Notes on the genus Sybota with a description of a new species from Argentina (Araneae, Uloboridae)

5 Pages·2001·0.2 MB·

2001. The Journal of Arachnology 29:11–15
NOTES ON THE GENUS SYBOTA WITH A DESCRIPTION OF A
NEW SPECIES FROM ARGENTINA (ARANEAE, ULOBORIDAE)
Cristian J. Grismado: Museo Argentino de Ciencias Naturales ‘‘Bernardino
Rivadavia,’’ Av. Angel Gallardo 470 (1405) Buenos Aires, Argentina
ABSTRACT. Sybota atlantica new species is described fromthe AtlanticcoastofBuenosAiresProv-
ince, Argentina. The morphology of genitalia and carapace suggests that the new species forms a mono-
phyletic group with S. mendozae Opell 1979 and S. rana (Mello-Leita˜o 1941). The female genitalia of
the genus shows an unusual grade of entelegyny, with copulatory and fertilization ducts leading to a
common tube.
Keywords: Uloboridae,Sybota, taxonomy, Argentina
RESUMEN. Sybotaatlanticanuevaespecieesdescriptaparalacostaatla´nticadelaprovinciadeBuenos
Aires, Argentina. La morfolog´ıa genital y cefa´lica sugiere que la nueva especie forma un grupo monofi-
le´tico con S. mendozae Opell 1979 y S. rana (Mello-Leita˜o 1941). Los o´rganos genitales femeninos
muestran un inusual grado de enteleginia, con los conductos de copulacio´n y fertilizacio´n convergiendo
en un tubo comu´n.
The genera of the family Uloboridae and cluded in the Opell’s revision, and describe
their Neotropical species were revised by detailsofitsgenitalia,anaspectomittedinthe
Opell (1979). In that work, he defined the ge- original description (Fig. 11). Although S.
nus Sybota Simon 1892 and included three rana is known from only a poorly-preserved
species: S. abdominalis (Nicolet 1849) and S. specimen, apparently collected during the
osornis Opell 1979 from Chile, and S. men- molting process, it can be placed close to the
dozaeOpell1979fromwesternArgentina.Fe- other two species.
males of the genus share with those of Pole- Thehomologyofthetegularscleritesofthe
necia Lehtinen 1967 an abdominal projection male palps of the Uloboridae is still unclear.
extending beyond the spinnerets (Figs. 1, 3; Coddington (1990) suggested that the terms
Opell 1979: figs. 51, 102, 110, 116). Never- median apophysis and conductor,asidentified
theless, this feature does not reflect a close by Opell, should be switched. Nevertheless I
relationship between both genera. According maintained Opell’s names only to ease com-
to Coddington (1990), Sybota is the sister parison with previously described species.
group of the clade Orinomana (Hyptiotes (cid:49)
METHODS
Miagrammopes),allunitedbyhavingthepos-
terior lateral eyes on conspicuous tubercles. Specimens are deposited in the following
Sybota males have a well-developed conduc- institutions:MuseoArgentinodeCienciasNa-
tor and a median apophysis with two or three turales ‘‘Bernardino Rivadavia,’’ Buenos Ai-
projections (Figs. 5–7; Opell 1979: figs. 6A, res (MACN, Cristina L. Scioscia), Museo de
B). LaPlata(MLP,LuisPereira),andInstitutoAr-
In the present paper I describe a new spe- gentino de Investigaciones de las Zonas Ari-
cies, Sybota atlantica, from specimens col- das, Mendoza (IADIZA, Sergio Roig Jun˜ent).
lected in the coast of Buenos Aires Province The format of descriptions follows Opell
(courtesy of Mart´ın J. Ram´ırez, MACN), (1979).Theabbreviationsare:C(cid:53)conductor;
whichseemstobecloselyrelatedwithS.men- CD (cid:53) copulatory duct; CO (cid:53) copulatory
dozae because some cephalic and genitalic opening; CY (cid:53) cymbium; E (cid:53) embolus; FD
features (see discussion). Here I also rede- (cid:53)fertilizationduct;MA(cid:53)medianapophysis;
scribe the holotype of S. rana (Mello-Leita˜o PP (cid:53) posterior plate; S (cid:53) spermathecae; ST
1941) from Salta province, a species not in- (cid:53) subtegulum; T (cid:53) tegulum. Abbreviations
11
12 THE JOURNALOF ARACHNOLOGY
Figures 1–4.—Sybota atlantica new species. 1. Female, dorsal view; 2. Male, dorsal view; 3.Female,
lateral view; 4. Male, lateral view (palps omitted). Scale bars (cid:53) 1 mm.
for eyes are standard for the Araneae. Thefe- length 1.08. Leg I: femur length 3.32, tibia
malegenitaliawereclearedwithcloveoiland length 3.04, metatarsus length 3.56, tarsus
observed with compound microscope. Mea- length 0.96. Carapace brown with yellowish
surements are expressed in millimeters. median area between median eyes and fovea,
marginswithdiffusedarkdots,moreapparent
Sybota atlantica new species
on anterior region. Eyes bordered by dark
Figs. 1–10
rings.Sternumdarkbrownwithareddishme-
Types.—Male holotype, and four female
dian stripe. Legs same color as carapace but
paratypesfromArgentina,BuenosAiresProv-
with tenuous, darker, longitudinal dorsal
ince, Mar del Tuyu´, 2 May 1981, M.J. Ra-
bands. Abdomen dorsally whitish with a gray
m´ırez (MACN No. 9639, 9640 and 9641, re-
longitudinal band (Fig. 2). Sides of the ab-
spectively).
domen with diffuse longitudinal bands (Fig.
