Contr. Tert. Quatern. Geol. 30(1-2) 19-27 1 tab., 1 pi. Leiden, June 1993

Spinucella a new of Miocene to Pleistocene , muricid gastropods from the eastern Atlantic

Geerat J. Vermeij

University of California

Davis, U.S.A.

— new of Miocene Pleistocene muricid from the Atlantic. Contr. Tert. Vermeij, GeeratJ. Spinucella, a genus to gastropods eastern

Quatern. Geol., 30(1-2): 19-27, 1 tab., 1 pi. Leiden, June 1993.

The muricid is for de C. 1825 from the Pliocene of the new gastropod genus Spinucella proposed Purpura tetragonaJ. Sowerby, (type species),

North Sea Basin, and for several other early Miocene to late Pleistocene species from southern Europe, North Africa, and southern

Africa. The is characterised the of labral on the of the shell and reticulate of genus by presence a spine outer lip by sculpture. Species and Acanthinucella Cooke, 1918. The Spinucella closely resemble members ofNucella Röding, 1798, Acanthina Fischer von Waldheim, 1807,

ofthat in the eastern Pacific Acanthina andAcanthinucella. Withthe removal of labral spine of Spinucellawas probably evolved independendy

from where authors have the the time of arrival of Nucella in the North Atlantic from the S. tetragona Nucella, many recent placed species,

North Pacific was late Pliocene, rather than middle Pliocene.

— words Key Spinucella, new genus, Acanthina, Nucella, Neogene, biogeography.

Prof. Dr G.J. Vermeij, Department of Geology, University of California, Davis, CA 95616, U.S.A.

Contents 1956; Glibert, 1959, 1963). In fact, Glibert (1959)

considered N. tetragona to be ancestral to N. lapillus, Introduction 19 p. the two species being linked by the late Pliocene 20 Systematics p. taxon N. lapillus incrassatus (J. de C. Sowerby, 1825). Comparisons p. 21 According to this interpretation, N. tetragona would Evolutionary and biogeographical be the earliest species of the genus in the North 22 relationships p. Atlantic, and invasion of Nucella from the Pacific, Acknowledgements p. 24 where be traced back the Nucella can to early References p. 24 would have taken later than Miocene, place no

middle Pliocene time (Crothers, 1983; Vermeij, Introduction 1991).

muricid Nucella The gastropod genus Roding, 1798, Authors who regard Purpura tetragona as a species

have overlooked several characters that comprises eight or nine cool-temperate species of Nucella found intertidal and shallow this all other members abundantly on rocky distinguish species from of

surfaces in the northern Its sublittoral oceans. type that genus. In our study of the phylogeny of Nucella

& in P. species, Nucella lapillus (Linnaeus, 1758) (see Kool (Collins et al., prep.), we found that tetragona

both the and small but distinct labral Boss, 1992), occurs on European possesses a spine, a ventral of and is the American sides the Atlantic, only living projection at the anterior end of the outer lip of the

of the in North Atlantic shell. This feature representative genus waters. is characteristic of Acanthina

All other in the North Pacific. Several Fischer 1807. species occur von Waldheim, Lecointre (1952), who

have also been to Nucella. other species assigned considered Acanthina to be a subgenus of Nucella (or

These include four and Pliocene in living one species Purpura his terminology), assigned P. tetragona, from South Africa (Kilburn & Rippey, 1982; Ken- along with several other Pliocene and Pleistocene sley & Pether, 1986) and the Pliocene species origi- species from Morocco and southern Europe, to

described de C. Acanthina A. monodon nally as Purpura tetragonaJ. Sowerby, [type species: (Pallas, 1774)].

Basin of One of the Morocco considered 1825, from the North Sea western Europe species from was by

Altena Lecointre be (see Harmer, 1914-1921; van Regteren et al., (1952) to specifically indistinguishable 20

from A. monodon unicornis (Bruguiere, 1789) (A. Netherlands, S. tetragona is found washed up on

beaches in in crassilabrum Lamarck in Lecointre's terminology), the estuary of the Westerschelde the

from southern South America. province of Zeeland (van Regteren Altena et al.,

A of and of It therefore has re-examination Purpura tetragona var- 1956). a geological range of middle

ious other species assigned to Nucella, Acanthina, and to late Pliocene.

