P. 199‒208 VOL. 69NO. 1 BOL. SOC.GEOL.MEX.2017 Palacio, Durango, México. Juárez delEstadodeDurango, 35010Gómez Facultad deCienciasBiológicas, Universidad Anselmo Orona-Espino Ulises Romero-Méndez [email protected] José LuisEstrada-Rodríguez Alexander Czaja Alexander Cuatrociénegas from NorthMexicoandtheirrelationwithextantspecies Two newsubfossilspeciesofspringsnails(Hydrobiidae: Manuscript November accepted: 20,2016 Corrected manuscript received: November 15, 2016 Manuscript received: 18,2016 September Czaja , José Luis Estrada-Rodríguez co, Viesca, Cuatrociénegas. species, sub-fossil, North Mexi Keywords: Cuatrociénegas valley. two extant fromendemic springsnails cies or, the likely, directof precursors Viesca are sister spe of springsnails gas. Wethat suppose bothsub-fossil Pyrgulopsis P. acarinatus esca, the second newspeciesfrom Vi of the genus. Inaddition,shells of bers served among fossil or extant mem thatshoulders have never been ob paleominckleyi ley, Coahuila. of Some specimens theCuatrociénegas val complex of philus minckleyi was originally described as similar shellfeaturesspecies —this minckleyi Pyrgulopsis shoulders. Extant endemic species whorlsshells withflat andbulbous leominckleyi Mexico. species, first The of part esca, Coahuila, in the northern Vi fromof subfossilspring deposits genus the We describe two newspeciesof ABSTRACT P. paleoacarinatus Pyrgulopsis speciesfrom Cuatrociéne , which isother endemic sp. nov., hastrochiform , Ulises sp. nov. show wing-like Boletín de la Sociedad Geológica Mexicana Geológica Sociedad la de Boletín Taylor from the spring Pyrgulopsis Call and Pilsbry Call and Pilsbry (Taylor) displays Romero-Méndez are similar to , new , Nympho P. pa .P. ------, Anselmo kleyi México. La primera especie, subfósiles de Viesca, Coahuila, norte de Pyrgulopsis especies del géneroSe describen dos nuevas RESUMEN México, Viesca, Cuatrociénegas. pecies nuevas, de subfósil, Norte Palabras clave: tes yendémicosdelvalledeCuatrociénegas. directos de dos caracoles de manantial recien o, más probable,pecies hermanas precursores que los caracoles subfósiles de Viesca son es Pyrgulopsis res a P. especie de Viesca, las conchas dela segunda bros fósiles o recientes del género. Asimismo, entre los miem que nunca fueron observadas dealas,hombrosnen característicasforma en especímenes de valle de Cuatrociénegas, Coahuila. Algunos minckleyi originalmente descrita como endémica con características similares posee la especie vueltas planas y hombros bulbosos. Conchas

paleoacarinatus sp. nov., con tiene conchas trochiformes P.

acarinatus Taylor del complejo de pozas del Pyrgulopsis Call and Pilsbry de depósitos dedepósitos Call and Pilsbry de Cuatrociénegas. Suponemos Orona-Espino P. Pyrgulopsis

