Cenozoic Nacella (Patellogastropoda: Nacellidae) from Peru and Chile: Filling in the Gaps

2008·12 MB·English

by  Thomas J Devriesi

THE VELIGER
© CMS, Inc., 2007
TheVeliger 50(4):274-291 (December 16, 2007)
Cenozoic Nacella (Patellogastropoda: Nacellidae) from Peru and Chile:
Filling in the Gaps
THOMAS DeVRIES'
J.
Burke Museum ofNatural History and Culture, University ofWashington, Seattle, WA 98195 USA
Abstract. The limpet genus, Nacella Schumacher, 1817 (Patellogastropoda: Nacellidae), is noted for its
adaptation to cold water at high austral latitudes. The finding ofat least five new Pliocene species (Nacella (Nacella)
lacrima, sp. nov.; TV. (Patinigera) oblea, sp. nov.; N. (Patinigera) chalaensis, sp. nov.; N. (Patinigera) intiforma, sp.
nov.; and N. (Patinigera) oconaensis, sp. nov.) and one new late Oligocene species (N (Patinigera) reicheae, sp. nov.)
from tropical latitudes ofsouthern Peru, as well as the recognition ofthe southern Chilean N. (Patinigera) nielseni,
sp. nov., newly named and reassigned to the late early Miocene, demonstrates the ecological range ofNacella once
overlapped that ofits warm-water sister genus, Cellana H. Adams, 1869. While determining the time and place of
Nacella's origin awaits thediscovery ofadditional fossils, thosefound so farshowmodern sub-AntarcticNacellataxa
may have had low-latitude ancestors.
INTRODUCTION 2007; Yoon & Kim, 2007). Cellana presently ranges
throughout the tropical Indo-Pacific region, with
The patellogastropod genus, Nacella Schumacher, species also found in Japan, Australia, New Zealand
1817, is comprised almost entirely of limpets living at and on the Juan Fernandez Islands, 700 kilometers
high southern latitudes (Powell, 1973), including
west ofChile (Powell, 1973). Fossil Cellana have been
several taxa from southern Chile and Argentina
(Valdovinos & Ruth, 2005). Just one extant South AruesptorratleidafraonmdSoNutehwAfZreicaala(nPdlioc(elantee: KEeoncselneey,, 19e7a2r)l,y
American species, the Chilean TV. (Patinigera) clypeater Miocene, and Pliocene-Pleistocene: Powell, 1973; Beu
(Lesson, 1831), ranges into warmer waters of the & Maxwell. 1990). the Antarctic Peninsula (late
Vsoaultdhoevaisntoesrn &PacRiufitch,Oc2e0a0n5; (VR.amiMroegzo-lBldohnm,e,wri1t9t9e6;n E(Polcieoncee:ne:StHiellrwmel,l 1&969)Z.inAsmneisEtaerrl,y C1r9e92t)a,ceoaunsdreCchoirlde
communication, 2008), as it did. too, during the from Australia, Cellana carpentariana Skwarko, 1966
Pleistocene (Herm, 1969). Other fossil Quaternary (fide Powell. 1973). remains unconfirmed. The oldest
Nacella include the extant N. (Patinigera) deaurata
Cellana verified on the basis of shell microstructure is
(Gmelin, 1791) and N. (Patinigera) ma.gella.nica. (Gme- the late Eocene C. ampla Lindberg & Hickman, 1986.
lin, 1791) from Patagonia, Argentina (Aguirre et al., from Oregon. The timing and place of the Nacella-
2005. 2006). Reported Pliocene examples of Nacella
Cellana evolutionary split and the reasons for the
include N. (Patinigera) cf N. concinna (Strebel, 1908)
Recent disjunct distribution of Cellana (mostly tropi-
from lower upper Pliocene basaltic conglomerates on
cal, Indo-Pacific) and Nacella (mostly cold-water.
Cockburn Island, Antarctic Peninsula (Jonkers, 1988;
Jonkers & Kelley, 1998) and N. (Patinigera) aff. TV. aSlo.,ut1h9e9r9n; OGcoledasnt)ieanreetstaill.l, d2i0s0p6u;teNdak(aKnouofo&paOnzoauwae,t
terroris (Filhol, 1880) from coarse-grained sandstones
& A 2007).
ofChiloe, southern Chile (Watters Fleming, 1972).
