Diversity and durability: responses of the Madeiran and Porto-Santan snail faunas to natural and human-induced environmental change

10 Pages·1996·4.4 MB·English

by  R A D Cameron

Diversity and durability: responses of the Madeiran and Porto-Santan
snail faunas to natural and human-induced environmental change
R. A. D. Cameroni and L. M. Cook2
'DivisionofAdultContinuing Education, UniversityofSheffield, 196 - 198 West Street, Sheffield, SI 4ET, United Kingdom.
2TheManchesterMuseum,The University ofManchester,Oxford Road, Manchester, Ml3 9PL,United Kingdom.
Abstract: The snail fauna of the Madeiran Archipelago has the high regional diversity and endemism, and high species and genus differentiation
between islands characteristic ofoceanic island faunas. It is unusual in two respects: the existence ofgood Pleistocene/Holocene fossil records, and the
apparentdurabilityoftheendemicfaunainthefaceofmassivehumandisturbanceandtheintroductionofnon-indigenousspecies.
We use the fossil record, the present microdistributions ofspecies, and the environmental records available to trackthe generation ofdiversity and the
responsetohuman disturbance. The natureoftheenvironmentavailable andthe life-habitsofendemic speciesappeartoaccount forthe relative resilience
ofthesespecies.
Land snail faunas of volcanic oceanic islands are fered much less. In this paper, we offer an explanation of
usually characterized by very high levels ofspecies diversi- this robustness, based on analysis of past environmental
ty and endemism (Solem, 1983, 1984, 1990a). Sample site changes both natural and human-induced. Subfossil, nine-
diversities are not high; there is marked microgeographical teenth-century, and modern records are available as evi-
differentiation within islands, and evolution at species level dence.
occurs mostly within rather than between islands. Overall Cameron and Cook (1992) gave a general account
species diversity in archipelagos is thus often very high of the development of faunal diversity. Environmental
indeed (Solem, 1990b). interpretation and estimates of extinction are made easier
This situation offers excellent opportunities to by the existence ofsnail-rich late Pleistocene and Holocene
study the process of speciation (Clarke and Murray, 1969; deposits spanning the last 300,000 years (Cook et al.,
Cowie, 1992a) but these are often compromised by the 1993), and by the application of amino-acid epimerization
extreme vulnerability of such faunas to habitat destruction techniques to the dating of individual shells (Goodfriend,
and the introduction of predators and competitors (Cowie, 1987, 1991; Goodfriend etal, 1994).
1992b). Thus three-quarters of the endemic fauna of the
Hawaiian archipelago is believed to be extinct (Hadfield,
1986; Solem, 1990a, b) and a similar situation occurs on THE ARCHIPELAGO AND ITS
ENVIRONMENTAL HISTORY
other Pacific islands. Extinction is often very recent:
Tomiyama and Kurozumi's (1992) studies on the
Ogasawara Islands south ofJapan indicate that nearly 40% Together with the Deserta Islands, Madeira (ca.
of endemic species have become extinct since 1945, with 740 km2) and Porto Santo and its neighbouring islets (ca.
higherfigures on the mostdisturbed islands. 41 km2) constitute an archipelago of volcanic, oceanic ori-
Not all oceanic islands have been so drastically gin. Madeira is mountainous, rising to over 1800 m, and
affected; the islands of the Gulfof Guinea, retaining some contains a wide range of habitats and climatic zones,
primary forest and lacking introduced predators retain most including subalpine regions, extensive laurel forests, and
if not all of their described endemic faunas (Gascoigne, lower coastal areas with an approximately Mediterranean
1994). climate. Although some rocks are 15+ million years (MY)
While similar in most ofthese respects to the fau- old, there have been more recent periods of volcanic activi-
MY
nas of other oceanic islands, that of the Madeiran ty, the last perhaps 0.75 ago (summary in Mitchell-
Archipelago differs in that, despite over 500 years of Thome, 1985). Substrata are almost exclusively volcanic in
human settlement and disturbance, it has apparently suf- origin, and coasts are generally rocky and steeply shelving.