paleominckleyi sp. nov. son muy simila , otra especie endémica de Pyrgulopsis

/2017 minckleyi Nymphophilus P. sp. nov. tie

paleominc (Taylor), , es 199 ) ------

Two new subfossil species of springsnails (Hydrobiidae: Pyrgulopsis) from North Mexico ABSTRACT Two new subfossil species of spring snails (Hydrobiidae: Pyrgulopsis) from North Mexico INTRODUCTION / MATERIAL AND METHOD 200 200 1. Introduction described species (Hershler described species (Hershler ter gastropods andcontainsapproximately 140 North Americanfreshwa most diverse genusof Pyrgulopsis ihddt) nyoeo these species, lished data). Only one of several new species (Czaja, unpub shells, possibly including contain an abundance of ments at the (Czaja vicinity bodies that have provided water to smallsettle several water 1) andthey belong to a systemof la Cadena (Figure the Sierra small hillsinfront of ers Túnel 4 and Túnel 8, are located at the foot of Taylor. springs, The called as bycurrent research to thegenushuila–originally assigned species of two endemicextant of ical similarities withshells 1886 were collected. These shells have morpholog the genus species of two Viesca, Coahuila, specimens of the town of two recently dried-up springs near In sediments of by Czaja sis Laterecordonly Holocene The of 1891. this genus but to the sister genus Paleo-Lakery Coahuila do notbelong to Irritilian ures e and f)as Two shellsdescribed by Czaja fossil records of Miocene (Hurt, 2004). There are still no reliable the Lower Colorado River in the late region of ular evidence that shows the genus colonized the 1935) but the Pliocene (Henderson, theremolec is oldest occurrence of The substrates ashabitat. the genus prefer emergent macrophytes andhard Hershler and restricted spring.to smallareas ortoasingle Mexico, they are endemic of Basin inthe northern North America,particularly western at theGreat the species in andSada, 2002). Many(Hershler of and have distribution a very smallgeographic thisgenuslive in springs mostly of members The / , Boletín de la Sociedad Geológica Mexicana Geológica Sociedad la de Boletín P. manantiali et al. et al. , commonlyknown asspringsnail,isthe Pyrgulopsis (2014b). 21)mnindta ebr f(2014) mentioned that of members (Hershler), was recently (Hershler), described Pyrgulopsis Pyrgulopsis from Cuatrociénegas, Coa Pyrgulopsis sp. from Late Quaterna Pyrgulopsis shellsfrom Mexico. et al. et al. Call and Pilsbry, et al. , 2015). Both sites Cincinnatia , 2014;2016). dates back to (2014a, Fig Nymphophilus Mexipyrgus Mexipyrgus Pyrgulop Pilsbry, ------/2017

2. Materialandmethod to related fromliving organisms Cuatrociénegas phylogenetic possible relation and differences ties, of new species the present study isto describe the aimof The were observed inbothsprings. tufa limestone (stromatolite) of structures inform maicense sedges( of Nymphaea(?) and endocarps Chara, seeds of vegetation, we found oogoniaof clay. aquatic remnants Amongthe remains of of pieces, shells, shellfragments (debris) and scant small travertine spring sediments consist of The ro-Méndez,described (Czaja was viescaensis The Late Holocene age of the superficial deposits deposits superficial the of age LateHolocene The (1939). Pilsbry cording tothemethod of Hemocytometer. Shells whorls were counted ac sureda Neubauer using Chamber Cell Counting and width,aperture height and width)were mea the shells (shellheight variables of Morphometric microscope-camera.with a Zeiss AxioCam ERc5s sieves.and 0.3mm shellswere The photographed sedimentswereThe screened through 0.5mm thesesprings. from sedimentsat thebottomof 2015directly were collected of during thesummer Cuatrociénegasaway(about 200 km from Viesca) lopsis minckleyi the extant species of debris. Empty shellsof dated sediments, smalltravertine pieces and shell approximately 2 mthickandcontainsunconsoli prox. 60 –70cmbelow the surface. sectionis The ap fissure, narrow spring a from directly 8 collected were Túnel of Shells surface. the below cm collected fromapprox.the spring acutinside 50 Túnel 4 were N,23” W). Shells 102°54’29” of 20’ 25° 8: Túnel spring W; 32” 52’ 102° N, 20” esca, Coahuila (Figure 1; spring Túnel 4: 25° 20’ Vi two recently dried-up near springs the town of the newspecieswere collected from Specimens of valley. Crantz and Czaja,Estrada-Rodríguez andRome fromPoza andPoza Becerra in Azul Pyrgulopsis Pyrgulopsis Schoenoplectus and toshowits similari sp.). Microbialite et al. Cladium ja , 2015). Pyrgu ------Figure 1 speiiay aimti aigo the shells,preliminary,is radiometric dating of white bleached (Czaja the region are always Late Pleistocene sites of of mollusks ing (Figure 2a-d; Figure 3a, b, f). Shells of shells which retain often their original shell color the supported also by the excellent conservation of likely latest Pleistocene/Early Holocene. is This of estimate the tafocoenosisage for the new species (Dr. the springs J.of Quiroz, data), personal we bonerecordsPleistocene megafauna at thebase (Czaja 1958-1959 the during the springs drought of desiccation of whichal reports andphotographs documentthe sever by confirmed is atViesca springs the from Mapof thestudyareawithlocalizationof thesprings of Viesca.1=Spring Túnel4,2=Spring Túnel 8. Pyrgulopsis not older than Late Pleistocene, very et al. , 2015). According to Late et al. , 2014a) (This dating, 2014a) (This Boletín de la Sociedad Geológica Mexicana Geológica Sociedad la de Boletín - - 3.1. SYSTEMATICS 3. Results h urzSaeUiest fDurango(UJMC). the Juarez State University of Biological Science of the Faculty of Collection of material atThe is deposited the Malacological the exact age). planned for ournext projectViesca, in willgive Subfamily Nymphophilinae Taylor, 1966 Genus Family Hydrobiidae Troschel, 1857 Pyrgulopsis Pyrgulopsis Call andPilsbry, 1886 /2017 201 201

