A Cladistic Analysis Of Sciomyzidae Fallen (Diptera)

48 Pages·2000·25.3 MB·

by  L Marinoni

PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
113(1):162-209. 2000.
A
cladistic analysis of Sciomyzidae Fallen (Diptera)
Luciane Marinoni and Wayne N. Mathis
(LM) Department of Zoology, Universidade Federal do Parana, Caixa Postal 19020, 81531-990,
Curitiba, Parana, Brazil;
(WNM) Department of Entomology, NHB 169, Smithsonian Institution,
Washington, D.C. 20560, U.S.A.
—
A
Abstract. preliminary cladistic analysis of adult characters is presented
that illustrates the phylogenetic relationships among the genera of the family
Sciomyzidae. The monophyly of Sciomyzidae is based primarily on larval char-
acters: the habit of malacophagy and the presence of a serrate ventral arch that
A
articulates with the lower margin of the mouth hooks. reduction in the num-
ber of spermathecae, from three to two, is also likely to be a synapomorphy
for Sciomyzidae. The analysis was done using Hennig86, and 37 morphological
characters were arranged among 50 genera. After using successive weighting,
six cladograms were produced, and from these a consensus cladogram was
obtained. The subfamilies Salticellinae and Sciomyzinae are confirmed to be
monophyletic, as are the tribes Sciomyzini and Tetanocerini. Eutrichomelina
Steyskal, which has been placed in the tribe Sciomyzini, is transferred to the
tribe Tetanocerini. The genus Antichaeta Haliday is confirmed to be in the tribe
Tetanocerini. Illustrations of antenna and male terminalia are presented.
Among families of Acalyptrate Diptera, in our knowledge, this cladistic study was
the Sciomyzidae Fallen (1820), more com- undertaken and is reported here. To provide
monly known as marsh or snail-killing flies, perspective, we begin this report with a
are comparatively well studied, especially brief overview of the higher-level classifi-
the biology of their immature stages (Berg cation.
&
Knutson 1978, Ferrar 1987, Knutson In the first comprehensive treatment of
1987, Rozkosny 1997). Sciomyzid larvae Palearctic Sciomyzidae, Hendel (1900) di-
are primarily parasitoids or predators on vided the family into two subfamilies: Scio-
aquatic or terrestrial mollusks. This feeding myzinae and Tetanocerinae. Hendel char-
proclivity may be of considerable impor- acterized these subfamilies by the proepi-
tance to the biological control of certain sternal seta (present in Sciomyzinae, absent
parasitic, mostly tropical diseases, such as in Tetanocerinae) and the frontal vitta (well
fascioliasis and schistosomiasis (Knutson developed and shiny in most Tetanocerinae,
1976). The trematodes causing both diseas- absent or reduced in most Sciomyzinae).
es parasitize many of the same aquatic mol- Cresson (1920), in a study limited to the
lusks, as intermediate hosts, that are also Nearctic fauna of Sciomyzidae, recognized
fed upon by sciomyzid larvae. Sciomyzinae, as characterized by Hendel,
Although the natural history and ecology and described two additional subfamilies:
and to a degree the descriptive taxonomy Dryomyzinae and Euthycerinae. Cresson
and cytology (Boyes et al. 1972) of the also proposed five tribes that were divided
Sciomyzidae are relatively well known, no among two of the subfamilies as follows:
cladistic analysis at the generic level is (1) Sciomyzinae with Oidematopsini and
available. As a step toward filling that void Sciomyzini; and (2) Euthycerinae with
VOLUME NUMBER
113, 163
1
Chaetomacerini, Euthycerini, and Sepedon- Sepsidae, Megamerinidae, and Cremifani-
tini. dae. Griffiths' studies of Sciomyzidae were
Hendel (1924) published a key to the Pa- based on the following species: Pherbellia
learctic genera and distinguished the genus guadrata Steyskal, Pherbellia griseola
Tetanura Fallen as a separate subfamily, (Fallen), Sciomyza simplex Fallen, Pterom-
Tetanurinae, based on the following com- icra apicata (Loew), Elgiva sundewalli
&
bination of characters: arista subapical, Kloet Hincks, and Tetanocera robusta
forefemur bare, and ovipositor telescoped. (Loew). The family Sciomyzidae, as char-
In the same paper and within the subfamily acterized by Griffiths (1972), includes Sal-
Tetanocerinae, Hendel also proposed the ticellinae + Sciomyzinae, and the family's
tribe Salticellini for the genus Salticella Ro- monophyly is based primarily on the ma-
bineau-Desvoidy. lacophagous habits of the larvae and the
Over 30 years ago, Steyskal (1965) pro- presence of a ventral arch in the cephalo-
posed a classification for the Sciomyzidae pharyngeal skeleton (Knutson et al. 1970,
that has been the most extensive treatment Barnes 1981, McAlpine 1989). The reduced
for the family from the standpoint of higher number of spermathecae, from three to two,
categories. Steyskal's classification, which is likely to be another synapomorphy for
has been adopted by most subsequent work- the Sciomyzidae, although in Salticellinae,
ers (Knutson et al. 1976, Barnes 1979, Roz- the number of spermathecae is four. We in-
&
kosny Elberg 1984, Knutson 1987, terpret the latter condition to be secondarily
Barnes & Knutson 1989, McAlpine 1989), derived from two and to be an autapomor-
recognized five subfamilies: Huttonininae, phy for the subfamily Salticellinae.