AmericanMalacologicalBulletin,Vol. 12(1/2)(1996):3-12
3
4 AMER. MALAC. BULL. 12(1/2) (1996)
Only at the eastern extremity ofthe island are there soils of studied intensively since the 1820s, and Wollaston (1878)
sea-sand origin on a low peninsula which is the driest part gave a remarkable and detailed account of the living and
of the island. Ecologically, this peninsula now resembles subfossil fauna then known. Many workers have studied the
parts ofPorto Santo. fauna in the second half of the twentieth century; Walden
Porto Santo differs in many respects. One hill only (1983) provided an annotated checklist for the archipelago,
MY
risesjust above 500 m; rocks are all dated to 12-14 old to which later workers have made minor alterations and
(Mitchell-Thome, 1985), and with the exception of sea- additions (Groh and Hemmen, 1984, 1986a, b; Hemmen
cliffs to the northeast and some hill summits, the landscape and Groh, 1985; Holyoak and Seddon, 1986; Cook et al,
is rounded, with sometimes massive colluvial deposits on 1990; Seddon, 1990; Rahle, 1992).
hillsides. There is an extensive sandy beach along the In addition to work already published, we have
southern coast, and sandy deposits cover most of the land drawn on data from our survey oflaurel forests and coastal
below 100 m. They sometimes ascend higher, and the low scrub in northern Madeira, and on a comprehensive survey
center of the island is entirely covered by them, separating of Porto Santo, the results of which will be published else-
the rocky hills to the west and east. Rainfall is lower than where. We thus have data on species diversity and occur-
on Madeira. No natural forest survives, and except for rence from subfossil material, from good nineteenth centu-
recent forestry plantations, the habitats available are heavily ry accounts, and from recent surveys which include detailed
grazed grassland (often with bare, eroding sand) or a very distributional data. Similar comprehensive surveys of the
open shrubby environment resembling Mediterranean gar- relatively inaccessible Deserta Islands have not been carried
rigue orphrygana. out, and we have not considered theirfauna.
Human occupation of the islands started in 1419- There are inevitable difficulties of taxonomic
1420 A. D. Apart from widespread habitat destruction, interpretation involved in such comparisons. We have cho-
there have been numerous deliberate and accidental intro- sen to ignore subspecific taxa, because early workers,
ductions of plants and animals. Substantial areas of both including Wollaston, appear not to distinguish reliably
islands are now dominated by non-native vegetation. There between geographically replacing forms and varieties found
are no indigenous terrestrial mammals, but goats, sheep, at the same site. In general, we have accepted Walden's
rabbits, mice, and rats have all been introduced. There are (1983) nomenclature and assignments of taxonomic rank,
many non-endemic mollusks, most of which have probably with some adjustments made in the light of later work.
been introduced (Walden, 1983; Goodfriend et al, 1994), Minor changes in assignment would make little difference
and these include Zonitidae with carnivorous habits. to ourconclusions. A list ofspecies and their status is given
Analysis ofthe stratigraphy and subfossil snails in in the Appendix.
the sandy deposits of Madeira demonstrates not only the There are also some difficulties in interpreting
locally catastrophic consequences of human disturbance nineteenth century statements concerning abundance and
and introductions (Goodfriend et al, 1994) but also the distribution. Wollaston (1878), while generally meticulous,
occurrence of Pleistocene and pre-colonization environ- occasionally admitted to conflating samples from different
mental changes between more wooded (damp) and open localities, and sometimes appears to rely on distant memo-
(dry) landscapes. These sequences are interrupted by mas- ry. Contemporaries were often far less reliable. Twentieth
sive accumulations offossil-free sand, indicating periods of century records are generally accurately localized.
dune mobility and (presumably) localized faunal extermi-
nations (Cook etal, 1993; Goodfriend etal., 1996).
Analyses of the far more extensive deposits on DISTRIBUTION PATTERNS AND DIVERSITY
Porto Santo are not yet complete, but it is clear that similar
fluctuations occurred there, including drastic changes in On both Madeira and Porto Santo, sample site
lowland areas following human occupation. Unlike diversities are modest, being mostly in the range of 5-15
Madeira, Porto Santo is surrounded by a shelf of shallow species (Solem, 1984). While there are clear differences in
water; sea-level depression in full glacial periods of the habitat between some species, there is also evidence ofgeo-
Pleistocene would not only have greatly increased the size graphical differentiation between faunas drawn from the
of the island, but would also expose sand subsequently same habitat (Cameron and Cook, 1992; Cook etal, 1993;
blown inland. Periods ofdune mobility would isolate east- Cameron etal, 1996).
