Contributions to Zoology, 68 (2) 83-93 (1999)
SPB Academic Publishing bv, The Hague
1919 Phylogenetic analysis of the Antarctic genus Oswaldella Stechow,
(Hydrozoa, Leptomedusae, Kirchenpaueriidae)
Alvaro+L. Peña+Cantero¹ & Antonio+C. Marques²
1 Departamento de Biologia Animal, Facultad de Ciencias Biologicas, Universidad de Valencia, Dr.
2 Moliner 50, 46100 Burjassot, Valencia, Spain. E-mail: [email protected]; Departamento de Biologia,
Sdo Av. Bandeirantes Faculdade de Filosofia, Ciencias e Letras de Ribeirao Preto, Universidade de Paulo.
3900, 14040-901, Ribeirao Preto, SP, Brazil. E-mail: [email protected]
Keywords: Hydrozoa, Kirchenpaueriidae, Oswaldella, Antarctica, systematics, cladistics
are Cairns on Abstract hydrozoans publications by (1984) Stylasteridae, Marinopoulos (1992) using muddled
methods on Eudendriidae (see Marques, 1996, for A carried out known of the cladistic study was on species a and further comments), and (1993, Antarctic reply Marques characteristically genus Oswaldella, adopting as out- Eudendriidae. other included in the Kirchen- 1996), on Other stud- groups some genera family phylogenetic ies include those of Boero & Gravier- paueriidae. The analysis resulted in a cladogram with low CI Bouillon, in between be which no relationship genera can depicted. Bonnet (1986), Petersen (1990), and Cunningham
However, the of ofthe hypothesis monophyly genus Oswaldella & Buss (1993). is corroborated, being supported in our cladogram by five The family Kirchenpaueriidae and more broadly synapomorphies (although all are homoplastic with other taxa the taxaPlumulariida and Leptomedusae havebeen or reversed within the species of the genus). The basal the of one (Boero, ofthe but three subject only phylogenetic study relationships genus are uncertain, species groups & This is remarkable are within the O. Bouillon Piraino, 1996). distinguishable Oswaldella: 1) incognita group,
the O. antarctica and clade formed because these when with antho- 2) group, 3) a by (O. groups, compared
O. blanconae O. number garciacarrascosai, O. elongata ( (O. gracilis medusans, have a larger of potential char- herwigi, Oswaldella two)))). sp. acters available for phylogenetic analyses. This
paucity of phylogenetic studies may be due to a
lack of general typological revisions of leptome-
Contents dusan groups, the traditionalism of systematists of
this group (cf. Marques, 1996), misconceptions
Abstract 83 concerning polymorphisms, and incomplete knowl-
Introduction 83 edge about life cycles in the group (cf. Migotto, Cladistic methods 84 1998). Choice of out-groups 84 The genus Oswaldella Stechow, 1919a is one Results and discussion 85
of the most diversified genera ofAntarctic Characters adopted 85 hydroids. Of 21 known 20 endemic to the Phylogenetic hypothesis and discussion 87 some species, are
Acknowledgements 91 Antarctic Region (the only exception, Oswaldella
References 92 herwigi El Beshbeeshy, 1991, is Patagonian). This
suggests an Antarctic origin of the genus (cf. Pena Cantero & Vervoort, 1998), and its striking distri-
Introduction bution suggests a possible monophyletic origin.
The has been in several genus investigated recent
Phylogenetic studies on hydrozoan taxa have been works (Stepan’yants, 1979; El Beshbeeshy, 1991;
few in number. In general, the systematics of the Pena Cantero & Vervoort, 1995, 1996, 1997, 1998;
is still Pena Garcia Carrascosa & group based mainly on essentialistic prin- Cantero, Vervoort, 1995;
ciples. & Examples of parsimony studies applied to Pena Cantero, Svoboda Vervoort, 1997), and a
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solid morphological knowledge of the taxon is bers 19, 20, 22). The systematics of the family
available. Other genera of Kirchenpaueriidae, a Kirchenpaueriidae is confusing, and we consid-
less well family of worldwide distribution, are ered that any informationabout the monophyly of
the here. and would be known, complicating analyses genera species groups important to
The goals of this study were to synthesize the guide future studies.
characters of previous revisions of the genus
in the Oswaldella phylogenetic hypotheses, to test Choice of out-groups
validity of some species (such as those presented
as Oswaldella sp. one and Oswaldella sp. two by The major question whether to choose one or sev-
Pena Cantero & Vervoort, 1995), and to discuss eral taxa that could be used as out-groups for this
the of characters and further was related to the applicability some analysis polymorphisms among
implications of the phylogenetic hypothesis in the species included in the family Kirchenpaueriidae,
evolution of the genus. and to the lack of a general recent revision for
this family. Bouillon’s (1985) synopsis, which
five in the constitutes recognized genera family, a
Cladistic methods unique compendium for classification ofthe group.