Two new subfossil species of springsnails (Hydrobiidae: Pyrgulopsis) from North Mexico RESULTS Two new subfossil species of spring snails (Hydrobiidae: Pyrgulopsis) from North Mexico RESULTS 202 202 Types. ures 2a,b) Romero-Méndez and Orona-Espino sp. nov. (Fig paleominckleyi Pyrgulopsis by originaldesignation. Type species: strong, bulb-like shoulder (Figure 2c, d) which in Ultimate and penultimate whorl frequently with a with coarses, wavies, andtransverse growth lines. a trochoid shape (Figure 2e, f). Teleoconch whorls shell the convex giving slightly to flattened whorls 4.50 whorls, apical whorls rounded, following two after 1.25 whorls, Figure 2n). Shells with 4.00 to lines growth (fine sculpture in change subtle a as leoconch transition is insome specimens visible tened, near often eroded.smooth, Protoconch-te flat Protoconch thin. lip outer thickened, slightly to the coiling axis. Peristome complete, innerlip 15 – 25° (some specimens up to 35°, Figure 2j) about of angle lateral profile an aperturein lies at whorl, adapically, angled rounded abapically. The nate to orslightlyseparated from the penultimate apertureoval is inoutline, longer than wide, ad the columellar lip. sutures The are shallow. The icate, perforation almostcomplete covered by erately high, the base rounded, narrowly umbil to trochiform (Figure 2a-e, f, spire l). The is mod species, shell small to medium sized, ovate-conic Description. astrong spiralkeel. lack of bulb-like shoulder; asmallerspire-angle andthe P. minckleyi related closely from differentiated is species new The flattened. whorls ultimate and penultimate ly umbilicate, ovate-conic to trochiform shell with Diagnosis. atrociénegas, Coahuila. the extant species ancestor of thatsuggests thesub-fossilprobablyis species an Etymology. UJMC-271-280a, 103specimens. N, 102°54’29”W. Paratypes from the same lot, the surface, Viesca, Coahuila, Mexico, 25°20’23” inside the spring, layer approx. 70–60cmbelow surface the below cm 70 approx. fissure, narrow / Boletín de la Sociedad Geológica Mexicana Geológica Sociedad la de Boletín ooye UM-7, úe 8 Spring, 8 Túnel UJMC-270, Holotype, inhavingsmall size andstrong, often Asalseiso Asmallspeciesof The name with the prefix “paleo” prefix the with name The Morphologically quite variable Morphologically