related indicates the existence of The shell of is groups an early Spinucella tetragona moderately large

Miocene to late Pleistocene lineage of eastern (up to 63 mm in length), characterised by a rela-

Atlantic muricids possessing a labral spine and reti- tively high spire, long siphonal canal, well-marked

culate The of this is rounded sculpture. purpose paper to pseudo-umbilical slit, a columella, a deep

and this the short labral and latticed recognise name lineage as new genus suture, a very spine, strong

with and dis- of six cords crossed Spinucella, Purpura tetragona as type, to sculpture consisting major spiral

the and fifteen axial folds cuss characters, evolution, biogeographical by as many as (PI. 1).

of this and sim- relationships group morphologically A second well-characterised species is S. plessisi

ilar muricids. (Lecointre, 1952) from the late Pliocene to late

Atlantic Pleistocene of the warm-temperate eastern

SYSTEMATICS (PI. 1, Fig. 5). This species had a range from near

Lisbon (Portugal) to Morocco and the Canary Family Rafinesque, 1815 has Islands; a single (presumably fossil) specimen Subfamily Ocinebrinae Cossmann, 1903 been collected in sediment near Cape Bojador, Genus Spinucella nov. gen. Spanish Sahara (see Brebion, 1974, 1979a, b; Meco,

— Type species Purpura tetragona J. de C. Sowerby, 1981). Spinucella plessisi is rather variable in shape

1825, here designated. and in the development of shell sculpture. Almost

— shorter smooth forms called Diagnosis Shell ovate; spire than adult were Purpura (Acanthina) body whorl; teleoconch whorls four to five in crassilabrum Lam. by Lecointre (1952). More heavily

rounded with of number, evenly or slightly shouldered; sculptured forms a reticulate sculpture spiral

of both and axial and axial ribs named P. sculpture spiral elements; spiral were (A.) plessisi, P. nicklesi, ribs and P. nicklesi all of Lecointre usually broad, up to seven primaries on body var. imsouanensis, whorl, with intercalated secondary ribs and finer (1952). Brébion (1974, 1979a, b) and Meco (1981)

axial ribs form reticulate all these forms under the threads; a or latticed pat- justifiably synonymised

with the earliest available tern spiral sculpture; aperture ovate; junc- name, P. (A.) plessisi Lecointre, tion of outer lip with body whorl continuous, with- 1952, which is here placed in Spinucella. S. plessisi

sinus of base differs from S. the absence of out posterior or notch; edge outer lip at tetragona by a pseudo-

canal with short labral formed umbilical of siphonal spine, as slit, by having a lower spire, and by hav- an elaboration of one of the denticles on the inner ing the suture indistinct rather than deeply surface of the outer lip; outer lip slightly thickened, impressed. denticulate within, the denticles developed close to Perhaps the earliest representative of Spinucella is

of the columella less S. from the middle the edge lip; more or straight, angulata (Dujardin, 1837) sometimes flattened, lacking folds; siphonal canal Miocene (Helvetian = Tortonian) of France. This

visible shell's differs from other members of the open, its trace on the exterior as a species most

fasciole often from the base its small size of adults 34 prominent separated by genus by (length up to mm)

slit. and its of six to thick axial a pseudo-umbilical by sculpture seven very

Geographical and stratigraphical distribution — Early ribs, which form nodes where they are crossed by

five six Miocene to late Pleistocene; North Sea Basin to or closely spaced spiral cords. The upper-

cord weak southern Africa. most spiral forms a shoulder, above

— The of S. which the axial ribs towards Included species type Spinucella is tetragona straight slope the indis-

(J. de C. Sowerby, 1825), which has been recorded tinct suture. in England from the Coralline Crag at Ramsholt Several other southern European species from the and from the Red Miocene and Pliocene throughout Crag (Waltonian, appear to belong to Spi- Newbournian, and Butleyan) (see Harmer, nucella. These include S. monacanthos (Brocchi, 1814)

1914-1921; Glibert, 1963). In Belgium the species is from the Pliocene of Italy, S. depressa (Bronn, 1831) known from the Oorderen Sands Member of the from the Pliocene of Italy, S. cancellata (Bellardi,

Lillo Formation (Glibert, 1958, 1959). In The 1882) from the early and late Miocene of Italy, S. 21

