LOWER LIAS OF ROBIN HOOD'S BAY 



127 



Remarks. Examples of Echioceras with strongly depressed whorls 

 and coarse ribs were not found by Bairstow, and the horizon of 

 Simpson's holotype WM 461 is not known; presumably it ought to 

 have come from the Raricostatoides Subzone. 



Echioceras raricostatoides (Vadasz, 1908) PI. 4, fig. 2 



1908 Arietites raricostatoides Vadasz: 373. 



1925 Echioceras fill gidum Trueman & Williams: 717, pi. 1, fig. 



12 (BM C. 17424, possibly from bed 489). 

 1973 Echioceras raricostatoides (Vadasz); Getty: 13, pi. 1, fig. 



12 (neotype, designated by Getty, from Nancy, France). 



Range. Beds 488^19 1.1, Raricostatoides Subzone; 1 5 specimens. 



Remarks. The very well preserved specimen from bed 489 fig- 

 ured in PI. 4, fig. 2 has a closely similar rib-density to that of the 

 neotype shown in Getty's (1973: 15, fig. 3) graph. The more densely 

 ribbed species E. aeneum Trueman & Williams, Echioceras 

 laevidomum (Quenstedt; Schleglemilch, 1976: pi. 21, fig. 12, 

 lectotype) which has modified ribbing at large whorl sizes, and E. 

 pauli (Dumortier, 1867: pi. 29, figs 5, 6), all said to occur in the 

 lowest part of the Raricostatoides Subzone by Getty (1973: 14), were 

 not identified amongst Bairstow's material. 



Echioceras intermedium (Trueman & Williams, 1925) 



1925 

 1973 



Range. 

 mens. 



Pleurechioceras intermedium Trueman & Williams: 720, 

 pi. 2 fig. 2 (holotype, BM C.26787, from bed 493. 

 Echioceras intermedium (Trueman & Williams); Getty: 16, 

 pi. 3, fig. 1 (BM C.79684, from bed 493). 



Beds 491.2 and 493.2, Raricostatoides Subzone; 7 speci- 



Genus LEPTECHIOCERAS, Buckman 1923 



Leptechioceras macdonnelli (Portlock, 1843) 



1843 Ammonites macdonnelli Portlock: 134, pi. 29A, fig. 12. 

 1880/81 Arietites nodotianus (d'Orbigny); Wright: 301 (1881), pi. 



37, figs 3, 4 (1880) (holotype of Ammonites macdonnelli 



Portlock, from Larne, northern Ireland, Ulster Museum no. 



K8117). 

 1923 Leptechioceras macdonnelli (Portlock); Buckman: pi. 443 



(BM C.41756, from Cheltenham). 

 1961 Leptechioceras macdonnelli (Portlock); Dean ef al: pi. 67, 



fig. 6 (BM C.41756, from ?Larne, Co Antrim, northern 



Ireland). 

 1973 Leptechioceras macdonnelli (Portlock); Getty: 16. 



Range. Beds 494^195.7, Macdonnelli Subzone; 5 specimens. 



Remarks. The earliest examples in bed 494 are identified as L. aff. 

 macdonnelli because reduced ribbing persists onto their outer whorls, 

 which do not become as smooth as in the later specimens from beds 

 495. 13 and 495.7. Nevertheless, in those early specimens the ribs are 

 more reduced than in L. nodotianum (d'Orbigny, 1843; Fischer, 

 1994: 48, pi. 20, fig. 4, holotype), L. charpentieri (Schafhautl, 1 847; 

 Getty, 1973: pi. 2, fig. 6, lectotype) or L. meigeni (Hug, 1 899), all of 

 which are more strongly ribbed throughout. 



Genus PALTECHIOCERAS Buckman, 1924 



Paltechioceras planum (Trueman & Williams, 1925) 



1925 Leptechioceras planum Trueman & Williams: 731, pi. 2, 

 fig. 5 (holotype, from Radstock, Somerset). 



1926 Leptechioceras planum Trueman & Williams; Buckman: 

 pi. 696 (holotype refigured). 