Salticellinae, Helosciomyzinae, Phaeomyi- The subfamily Salticellinae has three
inae, and Sciomyzinae. The subfamily Scio- species in two genera, the extant Salticella
myzinae included two tribes, Sciomyzini Robineau-Desvoidy and the fossil Prosal-
and Tetanocerini. Although Steyskal's char- ticella Hennig. The Sciomyzinae, which in-
acterization of Sciomyzidae did not identify clude 505 recent species, have 57, mostly
apomorphic characters, he distinguished the widespread genera.
family from related families by the follow- The purpose of this paper is to present a
ing set of morphological characters: costal classification for the genera of Sciomyzidae
vein (C) without breaks; subcostal vein (Sc) sensu Griffiths that is based on a cladistic
complete, free from vein R,; vein A, com- analysis of primarily morphological char-
plete; oral vibrissae absent; postvertical se- acters. Our analysis is intended more spe-
tae divergent to parallel; midfemur bearing cifically to test the hypotheses that the sub-
a seta on the anterior surface; and at least families Salticellinae and Sciomyzinae and,
one tibia with a preapical seta (Knutson within the latter subfamily, the tribes Scio-
1987, McAlpine 1989). The tribes Tetano- myzini and Tetanocerini are monophyletic.
cerini and Sciomyzini are distinguished by
the presence (Sciomyzini) or absence (Te- Material and Methods
tanocerini) of a proepisternal seta.
Griffiths (1972), who incorporated many Fifty of the 57 genera belonging to the
characters of the male genitalia in his high- Salticellinae and Sciomyzinae were exam-
er level phylogenetic study, introduced the ined and analyzed (Appendix 1). The seven
prefamily as a category between the super- genera not examined are: Ditaeniella Sack,
&
family and the family categories. Using this Eulimnia Tonnoir Malloch, Neodictya
classificatory structure, the prefamily Scio- Elberg, Oligolimnia Mayer, Pseudomelina
myzoinea comprises the families Coelopi- Malloch, Tetanoptera Verbeke, and Verbek-
dae, Phaeomyiidae, Dryomyzidae, Scio- aria Knutson. We also studied a new genus
myzidae, Helosciomyzidae, Ropalomeridae, and species from India, Steyskalina picta
164 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
&
Ghorpade Marinoni, that was recently (*) and "successive weighting" (xs w)
described (Ghorpade et al. 1999). Since it (Carpenter 1988, Dietrich & McKamey
was virtually impossible to examine all spe- 1995). The option "nelsen" (ne) was used
cies of each genus and suspecting that some to construct a strict, consensus cladogram
genera may be polyphyletic (e.g., Pherbel- (Pape 1992, Marinoni & Carvalho 1993).
lia Robineau-Desvoidy with 81 species; Se-
pedon Latreille with 75 species; and Tetan- Characters and Character States Used in
ocera Dumeril with 49 species) the analysis
the Analysis
was done with the type species serving as
exemplars of each genus. The type species The characters used in the analysis are
are always linked to the appropriate generic listed and discussed in the same sequence
name. as they appear in the cladogram (Figs. 323-
Pelidnoptera, represented by P.fuscipen- 324). The letters A and P represent the rel-
nis (Meigen 1830), was used as the out- ative apomorphic (derived) and plesio-
group. This genus, which is in the family morphic (primitive) conditions respectively.