The genus Halicornopsis Bale, 1882, includes
both in The phylogenetic analysis was performed follow- two known species, distributed Australian
ing the major principles proposed by Hennig (1966), waters. Halicornopsis elegans Lamarck, 1816 and
and general methods described by Forey et al. H. avicularis Bale, 1882 are poorly known spe-
(1992), Marques (1996), Ferrarezzi & Marques cies that have been recorded only a few times.
(1997) and Simoes, Marques, Mello & Anelli Halicornopsis is characterized by the denticulated
(1997). rim of the hydrothecal aperture (Bouillon, 1985),
The characters were ordered whenever infor- a feature also shared with some genera ofthe family
mation about ontogeny was present, or when the Aglaopheniidae. Because of this we decided not
existence of of the consider this within the contiguity similarity among states to genus potential out-
of the character clear. The for Oswaldella due to its uncertain was parsimony analy- groups posi-
sis 2.2 was performed using TreeGardener v. tion.
The (Ramos, 1997) emulating Hennig86 (Farris, 1988), genus Ophinella Stechow, 1919b, is mo-
employing the heuristic algorithms “mh*;bb*”. The notypic. The only known species, O. parasitica
strict (Sokal & Rohlf, 1981) and semi-strict G.O. Sars, 1874, is distinguishable by its long
for bear (Bremer, 1990) consensus trees were derived urticating organs that nematocysts on their
built the most parsimonious trees. The matrix was capitate tips. The position of the genus is uncer-
the using as many “out-groups” as possible (see tain; Stechow (1919b) and Bedot (1923) placed
about the in whereas exposition taxa adopted as out-groups below), genus Kirchenpaueriidae, Sars (1874,
the Allman to assure a more efficient optimization of char- original description as Ophiodes parasitica),
acters (Nixon & Carpenter, 1993). Firstly, an (1883), Bonnevie (1899), and Jaderholm (1909)
unrooted network was considered, and this was a placed the species in Haleciidae, drawing simi-
rooted larities the 1874. posteriori using ontogenetic or «out-group» to genus Hydrodendron Hincks,
& De useless principles (Nixon Carpenter, 1993; Pinna, These facts led us to consider Ophinella a
1994). Whenever necessary in the discussion, we out-group for the analysis.
adopted the group+ artifact, i.e., the whole clade The genus Pycnotheca Stechow, 1919b, is char-
is indicated of mark to its acterized the of abcauline intra- by the addition a “+” by presence an
most basal thecal The includes group (Amorim, 1982). septum (Bouillon, 1985). genus
Although autapomorphic characters of the out- two species: P. mirabilis (Allman, 1883), which
rela- is herein of group taxa are not informative for sorting adopted as an out-group Oswaldella,
the of the not included tionships among species in-group, we and P. producta (Bale, 1882; as out-
The choice decided to include these characters as well (num- group). of only one of the species of
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the related the total available infor- Results and discussion genus was to mation about them.
Bouillon Characters The last genus recognized as valid by adopted
with (1985) was Kirchenpaueria Jickeli, 1883, some
20 nominal species. According to Bouillon (1985: The characters used in this study are presented otherwise noted, information the 169; herein translated to English), it is character- below. Unless on ized as follows “Branched or unbranched, monosi- following taxa was obtained as follows: Oswaldella
& phonic or polysiphonic colonies. Hydrothecal spp. (Pena Cantero Vervoort, 1995, 1996, 1997, marginal rim non-denticulated. Hydrotheca with- 1998; Pena Cantero et al., 1995, 1997); Pycnotheca 1975); out intrathecal septum. Unforked hydrocladia. mirabilis (Millard, Kirchenpaueria spp. & 1995 Mesial nematotheca present or not, when present (Medel Vervoort, and personal observa-
inferior in Ventromma & either superior or or both positions”. tions); spp. (Ramil Vervoort, 1992;
& Hence, it is clear that, at least in an essentialistic Medel Vervoort, 1995, and personal observa-
view of and Naumovia et ah, 1997, (by now independent a phylogenetic ap- tions); (Stepan’yants proach), Kirchenpaueria is mainly characterized and personal observations). All data concerning summarized in the matrix of Table by the lack of the diagnostic features of the other the characters are characters in 1. genera of the family. 1; some are represented Fig,
Bouillon considered Ventromma Stechow, 1923 a of Neverthe- Table I. Matrix used for the cladistic analysis of Oswaldella junior synonym Kirchenpaueria.