Pyrgula nevadensis Pyrgula Czaja, Estrada-Rodríguez, P. minckleyi Pyrgulopsis Stearns, 1883, Stearns, from Cu , narrow ------/2017 consider that all specimens belong to one single with wing-likeshoulderorcollar;therefore, we betweentions and shells with weak shells shoulders the genus. There are smooth transi of members have never been observed among fossil or extant the body-whorlson showwing-like shoulders that Remarks. to Túnel8Springat Viesca, Coahuila,Mexico. Distribution. Table 1. Shell measurements andwhorlare counts given in beige tolightish gray. Operculumnot preserved. keel or collar (Figure shellsare 2i,j,o).The whit maysome specimens be converted to awing-like Túnel 8spring, 1specimen. the from and specimens 42 UJMC-282-289a, lot, 20” N, 102°52’32”W. Paratypes from the same the surface, Viesca, Coahuila, Mexico, 25°20’ cut inside the spring, layer approx. 50 cm below Types. guez, Romero-Méndez and Orona-Espino sp. nov. paleoacarinatus Pyrgulopsis ure 2k). spiral keel which reaches upto the aperture (Fig in shape. Besides,a strongpossess mostspecimens greater (up to 8 mm), stronger and more triangular thisextant species are considerably the shells of general similarity isevident (Figure 2g, h, k,l). But minckleyi Most similarto our newspeciesisundoubtedly shape. different completely a have shells the and strong keeled shells but these are basal carinae and larger. Only Furthermore, these shells are and mostly globose butshoulders these are never bulb- or wing-like. are many There other extant species of newspecies. this of identification clear a predation.against bulb-like This shoulder allows the shell as adaptation serve to reinforce the wall of et al. strong shoulder, often or with knobs spines(Czaja species. Manyother species inViesca alsohave a , 2015).We supposethat suchfeature could P. nevadensis ooye UM-8, úe 4 spring, 4 Túnel UJMC-281, Holotype, from Cuatrociénegas, Coahuila, and the Sm pcmn f of Some specimens P. archimedis Pyrgulopsis paleominckleyi Pyrgulopsis (Nevada, United States) have (Oregon, United States) Czaja, Estrada-Rodrí P. paleominckleyi Pyrgulopsis isendemic with .P. - - - - de laBecerra;(k)smallspecimenfrom PozadelaBecerra; (m)specimenfromPozaAzul,protoconchview. paratype 1,protoconchview;(n)5,detailsofthewing-like shoulders. (e) paratype3(UJMC-273);(f)4(UJMC-274);(h) 5(UJMC-275);(i)paratype 6(UJMC-276);(j)paratype7(UJMC-277);(l) Cuatrociénegas, Coahuila. Figure 2 ovate-conic spire to elongatemod The is conic. Description. conic shellshape. elongate more and size smaller a significantly ing ferentiated from closely related moderately convex whorls.dif newspeciesis The icate, ovate-conic to elongate conic shell, it has Diagnosis. atrociénegas, Coahuila. the extant species ancestor of thatsuggests the sub-recent species isa probably Etymology. Shellsof Pyrgulopsis paleominckleyi Asalseiso of small species A The name with the prefix “paleo” prefix the with name The Shell small to medium sized, P. paleominckleyi P. acarinatus P. acarinatus Pyrgulopsis sp.nov.: paratype (a,b)holotype 1(UJMC-271);(d) paratype2(UJMC-272); (UJMC-270);(c) sp.nov. fromViesca,Coahuilaand from Cu , umbil in

hav Boletín de la Sociedad Geológica Mexicana Geológica Sociedad la de Boletín - - - - - bodywhorl–toward to the aperture weak ribscan coarse, wavyand transverse growth lines, onthe whorls moderately convex, never shouldered, with to 4.50 whorls, apical whorls rounded, teleoconch leoconch transition is not visible. Shells with 3.75 Protoconch-te smooth. near flattened, toconch about 5 –10°to the coiling axis. Pro of angle abapically. The aperture in lateral profile lies at an the penultimate whorl, adapically, angled rounded wide, adnate to or –mostly– slightly separated from aperture is large and oval in outline, longer than erately high, the base rounded, umbilicate. The Pyrgulopsis minckleyi Pyrgulopsis minckleyi Taylor:(g)specimenfrom Poza Taylor fromPozaBecerra, /2017 203 203 - -

