-shaped gastric region, Remarks: Pilgrimcheles vonmeyeri n. sp. and P. kersteni bounded posteriorly by deep cervical groove; anterior part n. sp. can be distinguished from the type species of the ge- delimited by slightly undulose, post-rostral ridge and when nus, P. karolinae, in having a longer central gastric groove, cuticule is absent, covered by transverse crenulations. Post- smaller massetic region, longer anterior branchial area and rostral ridge centrally indented by relatively long gastric a central gastric rim. Pilgrimcheles vonmeyeri n. sp. is eas- groove fading posteriorly into faint central rim. Prominent, ily differentiated from the coeval P. kersteni n. sp. in having globose and elongated massetic region about 160 % length a less angular massetic region, a more convex postrostral of elongated anterior branchial area. Posterior part of cervi- ridge, a more distinctly rimmed frontal margin and a dis- cal groove pronounced and very deep, anteriorly curving tinct oval submassetic region. around reniform keraial region and laterally incising lateral margin below anterior branchial area. Anterior of keraial region a distinct oval submassetic region, bordering mas- Family Parapylochelidae Fraaije, kloMpMaker & setic region. Except for some very small parts posterior of artal anterior branchial area, no other posterior parts of carapace , 2012 preserved. Genus Housacheles Fraaije, van Bakel, jagt & sku- pien, 2013 Pilgrimcheles kersteni n. sp. Type species: Housacheles timidus raaije an akel Fig. 7D F , v B , jagt & skupien, 2013, by original designation. Etymology: Named in honour of geon kersten, a Dutch amateur palaeontologist and friend, who helped during sev- eral field trips and donated some of the material studied Housacheles ovalis n. sp. herein. Fig. 7F .

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