Phaeomyiidae (Griffiths 1972), was select- la. Larval feeding behavior: P (0) feed-
A
ed because it is morphologically similar and ing on Diplopoda; (1) feeding as a par-
closely related, perhaps the sister group asitoid or predator on terrestrial or aquatic
(Steyskal 1965, included it as a subfamily) Mollusca.
of the Sciomyzidae. Its characters are di- This is one ofjust a few characters in the
rectly comparable to those of Sciomyzidae. matrix that establishes the monophyly of
The family Helosciomyzidae (Griffiths Salticellinae + Sciomyzinae. The genus
1972), represented by Helosciomyza aliena Pelidnoptera is a parasitoid on Diplopoda,
Malloch (1928); Huttonina abrupta Tonnoir and numerous larval characters distinguish
&
Malloch (1928); Huttonina furcata Ton- it from the larvae of Sciomyzidae (Vala et
&
noir Malloch (1928), and Huttonina scu- al. 1990). Although malacophagy charac-
&
tellaris Tonnoir Malloch (1928), was terizes nearly all Sciomyzidae and is a syn-
studied to further confirm the polarization apomorphy for the family, there is at least
of characters. one species, Sepedonella nana Verbeke,
A
matrix with 37 morphological charac- that feeds on oligochaetes (Vala et al 2000)
ters of adults and one of the larval mor- as a secondary departure from the ground-
phology was produced (Table 1). Autapo- plan of the more basal clades of the family.
morphies for particular genera were not in- lb. Ventral arch in the larval cephalo-
A
cluded in the analysis. pharyngeal skeleton: P (0) absent; (1)
Multistate characters in the analysis were present.
first treated as unordered (Carvalho 1989, The serrated ventral arch articulates with
&
Pape 1992, Marinoni Carvalho 1993). the ventral margin of the larval mouth
The ordination of the characters was done hooks. This is the only larval structural
in accordance with standard procedures for character that is an autapomorphy for Sal-
cladistic analysis (Wiley 1981). The polar- ticellinae + Sciomyzinae and may be relat-
ization was done using the outgroup com- ed with the malaphagous feeding behavior.
&
parison (Watrous Wheeler 1981, Wiley 2. Number of spermathecae: P (0) three;
A A
1981, Brooks 1989). (1) two; (2) four.
The analysis was facilitated with the According to McAlpine (1989) the im-
computer program Hennig86, version 1.5 mediate ancestor of Muscomorpha had
(Farris 1988). To find cladograms supported three sclerotized spermathecae. This is the
by the most consistent characters, the fol- basic number in the main sections of Mus-
lowing command sequence was used: comorpha: Aschiza, Schizophora, Acalyp-
"mhennig" (mh), "branch and swapping" tratae, and Calyptratae. In Pelidnoptera, the
1
VOLUME NUMBER
113, 165
1
—
Table 1. Matrix of taxa and character states.
000 000 000 1 1 111 111 122 222 222 223 333
123 456 789 012 345 678 901 234 567 890 123
Pelidnoptera 001 010 001 000 000 000 000 000 000 000 000 000
Salticella 120 010 000 020 000 000 000 000 000 000 000 000
Sciomyza 110 120 110 101 000 000 000 000 000 000 000 000
Oidematops 110 020 110 101 000 000 000 000 000 000 000 000
Atrichomelina 110 120 110 100 000 000 000 000 000 000 000 000
Tetanura 110 102 110 110 000 000 000 000 010 000 100 000
Colobaea 111 110 110 110 000 000 000 000 000 000 000 000
Calliscia 110 110 110 000 100 010 000 000 000 000 000 000
Parectinocera 110 010 110 000 100 000 000 000 000 000 000 000
Pteromicra 110 010 110 000 000 000 000 000 000 000 000 000
Pherbellia 110 010 110 000 000 000 000 000 000 000 000 000
Eutrichomelina 111 101 001 000 001 000 000 000 000 000 000 000
Ectinocera 111 101 001 000 Oil 000 001 000 000 010 000 000
Renocera 111 101 001 000 Oil 000 000 000 000 000 000 000
Antichaeta 111 101 100 020 010 100 000 100 000 000 000 000
Chasmacryptum 111 101 001 000 011 110 000 000 000 000 000 000
Shannonia 111 101 001 000 000 112 001 000 000 000 000 000
Perilimnia 111 101 001 000 000 112 001 000 000 000 000 000
Hoplodictya 111 101 001 000 012 112 101 000 000 000 000 000
Dictya 111 101 001 000 012 112 100 000 000 000 000 000
Hydromya 111 101 001 000 011 112 110 000 000 000 000 000
Neolimnia 111 101 000 000 Oil 112 110 000 000 000 000 000
Tetanoceroides 111 101 Oil 010 Oil 112 110 000 000 000 000 000
Euthycerina 111 102 001 000 Oil 112 110 000 000 000 000 000
Tetanocera 111 102 001 000 Oil 112 110 000 000 000 000 000
Trypetolimnia 111 102 001 010 Oil 111 110 000 000 000 000 000