the remarks stated in the of the in authors have spp. following exposition less, several recent papers other characters. Polymorphic characters and non-comparable Manuel & treated it as a valid genus (Cornelius, coded and data characters are as hyphens missing are Ryland, 1990; Boero & Bouillon, 1993; Vervoort, coded as question marks (“?”). 1993; Medel & Vervoort, 1995; Migotto, 1996;
We the Taxon 00000 00001 mu11111 111122211112 22 Calder, 1997). concur based on a study of 12345 67890 12345 67890 12 is type species of both genera. It possible to note
distinct differences between them: in Ventromma, Kirchenpaueria 00000 00005 02000 -000 01 the mesial superior nematophore in the hydrothecate Ventromma -000 0-00- 0-00-0-00- -100-100 00
hydrocladial internodes is provided with a nema- Pycnotheca 00000 01015 01000 -0001 00
Naumovia 0000- 00001 010-1010-1 -0110 1- totheca, whereas in Kirchenpaueria that neinato- O.0. bifurca 00011 00203 10011 00000 1- phore is naked. Moreover, the cauline nematophores O.0. antarctica 00000 11210 01000 00000 1-1- are also provided with a nematotheca in Ventromma, O.0. erratum 10210 10211 11000 00000 1- whereas naked in they are Kirchenpaueria. O. shetlandica 11001 12211 1111011110 00000 1-
In conclusion, the genus Kirchenpaueria is con- O. herwigi 01001 01104 02001 11000 1-
0. 11000 1-210 01000 00000 1- sidered a useful out-group of Oswaldella, and O. stepanjantsae O.0. blanconae 00001 01100 00010 0000000000 1- constitutes a unique operational taxonomic unit O.0. elongata 000010000! 12110 01010 0000000000 1- clearly separated from Ventromma, another use- O.0. terranovae 01000 12210 01000 00000 1-
ful The need for a full revision of the out-group. O.0. tottoni 00100 10100 0700107001 00000 1- of Kirchen- species Kirchenpaueria, indeed all O. delicatadelicala 00000 00110 01000 00000 1-
paueriidae, is clear. O.0. encarnae 0000000000 10000 01000 -0000-0000 1-
has been O.0. garciacarrascosai 00001 11110 0100001000 00000 1- Recently, a new genus, Naumovia, es- garciacarrascosai O.0. gracilis 00001 00702 0100001000 -0000 1- tablished by Stepan’yants, Pena Cantero, Sheiko O.0. grandis 10100 12200 07001 00000 1- & Svoboda (1997). Its only known species, N. O. incognita 00000 10110 11000 00000 1- microtheca (Naumov, 1960), is distinctively char- O.0. obscura inoo11100 lino11110 01000oiooo 00000ooooo i-1-
acterized the absence of a mesial inferior by O. rigida 01110OHIO 10212 11000 00000 1-
in- one 01000 00710 01000 00000 nematophore in the hydrothecate hydrocladial O. sp. one 1-
ternodes. O.0. two 00000 01702 02000 00000 1- As an additional taxon for the family sp.
O.0. crassa 00201 11210 non 00000ooooo i-1- Kirchenpaueriidae, in which relationships among 0.O. curiosa 00001 00214 11100 10000 1- the this is here taxa are unknown, genus adopted O. billardi 00000 1011110111 02000 OOOOO00000 1- as an out-group of Oswaldella.
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= Character 1: Stem conformation (0 monosi- acter state 1 is usually related to the presence of
phonic, 1 = polysiphonic). Contrary to the infor- two nematophores. Nevertheless, Oswaldella
mationof Bouillon(1985: 169) thatKirchenpaueria stepanjantsae El Beshbeeshy, 1991 seems to have
but is also can assume both monosiphonic and polysiphonic two or four of these structures, it coded
conformations, we herein assume the monosiphonic as state 1. This assumption has no further impli-
habit characteristic for of this cation for the cladistic since this as species genus, analysis, possible
since with if it we are considering Ventromma, spe- polymorphism, actually exists, would lead one
cies and consider the character as an additive and showing polysiphonic monosiphonic stems, to one,
as a valid genus. therefore the presumptive state 2 (meaning the
Character 2: of the = un- eventual of 4 would be Branching stem (0 presence nematophores)
branched, 1 = branched). The same aspects noted not informative and autapomorphic for O.
