Late Mississippian gastropods of the Chainman Shale, west-central Utah

Abstract

Girtyspira circumsecta. A new name, Retispira eliasi, is proposed to replace Bucanopsis (Retispira?) reticulata Elias, 1958 [not Bellerophon reticulatus M'Coy, 1844], both of which belong in Retispira. A lectotype is designated for Glabrocingulum (Ananias) nevadense (Walcott), of late Meramecian age, from the Diamond Peak Formation of Nevada, and this species is figured by photographs for the first time. PREVIOUS WORK cies that may have come from beds of Late Mississippian age cannot be distinguished. CHESTERIAN GASTROPODS UTAH Sadlick and Nielsen (1963) described and figured some Late Mississippian pleutrotomariacean gastropods of the Chainman Shale from several localities in west-central Utah. Lunulazona costata Sadlick and Nielsen was described from the lower part of the formation on the basis of specimens collected in the foothills east of Granite Mountain, Juab County. Lunulazona sp. A [ = L. sadlicki n. sp.] came from beds of Chesterian age that they identified as Chainman Shale, 0.3 miles (0.5 km) northeast of Leppy Peak, Elko County, Nev., near Wendover, Utah. Mourlonia sp. [ = Ptychomphalina sp. of this report] is from that locality. Glabrocingulum binodosum Sadlick and Nielsen was based upon specimens collected near the top of the Chainman in the Foote Range, Millard County, Utah, and G. quadrigatum Sadlick and Nielsen, also from the upper part of the Chainman, was described from specimens collected on the northern slope of the Burbank Hills, Millard County. Sadlick and Nielsen included in G. quadrigatum specimens from the northern part of the Confusion Range, which we herein place in another species (Glabrocingulum (Glabrocingulum) confusionense n. sp.). They also described but did not figure Glabrocingulum. n. sp. aff. G. inflatum (Elias) (probably = G. (Ananias) seminudum Gordon and Yochelson), from near the top of the formation on the southern slope of the Burbank Hills. Finally, Sadlick and Nielsen cited the occurrence ofWorthenia tenuilineata Girty in the upper part of the Chainman. We herein assign this species to the subgenus W. (Yochelsonospira). Sadlick and Nielsen's paper covers approximately 10 percent of the gastropod fauna of the Chainman Shale described in this report. NEVADA The first late Chesterian gastropod was described from Nevada only relatively recently. Mount (1973) described and illustrated Straparollus (Euomphalus) pancakensis from the Adetognathus unicornis Conodont Zone in the Pancake Range in northern Nye County. The gastropod was found 20 feet (6 m) above the base of the Ely Limestone. Gordon and Yochelson (1983) described a large faunule of gastropods from a single bed, about 1.7 ft (0.5 m) thick, in the upper part of the Diamond Peak Formation at the northern end of the White Pine Range in White Pine County. This assemblage is associated with Cravenoceras hesperium , the name-bearer of the ammonoid zone of that name. This zone is Late Mississippian (late Chesterian) in age, though not latest Mississippian. More than half the species also occur in the Chainman Shale in wes...

Gastropods from the Carboniferous (Namurian) of Congleton Edge, Cheshire,UK

“…Angyomphalus regularis Gordon & Yochelson, from the Mississippian of Utah is more inflated than A. congletonensis and is reported to have radial riblets around the umbilicus; the radial extent of the sub‐sutural comarginal nodes is similar in both species. Angyomphalus desultoria Jeffery et al ., from the Imo Formation (late Mississippian, Chesterian) is lower spired than A. congletonensis and sub‐sutural comarginal nodes are weakly developed or absent.…”

“…Thein & Nitecki () described over 70 species from the late Mississippian (Chesterian) of the Illinois Basin. Gordon & Yochelson () described 79 species from the Chainman Shale (late Mississippian) of Utah. Batten () monographed more than 90 species from the Magdalena Formation (Pennsylvanian, Morrowan) of Texas, while Kues & Batten () identified 157 species from the Flechado Formation (Desmoinesian) of New Mexico.…”

“…Yoo , ) or maintaining full generic status (e.g. Batten ; Gordon & Yochelson ; Kues & Batten ). Weir () assigned Carboniferous bellerophontoideans with reticulate ornamentation to Bucaniopsis , an unjustified spelling emendation of Bucanopsis Ulrich in Ulrich & Scofield, employed by Cossmann (, p. 109) and Reed (, p. 58).…”

“…Angyomphalus kentuckiensis Thein & Nitecki, from the late Mississippian (Chesterian) of the Illinois Basin, USA, is known from a single specimen with more inflated whorls than the type species and A. congletonensis ; it also has a broad, raised, selenizone forming the vertical outer whorl surface, instead of flush with the outer margin of the upper whorl surface as in the latter two species. Angyomphalus kentuckiensis was transferred to Mourlonia by Gordon & Yochelson (). Angyomphalus penelenticulata Rollins, from the earliest Mississippian (Kinderhookian) of Iowa lacks sub‐sutural comarginal nodes and shows a higher degree of embracement of earlier whorls than A. congletonensis ; it may be better placed in Eoangyomphalus .…”

“…Q), in which feature the Pot Bank Quarry specimens resemble Glabrocingulum binodosum Sadlick & Nielsen, , described from the latest Mississippian (Chesterian) of the upper Chainman Formation of Utah. Neither Sadlick & Nielsen () nor Gordon & Yochelson () made comparison of G. binodosum with G. armstrongi , or with any other non‐American material. The two species are closely similar in terms of ornamentation, notably the two rows of sub‐sutural nodes and tendency for spiral ornamentation on the upper whorl surface to become less prominent as the selenizone is approached.…”