This paperfills biogeographical and temporalgapsin
doubtful account exists of Miocene N. deaurata from the history ofNacella with the description offive new
Patagonia (Brunet. 1997), where mollusks from Qua-
Pliocene species from tropical latitudes of southern
ternary marine terraces are interspersed among older
Peru: TV. (Nacella) lacrima, sp. nov.; 7Y. (Patinigera)
Tertiary taxa ofthe Entrerriense Formation.
oblea, sp. nov.; N. (Patinigera) chalaensis, sp. nov.; N.
Molecular phylogenetic studies show extant Nacella
(Patinigera) intiforma, sp. nov.; and N. (Patinigera)
to be a paraphyletic grade or monophyletic clade most
oconaensis, sp. nov. The Pliocene nacellid from Chiloe
closely related to a clade encompassing extant species
oHfaraCselelwayncah H&. MAcdAartmhsu,r,18260900;(KNoaukfaonpoano&u,Oz1a9w9a9,; nisamreeadssiNg.ned(Paatliantiegeeraar)lynMieilosecnein,e sap.ge naonvd. foNramcaellllya
(Patinigera) reicheae, sp. nov., from uppermost Oligo-
cene beds ofsouthern Peru, ranks as the oldest known
Mailing address: Box 13061, Burton, WA 98013 USA Nacella. The newly established longevity of Nacella
DeVries, 2007 Page 275
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Figure 1. Locationand CenozoicstratigraphyoftheCenozoicPiscoandSacacoforearcbasinsinsouthern Peruandtypeorother
significant localities with Nacella specimens. Ocona: type locality-sample (DV 1279-1) ofNacella {Nacella) lacrima, sp. nov., TV.
(Patinigera) intiforma, sp. nov.. and TV. (Patinigera) oconaensis, sp. nov. La Planchada: locality-sample DV 1267-1, with TV.
intiforma. Huacllaco: type locality-sample (DV 1254-2, DV 1254-bal6) of TV. (Patinigera) oblea, sp. nov. and (DV 1628-1) TV.
(Patinigera)chalaensis, sp.nov. CerroPoroma: typelocality-sample(DV61la-1)andlocality-samplesDV471-1 andDV638-1 with
TV. (Patinigera) reicheae, sp. nov. Road visible in each inset is the Pan-American Highway; images from Google Earth. Locality
details are in the Appendix. Stratigraphic column shows temporal distribution of South American patellogastropods, including
Nacella from Peru and Chile.
helps refine scenarios for its origin, while its low- Three outcrops of the La Planchada Formation
latitude diversity challenges our understanding of the along the Pan-American Highway deserve mention. A
biogeographical constraints on its modern distribution. 70-meter measured section at Huacllaco (Figure 1)
contains inferred upper lower Pliocene (Unit I) and
GEOLOGY upper Pliocene (Units II, III) bioclastic sediments
capped by the most elevated and oldest marine terrace
The Cenozoic stratigraphy of southern Peruvian (Unit IV, uppermost Pliocene) (DeVries, 2003). Spec-
forearc basins was reviewed by DeVries (1998). imens of Nacella occur throughout the section, as do
7Vace//a-bearing beds were encountered at Cerro Fissurella and other littoral invertebrates that lived on
Poroma, near Nazca (Figures 1, 2F), where upper rocky substrates (DeVries, 2003, 2006, 2007, 2008).
Oligocene bioclastic sandstone and conglomerate ofthe A second outcrop occurs in a quarry near Ocoha
Chilcatay Formation onlap an Eocene peneplain, and (Figure 1). The base consists of scour-bound lenses of
farther south in the Pliocene La Planchada Formation, angular boulders. Some lenses lack evidence ofmarine
which is composed of balanid coquina, bioclastic influence, but others have boulders encrusted with
conglomerate, coarse-grained bioclastic sandstone, barnaclesandoysters (Figure 2D). The rockylenses are
and fine-bedded gravel (Beaudet et al., 1976), the overlain with rippled and thin-bedded coarse-grained
remnants of littoral deposits dropped at the foot of sandstone (Figures 2A, 2B) with scour-and-fill struc-
steep sea cliffs. tures, imbricate slate pebbles, and ash laminae sur-
Page 276 The Veliger, Vol. 50, No. 4
Figure 2. Nacella localities in southern Peru. A. Ocona: interbedded rock-fall alluvium and finely bedded, tuffaceous, Nacella-
bearing gravel and coarse-grained sandstone. B. Ocona: cross-bedded and rippled tuffaceous gravel and sandstone containing N.
lacrima, N. intiforma, and N. oconaensis. Shoreline isto left. C. Ocona: close-upofN. intiforma, sp. nov., in fine-grainedgravel. D.