for character 1 are also valid for this character, stepanjantsae.
since Bouillon (1985) also considered Kirchen- Character 7: ‘Mamelons’ (0 = absent, 1 = one
both unbranched branched = paueria as having and ‘mamelon’, 2 two ‘mamelons’). A clear poly-
stem. We recognized only unbranched species of morphic condition for this character is presented
Ventromma Oswaldella This has Kirchenpaueria', spp. possibly repre- by stepanjantsae. species
of sent the branched hydroids «Kirchenpaueria» colonies without ‘mamelons’ (state 0) as well as considered by Bouillon (1985). colonies with two ‘mamelons’ (state 2). In the
Character 3: = condition is Cauline internodes (0 internodes matrix, this polymorphic coded as
= always present, 1 with occasional internodes, 2 «-». Oswaldella grandis Pena Cantero et al., 1997
= without internodes). This character is consid- usually has two ‘mamelons’, but the last cauline ered non-additive in the analysis, since there is no apophyses lack them. This fact could be due to
indication of an eventual ontogenetic or contigu- ontogenetic development, since the apical parts are
ity order. The state with occasional internodes is younger. According to De Pinna (1994), this as-
in considered different from the state which the pect could determine a polarity in an unrooted tree,
the in- internodes are always present because the former also used in this analysis to test out-group
is probably due to interruption in the development formation about the root point.
the Character 8: of colony whereas the latter is considered a Maximal order of hydrocladia constant feature. (0 = first, 1 = second, 2 = third or fourth). Oswal-
Character 4: Angle between cauline apophysis della gracilis Pena Cantero et al., 1997 has only and stem (0 = 45°, I = > 70°). This character is a first-order hydrocladia, but as was already pointed continuous but it is because those the described could one, even so adopted out by authors, specimen there is a clear gap between the two groups. Char- be a young colony. The available material of
is around but Oswaldella had four which acter state 0 always constant 45°, sp. one only hydrocladia state I may vary between 70° and 90°. Neverthe- did not allow a reliable character state designa- less, the variation observed in state 1 is consid- tion for the species. Both of these aspects prevented ered be a De us from the information for these to primary homology (sensu Pinna, considering spe-
1991). cies (represented in the matrix by a question mark).
Character Mesial inferior nematotheca = Oswaldella also described from 5: (0 sp. two was scarce
= present, 1 absent). When a nematothecais present material. However, it has at least second order
1 (state 0), it has either a conspicuous scale-shaped hydrocladia, corresponding to states or 2. Though form (e.g., Oswaldella incognita Pena Cantero et this information was considered in the cladistic al., 1997), or is inconspicuous [e.g., Oswaldella analysis when interpreting the resulting cladograms, antarctica (Jaderholm, 1904)]. Nevertheless, the it was also coded with a question mark in the data
nematotheca considered matrix. In of inconspicuous was not a species Kirchenpaueria, the gono- subdivision of the state due to the difficulty in the thecae are placed on the stem or on the cauline definition and delimitation of these putative states. apophyses. Oswaldella encarnae Pena Cantero et
Character 6: Number of axillary nematophores al., 1997, which has unforked hydrocladia, differs
= 1 = than (0 one nematophore, more one). Char- in having gonothecae on the hydrocladia. The
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change from possession ofunbranchedhydrocladia 1 = pointed end). The only species having hydro- to second-order hydrocladia (state 1) is interpreted cladia terminated in an internode with pointed end by us as an important step in the evolution of are Oswaldella shetlandica Stepan’yants, 1979, and
Oswaldella. A further step would be the increase O. curiosa. This internode is the terminal addition in number of the which could of the therefore it is hydrocladia (state 2), ontogenetic sequence; justifi- play an important role in the defense of the able to consider the pointed end as the apomorphic gonothecae. Hydrocladia tend to be arranged state of the truncated end, restricting the places
MPT. hemispherically, forming a protected zone between for possible root of the unrooted stem and hydrocladia in which the gonothecae are Character 14: Angle formed by the longitudi- situated. This, and the existence of contiguous nal axis of the hydrocladial internode and the side successive branching, induced us to treat the char- of the infrathecal elevation from where the mesial acter as additive. inferior nematophore emerges (0 = < 90°; 1 = 90°).
