Table Of ContentZOOLOGICAL SCIENCE 9: 1113-1126(1992) © 1992 Zoological SocietyofJapan
REVIEW
What is a Classification?
A Case Study in Insect Systematics: Potential
Confusion before Order
Kunio Suzuki1 and David G. Furth2
1Department of Biology, College of Liberal Arts, Toyama University, Gofuku,
Toyama City, 930 Japan; 'Museum of Comparative Zoology, Harvard
University Cambridge, Massachusetts 02138, U.S.A.
—
ABSTRACT A case studyispresented ofthe LeafBeetle genus Orthaltica (Coleoptera: Chrysomeli-
dae) as an example of a group involved in a variety of taxonomic problems and controversies
demonstratingmany ofthe technical and philosophicalcomplexitiesofsystematicsthatoften make the
derivation of a classification difficult and confusing. The history of Orthaltica is reviewed providing
discussion and illustration of the concepts of: multiple synonymy and homonymy; the genus and
subgenus; lumping and splitting; and a systematic character, especially morphological, and its
application in formulating higher classifications. Based on morphological characters Orthaltica
provides a good vehicle for considering the classification of the two largest subfamilies of the Leaf
Beetles, the Galerucinae and the Alticinae (approximately 500 genera each). The primary difference
between the Galerucinae and the Alticinae is the absence or presence, respectively, of the jumping
organ (metafemoral spring), althoughsome secondarydifferences exist in varyingdegrees. These two
chrysomelid subfamilies are so diverse and relatively unstudied systematically that deriving a higher
classification orspeculatingon theirphylogeny, includingtheirderivation from one (monophyletic) or
many (polyphyletic) lineages, is premature and needs a considerable amount of study of many
characters.
INTRODUCTION organizing them. What is the "inter-relationship"
among organisms? The authors use this term in
One purpose of systematics is to recognize the the sense ofevolutionary relationship; thatis, they
existence ofall organisms onthe earth, to describe assume that all organisms on the earth have evolu-
and order them, and to establish a good classifica- tionary relationships, and that they are descended
tionsystem. Awell-organizedclassificationsystem from the first organism about 4 billion years ago.
may be useful in deepening our understanding of One purpose of systematics is to organize all
the organic world. If we have no reliable system organisms by such evolutionary relationships, and
established by systematists, we cannot find any even though exact evolutionary history may be
order in the biologically diverse organic world. impossible to reconstruct completely, we can use
This can be easily understood ifwe go to a zoo, a systematic methods to make limited approxima-
botanical garden or a natural history museum. If tions. The authors do not adopt the viewpoint of
animals and plants are displayed without any con- numerical taxonomy (phenetics) which generally
sideration of their inter-relationships, we know ignores historical perspectives. The authors also
only that these various organisms exist. The do not completely follow cladistics, a type of
inter-relationship among organisms is the key to systematics which often forces taxonomists to
make premature choices based on a restricted
Received August 19, 1992 methodology oriented toward producing phy-
1114 K. Suzuki and D. G. Furth
logenetic (lineage) results. In this context the Beetles (Chrysomelidae) from a particular view-
authors follow more the methodology of 'evolu- point. In systematic studies there are different
tionary systematics' (sensu Mayr, 1963 [1]). Evo- problematic situations with theoretical and/or
lutionary relationships may be recognized based methodological viewpoints that differ from syste-
on close analysis of systematic characters in a matisttosystematistandfromtaxontotaxon. This
broad sense. Much of this paper will address the is occasionally an important obstacle to com-
question "what is a systematic character?" and its munication among systematists. Using these spe-
application. cific studies, the authors attempt here to present
What is a phylogenetic classification? Most of their awareness of the issues in systematics. The
the problems discussed here are interconnected authors would also like to help correct or improve
and relate to this question. To answer this ques- the present unfortunate situation which underesti-
tion is not a simple matter, as with a dictionary mates the role and importance ofsystematic study
difinition, but ratheracomplex multi-faceted issue as compared with other experimental biological