ern and western hills (Cameron etal, 1996). The range ofavailable habitats on Madeira is con-
siderable. Faunas from laurel forests at mid- to high alti-
MATERIAL tudes (500+ m) show little geographical variation, while
those from drier environments at lower altitudes show
The land snail fauna of the archipelago has been much more. While not entirely consistent, these differences
CAMERON AND COOK: MADEIRAN AND PORTO-SANTAN FAUNAS
5
can be attributed to climatic fluctuations which caused peri- and acomparison ofsubfossil and recent records.
odic isolation of fragments of dry, open, lowland habitats On Porto Santo, only one species, the massive
(Cook, in press). helicid Pseudocampylaea lowei, appears to have become
The range of habitats is much more restricted on extinct in this century. Even in the nineteenth century it was
Porto Santo, and there are numerous cases of allopatric known alive from one locality only (it is abundant as a sub-
replacements of sibling species in similar environments fossil, but no dates are available).
(Fig. 1A). These are examples of non-adaptive radiation in Our own survey of Porto Santo conducted over a
the sense defined by Gittenberger (1991). While there are three-week period in 1993 revealed all but two of the
some habitat differences between species, most ofthe diver- remaining species reliably identified by Wollaston, and
sity is related to the isolation ofhills caused by sand move- these two have also been found recently (M. Seddon, pers.
ment between them. The recent human disturbance has cre- comm.).
ated a number of vicariant distributions (Fig. IB): disjunct Where Wollaston (1878) gave sufficient detail,
distributions which are known from Holocene subfossil most species appear to have maintained their distribution
material to have been continuous (Cameron etai, 1996). and abundance, but a few which were found in lowland,
Geographical patterning is usually seen most clear- sandy areas appear to have retreated. Conversely, the intro-
ly in Helicidae, which are in general far more abundant and duced Theba pisana has expanded its distribution, now
diverse in open habitats than in the wetter and cooler laurel being found in nearly all locations with any sand in the soil.
forests of Madeira. This is reflected in the greater number The situation on Madeira is more complicated. A
of helicid species (35) found alive on the overwhelmingly number of species cataloged by Wollaston were known
open and dry Porto Santo than on Madeira (30); the latter from only one or a very few sites, and these are not always
island is ca.18 times as large and has a far greater diversity relocatable with certainty. The island has not been resur-
ofhabitats. veyed at the intensity involved on Porto Santo.
Of the 80 endemic species recorded alive at any
time described for Madeira, our recent surveys of eastern
EXTINCTIONS AND INTRODUCTIONS and northern Madeira have revealed 56. Of the 24 not
recorded by us, five were unknown in the nineteenth centu-
We have two ways of estimating extinctions, the ry, nine have certainly been found by others in recent years,
comparison of nineteenth and twentieth century records, but ten appear not to have been found during this century
Fig. 1. Distributionsofendemic specieson Porto Santo. A. Disculaechinulata (•), D. bicarinata (A), andD. leacockianu(). Othersites sampled shown
asopencircles. B.Pseudocampylaeaportosanctana. Contoursshownat200and400m.
6 AMER. MALAC. BULL. 12(1/2) (1996)
(Groombridge, 1992). Many of these ten were very local- Table 2. The numbers ofendemic species known in subfossil condition,
ized in the nineteenth century; five of them belong to the theirproportionsoftotal faunas,andtheextinctionrate forspeciesknown
genus Leiostyla - small and often cryptic. It is unlikely that assubfossilsforMadeira(a)andPortoSanto(b).
all ofthem are genuinely extinct; we suggest that, at a max- (a)Madeira
imum, ca.10% of endemic species known to Wollaston Helicidae OtherFamilies Total
have died out in the last 120 years, and that all of them KnownSubfossil 22 20 42
%
were very rare before that. ofallfauna 56.4 36.4 44.7
At least two species, Actinella arridens and %Extinct 9 5 14
Janulus stephanophora, appear to have become very much ofSubfossilExtinct 40.9 25.0 33.3
rarer in the last 100 years; no explanation occurs to us. The (b)PortoSanto
southwest ofMadeira, subject to heavy disturbance, has not Helicidae OtherFamilies Total
been surveyed in detail; other declines could have occurred KnownSubfossil 43 11 54
%
ofallfauna 87.7 55.0 78.3
there.