Two new subfossil species of springsnails (Hydrobiidae: Pyrgulopsis) from North Mexico RESULTS Two new subfossil species of spring snails (Hydrobiidae: Pyrgulopsis) from North Mexico RESULTS / DISCUSSION 204 204 SW, shellwidth;AH,aperture height;AW,aperture width.Allmeasurements inmillimeters. Table 1.Whorl countsand measurements ofshells P. paleominckleyi P. paleominckleyi P. paleominckleyi P. paleominckleyi P. paleominckleyi P. paleominckleyi P. paleominckleyi P. paleominckleyi P. paleominckleyi P. paleominckleyi P. paleominckleyi P. paleominckleyi P. paleominckleyi P. paleominckleyi P. paleominckleyi fof distinct species andnot an allopatric morphotype and Viescagas that suggest distancebetween Cuatrociénethe geographical the last whorl (Figure 3b, e). These differences and strongershape and pronouncedgrowth lineson inatus from differs Viesca from species new our that conclude we (1985) Hershler of illustrations But accordingcomparison. tothe description and and we for couldnotcollect gas specimens direct Remarks. la, Mexico. to Túnel 4 and Túnel 8 springs at Viesca, Coahui Distribution. and whorl countsare given inTable 2. Operculum not preserved. Shell measurements shellsareheight. The whitishbeige to light gray. the total shell er, it makes up 50 – 65 per cent of be developed. (Figure 3b, last whorl e). The larg / Boletín de la Sociedad Geológica Mexicana Geológica Sociedad la de Boletín P. acarinatus standard deviation only in itssmallsize, only more prolonged shell Specimen mean

P. acarinatus 1 (Holotype) 2 3 4 5 6 7 8 9 10 11 12 13 14 15 .

Pyrgulopsis paleoacarinatus Pyrgulopsis isvery rare in Cuatrociéne P. paleoacarinatus 4.25 4.50 4.00 4.25 4.25 4.00 4.00 4.25 4.25 4.25 4.25 4.50 WN 4.00 4.25 4.25 4.22 0.16 isendemic Pyrgulopsis paleominckleyi P. acar is a - - - - - /2017 2.74 2.68 2.82 2.93 2.24 2.21 2.19 2.97 2.25 2.95 2.34 2.91 2.51 2.26 2.39 2.56 0.31 SH 4. Discussion sa togadlresel fusual strong andlarge shells of that suggest as asynonym.the un authors These from showed that (2005) LiuandHershler lecular genetic studies of conchologically well characterized; however, mo congener with rounded whorls. genus The was valley chidae the marine Tro eral appearance… reminds one more of remarkably for un-hydrobiid large the family…most in gen ophilus minckleyi only onespecies: included inthissubfamily lor (1966) theNymphophilinae. subfamily He Cuatrociénegas valley established Taysprings of For large, carinate and trochoid shellsfrom the sp.nov. WN,totalnumber of whorls; SH,shellheight; . eslr 18) ae add o h same the to added later (1985) Hershler ”. Pyrgulopsis Nymphophilus acarinatus 1.83 1.77 1.92 1.84 1.45 1.43 1.42 1.96 1.62 1.94 1.42 1.86 1.68 1.59 1.58 1.69 SW 0.2 Nymphophilus Fr alr hs hls ee “… were shells these Taylor For . andshouldtherefore be treated 1.52 1.50 1.40 1.48 1.38 1.24 1.21 1.69 1.22 1.52 1.22 1.58 1.23 1.25 1.34 1.39 0.16 AH s ite differentiated little is , a second smaller Nymphophilus 1.33 1.04 1.28 1.37 1.02 0.94 0.97 1.38 1.02 1.38 AW 1.01 1.27 1.09 0.98 1.16 1.15 0.17 Nymph ( sensu ------on theab-apertural sideontheshell. sp. nov.: (k)specimen(UJMC-288)withdouble holes ontheab-apertural sideontheshell. (UJMC-287); (m)protoconchview(holotype). (UJMC-282); (d-e)paratype2(UJMC-283);(f) paratype 3(UJMC-284);(g)paratype4(UJMC-285);(i)5(UJMC-286);(j) 6 from Viescaand Cuatrociénegas, Coahuila(from Hershler,1985,Figure. 9,reprinted withauthor’s permission), Figure 3 (Chaves-Campos predation fish strong a from result features shell unusual mentioned the that confirm trociénegas Cua of snails and fishes on studies recent More Hershler, 2005,p. 293). habitats these in live crayfish) which commonly (e.g., predators other and fishes snail-eating the to response “ of history evolutionary within the ecosystems that occurred radiations in thermal lato …these separate clades represents a parallel evolutionary clades…these separate represents a parallel evolutionary Shellsof )” … )” may be viewed as one of the multiple independent the multiple independent as one of may be viewed P. minckleyi Pyrgulopsis paleoacarinatus et al. fromPozaAzulinCuatrociénegas. Pyrgulopsis , 2012; Covich, 2010; John … ” and added that P. acarinatus sp.nov. fromViesca,Coahuila, ” (Liu and ” Taylor:(h)specimenfrom Locality 113inCuatrociénegas. Boletín de la Sociedad Geológica Mexicana Geológica Sociedad la de Boletín - - P. paleoacarinatus son repaired shell injurieswere observed. Such traces leyi bly cichlids. Eleven shells(= 10 %)of proba were which fishes of scales and vertebrae, horizons, we found numerous teeth, pharyngeal Germany. Indeed, in and Covich (2014) from Miocene Lake Steinheim, Rasser by time first the for described were holes trociénegas a as fishperforations predator.of Such small holesinmanyshells from Viesca andCua Pyrgulopsis acarinatus sp. nov. were perforated (Figure 3k) andseveral et al. sp.nov.: paratype (a,b)holotype 1 (UJMC-281);(c) , 2007). Czaja P. minckleyi Pyrgulopsis paleominckleyi Taylorfrom Locality113in Pyrgulopsis Taylor:(l)specimenwithahole et al. (2015) interpreted (2015) interpreted sp. nov. specimen /2017 P. paleominckleyi P. paleominck sp.nov. 205 205 - - -