Ocona: Debris-flowconglomeratewith bouldersencrustedwith barnacles(left)and oysters(right). E. La Planchada: Finelybedded
N
acella-btavrng gravel, lowest left; early Pliocenecross-bedded bioclasticconglomerate, lowermost left-most set; Pleistocene cross-
beddedbioclasticconglomerate,center; laminatedsandstoneandcontinentalalluvium, upperleftandright. F. CerroPoroma: Post-
Incaic granitic peneplain dissected by late Oligocene and modern erosional fissures, with continental volcaniclastics of early
MioceneNazca Group in background. Marineconglomerates with Nacellareicheae, sp. nov., occurin shallowfissures and at base
ofsedimentary sequence.
rounding small basement paleo-stacks, features that contrasting Chilean strata as paleotsunami deposits).
indicate a low-energy paleoenvironment in an other- Bedded marine deposits grade upwards into boulder-
wise high-energy setting, perhaps below wave base choked alluvium. The thin-bedded sandstone contains
adjacent to steep sea cliffs (but see Cantalamessa & Di disarticulated flat-lying bioclasts of Ostrea, Chlamys,
Celma (2005) for an interpretation of texturally and Nacella (Figure 2C). A late early Pliocene age is
1
DeVries, 2007 Page 277
inferred from correlations with outcrops near Sacaco Ozawa, 2007). Some, finally, identify nacellids as a
having age-diagnostic molluscan taxa (Muizon & parphyletic group (Yoon & Kim, 2007).
DeVries, 1985; DeVries, 2003). Nacella species are characterized by shell microstruc-
The third Pliocene Nacel/a-bearing outcrop is tures that include an irregular spherulitic prismatic
exposed south of La Planchada (Figures 1, 2E). The structure type-A' M+2 layer and a 'regularly foliated'
lithology and sedimentary textures are similar to those M+l shell layerdorsal to the myostracum, an 'irregular
M—
at Ocona. The fauna consists ofbeds ofdisarticulated complex crossed foliated structure' 1 layer ventral
Ostrea valves, rare Chlamys valves, barnacles, and to the myostracum, and an absence ofcrossed lamellar
Nacella. layers [terminology of Fuchigami & Sasaki (2005); see
also MacClintock (1967) and Lindberg (1988, 1998)].
MATERIALS AND METHODS Most other patellogastropods from western South
America lack foliated layers, e.g., the Lottiidae Gray,
Specimens of fossil Peruvian Nacella described in this 1840, including Lottia and Scurria (Lindberg, 1988,
study were found by the author unless noted otherwise. 1998; Espoz et al., 2004). The nacellid genus, Cellana,
Examples of extant species of the patellogastropod represented in Peru and Chile by one Pliocene species
genera Lottia Sowerby, 1834, Cellana, and Scurria (Herm, 1969; DeVries, unpublished data), has a
Gray, 1847, were available for comparison. References prismatic M+3 and foliated M+2 layer, but also has
to modern sea surface temperatures (SSTs) in western crossed lamellar structures in layers M+l and M—
South America are based on the World Ocean Atlas (MacClintock, 1967; Lindberg & Hickman, 1986;
2005 (Locarnini et al., 2006). Fuchigami & Sasaki, 2005). The new species ofNacella
Locality and sample descriptions are listed in the described herein have clearly visible prismatic structure
appendix. Lengths (L), widths (W), and heights (H) are intheir M+2 layer, foliation intheir M+l layerand lack
measured in millimeters. Dimensions of broken spec- crossed lamellar layers.
imens are enclosed by parentheses. Most figured
specimens are coated with ammonium chloride. Types Subgenus Nacella Schumacher, 1817
and other numbered specimens are deposited at the
University ofWashington's Burke Museum ofNatural
History and Culture in Seattle, Washington (UWBM) Description: Shell very thin, apex very close to anterior
end (Powell, 1973).
and the Departamento de Paleontologia de Vertebra-
dos, Museo de Historia Natural, Universidad Nacional Nacella {Nacella) lacrima, sp. nov.
Mayor de San Marcos, in Lima, Peru (MUSM INV).
Figures 3-15
SYSTEMATIC PALEONTOLOGY
Diagnosis: Shell height extremely low. Aperture tear
Order Patellogastropoda Lindberg, 1988
shaped. Radial sculpture of 60 ribs, differentiated by
Family Nacellidae Thiele, 1891 size posteriorly, sometimes obsolete.