Range. Beds 493.3^493.5, Raricostatoides Subzone; 5 specimens. 



Paltechioceras tardecrescens (Hauer, 1 856) 



PI. 4, figs 3, 6 



71855 Ammonites aureolus Simpson: 94. 



1856 Ammonites tardecrescens Hauer: 20, pi. 3, figs 10-12. 



1876 Arietites tardecrescens (Hauer); Blake: 285, pi. 5, figs 5 



(?BM C. 17879, from bed 498), 5b (7BM C. 17898). 

 1889 Caloceras aplanatum Hyatt: 146, figs 23, 24 (on p. 147). 

 1889 Arnioceras tardecrescens (Hauer); Hyatt: 168, pi. 2, fig. 19. 

 71914 Echioceras aureolum (Simpson); Buckman: pi. 96 



(lectotype, designated by Donovan ( 1 958: 24), GSM 26402, 



from bed 497); ?senior synonym of P. tardecrescens. 

 1926 Metechioceras aplanatum (Hyatt); Buckman: pi. 640 



(holotype, MCZ 80 (Museum of Comparative Zoology, 



Cambridge, Massachussets), from bed 498). 

 1961 Paltechioceras aplanatum (Hyatt); Dean et al.: pi. 68, fig. 2 



(BM 37999, from bed 498). 

 1973 Paltechioceras aplanatum (Hyatt); Getty: 21, pi. 4, fig. 1 



(BM C. 17898, from bed 498). 

 1973 Paltechioceras tardecrescens (Hauer); Getty: 21, pi. 4, fig. 



2 (lectotype, designated Getty, from Adneth, Saltzburg, 



Austria). 

 1992 Paltechioceras tardecrescens (Hauer); Dommergues & 



Meister: 221, figs 5(l)-5(4) (from bed 497). 



Range. Beds 497-499, Aplanatum Subzone; 228 specimens. 



Remarks. P. tardecrescens is abundant in beds 497 and 498; those 

 in bed 498 are up to 175 mm diameter and are preserved in limestone 

 nodules (PI. 4, fig. 6), and many of the previously figured specimens 

 undoubedly came from this bed (including the holotype of Hyatt's 

 species aplanatum). Most of the specimens in bed 497 are much 

 smaller pyritized whorls up to about 40 mm diameter (PI. 4, fig. 3), 

 though there are a few crushed and partly pyritized fragments of 

 larger whorls up to 90 mm diameter. The lectotype of P. aureolum 

 (Simpson, 1855; Buckman, 1914: pi. 96) is pyritized like most 

 specimens in bed 497 and can be matched closely with several of 

 them (eg. CA 3456 and 3480); it is only 25 mm diameter, but 

 Ammonites aureolus Simpson, 1855, might be a senior synonym of 

 Paltechioceras tardecrescens (Hauer, 1856). In addition, two speci- 

 mens were found at the base of bed 499 and 0.08 m above the base of 

 that bed respectively. 



Paltechioceras regustatum Buckman, 1914 



1911 



1914 

 1973 



Echioceras aureolum (Simpson); Buckman: pi. 28 

 (paralectotype of Ammonites aureolus Simpson, WM 872, 

 from bed 497). 



Paltechioceras regustatum Buckman: 96c. 

 Paltechioceras aureolum (Simpson); Getty: 20, pi. 5, figs 3 

 (holotype of Echioceras regustatum Buckman, GSM 26439, 

 from bed 496 or 497), 4 (BM C.79681, from bed 497). 



RANGE. Beds 496 and 497, Aplanatum Subzone; 18 specimens. 



Remarks. P. regustatum is the second and less common species of 

 Paltechioceras in the Aplanatum Subzone, and is represented by a few 

 poorly preserved specimens in bed 496 and two in bed 497; it has much 

 more widely spaced ribs than P. tardecrescens at diameters of more 

 than 25 mm. Two larger examples figured by Getty (1973: pi. 5, figs 3, 

 4) as P. aureolum are 50 and 64 mm diameter respectively, and the latter 