Extinct 12 3 15
Despite this low overall extinction rate, some areas %
ofSubfossilExtinct 27.9 25.0 27.8
have clearly become impoverished. Sandy areas on both
islands have depauperate endemic faunas, and high densi-
ties of the introduced Theba pisana. On Madeira, planted ofPorto-Santan than Madeiran species occur as subfossils.
conifer forests are virtually devoid of snails (Cook et ai, Fossiliferous deposits occur all over Porto Santo; they are
1972) and some other areas dominated by introduced confined to a small and atypical part of Madeira. The pro-
mimosas are depauperate (Cook et ai, 1990). Conversely, portion of subfossil species now extinct is similar on both
some open country endemics, for example Discula poly- islands.
morpha and Actinella nitidiuscula, appear to have colo- In the case of Madeira, of the 14 extinct species
nized cleared areas with some success. known from the sand deposits, at least nine appear to have
The good subfossil record enables us to estimate died out after human colonization (Goodfriend et ai,
extinctions in another way. Table 1 shows the numbers of 1994). We are not yet able to offerfigures forPorto Santo.
species known alive or only subfossil on both islands. The The number and proportion ofrecent non-endemic
Helicidae are separated from other families for reasons species is much higher on Madeira than on Porto Santo
given below. Taking both islands together, they have ahigh- (Table 3) and a lower proportion of non-endemics than
er apparent extinction rate than the other families (%2 = endemics are Helicidae. Most non-endemics have probably
5.54, p< 0.05). been introduced (those which are anthropophilic almost
Interpretation, however, must take into account the certainly) but some, particularly very small species, could
chances of preservation in the deposits. Table 2 shows the be native. Three non-endemics {Punctum pygmaeum,
proportions ofspecies known in the fossil record which are Plagyrona placida, and Vitrea contracta) are found as sub-
now extinct, and the proportion ofthe total fauna known in fossils in pre-colonization deposits on Madeira, and V. con-
subfossil condition. Helicidae are better represented in the tracta and Baleaperversa have an exclusively montane dis-
deposits than other families, and a much higher proportion tribution on Porto Santo. A small number of non-endemics
also occur regularly in laurel forests. All slugs are non-
endemic (Rahle, 1992).
Table I.Thenumbersofspeciesrecordedaliveatanytime orfoundonly
as subfossils (extinct) in the endemic faunas of Madeira (a) and Porto
Santo(b). DISCUSSION
(a) Madeira THE EXTENT AND TIMING OFEXTINCTIONS
Helicidae OtherFamilies Total
Living 30 50 80
Extinct 9 5 14 As estimated by changes overthe last 100-150 yrs,
Total 39 55 94 the rate ofapparent extinction reported here is very low for
%Extinct 23.1 9.1 14.9 oceanic islands (Solem, 1990a; Groombridge, 1992) and
especially for those subject to intense human intervention.
(b)PortoSanto The archipelago was discovered and colonized more than
Helicidae OtherFamilies Total
400 yrs before detailed descriptions of the fauna were
Living 37 17 54
Extinct 12 3 [5 made. Early accounts (explored in Machado, 1947;
Total 49 20 69 Prestage, 1966; Crosby, 1986; and Ferraz, 1986) indicated
%
Extinct 24.5 15.0 21.7 large scale destruction of natural habitats by fire, fellings,
CAMERON AND COOK: MADEIRAN AND PORTO-SANTAN FAUNAS 7
Table3.Thenumbersofendemicandnon-endemicspeciesreportedalive cannot ascribe any extinctions totheirpresence.
on both islands. Of Madeiran non-endemics, 13 are restricted anthro- There is likewise little evidence of competition
pophiles.Figuresinparenthesesshow theeffectofexcludingthem. between native and introduced species. Site diversities of
endemic and non-endemic species are independent of one
(a)Madeira
Helicidae OtherFamilies Total another (Cook, 1984) and non-endemics fill spaces in the
Endemics 30 50 80 shell size and shape distribution unoccupied by endemics
Non-Endemics 12(6) 47(40) 59(46) (Cameron and Cook, 1989). In one instance, it is possible
%Non-Endemics 28.6(16.7) 48.5(44.4) 42.4(36.5) that competition has caused extinction: the extinct Caseolus
Total 42(36) 97(90) 139(126) bowdichianus was very abundant on sandy substrata on
(b)PortoSanto both islands before colonization. It has now been replaced
Helicidae OtherFamilies Total by the introduced Thebapisana which is similarly abundant
Endemics 37 17 54 on sandy substrata (Goodfriend etai, 1994).