Genus Nacella Schumacher, 1817 Description: Shell conical, very thin, length under
30 mm; height extremely low (L:H ratio about 5:1 to
Type species: Patella mytilina Helbling, 1779. Recent, 8:1). Aperture tear shaped: broadly elliptical posterior-
southern South America. ly, rapidly narrowing and linear anteriorly, sharply
rounded atanteriorend. Shellmargin planar, periphery
Discussion: The order Patellogastropoda encompasses of margin evenly curved, not crenulated. Apex
taxa with conical shells having numerous anatomical orthogonal to slightly obtuse, located one-eighth or
synapomorphies (Lindberg, 1988; Sasaki, 1998); its less of length from anterior end. Steep anterior slope
monophyly is strongly supported by molecular data concave, straight, or convex; posterior slope slightly
(Harasewych & McArthur, 2000; Nakano & Ozawa, convex; lateral slopes planar. Radial sculpture ofup to
2007; Yoon & Kim, 2007). The phylogenetic relation- 60 very low rounded ribs, often fewer in juveniles,
ships of families within Patellogastropoda, however, obsolete in some adults; ribs not corrugated. Differen-
remain uncertain (Ridgway et al., 1998; Nakano & tiation of primary and secondary ribs posteriorly, if
Ozawa, 2007). Some place Nacellidae or Nacelloidea present; rare secondary ribs inserted close to apex.
{Nacella + Cellana) in a clade with Patellidae (Powell, Concentric sculpture offine growth lines and irregular
1973; Sasaki, 1998), others as a sister group to weak growth rugae. Coloring of concentric brown
Acmaeoidea (Lindberg, 1988, 1998), still others as a mottling. Interior with smooth or weakly radially
monophyletic clade (Koufopanouet al., 1999), possibly striated intermediate area; central area broad and
related to Leptidae + Pectinodontidae (Nakano & extending 80 percent of shell length.
Page 278 The Veliger, Vol. 50, No. 4
DV
Figures 3-15. Nacella (Nacella) lacrima, sp. nov. All are paratypes except holotype. 1279-1. Late early Pliocene.
Figure 3. MUSM INV 177. Dorsal view. Length is 17.3 mm.
Figure 4. MUSM INV 179. Dorsal view. Length is 15.4 mm.
Figure 5. MUSM INV 179. Ventral view.
Figure 6. MUSM INV 177. Ventral view. Angular pitting is from contact with sand grains.
Figure 7. MUSM INV 176. Dorsal view. Length is 25.0 mm.
Figure 8. MUSM INV 176. Ventral view.
FFFFiiiigggguuuurrrreeee19110.2.1.. UUMUWWUWBBSBMMMM99I988866N622V627.1,.1C7hl6Lo.oalstoLeeta-rytuapepler.aovlfiDerovweri,gesuwaal,lnatraevnfritoieleowirr.aitoteLrodetnlMeogfttl+.hefLt1i.eslna2yg1et.rh8(rimisgm9h..t)7amnmd.prismaticM+2layer(left).Lengthofimageis7.4 mm.
Figure 13. UWBM 98620. Dorsal view. Length is 24.0 mm.
UWBM
Figure 14. 98621. Dorsal view.
UWBM
Figure 15. 98621. Ventral view.
Discussion: The extreme anterior position of the apex laterally compressed, deeply arched, and have a radial
places this taxon in Nacella (Nacella). The only other sculpture of weak wrinkles. Nacella (Nacella) kergue-
South American species in this subgenus, the Recent N. lenensis (E. A. Smith, 1877), a Recent species from the
(Nacella) mytilina, lives throughout the Magellanic southern Indian Ocean (about 49°S), is nearly three
Province (Valdovinos & Ruth, 2005). Its specimens are times longer than N. (Nacella) lacrima, has a high
DeVries, 2007 Page 279
profile, and is not laterally compressed (Powell, 1973; cent, intermediate area with fine radial striae and
Ubaldi, 1985a; note that images of N. kerguelenensis ridges; central area 60 to 80 percent of shell length.
differ in the two references).