Psacadina 111 102 000 000 Oil 112 110 000 000 000 000 000
Steyskalina 111 102 000 000 Oil 112 110 000 000 000 000 000
Dictyodes 111 101 001 010 012 112 110 110 000 000 000 000
IHone 111 101 001 010 Oil 112 110 100 000 000 000 000
Pherbina 111 101 001 010 Oil 112 110 100 000 000 000 000
Trypetoptera 111 101 001 010 Oil 112 110 100 000 000 000 000
Limnia 111 101 001 000 Oil 111 120 100 000 000 000 000
Poecilographa 111 101 001 010 Oil 112 130 100 000 000 000 000
Pherbecta 111 101 001 010 Oil 112 130 111 000 000 000 000
Protodictya 111 101 001 010 Oil 112 130 111 000 000 000 000
Guatemalia 111 101 001 010 Oil 112 110 000 100 000 000 000
Elgiva 111 102 001 000 Oil 112 110 000 111 000 000 000
Hedria 111 101 001 010 Oil 111 110 000 110 001 000 000
Dichetophora 111 101 001 010 Oil 111 110 000 111 000 110 000
Coremacera 111 101 001 000 Oil 111 120 000 101 000 000 000
Dictyacium 111 101 001 000 Oil 101 120 000 101 000 000 000
Euthycera 111 101 001 000 Oil 111 120 000 101 000 000 000
Ethiolimnia 111 101 000 000 Oil 003 120 000 010 110 000 000
Teutoniomya 111 101 001 0?0 Oil 11? 220 000 210 010 000 100
Thecomyia 111 102 001 000 Oil 113 220 000 110 111 111 010
Sepedoninus 111 102 101 000 012 113 230 000 110 111 111 110
Sepedonella 111 102 102 020 012 113 200 000 111 111 111 111
Sepedon 111 102 101 020 012 113 230 000 210 111 110 111
Sepedomerus 111 102 101 020 012 113 230 000 210 111 110 111 1
Sepedonea 111 102 102 020 012 113 230 000 210 111 110 111 1
166 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
number of spermathecae is also three, this lobaea, Calliscia Steyskal, Parectinocera,
number being considered the plesiomorphic Pteromicra, and Pherbellia. It is lacking in
condition for the Sciomyzidae. Only in Sal- all genera of the Tetanocerini. In Sciomyza
ticella is the number of spermathecae four, Fallen, Oidematops, and Atrichomelina
which we interpret to be a secondary con- Cresson, the subepandrial plate is well de-
dition, probably being derived from two. veloped and is a synapomorphic condition
Thus, four spermathecae are an autapomor- that characterizes these three genera. In Te-
phy for the Salticellinae, and two sperma- tanura (tribe Sciomyzini), the plate is also
thecae remain a synapomorphy for Scio- absent, a condition we consider to be ho-
myzinae. moplastic.
3. Position of sixth left abdominal spi- 6. Anterior surstylus (Figs. 161-203): P
racle of the male (Figs. 115-159): P (0) in (0) well developed; A (1) vestigial; A (2)
A
membrane; (1) in sclerotized tergite. absent.
Within the Sciomyzidae the abdominal The transformation series for this char-
spiracles of males may occur in the mem- acter is linear: —> 1 —> 2. Pelidnoptera
brane or the sclerotized tergite. Primitively has two pairs of well-developed, paired sur-
in Muscomorpha, the spiracles are in the styli, and thus the presence of an anterior
membrane, which is considered the ple- well-developed surstylus is the plesiom-
siomorphic condition for the Sciomyzidae.
orphic condition for this character. Within
The position of the sixth spiracle in the
the Sciomyzidae, the tribe Sciomyzini also
sclerotized portion of the tergite is a syna- has an anterior, well-developed surstylus.
pomorphy for the Tetanocerini. Males of
The genera Tetanura (tribe Sciomyzini) and
Colobaea Zetterstedt have the spiracle in
Elgiva Meigen; the assemblage formed by
the sclerotized tergite, a condition that
the genera Euthycerina Malloch, Tetano-
probably represents a secondary reversal.
cera, Trypetolimnia Mayer, Psacadina En-
4. Sixth abdominal tergite of the male
A derlein, and Steyskalina Knutson; and the
(Figs. 69, 74-76): P (0) present; (1) ab-
group of Thecomyia Perty, Sepedoninus
sent.
Verbeke, Sepedonella Verbeke, Sepedon,
Having all abdominal sclerites present is
Sepedomerus Steyskal + Sepedonea Steys-
undoubtedly the plesiomorphic condition.
Mc kal; lack an anterior surstylus, having only
According to Alpine (1989) the reduc-
the posterior one. The remaining genera of
tion of the sixth abdominal tergite in males
is an apomorphy for the superfamily Scio- Tetanocerini have a vestigial, anterior sur-
stylus.
myzoidea. Griffiths (1972) considered this
reduction to be a synapomorphy, confirm- 7. Shape of aedeagus (Figs. 61-63, 66-
ing the monophyly of Sciomyzidae. In 67, 204-322): P (0) asymmetrical; A (1)
symmetrical.