witharguablydifferentviewpointsconcerningboth disciplines. Such an attitude is based on scientific
present and past relationships of organisms. We ignorance and/or a glaring misunderstanding or
attempt here to recognize the various aspects and prejudice about the practice and significance of
problems in answering such a question. The term systematics. Unfortunately there are even some
"phylogeneticclassification" in this question refers systematists who do not understand the signi-
to a classification of a particular group which will ficance of systematics. This is all the more reason
reflect evolutionary history. Readers should note for a clear and consistent explanation ofbiological
that the authors use the term "phylogenetic" in- systematics and its role in basic science. In order
stead of "natural" classification. This is a con- to stimulate further development of biosystema-
scious usage in order to avoid confusion because tics, itisessential tocooperate withotherbiologic-
theterm "naturalclassification" hasalsobeenused al disciplines. This has been occasionally pointed
by numerical taxonomists in a restricted sense to out but has not been practiced effectively. One
mean a clustering of groups based on overall possible reason forthisscarcityofinterdisciplinary
similaritiesofmanycharacters. Theauthors'usage cooperation may be the lack of mutual awareness
of this term (natural classification) actually agrees of the issues existing between systematics and
more with its usage by cladists. One goal of those other disciplines. Systematists are at least
systematics, andthe taxonomistswhopracticeit, is partially to blame for this because they have not
to establish a better phylogenetic classification often stated their awareness ofsuch interdisciplin-
system which will be acceptable to more system- ary issues or the significance of systematics as a
atists and will result in a more consistant under- basic empirical science, and as a stepping stone to
standing and usage of scientific names for taxa. other modern aspects of biological sciences.
One ofthe intentionsofthispaperis todemons- The authors have recently conducted research
trate to other non-systematist biologists and other together concerning several topics in insect sys-
scientists some of the issues, problems and logic tematics. There are even differences in theoretical
present in the field of taxonomy/systematics. and/or methodological approaches between the
=
Although the examples used from insect (beetle authors even though they both have studied the
Coleoptera) systematics are at times somewhat same insectgroup formanyyears. However, it has
complicated and some problems are left unre- become increasingly apparent through discussion
solved, nevertheless, they illustrate some of the and mutual criticism that both authors have a
fundamental complexities of biological system- common recognition of the above-mentioned
atics. In this paper the authors discuss some of problems of cooperative efforts in systematics.
their opinions about phylogenetic systematic proc- Through this mutual and reciprocal interaction the
edure (theory and methods) based on recent stu- authors have managed to complete many systema-
dies. As with most basic systematic research, the tic studies within a relatively brief period that
authors are studying a specific group, the Leaf could not have been accomplished in the same
What Is a Classification? 1115
broad-spectrumed way, if each of us had studied organisms, isthis not an endless task, how can this
the same topics individually. The authors hope be sensibly planned and how can this survey of
that such cooperative studies will serve as an organisms be justified? Such questions are often
example to systematists studying different groups used as arguments against systematists; Sibatani
or using different methodologies, and to biologists (1960) [5] asked such an essential question to
of different disciplines who might mutually augu- systematists in Japan. Some systematists may
menttheirindividual researchthroughcooperative reply that the people who laugh at such a biotic
discussion and studies. inventory do not know the world and they cannot
Inthispaper,we aregoingtofocusonaproblem understand the significance oforganic diversity on
which we call the "GA Problem". G and A refer our earth. Yet systematists are convinced that
to the chrysomelid subfamilies Galerucinae and giving meaning to organic diversity on the earth
Alticinae, respectively. The core of the "GA from various aspects should be one of the most
Problem" may be summarized as follows: "How important priorities in biology.
