Page 51 - Land Snails of New Mexico

"heartland" of the group in the Black Range, O. metcalfei continued to evolve and speciate into the variants recognized theretodayassubspecies,andwhicharetreatedabove.Instead of this dispersalist model, one could, of course, contrive a vicariancemodel toexplainthedistributionalpatterns.
Oreohelix confragosa A. L. Metcalf, 1974. The Nautilus, 88:96, Figs. 4–7, 9, 11. T.L.: north-facing wall of Willow SpringsCanyon,0.3mileWSW ofwestsideofruinsof Georgetown, Grant Co., New Mexico. (Pinos Altos mountainsnail)
Distribution and Habitat—This species occurs in the Pinos
Altos Mountains, across the Mimbres River Valley from the
"stronghold" oftheOreohelix metcalfei complex in the southern
Black Range. As suggested above, it may belong to that
complex, but be an outlying member, which speciated in the Pinos Altos Mountains.
Living specimens of O. confragosa have been taken only at the type locality, southwest of the ghost town of Georgetown, below massive limestone outcrops. Snails were living under flat limestone rocks derived from the cliffsabove and strewing the slope below. Here, at 6,700-ft elevation, the canyon wall supported a pinyon-juniper-Gambel O a k association of trees. It seems likely that search in other areas of limestone outcrops in the eastern Pinos Altos Mountains might reveal further populations of this or closely allied species.
Oreohelix florida H. A. Pilsbry, 1939. Academy of Natural Sciences of Philadelphia Monograph, 3(I)1:513. T.L.: near the "central peak" (probably Baldy Peak) of the Florida Mountains on the west side, Luna Co., New Mexico. (Floridamountainsnail)
Pilsbry first reported (1915:349) this taxon as "Oreohelix strigosa var.". In his description, Pilsbry (1939) made it a subspecies of Oreohelix metcalfei. Metcalf (1974:98) raised
florida to the status of full species. Even in 1915, Pilsbry had reported (p. 349) that only " T w o broken and very old 'bones' were found..." at the type locality, presumably on Baldy Peak in the Florida Mountains. Baldy Peak, a high, isolated, massive limestone outcrop, m a y have been the last refuge of the species. In 1970, Metcalf found only a few weathered fragments on the north side of Baldy Peak, as has Richard D. Worthington in
1996. Collections m a d e in this century suggest that O. florida is nolongerliving.As afossil,itoccursintheFlorida,SantaRita, and Tres Hermanas Mountains, the Apache Hills, and on the lower, northern side of Cooke Peak near the ghost town of Cooke (or Cook).
Oreohelix litoralis C. R. Crews and A. L. Metcalf, 1982. Proceedings of the Biological Society of Washington, 95.256,Figs 1A-C,2A,3A.T.L.:Sec. 1,T.6 S,R. 12W, at 6,900-ft elevation, south side of San Agustin Plains, Catron Co., N e w Mexico.
Distribution and Habitat-Asknown presently, O. litoralis islimitedtocertainareasofoutcrop ofrhyoliticrocks around the
southern edge of former Pleistocene Lake San Agustin. Here, it isfoundincrevicesintherocksandinrockrubbleofwave-cut
cliffs.The localitiesareonthesouthernmarginoftheSan Agustin Plains at an elevation of ca. 6,900 ft. The area is grassland with sparse shrubs, in contrast to the forested habitats observed in association with most occurrences of Oreohelix.
Remarks--Populations of O. litoralis were discovered by
Dr. Robert H. Weber, New Mexico Bureau of Mines and
Mineral Resources, in the course of his investigations on former
pluvial Lake San Agustin. Dr. Weber collected this species at
sevensitesaroundthesouthernformershoreofthelake.One of theselocalitieswasonwhathadbeenanislandinthelakefora
period of time. Lorna L. M. Scarbrough has found fossil s p e c i m e n s o f O . litoralis i n s e d i m e n t s e x c a v a t e d f r o m B a t C a v e , also near the southern margin of the ancient lake.
A singlespecimenofaweatheredOreohelixwastakenin conifer forest just under the summit of Eagle Peak in the Tularosa Mountains, southwest of the San Agustin Plains. This specimen may appertain to O. litoralis (a very provisional identification). Search at several localities on Eagle Peak failed to reveal additional specimens.
Oreohelix magdalenae H. A. Pilsbry, 1939. Academy of Natural Sciences of Philadelphia Monograph, 3(I)1:515, Fig. 336b. The T.L. isrecorded simply as "Magdalena, SocorroCo." AstheenvironsofthetownofMagdalena, itself, d o n o t s e e m t o p r o v i d e l i k e l y h a b i t a t f o r t h i s s p e c i e s , we suppose that the type locality was, instead, in the nearby Magdalena Mountains to the east of the town. (Magdalena mountainsnail)
Distribution and Habitat--The Magdalena Mountains are
an isolated range, reaching 10,783-ft elevation on South Baldy
Peak, with considerable forest at higher elevations. Oreohelix
magdalenae seems to occur widely in the range, above
elevationsof7,000ft.We havetakenitatseverallocalities.
AlongNorthForkCanyon,abranchofWaterCanyon,we found
it at 7,320 ft on a north-facing slope near the bottom of the
canyon, living under loose, igneous stones in thick leaf litter from deciduous trees. Ithas been taken in coniferous forest as
h i g h a s 9 , 8 5 0 ft o n N o r t h B a l d y P e a k .
Pilsbry (1939:515) n a m e d this snail as a subspecies of O.
socorroensis (discussed below). Metcalf (1974:99) and Crews and Metcalf (1982:259) treated it as a full species, as w e do here.Inouropinion,thelarger,rounded shellofO. magdalenae, with itswell-developed color bands, bears littleresemblance to the small, carinate, sparsely pigmented shell that is the type of O. s. socorroensis. Thus, it seems judicious to consider magaalenae asafullspecies,typicalofandconfinedtothe Magdalena Mountains. Crews and Metcalf (1982:262) compared O. magdalenae with O. litoralis, which occurs to the west. They considered the two species to be closely related, but foundminordifferencesbetween them inshelland softanatomy. Theysuggestedthatthesespecieswere outlyingmembers ofthe large Oreohelix metcalfei complex. As a cautionary note, however,itshouldbepointedoutthatbothO. magdalenae and O . litoralis t h r i v e i n a r e a s o f i g n e o u s b e d r o c k , w h e r e a s m e m b e r s of the O. metcalfei group, to the south, seem to be obligate
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