Sciomyzidae, however, there is a complete
absence of this tergite in most genera. Only Asymmetry in the postabdomen of male
in Salticella and in four genera of Scio- Acalyptratae may involve internal struc-
myzini, Oidematops Cresson, Parectino- tures, including the aedeagus. Within gen-
cera Becker, Pherbellia, and Pteromicra era of Sciomyzidae, the aedeagus demon-
Lioy, is there a sixth tergite, which, how- strates great variation in shape and sym-
ever, is reduced. metry. Pelidnoptera has an asymmetrical
5. Subepandrial plate (Figs. 161-169, aedeagus, a condition that is considered to
197): A (0) absent; P (1) vestigial; A (2) be plesiomorphic. In most Tetanocerini, ex-
well developed. cept for Antichaeta, the aedeagus is a com-
The common, plesiomorphic condition, plex structure with several completely
is the presence of a vestigial subepandrial asymmetrical sclerites. In the Sciomyzini
plate found in Pelidnoptera, Salticella, Co- and in the group of Sepedoninus, Sepedo-
VOLUME NUMBER
113, 67
1
nella, Sepedon, Sepedomerus + Sepedonea, temalia Steyskal, Hedria Steyskal, Diche-
the aedeagus is completely symmetrical. tophora Rondani, Poecilographa Melander,
8. Attachment of gonopod (Figs. 204- Protodictya Malloch + Pherbecta Steyskal
322): P (0) fused to the hypandrium; A (1) (the later two genera are sister groups, as
"+"
free. indicated by the connection). The gen-
Mc
Alpine (1989) postulated the fusion of era Salticella, Antichaeta, Sepedonella, Se-
the gonopod to the hypandrium as a ple- pedon, Sepedomerus, and Sepedonea lack a
siomorphic condition for the Acalyptratae. basiphallus. The remaining genera have a
All groups examined that are closely related well-developed basiphallus.
to the Sciomyzidae have the gonopod fused 12. Setal investment of foretibia: P (0)
to the hypandrium. The presence of a gon- without preapical setae; A bearing a pair
(1 )
opod that is well developed and free is a of preapical setae.
condition that supports the monophyly of The presence of a pair of preapical setae
the tribe Sciomyzini. In Tetanoceroides on the foretibia is a synapomorphy for Oi-
Malloch, a free gonopod is apparently ho- dematops and Sciomyza.
moplastic. 13. Vestiture of the aedeagus (Figs. 214-
9. Paramere (Figs. 204-322): A (0) not 217): P (0) without scalelike structures; A
digitiform, elongate and well developed; P (1) with scalelike structures.
A
(1) digitiform and well developed; (2) ab- In Calliscia and Parectinocera, the ae-
sent. deagus is covered with small scalelike
Pelidnoptera has a digitiform, well-de- structures, a synapomorphy for these gen-
veloped paramere that is considered to be era.
plesiomorphic. In Salticella, the paramere is 14. Proepisternal seta: P (0) present; A
elongate and well developed, as in the Scio- (1) absent.
myzini and in the genera Antichaeta, Psa- Steyskal (1965) used the presence of the
cadina, Neolimnia, Ethiolimnia, and Steys- proepisternal seta to distinguish the tribe
kalina. Two genera, Sepedonea and Sepe- Sciomyzini from the Tetanocerini. Most
donella, lack a paramere, a condition that is genera of Tetanocerini lack this seta, al-
considered homoplastic. though Shannonia Malloch and Perilimnia
10. Shape of aedeagal apex (Figs. 204- Becker possess one. For the latter genera
213): P (0) variously shaped, but not flat- this condition is considered to be homo-
A
tened; (1) flattened. plastic.
The presence of an aedeagus with a flat- 15. Male terminalia (Figs. 57-59, 64-65,
tened apex is a synapomorphy for the group 68-160): P (0) with the 6th, 7th, and 8th
of Sciomyza, Oidematops, Atrichomelina, sternites separated, the 6th and 7th asym-
Tetanura, and Colobaea within the Scio- metrical; A (1) with the synsternite 7+8
myzini. and 6th sternite separated and asymmetri-
11. Basiphallus (Figs. 203-322): P (0) cal; A (2) with the synsternite 6+7+8 sym-
A
well developed; (1) present but poorly metrical.
A
developed; (2) absent. According to Steyskal (1957) the asym-
This character has the greatest number of metry of the male Acalyptratae postabdo-
steps in the matrix and analysis, indicating men, including segments beyond the fifth,
a large number of homoplasies and rever- is due to three basic movements within the
sals. The taxa that have the intermediate pupa: circumversion, reflection, and "stro-
apomorphic condition, the basiphallus phe." The symmetry may occur as a result
poorly developed, are Colobaea, Tetanura, of the obliteration of these movements.