S. from Helvetian whereas in Nucella they are deeply benoisti (Degrange-Touzin, 1895) the Spinucella,

The inner surface of the ofNucella of France, and S. lesvignesi (Cossmann & Peyrot, recessed. outer lip In the the of France. It is doubtful is thus bevelled, whereas in Spinucella it is not. 1923) from Tortonian

distinct but I third the lattice-like characteristic that all these names refer to species, place, sculpture

in In of of these of does not occur Nucella. have not undertaken a critical review taxa. Spinucella species

either Nucella with axial elements, the latter are Another species that appears to belong to Spi-

in thick-shelled of nucella is the Pliocene South African S. praecingulata discrete knobs, as some morphs

from from the west coast of N. (Deshayes, 1839) California, or (Haughton, 1932), described emarginata that override the This which reaches a are irregularly spaced flanges Cape Province. large species, they Pacific variable in cords, as in the northeastern N. length of 115 mm, is highly spire height spiral

As lamellosa 1791) and the northwestern and in the development of shell sculpture. Ken- (Gmelin, shells Pacific N. (Dunker, 1882). sley & Pether (1986) pointed out, low-spired heyseana

whereas The four South African that have are typically strongly sculptured, higher- living species

ornamented. On shells been to Nucella previous authors com- spired shells are less heavily assigned by in shell with well-developed sculpture (PI. 1, Figs 1, 2), there prise a heterogeneous group differing sculp-

the whorl ture and characters from northern are seven primary spiral ribs on body egg-capsule also the network members of Nucella d'Asaro, (three on penultimate whorl), forming a hemisphere (see from of axial folds in the as well as species sculpture with subsidiary visible 1991; Vermeij, 1992) ’Nucella’ (Lamarck, 1816) and interstices between the spiral elements. The axial Spinucella. squamosa ’N.’ dubia differ from both in sculpture is often missing in later whorls, but is (Krauss, 1848) genera the inner There is of a a on lip adja- usually present on early whorls. a trace possessing slight thickening

in of the thatI have been cent to the of the outer with the labral spine one specimens junction lip body notch the South whorl. Moreover, ’N.’ has a slight or able to examine, courtesy of J. Pether at squamosa

In sinus at the end of the outer lip. Many African Museum (PI. 1, Figs 1, 2). specimens posterior have is the are of regularly spaced whose outer lip thickened within, denticles specimens ’N.’ squamosa

thin axial folds that cross eleven to seventeen spiral close to the edge of the outer lip. There is typically

whorl form fine slit. The reticulate cords on the to a relatively no pseudo-umbilical sculpture, body

axials tend to override the obsolete but recognisable labral spine, and the char- cancellate sculpture. The

dentition all remi- whereas in of Spinucella acter of the outer lip are strongly spirals, sculptured specimens

' differ in that the elements tend to be dominant. ’Nucella’ niscent of S. tetragona. The two species spiral

115 dubia has weak spiral cords and lacks well- S. praecingulata is larger (up to mm as compared irregular

' axial ’Nucella’ has a defined sculpture. cingulata (Linnaeus, to 63 mm), lacks a slit-like pseudo-umbilicus, of Trochia Swainson, 1840, has weaker labral spine, and has reduced axial sculp- 1758), type species five almost ture. Differences between S. praecingulata and the up to broad, prominent, T-shaped spiral but lacks axial This species, other South African species typically referred to cords, again sculpture.

well and has Nucella will be treated below. as as ’N.’ dubia ’N.’ squamosa, generally a

thin outer lip that is not denticulatewithin. Finally,

’N.’ wahlbergi (Krauss, 1848) differs greatly from all COMPARISONS other species discussed here in having a high spire, a

closed is understand has almost siphonal canal, and a sculpture It easy to why Spinucella tetragona long,

fine axial and lines. There is a long been regarded as a species of Nucella. Spinucella of numerous spiral inner the similar in shell in the absence distinct on the lip at and Nucella are shape, posterior thickening

end of the in of columellar folds, in the absence of a posterior posterior aperture, as ’N.’ squamosa.