can we classify the Galerucinae and Alticinae?" or Even though systematics has its own issues and
more specifically "How sh—ould the Galerucinae perspectives, it also gives a kind of a bird's eye
and Alticinae be defined?" thisform ofquestion viewto otherbiological disciplines. The bird'seye
may show that this problem is one ofgroup/taxon view which systematists offer resembles a topo-
recognition or establishment. Most systematists graphical map. The precision (scale) of the map
haveacceptedtheviewthatthefamilyChrysomeli- depends on the area (organicgroup). Ifwe do not
dae should be classified into 19 subfamilies; Gale- have any map, we cannot walk even one step. At
rucinae and Alticinae are the largest. Various the same time, even ifwe have a mapwe may lose
opinions have been proposed concerning the sys- ourwaybecause ofdisagreementbetween the map
tematic position or phylogenetic relationships of and our present spot. We must make an effort to
these two groups (e.g. Crowson, 1955, 1982 [2, 3]; improve the map in order to reflect our present
Lawrence & Britton, 1991 [4]) but it is generally position; this analogy resembles the relationship
accepted that they are closely related to each between systematics and other biological disci-
other. However,withinthesetwogroupsthereare plines. The opinion that systematics is a synthetic
several taxa (mostlygenera) whosetruesystematic discipline in biology may have originated from the
position (even subfamily placement) has not been viewpoint that both systematics and other biologi-
decided. So that, the above question may be cal disciplines should be mutualistic. Extensive
better expressed as: "Howshould the Galerucinae survey ofour present position will be necessary in
and Alticinae be distinguished?". There is a ordertoimprovethe maptothe pointofmaximum
variety of possible ways to express this problem usefulness. The opinion that we do not need so
depending on differences in the awareness of the many kinds of organisms for biological research
issues and/or which points are emphasized. Var- shows gross misunderstanding of science. Biolog-
GA
ious practical aspects derived from this Prob- ical inventory studies have limitations and, be-
lem may be included in this type ofquestion. The causeofrapiddestructionofnaturalecosystemsby
authors will introduce these aspects using exam- humansinrecentyearsandthe resultingextinction
ples wherever possible because they involve many of many organisms, there is an intense crisis and
typical problems encountered in systematic study urgency that systematists realize more than any
of other organisms. scientists. Systematists are the only ones who can
Systematics has, ofcourse, an essential purpose record the great biological diversitythat exists and
to deepen our recognition of a particular toxon. thatwhichisbeinglostforever. Therefore,system-
However,ifwearesatisfiedwithonlythisaspectof atists should play a leading role in alerting others
systematics one might ask "why is systematics (scientists, politicians, etc.) to the current crists
needed?", especially when such a huge number of and in devising plans for conservation of this
organisms exists on the earth. In other words, if organic diversity.
we say that a purpose ofsystematics is to know all
1116 K. Suzuki and D. G. Furth
GA PROBLEM from North America. [The genus Crioceris cur-
rently belongs to the subfamily Criocerinae.
Crotch considered O. copalina as a member of a
Orthaltica: History and Confusion previously unknown genus currently in the Altici-
In order to consider "GA Problem" (Galeruci- nae. However, even by Crotch's time higher
—
nae Alticinae Problem) the authors have chosen classification of the family Chrysomelidae had
the genus Orthaltica as a good example to demon- been only gradually and not well established.
strate many ofthe problems ofsystematics, begin- Chapuis (1874) [8] was the firstto propose a higher
ning with a brief historical review. The authors classification system; this was the basis of our
would like to give an explanation of the present modern system. However, not until Jacoby (1908)
problem based on Scherer (1974) [6] and using the [9] was an actual subfamilysystem established. So
following table (list of synonymous names) from that, we should understand that Crotch regarded
his article: thespeciescopalinaasamemberofacloserelative
ofmanygenerawhichare includedin the Alticinae
Genus Orthaltica Crotch, 1873 today]. After Crotch, Horn (1889) [10], Blatchley
Orthaltica Crotch, 1873:69 (type-species: (1910) [11], Heikertinger (1925) [12], and Arnett
Crioceris copalina Fabricius; N. America); (1963) [13] followed his treatment. [This also
Horn, 1889:236, 247; Blatchley, 1910:1206, means that all of them recognized the genus
1215; Heikertinger, 1924-25 (1925): 65; Orthaltica as valid].