Non-Endemics 14 8 12 Most of the indirect evidence we have points to
%Non-Endemics 9.8 32.0 18.2
habitat destruction as the primary cause of extinction.
Total 41 25 66
Human intervention caused instability in sand-based habi-
tats, and these now have lower than average diversities on
and introduced mammals, and substantial agricultural both islands (Cook et ai, 1990; Cameron et ai, 1996). On
exports were being made before the end of the fifteenth Madeira, regions dominated by planted conifers are nearly
century. Extinctions could therefore have occurred on a snail-free (Cook etai, 1972), and areas dominated by other
non-native vegetation are species-poor (Cook etai, 1990).
large scale priorto nineteenth century surveys.
The subfossil record, which spans this period, sug-
gests a higher rate ofextinction ofca. 30% on both islands. DIVERSITY AND DURABILITY IN THE
The evidence from dating in the case of Madeira SURVIVING FAUNA
(Goodfriend et ai, 1994) suggests that two-thirds of this Both islands support numerous sites in which the
occurred afterhuman occupation. fauna is dominated by endemic and native species, at diver-
The record on Porto Santo is remarkably com- sity levels (5-20 species) which are not depauperate by
plete. Most parts of the island are sandy or near sand. world standards (Solem, 1984). On Porto Santo, site diver-
Living species not found in deposits are mostly small rock- sities in rocky habitats are almost identical to those report-
dwellers. Pending detailed analysis and dating, we can esti- ed for similar maquis and phrygana habitats in the Aegean
mate that 20-25% of the fauna was destroyed by human region (Cameron etai, unpub.).
colonization, but that it has since stabilized. Thus while there is evidence of damage, and
The record on Madeira is less complete, and could indeed of extinctions, the present state of the archipelago's
be unrepresentative of the island as a whole. Living faunas fauna appears to be much healthier than that in many other
in the area of the deposits are poorer in endemics than oceanic islands subject to extensive human intervention.
many elsewhere (Cook etai, 1990). On the other hand, the Comparison with accounts of extinctions in these
deposits have yielded nearly half the endemic species
other islands suggests that there could be significance in the
known from the island. An overall extinction rate similar to fact that many Madeiran and Porto Santan species have
thaton Porto Santo must beourbestestimate. evolved to live in rather dry, rocky, and open environments,
Even these levels of post-colonization extinction rather than being arboreal or dependent on damp litter from
are considerably lower than those recorded for the much native trees. Not only did this preadapt them to resist clear-
shorter period of European colonization on many Pacific ance, it is also these habitats which have been subject to the
islands. These islands undoubtedly suffered earlier extinc- greatest fluctuations in size and continuity before human
tions also, as a consequence of disturbance caused by the colonization, building up allopatric diversity, and tolerance
first human settlers. ofchange.
CAUSES OF EXTINCTION It is also the case that substantial areas of native
laurel forests survive on the northern side of Madeira.
There is no direct evidence as to the causes of Where native forests survive on some Pacific islands, high
extinction, of the kind available for Partula, achatinellids, levels of extinction have followed the introduction of mol-
and endodontids on Pacific islands (Hadfield, 1986; Solem, luscan, arthopod, and vertebrate predators (Solem, 1990b;
1990b; Cowie, 1992a). Some introduced Zonitidae and Cowie, 1992b). Introduced predators have not had this
Subulinidae are potential predators, and introduced rodents effect here (see above), nor in the Gulf of Guinea
certainly eat both native and introduced species, but we (Gascoigne, 1994), where Euglandina rosea (Ferussac,
8 AMER. MALAC. BULL. 12(1/2) (1996)
1818), the introduced predatory snail which has devastated SocietyofLondon, B335:167-191.
many Pacific island faunas, has not been introduced. Cowie, R. H., ed. 1992b. The impact of alien species on island ecosys-
In general, the pattern seen on Madeira resembles tems: extended abstracts of a symposium, 30 May 1991,
Honolulu, Hawaii, XVII Pacific Science Congress. Pacific
that found in the Mediterranean region, where despite mas- Science46:383-404.