Trypetolimnia, Tetanoceroides, Dictyodes Asymmetry in Sciomyzidae is restricted to
Malloch, Ilione Verbeke, Pherbina Robi- the sixth, seventh, and eighth segments.
neau-Desvoidy, Trypetoptera Hendel, Gua- There is a modification gradient of these
168 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
A
segments, changing from completely asym- length of the first flagellomere; (2) ped-
metrical to completely symmetrical, asso- icel approximately twice the length of the
ciated to the fusion of the segments men- first flagellomere.
tioned above. The plesiomorphic condition is present
16. Placement of sixth right abdominal from Sciomyzini until Shannonia + Peri-
spiracle of the male (Figs. 68-114): P (0) limnia. From this group to Ethiolimnia the
A
in membrane; (1) in sclerotized tergite. intermediate apomorphic condition (1) is
Sciomyzini and Eutrichomelina, Reno- present. The apomorphic condition (2) is
cera Hendel, and Ectinocera Zetterstedt present in the following genera: Teutoni-
have the plesiomorphic condition of this omyia, Thecomyia, Sepedoninus, Sepedo-
character, the spiracle is in the membrane. nella, Sepedon, Sepedomerus, and Sepedo-
From Antichaeta to Sepedonea, the spiracle nea.
is in the tergite. In Ethiolimnia, there is a 20. Condition of sternites of female ter-
reversal to the plesiomorphic condition. minalia (Figs. 53-56): P (0) with sternites
A
17. Placement of seventh right abdominal 6th, 7th, and 8th separate; (1) with 6th
spiracle of the male (Figs. 68-114): P (0) separate and 7th and 8th fused; A (2) 6th,
A A
in membrane; (1) in sclerotized tergite. 7th, and 8th incompletely fused; (3) 6th,
The plesiomorphic condition occurs in 7th, and 8th completely fused.
most Sciomyzini except for Calliscia. From The transformation series was linear.
Chasmacryptum Becker to Sepedonea most Two lineages arose from state 1. One of
genera have the spiracle in the tergite, ex- these goes through the third state and the
cept for Dictyacium Steyskal and Ethiol- second goes through the fourth state. The
imnia. evolution occurred from separated sternites
18. Shape of head: P (0) as in Fig. 52a; passing through steps of fusion to the com-
A A
(1) as in Fig. 52b; (2) as in Fig. 52c; plete fusion of 6th, 7th, and 8th. All Scio-
A
(3) as in Fig. 52d. myzini and the Tetanocerine genera until
The head, from the ancestor to Chasma- Hoplodictya Cresson + Dictya Meigen
cryptum, has the shape shown in Fig. 52a. have sternites 6th, 7th, and 8th separate.
Beyond the group of Shannonia + Perilim- From the polytomy of Hydromya Robi-
nia the intermediate apomorphic condition, neau-Desvoidy to the ancestor of Ethiol-
represented by Fig. 52c, is present. From imnia the 7th and 8th sternites are fused.
this state the other two apomorphic states Protodictya + Pherbecta and Poecilogra-
evolved. The pattern of head shape, as in pha have the three sternites completely
Fig. 52b, is present in Trypetolimnia and fused as Sepedoninus, Sepedon, Sepedom-
Limnia Robineau-Desvoidy as homoplasies erus, and Sepedonea. In Sepedonella, a ge-
and in Hedria, Dichetophora, Coremacera nus belonging to this group, the three ster-
Rondani, Dictyacium, and Euthycera La- nites are separate. The monophyletic group
treille. The shape, as in Fig. 52d, defines formed by Coremacera, Dictyacium, and
the group of Ethiolimnia, Thecomyia, Se- Euthycera, and the genera Limnia, Teuto-
pedoninus, Sepedonella, Sepedon, Sepe- niomyia, and Thecomyia have the sternites
domerus, and Sepedonea. Because Teuto- 6, 7, and 8 almost fused. Lines separating
niomyia Hennig has a very different head, these sternites are perceptible.
compared to other genera, this character 21. Aedeagus with lobed apex (Figs.
was coded as missing in the matrix (Table 222-224, 230-238): P (0) absent; A (1)
1). present.