notch and the denticles the The’N.’ventral of the whorl of wahl- or sinus, presence of on portion body

the of the inner surface of the outer lip. The diagnostic labral bergi projects ventrally beyond plane aper-

in all is often because the ture. A labral is absent four living South spine of S. tetragona invisible spine

anterior of the corroded African of ’Nucella’. part outer lip is frequently species

in shells. Lecointre and Brebion (1974) assigned or damaged fossil (1952) the Acan- Spinucella differs from Nucella in three shell charac- species of Spinucella to genus or subgenus

it whereas Nucella thina to the of a labral and to ters. First, possesses a labral spine, owing presence spine

denticles the inner the in overall shell to the does not. Secondly, the on sur- similarity shape type spe- Both have in cies of that A. monodon. a face of the outer lip lie close to the edge of the lip group, genera 22

low and spire, a denticulate outer lip, a smooth, (see above), is found in some thick-walled individ-

more or less straight columella. uals of Nucella emarginata from California, but is

Acanthina differs from in details of in all of in Spinucella sculp- absent other species Nucella as well as

and in the the labral The ture placement of spine. Acanthina s. str. and in Spinucella. The Recent Acan-

living A. monodon is a highly variable that is thinucella species spirata (de Blainville, 1832), A. punctulata, divided into northern A. sometimes a m. and A. subspecies paucilirata (Stearns, 1872) are characterised

unicornis from northern and of fine riblets (Bruguiere, 1789) cen- by a sculpture spiral threads or and a

tral and A. monodon less Chile, a southern form, m. from more or well-developed shoulder on the body

southern Tierra del and the Falkland whorl. Axial is the Chile, Fuego, sculpture lacking on body whorl,

Islands but (E.H. Vokes, personal communication). In does occur as nodes on early teleoconch whorls.

there are various Pliocene forms such A. A second of addition, as group Acanthinucella, including A. lugubris

costata and A. acuminata, both of J. de C. Sowerby, (J. Sowerby, 1821) from northwestern Mexico and

1825 In the (see Herm, 1969). unicornis form, the the Pliocene Chilean A. mirabilis (Moricke, 1896) consists of low smooth which and A. sculpture spiral cords, philippii (Moricke, 1896), has the fine spiral

may be obsolete on the body whorl. Their number sculpture overridden by thick rounded axial folbs,

from in the which form typically ranges ten to twenty, but a nodose sculpture. In A. l. lugubris and

Pliocene there four six variety costata are only to A. l. angelica (Oldroyd, 1918), the nodes are arranged

cords. Axial is absent. In in strong sculpture the south- two to four widely separated spiral bands. The

ern A. the cords often axial elements of these different m. monodon, spiral are scaly by species are quite

virtue of thin lamellae the from rounded axial the development of on the thick ribs of Spinucella, in

cords also Wu, The labral of the ribs overridden (see 1985). spine which these are by the spiral cords.

South American species is unique in that it arises As Cooke (1918) and Wu (1985) recognised,

’ the middle shell In adult well in from layer. as as ’Acanthina brevidentata (Wood, 1828) from the tropi-

the of the cal thin-lipped juvenile shells, edge outer lip eastern Pacific is not a true Acanthina but instead

is and sharp continuous, being slightly creased at is related to Thais Roding, 1798 and Stramonita

the of position the spine but showing no other indi- Schumacher, 1817. The species differs from Acan-

cation of that The inner of the thina and from tuber- projection. edge lip s. str. Spinucella by possessing a

also forms often a continuous, finely denticulate, cle on the inner lip at the posterior end of the

Between this inner and the weak sinus ledge. ledge sharp outer aperture, by having a in the outer lip of the the labral arises from bev- where edge lip, spine a the latterjoins the body whorl, and by having

elled surface in the middle of the wall of the of knobs outer two spiral rows on the body whorl, as well

In the labral arises the of weak lip. Spinucella, by contrast, spine as by presence two folds on the col- from both the and inner shell outer layers, and is umella. The columellarplication and outer-lip sinus

therefore a ventral projection of the lip as a whole set the species apart from the sculpturally similar

rather than only of the middle layer. Acanthinucella lugubris angelica.

