Two new species of Curvella Chaper (Gastropoda, Pulmonata, Subulinidae) from the East Usambara Mts., Tanzania

6 Pages·2002·0.59 MB·English

by  Verdcourt, B

BASTERIA, 66:107-112,2002
Twonewspecies ofCurvella Chaper (Gastropoda, Pulmonata,Subulinidae)
fromtheEastUsambaraMts., Tanzania
B.Verdcourt
RoyalBotanicGardens,Kew, Richmond, SurreyTW93AB,U.K.
Curvella myrmecophilaand C. usambarensis are described as new species from Tanzania, East
Africa.AconspectusofEastAfricanCurvella isaddedasaguidetonamingofshellsinthisgenus.
Key words: Gastropoda,Pulmonata,Subulinidae,Curvella, East Usambara Mts.,Tanzania,
EastAfrica.
INTRODUCTION
I havebeen gathering materialsforarevision oftheCurvellaspecies occurringin eastern
Africabutalthough manyspecies are distinctivethemajorityare smalland characterless.As
in manysubulinidsitisoftendifficultto decideifaspecimen isadultornotunlessmanyspe-
cimens areavailable fromonepopulation.AllmajormuseumsholdingAfricanmaterialhave
hundredsofunidentifiedspecimens of thegenus, manybearing manuscriptnames ofH.B.
Preston which cannotbenamedatthepresenttime.The two species describedbeloware,
however, quitelargeand distinctive.ThefirstI collectedwhilstworkingin Tanzaniaaslong
agoas 1950. Thesecondwas collectedby FrontierTanzaniasome45yearslater duringasur-
veyofthecoastalforests.
For collections the following abbreviations are used: BM, British Museum (Natural
History), London;RMNH, NationalMuseumof Natural History (formerly Rijksmuseum
vanNatuurlijke Historie), Leiden.
DESCRIPTIONS
Curvella myrmecophila spec.nov.(fig. 1)
Curvellacaloraphe; Verdcourt,1957:41; [1981]: 67. NotPreston, 1910.
Material examined.- Tanzania,EastUsambaraMts,Amani,Kiumba,5°5.5'S38°38.5'E,900 malt.,inants'
nest,B. Verdcourtleg.,1950(RMNH 93498/holotype,93499/8juvenileparatypes[allexVenmansColinno.
6400]);Amani, Mavumbi track, B. Verdcourt leg., 1950 (RMNH 93500/1juvenileparatype [exVenmans
Colin no.6399]);Amani,inants'nest,900 m alt.,B.Verdcourtleg.,1950(RMNH 93501/2juvenileparatypes
[exVenmansColinno.6401]).
Diagnosis. -A typicalovoid-conicCurvellaoffairlylarge size,strongly ribbedandwiththe
aperture distinctly produced toleft.
108 Basteria, Vol. 66,No. 1-3, 2002
Description. - Shellwhitebutoftenwith reddishstaining dueto lateritesoil, ovoid-conic,
narrowly but distinctly umbilicate, not very thin; spire produced, obtuse, the apical angle
about60°.Whorls6, convex, quiterapidly increasing, theapical 1V2smooth,therest with
ratherirregular strongly curved(particularlywheremeetingthesuture) ribs atabout8per
mm; sutureimpressed. Aperture narrowly obovate, distinctly produced toleft below the
columella;peristomesharp, strongly curved,excised attheapex; columellaslightly curved,
strongly reflectedovertheumbilicus.Animalyellow.
Measurements:12 x 6 mm, length oflastwhorl9 mm,aperture6.5 x 3.5mm
Distribution.- Tanzania, Tanga Province,East UsambaraMts.
Discussion. - During my earlycollecting atAmaniI designated species by aletterorlet-
ters.This CurvellawasAWandIhavearecord thatmaterialwasalso sent to H.Watsonin
spiritandDr. K.L.Pfeiffer.Watsondid nothavetime toinvestigate itbeforehis death.His
collectionis now in the Zoology Museumat Cambridge but this specimen has not been
traced.Dr.Pfeiffer'scollectionis atFrankfurtandaspecimen shouldbethere.Dr.Venmans
identifiedthe species as Curvella conoidea (Von Martens, 1892)butthat has a muchmore
obvious umbilicus and compared with juveniles of C. myrmecophila of the same size is
distinctlybroaderbelowthemiddlewhich IconfirmedwhenI examinedthetypein 1959.
Later I identifiedAW as Curvella caloraphe Preston, 1910,a species described from the
ShimbaHillsin Kenya anditis to thisspecies thatCurvellamyrmecophila bears mostresem-
blance.