19. Proportion between the length of the Ectinocera, Hoplodictya, and Perilimnia
pedicel and first flagellomere (Figs. 1-51): + Shannonia have the aedeagus with the
P (0) pedicel approximately half of first fla- distal end lobed. This character apparently
A
gellomere; (1) pedicel subequal to the appeared independently in these genera. In
VOLUME NUMBER
113, 169
1
the other genera, the distal end of the ae- apomorphy for the group Elgiva, Hedria,
deagus has several different shapes. Dichetophora, Ethiolimnia, Teutoniomyia,
22. Subalar setae: P (0) absent; A (1) Thecomyia, Sepedoninus, Sepedonella, Se-
present. pedon, Sepedomerus, and Sepedonea. In
The subalar setae are present in Dictyo- Coremacera, Dictyacium, and Euthycera,
des, Ilione, Pherbina, Trypetoptera, Limnia, there is a reversal to the plesiomorphic
Poecilographa, Pherbecta + Protodictya. state. Tetanura has this seta, a condition
The apomorphic state apparently evolved that is considered homoplastic.
independently in Antichaeta. 27. Seventh and 8th abdominal tergites
23. Aedeagus convoluted as in Figs. of the female: P (0) separate; A (1) fused.
263-265, 281-286: P (0) absent; A (1) The fusion of the 7th and the 8th abdom-
present. inal tergites of the female is a character
A
convoluted aedeagus occurs in Proto- state that links the genera Dichetophora,
dictya, Pherbecta, and Dictyodes. For Pro- Coremacera, Dictyacium, and Euthycera.
todictya and Pherbecta this character de- In Elgiva and Sepedonella, the fusion is ho-
common
fines the ancestor. moplastic.
24. Fourth abdominal sternite of the male 28. Prominent eyes: (0) absent; (1) pres-
fused to fifth, forming a medioapical pro- ent.
cess: P (0) absent; A (1) present. Ethiolimnia, Thecomyia, Sepedoninus,
The presence of a well-developed, me- Sepedonella, Sepedon, Sepedomerus, and
dioapical process in the fifth abdominal Sepedonea have prominent eyes, a syna-
sternite of the male as a complex structure pomorphy for these genera. As Ethiolimnia
is a synapomorphy for the species of Pro- is in a polytomy with Teutoniomyia, prom-
&
todictya (Marinoni Knutson 1992, Mar- inent eyes are a confirmed synapomorphy
&
inoni Carvalho 1993). In Pherbecta, for Thecomyia, Sepedoninus, Sepedonella,
however, there is, at the same position, a Sepedon, Sepedomerus, and Sepedonea and
process that is less well developed and only perhaps for Ethiolimnia.
which may be homologous to that of Pro- 29. Number of postalar setae: P (0) 2; A
todictya. (1)0-1.
25. Lunula: P (0) not exposed; A (1) ex- The presence of two postalar setae is the
A
posed; (2) greatly exposed. plesiomorphic condition. In Ectinocera and
In the outgroup, Pelidnoptera, genera of in the genera beyond Ethiolimnia, the num-
Sciomyzini, and genera of Tetanocerini ber of postalar setae is reduced to one or
from Eutrichomelina to Protodictya, the lu- none.
nula is not exposed. From Guatemalia to 30. Ocellar setae: P (0) present; A (1)
Sepedonella, the intermediate state (1) is absent.
present. In Ethiolimnia, there is a reversal The presence of a pair of strong ocellar
to the plesiomorphic state. In the apical setae has been considered a plesiomorphic
genera, Sepedon, Sepedomerus, and Sepe- condition for the Muscomorpha (McAlpine
donea, the lunula is greatly exposed, which 1989). In Pelidnoptera, these setae are pres-
is interpreted as an even more derived con- ent, as they are in most Sciomyzidae, in-
dition from the intermediate state. In Teu- cluding Salticella. These setae are absent in
toniomyia, which also has a greatly exposed Hedria and in the group of Thecomyia, Se-
lunula, this character state is homoplastic. pedoninus, Sepedonella, Sepedomerus +
26. Presutural supra-alar setae: P (0) Sepedonea.
present; A (1) absent. 31. Postpronotal setae: P (0) present; A
The plesiomorphic condition of this char- (1) absent.
acter is the presence of presutural supra-alar Most Sciomyzidae have postpronotal se-
setae. The absence of these setae is a syn- tae. The absence of these setae character-
170 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
izes the group of genera beyond Thecomyia. Discussion
In Dichetophora and Tetanura, the absence —
Relationships. The monophyly of the
of postpronotal setae is considered to be ho-
Sciomyzidae is defined by a behavioral
moplastic.
character, the larvae are predators or para-
32. Number of scutellar setae: P (0) 2
A sitoids on aquatic or terrestrial Mollusca
pairs; (1) 1 pair.