Arnett, 1963:914, 938. Until now the following have been considered
Leptotrix Horn, 1889:236, 249 (type-species: L. synonyms of Orthaltica:
recticollis LeConte; N. America (nee Menge, Leptotrix: This genus was established by Horn
1868; Araneae) see Leptotrichaltica. (1889) [10] based on the species recticollis de-
Livolia Jacoby, 1903:15 (type-species: L. sulci- scribed by LeConte from NorthAmerica. Howev-
collis Jac; Africa); Scherer, 1961 :268; 1969: er, thisgenusname {Leptotrix) wasahomonym, in
10, 19, 118, 242; 1971 1-37. New Synonym. otherwords, the name was alreadypreoccupiedby
:
Leptotrichaltica Heikertinger, 1924-25 (1925): Menge (1868) [14] as aname ofaspidergenus (see
68 for Leptotrix Horn. New Synonym. also Leptotrichaltica). [Here, some readers may
Micrepitrix Laboissiere, 1933:205 (type-species: think that Horn should have recognized the inde-
M. coomani Lab.; Tonkin); Gressitt, 1955 :35 pendence of Orthaltica from Leptotrix within his
(Alticinae); Gressitt & Kimoto, 1963:404, 1889 article [10]. This suggests the following two
575; Samuelson, 1965 :215; Scherer, 1969: 10, possibilities: (1) Horn positively recognized the
19, 98; 1971 : 10 (as synon.) independence ofboth genera or (2) he established
Serraticollis B. E. White, 1942 17 (type-species: Leptotrix because he did not recognize the identity
:
S. rhois White; Calif.); Arnett, 1963:938 (as ofOrthaltica. Inorderto judge which possibility is
synon.) probable, we have to examine Horn's 1889 paper
[10]. In thispaper. Horn pointed out that Orthalti-
The essence of the history of systematic treat- ca was similar to other genera like Crepidodera
ment of Orthaltica is compiled in the above table. and Pseudoepitrix. He then described Orthaltica
A trained systematist can easily understand not melina as a new species and. following the descrip-
only the formal meaning but also the fact that tion of O. melina, he established Leptotrix and
beyond the nomenclature this group may contain pointed out thatthisnewgenus resembles Orthalti-
many systematically difficult problems. The main ca and Pseudoepitrix but did not belong to any
information that should be deduced from thistable genus of the tribe Crepidoderides. Subdivision of
may be arranged as follows (supplemental com- Alticinae into tribes has been partially attempted
ments in brackets). by Leng (1920) [15] and Bechyne and Bechyne
This genus was established by Crotch (1873) (7] (1975) [16] but remains veryconfusingand invalid.
based on Crioceriscopalina described by Fabricius According to the above facts, the authors judge
:
What Is a Classification? 1117
that Horn took the first possibility mentioned Leptothrix Heikertinger et Csiki (1940) [27] as a
above. Moreover, we should pay attention to the synonym of Orthaltica; however, such a differece
fact that in Horn's era a genus was likely to have in spelling between Leptotrix and Leptothrix is not
been defined more typologically than in recent significant. Because Leptotrix is a homonym of a
times. In other words, a genus was established spider genus, the species belonging to it should be
based on a comparison with type-species and, in automaticallytransferredto Leptotrichalticaestab-
general, it was likely to be more subdivided. Of lished by Heikertinger (1925) [12] as a new name
course, this may vary from worker to worker and for Leptotrix. This is merely follows proper sys-
from group to group]. tematic treatment in accordance with the interna-
Livolia This genus was established by Jacoby tional rules of zoological nomenclature. We have
:
(1903) [17] based on a new speciessulcicollis from to consider the other four genera Livolia, Micr-
Africa. Scherer (1961, 1969, 1971) [18, 19, 20] epitrix, Leptotrichaltica and Serraticollis, the first
followed this but synonymized itwith Orthaltica in three of which were synonymized with Orthaltica
his 1974 article [6]. by Scherer (1974) [6].
Leptotrichaltica: Heikertinger (1925) [12] gave 1. Livolia
a new name to Leptotrix Horn because the exis- When this genus was established, Jacoby (1902)
tence of a homonym (mentioned above); this [28] mentioned that this genus may be transitional
genus was also synonymized with Orthaltica by between the Alticinae and Galerucinae. In his
Scherer (1974) [6]. revisional study of this genus, Scherer (1971) [20]
Micrepitrix: This genus was established by treated the following 20 species, which included
Laboissiere (1933) [21] based on the type-species seven known and 13 newspecies. Alsoin this 1971
M. coomani from Tonkin. [Laboissiere described paper Scherer synonymized Micrepitrix with Livo-
this genus as a member of the Galerucinae but lia species ([20]; see also Scherer, 1981 [29]). In
Gressitt (1955) [22] transferred it to the Alticinae. the list below "nov. comb." (new combination)
Afterthat, Gressitt&Kimoto (1963) [23], Samuel- means a new change of genus assignmnet of the
son (1965) [24], and Scherer (1969) [19] followed species in question, "nov. spec." (new species) a
this, but Scherer synonymized itwith Orthaltica in new species is described and in brackets is the
his 1974 paper [6]]. original locality (type-locality).