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This apparent durability does not justify compla-
ization dating using radiocarbon-dated fossil land snail shells.
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would eliminate three endemic species, and the destruction amino acids in land snail shells over the course ofthe Holocene.
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22.Brill,Leiden. Wollaston,T.V. 1878. TestaceaAtlantica. Reeve,London. 588pp.
Solem, A. 1990a. Limitations ofequilibrium theory in relation to land
snails. AttideiCongresiLincei85:97-116. Dateofmanuscriptacceptance: 8February 1996
Solem, A. 1990b. How many Hawaiian land snails are left?and what we
APPENDIX
Three lists are given here: (a) species known only in subfossil condition, (b) endemic species recorded alive at some
time,and(c)non-endemicspeciesrecordedalive.Thereare, inevitably,casesoftaxonomicuncertaintyandofdifficul-
ties in interpreting the status ofrecords. Minordisagreements in categorization do not affect ourgeneral conclusions,
andsowehavenotannotatedthelists,whichshouldnotberegardedasdefinitiveaccountsofthefauna.
(a)Speciesknownonlyassubfossils,presumedextinct(allendemic).
Madeira PortoSanto
Helicidae: Helicidae:
Geomitradelphinula(Lowe, 1831) GeomitragerberiGrohandHemmen, 1986
G. watsoni(Johnson, 1897) G. acarinataHemmenandGroh, 1985
Caseolusbowdichianus(Ferussac, 1832) Caseolusbowdichianus(Ferussac, 1832)
C. sphaerulus(Lowe, 1854) C. baixoensisWalden, 1983
C. abjectus(Lowe, 1831) ActinellamorenensisSeddon, 1990
C. subcalliferus(Lowein Pfeiffer, 1859) A. crassiuscula(Cockerell, 1922)
Actinellaarcinella(Lowe, 1854) A. arcinella(Lowe, 1854)
A.promontoriensisWalden, 1983 Spirorbulalatinea(Paiva, 1866)
Disculaechinoderma(Wollaston, 1878)
Others: D.cockerelli(Noronha, 1923)
Leiostylawollastoni(Paiva, 1866) Leptaxischrysomela(Pfeiffer, 1846)
Amphorellagrabhami(Pilsbry, 1908) L.psammophora(Lowe, 1852)
Cylichnidiacylichna(Lowe, 1852)
BoettgerialorenzianaGrohandHemmen, 1984 Others:
PhenacolimaxcrassusGrohandHemmen, 1986 Craspedopomamucronatum(Lowe, 1830)
LeiostylaespigaoensisSeddon, 1990
L subcorneocostataSeddon, 1990
(continued)
)
AMER. MALAC. BULL. 12(1/2) (1996)
Appendix(continued)
(b)Endemicspeciesfoundalive.(*,alsofoundassubfossils;+, notfoundaliveintwentiethcentury).
Madeira PortoSanto
Helicidae: Helicidae:
*Heterostomapaupercula(Lowe, 1831) *Heterostomapaupercula(Lowe, 1831)
*Geomitratiarella(WebbandBerthelot, 1833) *Geomitracoronata(DeshayesinFerussac, 1819)
G. moniziana(Paiva, 1867) *Spirorbulaobtecta(Lowe, 1831)
+G. delphinuloides(Lowe, 1860) *S. depauperata(Lowe, 1831)
Spirorbulalatens(Lowe, 1852) *Caseoluscompactus(Lowe, 1831)
*S. squalida(Lowe, 1852) *C. consors(Lowe, 1831)
*Caseoluscompactus(Lowe, 1831 *C. commixtus(Lowe, 1854)
C. leptostictus(Lowe, 1831) *C.sphaerulus(Lowe, 1854)
Disculellacompar Lowe, 1831 *C. abjectus(Lowe, 1831)
D. spirulina Cockerell, 1921 *C. subcalliferus(LoweinPfeiffer, 1859)
Actinellalentiginosa(Lowe, 1831) *C. calculus(Lowe, 1854)
*A. actinophora(Lowe, 1831) *C. Iiartungi(Albers, 1852)
A.arcta (Lowe, 1831) *C.punctulatus(Sowerby, 1824)
A.fausta (Lowe, 1831) *C. solidus(Lowe, 1831)