Discussion: Specimens ofNacella obleagreatly resemble
Etymology: Latin iacrima,' meaning 'tear,' referring to those of N. clypeater (Figures 27, 28), differing
the teardrop shape ofthis species. principally in being thinner, having an anterior end
that is more constricted, primary and secondary ribs
DV
Type Locality: 1279-1, base of southeast wall of that are more differentiated, and a uniformly cream
sand-and-gravel quarry along the Pan-American High- color. One specimen from 37 meters (Unit II) in the
way, five km (straight distance) from village of Ocoha Huacllaco section (Figure 25) has a less constricted
(Figure 1). Limpets were found in finely bedded and anterior, subdued to obsolete radial sculpture, and a
cross-bedded fine-grained gravel (Figures 2A-2C). purple-brown exterior like specimens of modern N.
16°25'28"S, 73°09'14"W. clypeater. Upper Pliocene Huacllaco specimens from
(UWBM
MPWM1la7Ui6to,1eSc3reL.i9Mna,e2l;5H.Ia0(lNa,2ll.Vl2Wb;ustM1p271ehU9.c.o0iSl,moLMeHtnyspI145e.N.6f4;Var,rMoe1mW7Up8a,SDr1aLVM2t.y10pI8,1e.N2s3H7),V9:W-11M2.7.751U;,3l.Sa8LUt,Me(WH1e7IBa.3Nr3.Ml)0Vy,; 49utsh88cnau6wtlm8ope4mtr,tuaenrUryesWsip(tnBeUhdcnaiMiicntamte9leIn8oI6Iaw)8ef5trra,ronarmdnPeslsii6Upto8eniccoiemtntneietvheeIalIrsdyIsp)eb(hcaeUairgnsemuiettnnchsoiI,tacVork)sectrehyraparincaradcaltdetiNrha.esl
9U187.W611,B9,MHL 234.0.;8,UWW2B1.M7, H9846U.23W1;,UBLWMB9.M7,9W86207,.6,L 2H4.01..9W; AclmyNeparecaietcelarl.na cNlaycpeelaltaertois otchecuornlnyorRtehceonfttwheestMeargnelSloauntihc
21.8, W 1968.60,22H. 3L.9;(7.U8)W;BM 986249,86L23(,7.1h)o.lotype, L nPorrotvihncaes(VAarlicdao,vinCohsil&e R(uatbho,ut200158)3,0'rSa)ngi(nRgamaisrefza-r
Bohme, 1996) and Atico, southern Peru (about
Occurrence: Late early Pliocene: southern Peru.
16°12'S); almost certainly it is not found as far north
Subgenus Patinigera Dall, 1905 as Lima or north-central Peru, as claimed by Ubaldi
(1985b) (A. Indacochea, V. Mogollon, written commu-
nication, 2008). Nacella clypeater differs from Magel-
Typespecies: PatellamagellanicaGmelin, 1791. Recent,
lanic Nacella by favoring subtidal habitats, especially
southern South America. the 'fondos blanqueados' described in Vasquez & Vega
Description: Shell more solid than Nacella (Nacella); (2004), expanses of subtidal substrate covered with
apex closer to a central position (Powell, 1973). white coralline algae (Meneses, 1993; Valdovinos,
written communication, 2008). The great numbers of
Nacella (Patinigera) oblea, sp. nov. N. clypeater that congregate on the coralline blankets
are usually encrusted with the algae. Oddly, though,
Figures 16-26
Peruvian Pliocene specimens of N. oblea are entirely
free of coralline encrustations, having only rare
Diagnosis: Shell very thin, height very low. Aperture attachment scars from barnacles or Scurria limpets
nearly circular posteriorly; apex one-third of length (Figure 24).
from anterior. Radial sculpture of nearly 80 low ribs, Etymology: Spanish 'oblea/ a Roman Catholic com-
usually with pronounced differentiation by size.
munion wafer, which this species resembles.
Description: Shell conical, very thin, length to about Type Locality: DV 1254, Huacllaco, ten km southeast
40 mm; height very low (adult L:H ratio about 5:1). of Chala along the Pan-American Highway, about
Aperture nearly circular posteriorly, broadly oval and 37 m in measured section (DV 1254-2; Figure 1).
slightly constricted anteriorly. Shell margin planar to 1553'25"S. 7409'52"W.