In the of the labral The distribution of character states the position spine, Spinucella among resembles several northeastern Pacific species that various taxa discussed above is summarised in

Cooke his Table 1. for were assigned by (1918) to new taxon New supraspecific taxa are warranted

which he of least Acanthinucella, regarded as a subgenus at some of the living South African species as

' Acanthina but which Wu with ’Acanthina’ (1985) synonymised well as for brevidentata from the eastern the latter genus. Acanthinucella punctulata (G.B. Pacific, but formal proposals will be deferred until

the radula and Sowerby, 1835), type species, has a that more information on anatomy reproductive is essentially identical to that of Nucella and some- characters becomes available.

from that of what different Acanthina s. str. (Cooke,

of which in 1918). Species Acanthinucella, range age EVOLUTIONARY AND BIOGEOGRAPHIGAL from late Miocene to Recent in California, north- RELATIONSHIPS western Mexico, and Chile, share with Nucella the

recessed dentition of the but The of deeply outer lip, they recognition Spinucella as distinct from Nucella differ from has several most species of Nucella by possessing a implications for the interpretation of small but distinct tubercle on the inner at the historical lip Neogene biogeography. One of these con-

the This end of which cerns the Nucella. With posterior aperture. tubercle, genus Spinucella tetragona also in South African of occurs some species ’Nucella’ excluded from Nucella the earliest of , representative 23

“Nucella”"Nucella"

cingulata Acan- “Acan-"Acan-

Nucella “Nucella”"Nucella" “Nucella”"Nucella" (type of “Nucella”"Nucella" AcanthinaAcanthina thinucella thina”thina" Spinucella

Character dubiadubia brevidentata species squamosasquamosa Trochia)Trochia) wahlbergi species species species

_*-* Inner-lip posterior knob + + - + - + + -

Outer-lip posterior - + - - - - - + - notch

Outer-lip dentition + ------+ + + +

Dentition deeply ------+ - + recessed

Reticulate sculpture - + ------+

Labral spine ------+ + + +

Whole outer lip forms ------+ + + spine

Columellar plaits ------+ -

* Table Presence absence of shell characters in related and = in individuals of 1. (+) or (-) taxa toNucella, Acanthina, Spinucella. present some

N. emarginata.

labral Nucella in the North Atlantic is the late Pliocene N. alternative interpretation is that spines were lapillus incrassatus (J. de C. Sowerby, 1825) from the evolved independently by Acanthina in the eastern

Merksemian of Belgium and the Red Crag of Eng- Pacific and by Spinucella in the eastern Atlantic.

that direct land (Harmer, 1914-1921; Glibert, 1958, 1959, Support for the interpretation a phy-

1963; Cambridge & Kitching, 1982). That this form logenetic connection exists between Acanthina and is is indicated the absence of axial would from that other lin- a true Nucella by Spinucella come evidence sculpture and of a labral spine, as well as by the eages also occurred in both the eastern Pacific and

Atlantic. Two this distinctly bevelled outer lip. The invasion of Nucella eastern gastropod genera satisfy from the North Pacific via the Bering Strait to the criterion. One of these is the limpet-like muricid

North Atiantic therefore have occurred later 1792. the mid- may genus Concholepas Bruguiere During

dle this (during late Pliocene time) than had been supposed Miocene, genus (or a group very closely by Durham & MacNeil (1967) and Vermeij (1991), related to it) is known from France, Florida, Austra- who indicated mid-Pliocene date. and New Zealand a lia, (Beu, 1970; Vokes, 1972a).

It could be argued that the stock ofNucella lapillus From Pliocene to Recent time, Concholepas has been

loss of confined the in the Atlantic is derived from Spinucella by essentially to temperate west coast of the labral spine, and that N. lapillus is not the South America (Herm, 1969), although Kensley descendant of a North Pacific invader at all. (1985) reported one late Pleistocene find on the west

Molecular data in well far- of South Africa. The (Collins et al., prep.) as as coast calyptraeid genus reaching similarities between N. lapillus and Pacific Trochita Schumacher, 1817, is known from the species of Nucella cast doubt on this hypothesis. Pliocene to middle Pleistocene of Morocco and the

An interesting question is how Acanthina and Spi- Canary Islands (Brebion, 1979b; Meco, 1981) and nucella related. French authors in the Miocene and Pliocene from America are evolutionarily tropical

Afri- the have generally referred European and North (Vokes, 1975). Today genus occurs sporadically

in the Verde southern can Nucella-like gastropods with a labral spine to the Cape Islands, Angola, Africa,

and in have the Gulf of New southern South genus or subgenus Acanthina, doing so Oman, Zealand,

inferred close and from Mexico Chile in the implicitly or explicitly a phylogenetic America, to eastern connection with South American representatives of Pacific (Taylor & Smythe, 1985). Fike Spinucella, that The Trochita became extinct the mainland of group (Lecointre, 1952; Brebion, 1974). on coast 24