A. carinofausta Walden, 19983 *ActinellaeffugiensWalden, 1983
A. robusta(Wollastonin Pilsbry, 1894) Lemnisciamichaudi(Deshayes, 1831)
A. arridens(Lowe, 1831) *Disculabicarinata(Sowerby, 1824)
*A. obserata(Lowe, 1854) D. echinulata(Lowe, 1831)
A. armitageanaLowe, 1854 *D. leacockiana(Wollaston, 1878)
*A. nitiduscula (Sowerby, 1824) *D. oxytropis(Lowe, 1831)
A. giramica (Lowe, 1852) D. turricula(Lowe, 1831)
A. anaglyptica(Reeve, 1852) *D. cheiranticola(Lowe, 1831)
*Leminisciacalva(Lowe, 1831) *D. calcigena(Lowe, 1831)
+L. galeata(Lowe, 1860) *D. tectiformis(Wood, 1828)
*Disculapolymorpha(Lowe, 1831) D. albersiLowe, 1852
*Leptaxiserubescens(Lowe, 1831) *D. bulverii(Wood, 1828)
*L.furva(Lowe, 1831) *D. rotula(Lowe, 1831)
*L membranacea (Lowe, 1852) *D.pulvinata(Lowe, 1831)
*L. undata(Lowe, 1831) *D. attrita(Lowe, 1852)
*D. testudinalis(Lowe, 1852)
Others: Leptaxiserubescens(Lowe, 1831)
Craspedopomaneritoides(Lowe, 1860) *L. wollastoni(Lowe, 1852)
*C. mucronatum(Lowe, 1830) *L. nivosa(Sowerby, 1824)
C. lyonnetanum(Lowe, 1852) *Pseudocampyleaportosanctana(Sowerby, 1824)
C. monizianum(Lowe, 1860) *+P. lowei(Ferussac, 1835)
*C. truchoideum(Lowe, 1860) *Lampadiawebbiana(Lowe, 1831)
Columellamicrospora(Lowe, 1852) *HelixsubplicataSowerby, 1825
*Truncatellinalinearis(Lowe, 1852)
*Staurodonsaxicola(Lowe, 1852) Others:
Leiostylacheilogona(Lowe, 1831) *Leiostylacorneocostata(Wollaston, 1878)
L, vincta(Lowe, 1852) L. relevata(Wollaston, 1878)
L. irrigua(Lowe, 1852) L.ferraria(Lowe, 1852)
L. loweana(Wollaston, 1878) L. degenerata(Wollaston, 1878)
+L. cassidula(Lowe, 1852) L. monticola(Lowe, 1831)
L. concinna(Lowe, 1852) *L. calathiscus(Lowe, 1831)
*L. laurinea(Lowe, 1852) Eucobresiamedia(Lowe, 1854)
*L. sphinctostorna(Lowe, 1831) *Cecilioideseulima(Lowe, 1854)
L. arborea(Lowe, 1854) *Amphorellamelampoides(Lowe, 1831)
L. simulator(Pilsbry, 1923) *A. triticea(Lowe, 1854)
L.fusca(Lowe, 1852) *A. oryzae(Lowe, 1852)
+L. laevigata(Lowe, 1852) A. tuberculata(Lowe, 1852)
L. recta(Wollaston, 1878) A.cimensisWalden, 1983
*L. millegrana(Lowe, 1852) A.gracilis(Lowe, 1831)
+*L. abbreviata(Lowe, 1852) A. terebella(Lowe, 1852)
*L. cassida(Lowe, 1831) *Cylichnidiaovuliformis(Lowe, 1831)
+*L. lamellosa(Lowe, 1852) Boettgerialowei(Albers, 1852)
+*L.gibba(Lowe, 1852)
(continued)
) ) )
CAMERON AND COOK: MADEIRAN AND PORTO-SANTAN FAUNAS
Appendix(continued)
L.filicumHolyoakandSeddon, 1986
Lauriafanalensis(Lowe, 1852)
Hemilaurialimneana(Lowe, 1852)
+Discusguerinianus(Lowe, 1852)
+D. defloratus(Lowe, 1854)
Phenacolimaxnitidus(Gould, 1848)
*P. marcidus(Gould, 1848)
P. riuvensis(Lowe, 1831)
P. behnii(Lowe, 1851)
P.albopalliatusGrohandHemmen, 1986
*Janulusbifrons(Lowe, 1831
*J. stephanophora(Deshayes, 1835)
+Cecilioideseulima(Lowe, 1854)
Amphorellatornatellina(Lowe, 1831)
*A. cf.minor(Wollaston, 1878)
A. mitriformis(Lowe, 1852)
A.producta(Lowe, 1852)
A. ihdescens(Wollaston, 1878)
Pyrgellaleacockiana(Lowe, 1852)
Boettgeriadeltostoma(Lowe, 1831)
B. depauperala(Lowe, 1854)
B. obesiuscula(Lowe, 1863)
B. exigua(Lowe, 1831)
B. crispa(Lowe, 1831)
(c)Non-endemicspecies(allrecordedalive). (*=veryrestrictedorstrictlyanthropophile).