slightly arched longitudinally, evenly curved with fine
crenulations corresponding to primary ribs. Apex Material (specimensare paratypes from DV 1254-2 and
MUSM
obtuse, located one-third of length from anterior end. early late Pliocene unless otherwise stated):
Anterior slope usually planar, lateral and posterior INV 180, DV 1254-bal6, L 38.2,W 31.7, H 7.2; MUSM
slopes slightly convex. Radial sculpture of about 80 INV 181, L 27.8, W 23.6, H 4.9; MUSM INV 182, L
fine, low, rounded ribs nearmargin, including frequent 29.3, W25.4, H 5.2; MUSM INV 183, L (27.0). W25.3,
distal insertions of secondary ribs; differentiation of H 5.9; UWBM 98625, holotype, L 35.7, W 31.7. H 7.2;
primary and secondary ribs usually pronounced. UWBM 98626, DV 1254-bal6, L 25.8, W 23.3, H 5.4;
UWBM UWBM W
Concentric sculpture ofclosely spaced, finely crenulat- 98627, L (20.3); 98628, L 30.0,
erudgager.owCtohlolrineusniafnodrmilryregcurleaarml.y sIpnatcereidorcofaarisnetrlygirroiwdetsh- 2U5.W5,BHM(948.06)3;0,ULWB15M.0,9W86289.,1,LH282..55,; WUW2B5.M8. 9H8643.18,;
Page 280 The Veliger, Vol. 50, No. 4
Figures 16-26. Nacella (Patinigera) oblea, sp. nov. All paratypes except holotype.
Figure 16. UWBM 98629. DV 1254-2. Early late Pliocene. Dorsal view. Length is 28.5 mm.
FFiigguurree 1187.. UMWUBSMM 9I8N6V27.18D2.VD1V2541-225.4-R2e.guVleanrtrfaollivaiteewd.miLcernogsttrhucistu2r9e.,3fmirms.t-orderfoliaofM+ 1 layeradjacenttomyostracum.
Width ofbroadened anterior end ofcentral area (lower right) is 7.8 mm.
Figure 19. MUSM INV 180. DV 1254-bal6. Early late Pliocene. Lateral view, anterior to left. Length is 38.2 mm.
FFiigguurree 2210.. UUWWBBMM 9988662265., hDoVlot1y2p5e4.-bDalV6.1D2o54r-s2a.lDvoiresw.alLveinegwt.hLiesn2g5t.h8 imsm3.5.7 mm.
Figure 22. MUSM INV 180. Dorsal view.
Figure 23. MUSM INV 181. DV 1254-2. Lateral view, anterior to left. Length is 27.8 mm.
FFiigguurree 2254.. UUWWBBMM 9988662381., DDVV 11225544--2b.alD6.orDsoarlsavilewv.ieAwrsrhoowwipnoigntdsaraktcSocluorrraitaioscnar(.brLoewnng)thneiasr30m.a0rgmimn..Length is 34.6 mm.
UWBM
Figure 26. 98625. Ventral view.
Figures 27. 28. Nacella (Patinigera) clypeater (Lesson, 1831). Pucatrihue, south-central Chile. Recent.
Figure 27. UUWWBBMM 98632. Dorsal view. Length is 38.0 mm.
Figure 28. 98633. Ventral view. Length is 43.3 mm.
DeVries, 2007 Page 281
Figures 29-39. Nacella (Patinifera) intiforma, sp. nov.
Figure 29. UWBM 98635, paratype. DV 1279-1. Late early Pliocene. Dorsal view, apex missing. Length is 33.1 mm.
UWBM
Figure 30. 98635. Ventral view, central area missing.
UWBM DV
Figure 31. 98637. 1267-1. Late early Pliocene. Dorsal view, posterior missing.
Figure 32. UWBM 98637. Close-up ofmicrostructure: regular foliated M+l layer and prismatic M+2 layer.
FFiigguurree 3334.. UUWWBBMM 9988663376.. CDlVose1-26u7p-1o.fDmiocrrsoasltrvciuetwu.reL:enrgegtuhlairs 3f7o.li6atmemd.M+l layer and cross foliated M—1 layer.
Figure 35. UWBM 98634, holotype. DV 1279-1. Dorsal view. Length is 26.6 mm.
UWBM
Figure 36. 98634. Ventral view.
Figure 37. MUSM 185, paratype. DV 1279-1. Dorsal view. Length is 22.0 mm.
UWBM
Figure 38. ' 98635. Lateral view, anterior to left.
UWBM
Figure 39. 98634. Lateral view, anterior to left.
DV 1254-bal6, L 34.6, W 30.3, H 7.0; UWBM 98684, 60 strong corrugated ribs, usually alternatingly differ-
DV 1254-10, late Pliocene, L 43.2, W 41.3, H 11.1; entiated by size anteriorly and posteriorly.