I foundthespecies in loosesoil around theants' nest and in it;ajuvenile was also seen
beingcarriedby anant.Atthe time using Stadelmann(1898) Ithought itvery likely thatthe
black ant concernedwasMyrmicariaeumenoides(Gerstacker, 1859) knownin Kishambaa as
'Korokoro'.I sent someoftheants toHoraceDonisthorpe whomislaidthem.He diedshort-
lyafterreceiving the secondbatch butdeterminedthemasanewspecies ofMyrmicaria. This
maybe correct since Gerstacker (1859) describeshis antas 'obscurerufus'.
Itis undoubtedly closesttoC.caloraphe butthatdiffersin having aconcavedepressed area
belowthesuturewherethetransverse ribs arestrongly bent. C.nyasana E.A.Smith, 1899,is
similarin size andshapetoC. myrmecophilabuttheapertureis muchless spout-like attheleft,
ribbing stronger, columellastraighter, shell thickerandumbilicuslarger; otherspecies with
spout-like apertureseg. C.campyla Connolly, 1923,and C. blacklockiConnolly,1928, aresmal-
lerandnarrow. C. disparilis (E.A.Smith, 1890)is largerwithstrongerstriae butclearly related
andalsofromtheEasternArcforests; C.subvirescens(E.A.Smith, 1890)also fromthe Eastern
Arc forests is muchnarrowerwithastraighter columella.
Curvellausambaricaspec. nov. (fig.2)
Material examined.- Tanzania,TangaProvince,East Usambara Mts.,Kwamgumi Forest Reserve, Plot
39/111,4°57'S38°44'E,FrontierTanzania leg., 1996(RMNH 93502/ holotype,93503/twojuvenileparatypes;
BM/paratype).
Verdcourt: Twonewspecies ofCurvella 109
Figs 1,2.Curvella spec.1,C.myrmecophilaspec.nov.,holotype(RMNH93498);Tanzania,EastUsambaraMts,
Amani,Kiumba,5°5.5’S38°38.5’E,900m alt.,in ants’ nest, B.Verdcourt leg., 1950 (actual shell height 12
mm);2,C. usambarica spec.nov., holotype(RMNH93502);Tanzania,TangaProvince,EastUsambaraMts.,
Kwamgumi Forest Reserve, Plot 39/111,4°57’S 38°44’E,Frontier Tanzanialeg., 1996 (actualshell height
14.5 mm).I.vanNoortwijkdel.
Diagnosis. - Atypical, ratherbroadly ovoid-conic Curvellaoffairlylarge size, ribbed,
the peristome deeplyexcised nearjunction withbodywhorl andaperturenot produced
toleft.
Description. - Shell white, glossy, rather broadly ovoid-conic, distinctly rather nar-
rowly umbilicate,thefissureoblonginsection, not very thin;spire produced, obtuse,the
apical angle about 53°. Whorls 6, convex, rapidly increasing, the first 2 practically
smooth,the restwith close curvedribs 7-8permm,strongly benttorightjustbelowthe
suture andentering the umbilicus; undervery high powers there are very close wavy-
lines; suture moderately impressed. Aperture oblong-pyriform, not produced to left
below the columella; peristome sharp, with outer margin not strongly projecting at
middlebut deeply excised at junction with body whorlto forma well marked sinuous
slit; columellastraight, very strongly reflectedoverthe umbilicus whichis notvisiblein
frontalview.Animalnotknown.
Measurements:holotype - 14.5x8.5mm,length oflastwhorl 11.5mm,aperture8.5x
5.3 mm;paratype - 14x7.5mm,aperture 8x5.2;juvenile paratypeof4whorlsmeasu-
res 5.3x3.3mm and of5 whorls9x5 mm.
110 Basteria, Vol. 66, No. 1-3,2002
Distribution.- Knownfromthe typelocality only.
Discussion. - This species is distinctive by itsroundedcontour and ratherlarge size,
andvery deepexcisionatjunction ofperistome andbody whorl.ItdiffersfromC. myrm-
ecophila in the aperturelacking theprojection totheleft andwidercontour. Theforest
has some otherendemics, notably theAnnonaceous genusSanrafaeliaVerdcourt,1996,
only recently discovered.
CONSPECTUS OF EASTAFRICANCURVELLA
Although it is notpossible togive a key tothespecies ofCurvellaocurring in EastAfrica
thefollowingconspectus may help to limitthenumberoftypeswhichneed tobelookedat.