North Africa during the late Pleistocene. Many pre-Pliocene record of Spinucella is unknown in

known have discontinuous southern in West the does tropical genera are to or tropical Africa, genus modern in is distributions, with species the eastern conform to a biogeographical pattern that seen in

Atlantic and eastern Pacific but not the intervening several other temperate genera. As documented by

include the connection western Atlantic. Examples gastropods Vermeij (1992), a biogeographical

between the northern and southern Harpa Roding, 1798, Pseudozonaria Schilder, 1927, temperate zones

Erosaria Troschel, 1863, Purpurellus Jousseaume, in the eastern Atlantic had been established by

1880, and Sveltia Jousseaume, 1887 (see Rehder, Pliocene time. It will be interesting to see if other

1973; Vokes, 1984, 1989; Vermeij, 1986; Jung & extinct elements of the North Sea Basin biota of the

Petit, 1990). Western Atlantic representatives of Miocene and Pliocene can be linked with species these known the genera are only from Miocene or from the temperate southern hemisphere. Max-

well's that Pliocene. If Acanthina and Spinucella have a common (1988) interpretation the middle Miocene

labral would North Sea Basin dittmeri ancestor possessing a spine, they con- turrid Magnella Anderson, stitute that should conform the of the New Zealand a single lineage to 1960, represents a species genus biogeographical history of the genera discussed Mioawateria Vella, 1954, is consistent with a link above. In other words, there should be a Nucella-like between northern and southern temperate faunasin

with labral in the species a spine the Miocene or the Old World during the Miocene. So is distri-

Pliocene of the Atlantic. To such bution western date, no of Pterynopsis Vokes, 1972, an Oligocene to candidate has been in the rich late Pliocene of muricids from both species yet found very genus known

of North and the North Sea Basin and Namibia fossil record on the Atlantic coasts (Vokes, 1972b).

South Future worldwide revisions of will be needed America. groups

I and Acan- and such these. am inclined to think that Acanthina to uncover document patterns as thinucella in the Pacific evolved labral spines inde- ACKNOWLEDGEMENTS pendently of the eastern Atlantic Spinucella. The difference in spine formation and in shell sculpture I thank Arie W. Janssen at the Nationaal Museum between Pacific and Atlantic forms (see Table 1) voor Natuurlijke Historie (Leiden, The Nether- indicates convergence rather than common descent. lands), Gary Rosenberg at the Philadelphia Acad- Cooke's finding that the radula of the north- (1918) of Natural and Pether the emy Sciences, John at eastern Pacific Acanthinucella is virtually identical to South African Museum (Cape Town) for sending that of close Nucella points to a phylogenetic affinity loan for Coo- specimens on my examination; Janice between these both of which date from the genera, for valuable technical and per assistance; Mary Miocene in the North Pacific. The South American Graziose for the for taking photographs this paper. Acanthina could then have been derived from an Gary Rosenberg, Emily Vokes, Arie Janssen and stock in the that several other intervening same way Martin Cadee kindly reviewed the manuscript and South American derived from northern groups are provided helpful suggestions. Pacific invaders across the equator (Lindberg,

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308-324. 30 October 1992. 26

PLATE 1

Figs 1, 2. Spinucellapraecingulata (Haughton, 1932), Hondeklip, South Africa. Dorsal (Fig. 1) and apertural (Fig. 2) views. Collections

of the South African Museum, SAMPQHB 136, x 1,4.

4. de C. of The Netherlands. The small labral Figs 3, Spinucella tetragona (J. Sowerby, 1825), Ellewoutsdijk, province Zeeland, spine

(Fig. 3) is clearly visible despite slight damage to the outer lip. Collections Nationaal Natuurhistorisch Museum, Leiden,

ST 101186, x 2.5 and 4.1, respectively.

Fig. 5. Spinucella plessisi (Lecointre, 1852), Sidi Bou Maleh, Morocco. Collections of the Academy of Natural Sciences, Phila-

delphia, ANSP 77360, x 2.5. 27\1

PLATE 1