UWBM 98685, DV 1941-1, latest Pliocene, L 43.9, W
H
38.4, 11.2. Description: Shell conical, moderately thin, length to
about 60 mm; height very low (L:H ratio about 4:1 to
Occurrence: Early late Pliocene: southern Peru.
6:1). Aperture elliptically quadrate, broader posterior-
Nacella (Patinigera) intiforma, sp. nov. ly. Shell margin planar to slightly arched longitudinal-
ly, evenly curved with crenulations corresponding to
Figures 29-39, 46 ribs. Apex obtuse, located one-quarter of length from
anterior end. Anterior slope steep, planar to slightly
Diagnosis: Shell moderately thin; height very low. concave, posterior slope slightly convex, lateral slopes
Aperture elliptically quadrate; aperture one-third of planar. Radial sculpture of about 55 to 60 ribs,
length from anterior. Radial sculpture of about 55 to differentiated by size anteriorly and posteriorly, some-
Page 282 The Veliger, Vol. 50, No. 4
times laterally. Ribs weakly to strongly corrugated by 38.7, H 10.4; UWBM 98644, DV 1254-bal6, L 23.1, W
intersections with strong concentric growth lines; (17.0), H 4.0.
corrugations somewhat irregularand not always evenly
Occurrence: Late early Pliocene to early late Pliocene:
sized or spaced. Interior faintly iridescent; interior
southern Peru, south-central Chile.
margincrenulated; central area 60to 80percent ofshell
length. Nacella {Patinigera) oconaensis, sp. nov.
Discussion: Specimens of Nacella intiforma have a Figures 40-45, 47, 48
shape similar to those of TV. oconaensis, sp. nov. (see
below), but primary ribs ofthe latter species are fewer
Diagnosis: Shell thick, height low. Aperture elliptical to
and coarser. Specimens ofTV. intiforma resemble small oval; apex one-third of length from anterior. Radial
deep-water nacellids assigned by Powell (1973) to TV. sculpture of about 30 to 40 strong but weakly
(Patinigera) deaurata form delicatissima (Strebel, 1907),
which have equally low profiles (but see Valdovinos & caonrdrupgoastteerdiorrilbys., usually differentiated by size laterally
Ruth (2005) for statistics on higher profiles) and
equally strong ribs, albeit fewer. Also similar are Description: Shell conical, moderately thick, length to
specimens ofthestrongly ribbed TV. (Patinigera) terroris about 50 mm; heightlow(H:L ratio4:1 to 5:1). Aperture
(Filhol, 1880), which are found only on sub-Antarctic ellipticaltooval, broaderposteriorly. Shellmarginevenly
Campbell Island (52°32S, 169°09'E),. near New Zeal- curved, sometimes deformed; longitudinally planar to
and, but these have a more centrally located apex, a arched; with crenulations corresponding to ribs. Apex
muchhigherprofile(L:H ratio about 2:1 to 3:1) and are obtuse, located one-quarter to one-third oflength from
less elongate. anterior end. Anterior slope steepest, all adult slopes
Specimens similar to those of N. intiforma were planar to slightly convex; break in slope separates more
found in early late Pliocene bioclastic deposits of the elevatedjuvenilestage. Radialsculptureofabout 30to40
Huacllaco section (DV 1254-bal6). Ribs on the larger primary ribs, with insertion ofsecondary ribs posteriorly
specimen (UWBM 98643; L 46 mm) are worn, but and laterally, generally not anteriorly. Ribs weakly
present in sufficient number for it to be assigned to TV. corrugated at intersections with fine concentric growth
intiforma. The anterior, posterior, and lateral slopes of line crenulations and coarser rugae. Interior margin
the specimen are convex, but slopes closer to the apex crenulated; intermediate area smooth; central area about
are planar. A 30-mm long Pliocene specimen ofNacella 60 to 80 percent ofshell length.
was reported from south-central Chile (Le Roux et al.,
Discussion: Specimens ofNacella (Patinigera) oconaen-
2008). Photographs provided by S. Nielsen (written
communication, April, 2008) reveal an apertural form, sisat the type locality (DV 1279-1) resemble thoseofN.
intiforma, with which they occur, but they are thicker
height, and nearly obsolete sculpture similar to that of
the large Huacllaco example ofTV. intiforma. and have fewer and coarser ribs. Both taxa may be
ecophenotypic variants ofthe same species.