1. Body whorl/spireratio over4 2
Body whorl/spireratio under4 3
2. Shellbroadly ovate-conic, 7.6x5.5 mm with deep suture andopen umbilicus; body
whorl/spireratio4.1 (Zaire, nearMasisi) CI . bathytoma Pilsbry, 1919
Shellbroadly ellipsoid (ie widestnearmiddle), 8.5-9.2x5.2-5.5mm; body whorl/
spire ratio5.6(E. Zaire/W. Uganda) C. dautzenbergi Pilsbry, 1919
3. Shelllarge, 31x 13mm withspire 1/3the lengthofthebody whorl (Ethiopia) . .
C. aethiopica Thiele, 1933
Shellmuchsmaller 4
4. Shell small, 3.1 x 1.7 mmwith very deep suture and wideumbilicus; body whorl/
spire ratio2.07 (Zaire, Tschibinda) C. bathyraphe Pilsbry &Cockerell, 1933
Shellnot as above,usually larger withshallower suture 5
5. Body whorl/spireratio over 2 6
Body whorl/spireratio under2 11
6. Shell ovoid with ratio 3.3, 8.5 x 3.5 mm; montane species at 2700-3000 m
(Mt.Kenya) (C. deliciosaPreston, 1911
Not amontane species or ifso thenratiounder2.5 7
7. Shellimperforate whenadult;Uganda or E. Congo 8
Shellperforate or distinctlyumbilicate 10
8. Body whorl/spire ratio 2.79-2.48; 9.1 x 4.3 mm, incised sculpture (W. Uganda)
C. campyla Connolly, 1923
Body whorl/spireratio 2.2-2.23; sculpture ofratherfinearcuate costulae 9
9. Shellovoid,7.75 x 4mm (Uganda) C. entebbensisPreston, 1912
Shellovoid-conic, 10-11x4.7-4.8mm (E. Zaire) <C. langiPilsbry, 1919
10. Multipleentry in orderof size:
a. Shell ovoid-conic, 6.1 x 3.2 mm; ratio 3.14 (Tanzania, KilwaDistrict, Matumbi
Hills) C. sp.
b. Shellelongate-conic, 7.75x 4mm; ratio2.2 (Uganda) C. entebbensisPreston,1912
c. Shellovoid-conic, 9.2-10 x 5.5 mm; ratio 2.3, openly umbilicate; submontane
species at2000m(W. Uganda, Ruwenzori) Ci . conoidea(Von Martens, 1892)
d. Shellovoid-conic, 9.5 x 4.5 mm; ratio 2.17 (Tanzania, Kilwa District, Matumbi
Hills) C. sp.
e.Shellovoid, 11.5x6.5mm; ratio 3.09 (Kenya, coastal) (A specimen fromKenya,
KilifiDistrict, Vipingo collectedandidentifiedbymeas thisis probably yetanother
newspecies) C. calorhaphe Preston, 1910
Verdcourt: Twonewspecies ofCurvella 111
f. Shellovoid-conic, 12x 5.5 mm; ratio 2.04 (Tanzania, Ulanga District, Mahenge,
Kwiro) iC. afra C.R. Boettger, 1917
g.Shellovoid-conic, 12x6 mm;ratio2.96 (Tanzania, East Usambaras) (seeabove)
C. myrmecophila spec. nov.
h. Shellovoid-conic, 11-12.2x 6.2-6.5mm;ratio 1.86-2.13(W. Uganda)
(C. masakanaConnolly, 1923
i. Shell narrowly bulimoid, 13 x 6.5 mm; ratio 2.5 (Tanzania, Morogoro District,
Nguru Mts., Mamboia;alsorecordedfromW. Uganda/Zaire; someso-namedfrom
Tanzania,Usagara areimperforate) Ci . disparilis(E.A. Smith, 1890)
j. Shell broadly ovoid-conic, 14-14.5 x 7.5-8.5 mm; ratio 3.83 (Tanzania, East
Usambaras) (see above) C. usambaricaspec. nov.