Two new subfossil species of springsnails (Hydrobiidae: Pyrgulopsis) from North Mexico DISCUSSION Two new subfossil species of spring snails (Hydrobiidae: Pyrgulopsis) from North Mexico DISCUSSION 206 206 SW, shellwidth;AH,aperture height;AW,aperture width.Allmeasurements inmillimeters. Table 2.Whorl countsand measurements ofshells P. paleoacarinatus P. paleoacarinatus P. paleoacarinatus P. paleoacarinatus P. paleoacarinatus P. paleoacarinatus P. paleoacarinatus P. paleoacarinatus P. paleoacarinatus P. paleoacarinatus P. paleoacarinatus P. paleoacarinatus P. paleoacarinatus P. paleoacarinatus P. paleoacarinatus rdrc rcroso two extant endemic species or direct of precursors paleominckleyi Cuatrociénegas are. Our hypothesisis that P of “ so not would explain why their general appearance is as the extant species from Cuatrociénegas. That ently exposed topredation notthat much time extinct. fromOur new snails Viesca were appar thin layer and we donotknow whythey became sis the described two species of Shells of canbemutuallypaleontology supportive. and how biology same time, a good example of tween fishes and snails also for Viesca and is, at the (2005)aboutthe parallel evolutionHershler be Liuand directly thementionedpresumption of in confirms This shell. repaired a shows one and 5 %)of predatoryunsuccessful attacks. Two(= specimens were by interpreted Lindström andPeel (2005) as / aepeeti h eto fViesca onlyina are present in the section of Boletín de la Sociedad Geológica Mexicana Geológica Sociedad la de Boletín standard deviation Specimen un-hydrobiid P. paleoacarinatus mean and 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 (Holotype) P. paleoacarinatus ” (Taylor, 1966) as the shells sp. nov. were perforated are sisterspecies 4.25 3.75 4.00 3.75 4.00 4.50 4.50 4.25 4.50 4.50 4.25 4.25 4.00 4.25 4.25 4.20 0.25 WN Pyrgulopsis paleoacarinatus Pyrgulop - - - - /2017 . 2.49 2.17 2.74 2.12 2.23 2.99 3.08 2.49 2.62 2.98 2.75 2.72 2.63 2.76 2.62 2.63 0.29 SH Coahuilix where almost all genera ( Cuatrociénegas, similarity to the malacofauna of could beobserved. Viesca regiona remarkablehas minckleyi Pyrgulopsis the two dence, there is another similarity: One of unlikely. Noteworthy, and surely also no coinci snails but a “double convergence” would be highly ces were indeed frequently observed in hydrobiid Pyrgulopsis of clade” “separate the of shells precisely semble Cuatrociénegas–but two speciesandthat they re that in Viesca we did notfound one–aswell as in or convergencecoincidence certainly no tion. Itis But also other considerations point to characters. the same direc shell similar the in justification of Viesca, highshell variability in only rinatus Pyrgulopsis sp.nov. WN,totalnumber of whorls; SH,shellheight; produce shells. very Similarly, uniform in – show high shell variability, while 1.62 1.48 1.61 1.52 1.39 1.98 2.07 1.59 1.74 1.96 1.92 1.99 1.88 1.81 1.81 1.76 0.21 SW , extant species from Cuatrociénegas– (= Juturnia from Cuatrociénegas.its main Ithas Nymphophilus sensu lato n pce fsnails that today ) and species of 1.33 1.13 1.32 1.14 1.22 1.51 1.62 1.22 1.46 1.53 1.28 1.58 1.52 1.38 1.42 1.38 0.16 AH Mexipyrgus P. paleominckleyi ). Convergen , 1.17 0.98 1.22 0.99 0.97 1.28 1.38 1.03 1.14 1.23 1.19 1.24 1.15 1.19 1.22 1.16 0.12 AW Paludiscala P. aca .P. - - - - - ,