Etymology: Quechua 'inti,' meaning sun, referring to The radial sculpture and rib number of Nacella
the well formed ribs that produce a sunburst pattern on oconaensis match those of extant TV. (Patinigera)
this species. macquariensis Finlay, 1927, from Macquarie Island
(54°30'S, 159°E) and Heard Island (53°S, 74°E)
Type Locality: DV 1279-1, base of southeast face of (Powell, 1973), but the latter species has a much higher
sand-and-gravel quarry along the Pan-American High- profile (L:H ratio about 2:1).
way, 5 km (straight distance) from village of Ocoha
(Figure 1). Limpets were found in finely bedded and Etymology: Named for Ocoha, a nearby village.
cross-bedded fine-grained gravel (Figures 2A-2C). Type Locality: DV 1279-1, base of southeast face of
16°25'28"S, 73°09'14"W. sand-and-gravel quarry along the Pan-American High-
way, 5 km (straight distance) from village of Ocoha
IMHUM1a4NU.Wt48Ve.,SBr8;i1HMMa8U4l,(W9I3(8D.aNB76l)VVl3;M4s,M11p298DeU785c9,6VS-i31m5DM,e,1nV2pDs7Ia9rVN-1la1V2at,t71ye92p1h-7e8o1e9,6l,a-,or1Ltl,pDyya2pprV0eaPa.,rlt9ai1,ytoL2pcyW6eep72,ne-6e,1.1)L,63:L,.8L2,WM323.(LH.021I,51,.83S9..WW)63M;;, ceM(7arFa3riot°lgse0yurs9ri-PTeabl4lei1"do)d.Wc(aee.lndLlei)ml:opceaMftliisUnteiSwe-sgeMrraeeixIncfeeNodpVutndD18gV7ir,navf1eDil2nV.5e4l-y1b2ab7l1e966d-°1d2a,e5r'dep2a8alr"anaStd,-e
42236725....0768,,,, HHHH89((.59.1..2;50;))U;;UWUUWBWWBMBBMMM989689946883366,733,86D,,VDDDV1VV2514211-602b746a-571l--,611,,,LLLL((34365670....2364)),,,, WWWW tHU1y2pW55e4.,B-5;bMLaUl63W9,08.B6e73a,Mr9l,Wy9D8l62aV4t1e.09,1,P2lD7iH9oV-c1e,61n.2e8h7,;o9l-LMo1t,Uy1pp9S.ea9,rM,atLWyIp2Ne9,1.V27.,L51,W8187H,.92,0D3..W67V,;
DeVries, 2007 Page 283
Figures 40^5, 47, 48. Nacella (Patinifera) oconaensis, sp. nov.
Figure 40. MUSM INV 187, paratype. DV 1279-1. Late early Pliocene. Dorsal view. Length is 30.7 mm.
Figure 41. MUSM INV 187. Ventral view.
Figure 42. UUWWBBMM 98639, holotype. DV 1279-1. Dorsal view. Length is 29.7 mm.
Figure 43. 98639. Ventral view.
Figure 44. MUSM INV 187. Lateral view, anterior to left.
UWBM
Figure 45. 98639. Lateral view, anterior to left.
Figure 46. Nacella (Patinifera) intiforma, sp. nov. UWBM 98638. DV 1045-1, late early Pliocene. Dorsal view showing growth
lFiingeurscear47s.andUdWeBfoMrm9e8d64a1p,erptaurrae.typLee.ngDtVh i1s26709.-41.mDmo.rsal view, showingdeformed aperture and six scars fromepibiotic limpet.
Scurria. Length is 28.6 mm.
UWBM
Figure 48. 98641. Ventral view.
13.1, WH 3.9; UHWBM 98641, DV 1279-1, paratype, L 45 weakJy nodular ribs; secondary ribs absent or barely
28.6, 22.5, 6.5. differentiated by size.
Occurrence: Late early Pliocene to early late Pliocene: Description: Shell conical, estimated length to 50 mm,
southern Peru. height low (L:H ratio about 4:1). Aperture broadly
oval, slightly constricted anteriorly. Shell margin
Nacella (Patinigera) chalaensis, sp. nov. planar to arched longitudinally, evenly curved with
Figures 49, 50 weak crenulations corresponding to coarsest ribs. Apex
obtuse, located two-fifths of length from anterior end.
Diagnosis: Shell broadly oval. Apex located two-fifths Anterior and posterior slopes planar, lateral slopes
oflength from anterior end. Radial sculpture ofabout slightly convex. Radial sculpture of about 45 low