11. Shellimperforate 12
Shellperforate,rimateordistinctlyumbilicate 13
12. Multiple entryin orderofsize:
a. Shellnarrowly bulimoid, 7.5x3.3 mm; ratio 1.72 (Tanzania, Morogoro District,
Nguru Mts.) C.associata(E.A. Smith, 1890)
b. Shell narrowly ovoid-conic, 11.4-14 (-16?) x 5-5.3 mm; ratio 1.5 (Tanzania,
Morogoro District, Nguru Mts.) C.subvirescens(E.A. Smith, 1890)
c. Shellvery narrowly bulimoid, 12.5 x3mm; ratio 1.25 (Malawi, Mt. Chiradzulu
andZomba;materialfrom Tanzania,UluguruMtsis probably correctly namedbut
thatfromKenya, Naivashais probably Opeas lamoense)C. whytei E.A. Smith, 1899
d.Shellturrited, 13.2x 5mm; ratio 1.23; 71/3whorls (E. Zaire)
C. chapini Pilsbry, 1919
13. Multiple entryinorderofsize:
a. Shell narrowly bulimoid, 4 x 1.6 mm; ratio 1.86; narrowly umbilicate(Kenya,
Kakamega) (? adult) C. babaultiGermain, 1923
b. Shell'elongate-ovate', 8 x 3.2 mm; ratio notknown but body whorl said tobe
underhalfthelength ofshell(Tanzania, ArushaDistrict, base ofMt. Meru)
C. subgradata D'Ailly, 1910
c. Shellnarrowly bulimoid,9.4x4.1 mm;ratio 1.43-1.76(Uganda, . .. .Elgon and
Entebbe) iC. elgonensis woodhouseiConnolly, 1923
d. Shellbulimoid,10.2x 4.9mm; ratio 1.83-1.87;minutely rimate(Uganda, Elgon)
CC.. eellggoonneennssiiss Connolly,1923
e. Shellovoid-conic, 10.25x6 mm; ratio 1.46; shell solid, very coarsely sculptured
(Uganda, Entebbeto Mbarara) C. solidulaPreston,1912
f. Shell narrowly bulimoid, 11 x 4.25 mm; ratio 1.55(Kenya, widespread buttype
locality ShimbaHills- somematerialis 8-9x4 mm)
Ci .pertranslucenspertranslucens Preston, 1910
g. Shellelongate-conic, 12x 5mm;ratio 1.36;striaeweak,slightly curved, columella
thick, reflected into a tube (Kenya/Tanzania border, Kilimanjaro, Lake Chala)
(perhaps anOpeas) CC. kretschmeri(Von Martens, 1897)
h. Shellovoid-conic, 11-12.2x6.2-6.5mm; ratio 1.86-2.13(W. Uganda)
iC. masakanaConnolly, 1923
i.Shellconic, 12.5x6.5mm; ratio 1.86(Malawi; aTanzania,Tukuyu specimen leg.
Fiilleborncompareswiththis) (note avariety from ZombaMt. is 18.5x 11mm) . .
C. nyasanaE.A. Smith, 1899
j. Shellnarrowly bulimoid, 13x 4.5mm; ratio1.25-1.4(Central Kenya, Nairobietc)
C.pertranslucensfallooniConnolly, 1923
112 Basteria, Vol. 66,No. 1-3, 2002
k. Shellnarrowly conical, 13.2-13.5x5.8-6.1 mm;ratio 1.4 (W. Zaire)
C< . thysvillensis Pilsbry, 1919
1.Shellnarrowly bulimoid14x5.5-6mm;ratio 1.64;suturebordered;very strongly
curved columella(Tanzania,LindiDistrict, Rondo Plateau)
iC.suturalis(Von Martens, 1897)
m. Shell narrowly bulimoid-conic, 18-18.5 x 6 mm; ratio 1.16(Kenya, Machakos
District, 'Ukamba') C. sinulabris(Von Martens, 1878)
There are many specimens at Berlin, Brussels and The Natural History Museum
(London) bearing manuscript names ofPreston. Someofthese are Opeas, Pseudopeas or
Euonyma (sensu Connolly) but others have beenidentifiedby Connolly with described
species of Curvellaand thematerialannotated.These Prestonmanuscript species are in
a separatedrawer atthe NaturalHistory Museumwitha card index.Connolly did not
see materialfrom Berlin or Brussels some ofwhich is not duplicated in Londonand
there appear to be several undescribed species of Curvella there. Curvella shimbiense
Preston and Curvella alabastrinaPreston, nonDaCosta, are both Opeaslamoense(Melvill
&Ponsonby, 1892).
REFERENCES
GERSTACKER, C.E.A., 1859. [Report on Peters' Formicariae].— Monatsberichte der Koeniglichen
Preussischen Akademie der WissenschaftenzuBerlin 1858:261-264.
STADELMANN, H., 1898. Die Hymenopteren Ost-Afrikas.In: K. MOBIUS, ed., Deutsch-Ost-Afrika 4.
Wirbellose Thiere 3: 1-74.Berlin.
VERDCOURT, B., 1957. Snailsin ants'nests.—Entomologists'MonthlyMagazine93:41
VERDCOURT, B.,[1981],Photographs& drawingsofEastAfrican snails. Unpublished,but copiesinseve-
ral places.