Character 9: Height of hydrotheca (0 = low, 1 = Character 15: Conspicuous free portion of the
= high). We have considered as low hydrothecae those adcauline hydrothecal wall (0 present, 1 = ab-
in which height is equivalent to the diameter of sent). the hydrothecal aperture; in those considered high, Character 16: Hydrocladial arrangement (0 = the hydrotheca is deeper than wide. symmetric, 1 = asymmetric). All the species with
Character = 10: Hydrothecal aperture (0 even; forked hydrocladia, with the exception of Os-
1 = = 3 and adcaudally directed, 2 laterally depressed, waldella kerwigi O. curiosa, have a symmetrical
= frontally depressed, 4 = abcaudally directed with disposition of the higher-order hydrocladia.
5 = asymmetrical hydrotheca, abcaudally directed Oswaldella encarnae and O. gracilis have un-
with symmetrical hydrotheca). This character is branched hydrocladia and so this character is not
composed of several states without relation of order. comparable for them.
Hence, it is considered nonadditive in the analy- Character 17: Hydrocladial internodes (0 =
sis. in the 1 = We changed some aspects interpreta- homomerous; heteromerous). Though the ho- tion of this character from the Appendix presented momerous hydrocladial division into internodes
the by Pena Cantero et al. (1997). First, laterally de- (i.e., only thecate internodes) is common con-
defined for Oswaldella also dition in Oswaldella O. has alter- pressed, as gracilis, spp., herwigi
includes the adcauline elevation of Oswaldella nate series of thecate and athecate internodes. rigida Pena Cantero et al., 1997. This also occurs Character 18: Mesial superior nematophore
in Oswaldella = = sp. two (fig. 3 in Pena Cantero & (0 naked, 1 with nematotheca). This character
Vervoort, 1995). Second, we have considered O. is distinctive for Ventromma in relation to
herwigi to have an even but abcaudally directed Kirchenpaueria.
hydrothecal aperture. Character state 4 of Character 19: Mesial inferior nematophore
Oswaldella = = curiosa Pena Cantero & Vervoort, 1998 (0 present, 1 absent). is also abcaudally directed as in O. herwigi. Character 20; Intrathecal septum (0 = absent,
Character 11: Node between apophysis and hy- 1 = present).
drocladia = 1 = 21: = (0 present, absent) Character Cauline nematophore (0 present,
Character 12: Position of the hydrotheca on the 1 = absent).
internode (0 = basal, 1 = in the middle, 2 = distal). Character 22: Cauline nematophore (0 = with To avoid problems in understanding information nematotheca, 1 = naked). given by Pena Cantero et al. (1997), we consider
only the three states described above. Therefore, Phylogenetic hypothesis and discussion the conditions “distal half’ and “distal third” of
these in A authors are grouped as «distal» this analysis. maximum parsimony analysis resulted in 14 most
The character is considered additive in the analy- parsimonious unrooted trees (MPUTs) (L=76; sis. CI=0.39; RI=0.55). Due to the low Cl of these
Character = 13: Branch end (0 truncated end, unrooted cladograms, we conducted a PTP analy-
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the numbers in the refer to the Fig. I. Morphological representations of the different states of characters used in analysis (the figs,
character states listed in the text).
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Fig. I. Continued.
sis (“permutation tail probability” test, see Faith that the matrix could be generated randomly (P
& = Cranston, 1991) to test the possibility that the value 0.02).
the MPUTs = matrix could produce same results “randomly”. The strict consensus of the (L 81;
We removed the autapomorphic characters and the Cl = 0.37; RI = 0.50) was rooted between the “out-
resulting similar taxa were merged into single group” and “in-group” taxa, in accordance with
operational taxonomic units to avoid bias in the the procedure ofNixon & Carpenter (1993). Never-
test. The result rejected the null-hypothesis, i.e., theless, we prefer to represent the out-group taxa
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of most trees CI=0.39, RI=0.55), The out- Fig. 2. Strict consensus cladogram (L=81, CI=0.37, RI=0.50) 14 parsimonious (L=76, urouns are kent in an unrooted form and onlv the in-uroun ( Oswaldella) is rooted. A semi-strict consensuswould join the species O. elongata with the clade O. blanconae+.
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graphically in the unrooted pattern, and only the group is composed of two minor clades: 1) O.