Madeira PortoSanto
Helicidae: Helicidae:
*Candidulaintersecta(Poiret, 1801) Cochlicellaacuta(Miiller, 1774)
*Cernuellavirgatu(daCosta, 1778) C barbara(Linne, 1758)
C. vestita(Rambur, 1868) Caracollinalenticula(Michaud, 1831)
*Helicellaconspurcata(Draparnaud, 1801 Thebapisana(Miiller, 1774)
Cochlicellaacuta(Miiller, 1774)
C. barbara (Linne, 1758) Others:
Caracollinalenticula(Michaud, 1831) Vitreacontracta(Westerlund, 1871
Thebapisana(Miiller, 1774) Cecilioidesacicula(Miiller, 1774)
*Otalalactea(Miiller, 1774) Ruminadecollata(Linne, 1758)
*Cepaeanemoralis(Linne, 1758) Baleaperversa(Linne, 1758)
HelixaspersaMiiller, 1774 Oxychilusalliarius(J.S.Miller, 1822)
TestacellamaugeiFerussac, 1819
Others: Milaxgagates(Draparnaud, 1801)
Carychiumtridentatum(Risso, 1826) Lehmanniavalentiana(Ferussac, 1823)
C. minimumMiiller, 1774
Cochlicopalubrica(Miiller, 1774)
C. lubricella(Porro, 1838)
ColumellaasperaWalden, 1966
Vertigopygmaea(Draparnaud, 1801
Lauriacylindracea(daCosta, 1778)
Discocharopaaperta(Moellendorff, 188!:
Valloniacostata(Miiller, 1774)
V.pulchella(Miiller, 1774)
V. excentricaSterki, 1893
Acanthinulaaculeata(Miiller, 1774)
Plagyronaplacida(Shuttleworth, 1852)
Punctumpygmaeum(Draparnaud, 1801)
Tolteciapusilla(Lowe, 1831)
Helicodiscussingleyanus(Pilsbry, 1890)
*Discusrotundatus(Miiller, 1776)
*Hawaiiaminuscula(Binney, 1840)
(continued)
)
12 AMER. MALAC. BULL. 12(1/2) (1996)
Appendix(continued)
Vitreacontracta(Westerlund, 1871)
Nesovitreahammonis(Stroem, 1765)
Oxychilusdraparnaudi(Beck, 1837)
O. alliarius(J. S. Miller, 1822)
*0. helveticus(Blum, 1881)
Zonitoidesarboreus(Say, 1816)
*Z nitidus(Muller, 1774)
Euconulusfulvus(Muller, 1774)
Cecilioidesacicula(Muller, 1774)
C. nyctelia(Bourguignat, 1856)
Ferussaciafolliculus(Gronovius, 1781)
Subulinastriatella(Rang, 1831)
Ruminadecollata(Linne, 1758)
TestacellamaugeiFerussac, 1819
*T. haliotideaDraparnaud, 1801
ArionlusitanicusMabille, 1868
A. hortensisFerussac, 1819
A. intermedius(Normand, 1852)
A.pascalinusMabille, 1868
Milaxgagates(Draparnaud, 1801
*M. sowerbyi(Ferussac, 1823)
Deroceraslaeve(Muller, 1774)
D. panormitanum(Lessonaand Pollonera, 1882)
D. lombricoides(Simroth, 1891)
D. reticulatum(Muller, 1774)
Lehmanniavalentiana(Ferussac, 1823)
LimaxflavusLinne, 1758
L. maximus(Linne, 1758)