6. References 5. Acknowledgements Pyrgulopsis the genus know more onthe evolutionary path of sub-fossil shellsinboth localities will allow usto endemic speciesof paleoacarinatus that proof final the provide investigations (excavations) inCuatrociénegas can Paleontological 1859). (Darwin, literature the in (Wesselingh smallshellsbybirds veryis common tribution of atrociénegas possibly by avian dis transport. The earlywereHolocene?) thesnails introduced toCu Pleistocene or earlier in Viesca andafterward (in of clade” “separate the precursors, rather than sisterspecies. We suspect that bothsub-fossilfromspecies Viesca are direct In summary, the aforementioned ideas suggest Pyrgulopsis the genus contain alsonarrowlyrelated speciesof thatGiven both localities thisfact, is notsurprising (Czaja confirmed are endemic to the Cuatrociénegas Valley were Chaves-Campos, J.,Al-Salamah, Coghill,L.M., thetext inEnglish. of New Jersey, USA, for his assistanceinthe revision ments. Aspecialthankyou goesto Allen Kosinski, an anonymousreviewer for its constructive com the Poza AzulinCuatrociénegas. Weof thank to recollect soil samples ciénegas, for permission Fauna y the Área deProtección deFlora Cuatro trociénegas and Lic. Juan of Carlos Flores Ibarra the Poza Cua dela Becerra, the dissected part of to recollect of samples soil ahuila, for permission the Museo del Desierto in Saltillo, Co director of We thank bothBiol. Arturo H.González González, il eiaiiisadlc f orlto f correlation of Field heritabilities and lack of M.A., DeWitt, T.J., Johnson,S.G., 2012, from northern Mexico. from northern . et al. aedrc rcroso two extant are direct of precursors , 1999) and has long beenknown, 1999)andhas et al. Pyrgulopsis , 2015;unpublished data). Pyrgulopsis P. paleominckleyi . Future workon evolved during and Boletín de la Sociedad Geológica Mexicana Geológica Sociedad la de Boletín .P. ------Czaja, A.,Estrada-Rodríguez, J.L., Romero- Covich, A.P., 2010,Winning the biodiversity Hershler, R.,Liu,H-P., Stevens, L.E.,2016, A Hershler, R.,Liu, H.-P., Howard, J., 2014, the of revision Systematic 1985, R., Hershler, J.,Henderson, 1935, Fossil non-marine species: the of origin The 1859, C., Darwin, Czaja, A.,Estrada-Rodríguez, J.L., Romero- Czaja, A., Palacios-Fest, M.R.,Estrada- Geológica Mexicana, 66(3),459–469. Cuatrociénegas: Boletín de la Sociedad Mexico –asubfossil similar to ecosystem Sobaco,the Valley Coahuila, Northeastern of Méndez, U., 2014a,Fresh waterof mollusks Hydrobiologia, 653,191–215. shell variability andpredator avoidance: competition and coexistence through race amongfreshwater gastropods: arms Research, 14,743–755. likelihood methods: Evolutionary Ecology estimated Bayesianusing andmaximum andanti-predator function snail shellform from the lower Colorado River Basin, new springsnail(Hydrobiidae: 693–700. North America: BioScience,western 64, Springsnails: anewconservation focusin Malacologia, 26(1–2),31–123. CuatroCienegas Basin,Coahuila, Mexico: the Hydrobiidae (: Rissoacea) of America SpecialPapers, 3,1–313. North America: Geological Society of of p. 439 (1998), OxfordPress, University Oxford Mexico: Nautilus, The 129,163–168. in Viesca, Holocene springdeposits Coahuila, : Cochliopidae) from late Mexipyrgus the genus Méndez, U., 2015,Anewspeciesof Mexicana, 66(3),541–551. Mexico: Boletín de la Sociedad Geológica Comarca Lagunera, Coahuila, Northern fauna from the Paleolake in the Irritila Avila, J.A., 2014b,mollusks InlandDunes Rodríguez, J.L., Romero-Méndez, U., Alba- Taylor, 1966(: /2017 Pyrgulopsis 207 207 )