Etymology.—The specific name refers to
4). Venter pale reddish with a dark central
the type locality, on the Atlantic Coast of Ar-
band between pedicel and spinnerets. Palp:
gentina.
Femur with an excavated area where the bulb
Diagnosis.—Males differ from those of S.
presumablyfits(Fig.5),tibiawithaprolateral
abdominalisandS.osornisbyhavingalonger
translucentprolongation(Fig.7)coveringpar-
embolus and conductor (Figs. 5–7), and by
tiallythebaseofcymbium,whichhasaretro-
having the AMEs on a conspicuous tubercle
(Figs. 2, 4). Females resemble those of S. lateral basal tubercle (Fig. 5, arrow). Copula-
mendozae and S. rana by having an elongate tory bulb: retrolateralsurfaceoftegulumwith
carapace, the AMEs on a tubercle, and the a translucent membrane (Fig. 5); median
convoluted copulatory ducts, but differ by the apophysis with one basal and three distalpro-
shape of the epigynum and spermathecae jections (Figs. 5, 6); conductor long with two
(Figs. 8–10). prongs: the proximal digitiform and the ter-
Description.—Male (holotype): Total minal flattened; embolus long, with tip fitting
length 4.76, carapace length 1.72, sternum into the terminal prong of conductor.
GRISMADO—NEWSYBOTA FROM ARGENTINA 13
Figures5–11.—Genitaliaof Sybota. 5–10. Sybotaatlantica newspecies.5.Leftmalepalp,retrolateral
(arrow:cymbialtubercle;asterisk:tegularmembrane);6.Same,ventral;7.Same,prolateral;8.Epigynum,
ventral view; 9. Same, posterior view; 10. Same, cleared, dorsal view. 11. Sybota rana (Mello-Leita˜o),
cleared epigynum, dorsal view. Scale bars (cid:53) 0.2 mm.
Female (paratype): Total length 7.35, car- tubercle less pronounced; sternum as in male,
apacelength2.00,sternumlength1.32.LegI: but with astriperestrictedtotheanteriorhalf.
femur length 3.20, tibia length 2.60, metatar- Dorsum of abdomen yellowish with a gray
sus length 2.96, tarsus length 0.80. Color: longitudinalband,wideranteriorlyanddiffuse
Carapace, legs and eyes as in male, but AME dark spots, more evident in caudal and lateral
14 THE JOURNALOF ARACHNOLOGY
areas; dorsal and dorsolateral surfaces with are no longer evident, probably faded. Epi-
aligned bundles of long setae (Figs. 1, 3). gynum: The poor condition of the specimen
Venter yellowish with a brown median stripe makes it impossible to distinguish the main
betweenepigastricfurrowandspinnerets.Epi- epigynal structures; internally, only the reni-
gynum: Lateral lobes flattened with a wide form spermathecae and the distal portion of
posterior notch (Fig. 8), copulatory openings copulatory ducts remain; the preserved por-
undertwoelevatedanterolateralmargins(Fig. tionofthemsuggeststhattheywerelong(Fig.
9). Copulatory and fertilization ducts leading 11).
to a common convoluted tube. Material examined.—Only the holotype.
Natural history.—The specimens were
collected in typical uloborid horizontal orb- DISCUSSION
webs on shrubs and other medium-sized
plantsnearthesandygroundinMardelTuyu´. Sybota atlantica, S. mendozae and S. rana
The spiders rested with legs I and IIextended differfromtheChileanspeciesS.abdominalis
anteriorly (Mart´ın J. Ram´ırez pers. comm.). and S. osornis by the longer carapace, with
Materialexamined.—Onlythetypeseries. the anterior median eyes on a prominent tu-
bercle, by the epigynum with a posterior
Sybota mendozae Opell 1979
notch, and by the smaller spermathecae, with
SybotamendozaeOpell1979:496(femaleholotype long and convoluted copulatory ducts (Figs.
andthreefemaleparatypesfrom7kmWofMen- 1, 8–11; Opell 1979: figs. 115–119). Given
doza, Argentina, collected in ‘‘chaparral’’ at an
that these conditions are not present in other
elevation of 1200 m, March-April 1958, B. Pat-
closely related uloborid genera, they seem to
terson col., in MCZ and AMNH, not examined.)
be synapomorphies of the three Argentine
New record.—ARGENTINA: Mendoza, species. If long copulatory ductsarefunction-
Divisadero Largo, 8 March 1993, Debandi ally correlated with long embolus, the males
and S. Roig col., 1 penultimate female (IA- of S. mendozae and S. rana, which are still
DIZA). Note: Although this specimen is sub- unknown, should also have a long embolus.