(Berg 1953, Knutson et al. 1970, Griffiths
Primitively the family Sciomyzidae has
1972, Barnes 1979) and the presence of a
two pairs of scutellar setae. One pair of scu-
serrate ventral arch below the mouth hooks
tellar setae occurs in Dichetophora and the
in the larvae (Griffiths 1972). The serrate
group of genera beyond Thecomyia.
ventral arch could be closely correlated
33. Number of notopleural setae: P (0) 2; with the malacophagous feeding behavior.
A(l)
1. The genus Salticella, representing the
Two notopleural setae are present in most Salticellinae, remains at the base of the
Sciomyzidae and in Pelidnoptera. Only the cladogram, being distinguished from the
genera Thecomyia, Sepedoninus, and Sepe- subfamily Sciomyzinae and its monophyly
A
donella have a single notopleural seta. confirmed by the following three autapo-
M
reversal of this characters to the plesio- morphies: four spermathecae; cell nar-
morphic state of two notopleural setae oc- rowed apically (this character was not used
curs in the genera Sepedon, Sepedomerus, in the analysis because of its variability
and Sepedonea. among genera of Sciomyzidae); and three
34. Hindtibia arch-shaped: P (0) absent; pairs of surstyli. Knutson et al. (1970),
A (1) present. working on the biosystematics of Salticella
The genera Teutoniomyia, Sepedoninus, fasciata (Meigen), concluded that this ge-
Sepedonella, Sepedon, Sepedomerus, and nus is more closely related to Sciomyzini
Sepedonea have an arch-shaped hindtibia. than to the Tetanocerini in morphological
Only Thecomyia does not have the hindtibia and biological aspects. This relationship is
arch-shaped. corroborated in the present analysis.
35. Head with sutures: P (0) distinct; A Among genera of the subfamily Scio-
myzinae, two main monophyletic clades
(1) indistinct.
The head sutures of Thecomyia, Sepe- were formed, the first including Pherbellia,
Pteromicra, Calliscia, Parectinocera, Te-
doninus, Sepedonella, Sepedon, Sepedome-
tanura, Colobaea, Atrichomelina, Oidema-
rus, and Sepedonea are indistinct. This con-
tops, and Sciomyza; and the second includ-
dition is considered a synapomorphy for
ing the 40 remaining genera. The two
this group.
clades are concordant with the tribes Scio-
36. Epandrium (Figs. 68-160): P (0) free;
A myzini and Tetanocerini of Steyskal (1965).
(1) fused to the 8th sternite.
The genus Eutrichomelina, which tradition-
The fusion of the epandrium to the 8th
ally has been placed in the Sciomyzini, is
sternite is a synapomorphy for the genera shown to be allied to the Tetanocerini in
Sepedonella, Sepedon, Sepedomerus, and
this analysis.
Sepedonea.
Behavioral aspects of the larvae have
37. Hindtibia with a spinelike projection: been discussed as possible synapomor-
P (0) absent; A (1) present. phies for the tribes (Knutson & Lyneborg
In most Sciomyzidae, there is no projec- 1965, Abercrombie 1970). Toward one end
tion from the hindtibia. Sepedonea and Se- of the scale, where the Sciomyzini are
pedomerus have a hindtibia that bears a placed, the species that have been reared
spinelike projection, which is a synapomor- are parasitoids on stranded aquatic or ter-
phy that links these two genera. restrial mollusks {Colobaea (Knutson
VOLUME NUMBER
113, 171
1
mm
0,5
mm
1
10
Figs. 1-1 1. Right antenna, right lateral view: 1, Pelidnoptera; 2, Salticella; 3, Sciomyza; 4, Oidematops; 5,
Atrichomelina; 6, Tetanura; 7, Colobaea; 8, Calliscia; 9, Parectinocera; 10, Pteromicra; 11, Pherbellia. Fig.
1 1, scale = 1.0 mm; remaining Figs, scale = 0.5 mm.
&
1973); Pherbellia (Bratt et al. 1969); Pter- al. 1983, Vala Caillet 1985); Hoplodic-
& &
omicra (Rozkosny Knutson 1970); Scio- tya (Neff Berg 1962); Hydromya (Knut-
& &
myza (Foote 1959); Tetanura (Knutson son Berg 1963); Ilione (Knutson Berg
&
1970)). Toward the other end, most Tetan- 1964b); Limnia (Vala Knutson 1990);
ocerini are predaceous on aquatic or ter- Perilimnia (Kaczynski et al. 1969); Pher-
restrial mollusks (Coremacera (Knutson becta (Knutson 1972); Pherbina (Knutson
&
1973); Dichetophora (Vala et al. 1987); et al. 1975, Vala Gasc 1990); Protodic-
& &
Dictya (Valley Berg 1977); Dictyodes tya (Abercrombie 1970, Neff Berg
&
(Abercrombie 1970, Abercrombie Berg 1961); Psacadina (Knutson et al. 1975);
& &
1978); Elgiva (Knutson Berg 1964a, Renocera (Foote Knutson 1970); Sepe-
& &
Orth Knutson 1987); Euthycera (Vala et don (Neff Berg 1966, Knutson et al.