DISCUSSION / ACKNOWLEDGEMENTS / Two new subfossil species of springsnails (Hydrobiidae: Pyrgulopsis) from North Mexico REFERENCES Two new subfossil species of spring snails (Hydrobiidae: Pyrgulopsis) from North Mexico REFERENCES 208 208 Hershler, R.,Sada, D., 2002,Biogeography of Lindström, A.,Peel, J.S., 2005, Repaired in Johnson,S.G., Hulsey, C.D., García deLeón, Hurt, C.R., 2004,Genetic divergence, population / Boletín de la Sociedad Geológica Mexicana Geológica Sociedad la de Boletín systems history: Smithsonian,Smithsonian history: systems Currey, D.R. (eds.), Great Basin aquatic Pyrgulopsis the genus Great Basin aquatic snails of American Naturalist, 76(1),72–81. Arizona: Westernnorthwestern North Palaeontologica Polonica, 50,697–704. pleurotomarioid gastropods: Acta insomePaleozoic juries andshell form 7, doi:10.1186/1471–2148–7–50 defensive traits: BMC Evolutionary Biology, F.J., snail 2007,Spatial evolutionmosaic of 13 (5):1173–1187. Colorado RiverMolecular Ecology, basin: are ( springsnails structure andhistoricaldemographyof 255–276. Contributionsto theEarth Sciences, 33, , in Hershler, R.,Madsen,D.B., Pyrgulopsis ) inthe lower /2017 Wesselingh, F.P., Cadée, G.C., Renema, W., Taylor, D.W. 1966, Aremarkable snail fauna from Rasser, W.M., Covich, A.P., 2014,Predation on North Pilsbry, H.A.,1939,LandMolluscaof Liu, H.-P., Hershler, R.,2005,Molecular Coahuila, Mexico: Veliger, The 9,152–228. Lethaia, 47(4),524–532. fora trigger intralacustrine evolution?: freshwater snails inMiocene Lake Steinheim: 3,1,547p.Philadelphia, Monograph Natural Sciences of America: Academy of 284–298. Molecular Phylogenetics and Evolution, 34, American nymphophiline gastropods: North western systematics andradiation of Geologie enMijnbouw, 78,165–174. the gastropod genera: distribution historiesof aquatic as illustratedorganisms by the of dispersal high:onthe airborne 1999, Flying