adult, the internal genitalia are developed and Although Ponella Opell 1979, some Zosis
almost identical to those illustrated by Opell Walckenaer1837andsomePhiloponellaMel-
(1979). lo-Leita˜o 1917 (genera which are not closely
related with Sybota) also have long and con-
Sybota rana (Mello-Leita˜o 1941)
Fig. 11 voluted copulatory ducts (Muma & Gertsch
1964; Opell 1979, 1981), they differ fromSy-
Uloborus rana Mello Leita˜o 1941: 111 (holotype
botabybeingentelegynes(i.e.,thecopulatory
No14635fromCoronelMoldes,Salta,Argentina,
in MLP, examined). Roewer 1954: 1344. ducts and fertilization ducts are separated),
Sybota rana Lehtinen 1967: 266. while Sybota presents an intermediateandpe-
culiar grade of entelegyny: the fertilization
Diagnosis.—The femaleresemblesthoseS.
ducts arise from the proximal part of the cop-
mendozae and S. atlantica by cephalic mor-
ulatory ducts, without a direct conection with
phologyandbythelongcopulatoryducts,but
spermathecae. As noted by Opell (1983), the
are distinguished by the reniform spermathe-
Uloboridae show a great diversity in genital
cae (Fig. 11) and the dorsal design of abdo-
features and comprises members both haplo-
men.
gyne,entelegyneandsomeintermediatetypes.
Description.—Female (holotype, poorly
The observation of the web of S. atlantica
preserved): Carapace length, ca. 1.46; abdo-
in the field, and the photograph of an unde-
men length, 3.96; leg I, femur length 2.34,
tibia length 1.74, metatarsus length 2.00, tar- terminated Chilean specimen showed in Figs.
sus length 0.74. Color: carapace dark brown; 12 and 13 (in American Museum of Natural
legs same color but with light longitudinal ar- History,notexamined),confirmthatthesespi-
eas; chelicerae lighter than carapace. Abdo- dersrestwithlegsIandIIanteriorlyextended,
men (Mello-Leita˜o 1941, fig. 10) light brown and that they construct typical horizontal orb-
with a dorsallongitudinaldarkband(widerin webs, as mentioned by Opell (1984) basedon
front), and two large dorsolateral spots. The ajuvenilespecimenphotographedbyNorman
caudal parallel lines figured by Mello-Leita˜o Platnick.
GRISMADO—NEWSYBOTA FROM ARGENTINA 15
Figures 12–13.—Sybota sp. from Alto de Vilches, Talca, VIII Regio´n, Chile. 12. Web; 13. Living
specimen (photographs by Mart´ın J. Ram´ırez).
ACKNOWLEDGMENTS colectadas por los profesores Birabe´n. Revista
del Museo de la Plata, Seccion Zoologia 2:12,
Iamgreatlyendebtedtotheinstitutionsand
99–198.
curators for loaning the specimens; to Mart´ın
Muma,M.M.&W.Gertsch. 1964. Thespiderfam-
J.Ram´ırez,whocollectedthespecimensstud-
ily Uloboridae in North America north of Mex-
ied here, brought them to my attention, and ico. AmericanMuseum Novitates 2196:1–43.
provided the photographs of a Chilean speci- Nicolet,H. 1849. Ara´cnidos.InHistoriaf´ıs.ypol-
men; and to Jonathan A.Coddington(Nation- ´ıt.deChile.(C.Gay,ed.).Zoolog´ıaIII:319–543.
al Museum of Natural History, Smithsonian Opell,B.D. 1979. Revisionofthegeneraandtrop-
Institution,Washington,D.C.),BrentD.Opell ical American species of the spider family Ulo-
(Virginia Polytechnic Institute and State Uni- boridae.BulletinoftheMuseumofComparative
versity, Blacksburg), Martı´n J. Ramı´rez Zoology 148:443–549.
Opell, B.D. 1981. New Central and South Ameri-
(MACN) and two anonymous reviewers for
canUloboridae(Arachnida,Araneae).Bulletinof
helpful comments on a draft of the manu-
the American Museum of Natural History 170:
script.
219–228.
LITERATURECITED Opell, B.D. 1983. The female genitalia of Hypti-
otescavatus(Araneae:Uloboridae).Transactions
Coddington, J.A. 1990. Ontogeny and homology
of the American Microscopical Society 102:97–
in the male palpus of orb-weaving spiders and
104.
theirrelatives,withcommentsonphylogeny(Ar-
Opell,B.D. 1984. Comparisonofcarapacefeatures
aneoclada:Araneoidea,Deinopoidea).Smithson-
in the family Uloboridae (Araneae). Journal of
ian Contributions to Zoology 496:1–52.
Arachnology 12:105–114.
Lehtinen,P.T. 1967. Classificationofthecribellate
Simon, E. 1892. Histoire NaturelledesAraigne´es,
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I. Paris.
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Annales Zoologica Fennici 4:199–468.
Mello-Leita˜o, C.F. 1941. Las aran˜as de Co´rdoba, Manuscript received 1 February 2000, revised 1
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