8 species of Oswaldella are in the rooted pattern. antarctica+ supported by the character (state 2;
with O. The two characters based on ontogenetical evi- homoplastic erratum++); and 2) (O. O. blanconae dence (characters 7 and 13) did not determine garciacarrascosai, elongata (O. ((O. Oswaldella precisely a root point, but they allowed some points gracilis (O. herwigi, sp. two)))) sup- ported by the character 5 (homoplastic with O. among the out-group terminals (and several among shetlandica and O. curiosa+). the in-group taxa) for the location of the root (De
There is only one difference between the strict Pinna, 1994). This procedure then allowed a char- consensus tree and the semi-strict consensus tree acter polarity for our working hypothesis for the for the 14 MPTs; the latter recognizes the sister- group (Fig. 2). group between O. and the The of does sis- relationships elongata topology Fig. 2 not depict any O. blanconae clade. the of Kirchen- ter-group relationship among genera In general, it is clear that all supraspecific groups paueriidae, but it does reveal the genus Oswaldella are defined by homoplastic characters. A bootstrap as a The of Oswaldella monophyletic group. stem analysis (Felsenstein, 1985) showed that all the is supported by five synapomorphies. However, clades supraspecific have low bootstrap propor- these are homoplastic and reverse within the ge- tion values (BP < 40). This suggests high level of nus. These synapomorphies of the genus are: char- instability for the present hypothesis, which thus acter the of than one 6, presence more axillary must be tested with the addition of further taxo- nematophore (reversing to one nematophore in O. nomic data in the future. We attribute this insta-
delicata, Oswaldella sp. one, O. curiosa, O. bifurca, bility to two factors: 1) the morphological plastic-
and in the O. character sec- group blanconae+)\ 8, ity that seems inherent in hydrozoan taxa, and which ond-order hydrocladia (reversing to first-order is still not satisfactorily understood, and 2) restricted in O. hydrocladia encarnae and evolving to the and scattered samples from the Antarctic Region,
third or fourth order in O. erratum++ and O. generally confined to only a few areas (e.g. Ant-
antarctica+); character 9, in high hydrothecae (homo- arctic Peninsula), which possibly results an plastic with and low Pycnotheca reversing to underestimation of the number of species in the hydrothecae in O. O. O. tottoni, encarnae, bifurca, region, and, consequently, may have implications O. grandis, and in the group O. blanconae+); char- for underestimating morphological knowledge and
acter 10, the even hydrothecal aperture (subse- links amongst the species. These aspects must be
quently transforming eight times in the group); and remembered as guidelines for future hydrozoan
character 21, the absence ofcauline nematophores taxonomic and systematic research for Antarctic
(homoplastic with Naumovia). hydroids. In addition, an increase ofcladistic studies
Thebasalmost relationships remain presently un- for marine groups with representatives in the
defined Antarctic will a better understand- among the species of Oswaldella, yield- region permit of the evolution of its biota. lng a polytomy in the consensus tree, in which the ing
species O. encarnae, O. tottoni, O. billardi, O. deli-
Oswaldella cata, sp. one, and two other major
groups (O. incognita+ and O. antarctica++) are Acknowledgements
placed.
The authors are deeply indebted to Prof, Dr. Wim Vervoort The first O. of these, the incognita species group, (Nationaal Natuurhistorisch Museum - Leiden, Netherlands) 18 supported by character 11 (absence of node for his extensive support to this study (largely done in his between apophysis and hydrocladia), but this is laboratory) and comments on the manuscript. Dr. Alvaro E.
homoplastic with O. shetlandica. Migotto (Centro de Biologia Marinha da Universidade de Sao
The contains all Paulo - Sao Sebastiao, Brazil), Prof. Dr. Frederick Schram (Uni- second, O. antarctica group,
versiteit van Amsterdam), and Dr. D.R. Calder also made valuable is the remaining species. It supported only by pres- to version of the text. The suggestions a previous study was ence of one mamelon (character 7, which in turn supported by FAPESP (grant 96/10544-0). Alvaro L. Pena >s modified four times inside the and is group), Cantero had financial support from the Secretaria de Estado de
homoplastic with crassa. The Universidades, Desarrollo del Ministerio de Pycnotheca and O. Investigation y
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Education Ciencia of Antonio Felsenstein J. 1985. Confidence y Spain (Ref. ANT97-2097/E). limits on phytogenies: an ap-
C. Marques had a personal grant from FAPESP (97/04572-4). proach using the bootstrap. Evolution 39: 783-791.
Ferrarezzi H, Marques AC. 1997. Cap. 13. Analise cladistica
numerica e recursos computacionais. In: Amorim DS, ed.
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