Serraticollis: This genus was established by
White (1942) [25] who described the type species vestita (Baly, 1877) nov. comb. [W. Australia]
(S. rhois) from California. After that, Arnett sulcicollis Jacoby, 1903 [Mashonaland: Salis-
(1963) [13] synonymized this genus with Orthalti- bury]
ca. [Though his opinion cannot be determined *africana nov. spec. [W. Africa]
from this synonym list, this was suggested to coomani(Laboissiere, 1933) nov. comb. [China:
Arnett by J. A. Wilcox, an authority ofthe Gale- Tonkin; Hainan I.]
rucinae]. The items mentioned above are the Carolina (Chujo, 1943) nov. comb. [Yap; Palau]
things which are summarized in Scherer's (1974) minuta (Jacoby, 1887) [Ceylon]
[6] synonymlist. Oneshouldexaminefurthereach *minor nov. spec. [Singapore]
ofthepreviousworker'sopinions;thisisanimpor- *fulva nov. spec. [W. Sarawak]
tant routine for many systematists. *nigripennis nov. spec. [Singapore]
The authors will now examine some of the *sarawakensis nov. spec. [W. Sarawak]
detailsoftheconfusioninthesystematictreatment *parva nov. spec. [Singapore]
of Orthaltica. Scherer (1974) [6] synonymized five *malayaensis nov. spec. [Malaya]
generawith Orthaltica. In consideringwhetherhis *perakensis nov. spec. [Malaya]
treatments are reasonable or not one has to ex- *assamensis nov. spec. [India: Assam]
amine all the literature involved and often to *serraticollis nov. spec. [Burma] [=impres-
examine original type-specimens, depending on siceps: Scherer, 1974]
the situation. Seeno and Wilcox (1982) [26] listed *tenasserimensis nov. spec. [S. Burma]
1118 K. Suzuki and D. G. Furth
*ceylonensis nov. spec. [Ceylon] is a very big group, even if there are systematic
minutiuscula (Csiki, 1940) [Sumatra] changes for some species treated as members of
*laticollis nov. spec. [Singapore] this genus, all other species are not necessarily
laboissierei (Chen, 1935) nov. comb. [E. China: transferred to Livolia. Forthe second problem, as
Kiangsi] with other species which have been treated as
members of Micrepitrix, the true systematic posi-
Of these 20 species, we exclude here the 13 tionofthisspeciescannotbe determinedautomati-
species with asterisks described by Scherer in this cally.
paper [20] from our present discussion because minuta: This species was described by Jacoby
they were originally described as members of (1887) [32] as a memberofCrepidodera and, thus,
Livolia; we will examine the seven remaining the same situation as in vestita can be pointed out.
species. Naturally in such cases systematists have Scherer (1969) [19] already pointed out that this
to examine all the original literature involved, species should belong to Livolia.
even though in a practical sense this is sometimes minutiuscula: Concerning systematic treatment
quite difficult for taxonomists who do not have ofthis species, there is a problematic history. The
easy access to good libraries. authorofthisspeciesisCsiki (1940) [33] inHeiker-
vestita: This species was described by Baly tinger and Csiki (1940) [27]. But, the taxon
(1877) [30] as a member of Crepidodera. This correspondingtothisspecieswasfirst describedby
means that in Scherer's opinion at least some Jacoby (1895) [34] under the name ofminuta as a
specieswhichbelongtoLivoliahavebeenmixedin member of Crepidodera. But, as above, Jacoby
Crepidodera (see also Scherer, 1982 [29]). (1887) [32] already used the name minuta as a
sulcicollis: This is the type-species of Livolia. memberofCrepidodera. Thatis, Jacobyproduced
Thus, as far as the genus continues to exist this a new homonym to his other species in the same
species plays an important representative role. genus! This is a very unusual example of a
coomani: This species was described by Laboi- homonym. By discovering this fact, Csiki (1940)
ssiere(1933) [21] asamemberofMicrepitrix. Ifwe [33] became the author of this species without
regard this species as a member of Livolia, this describing even one line about this species.
means that at least some species of Livolia have laboissierei ThisspecieswasdescribedbyChen
:
been mixed in Micrepitrix. If we agree with (1935) [35] as a memberofMicrepitrix. This is the
Scherer's (1971) [20] opinion that Micrepitrix is a same situation as in the above cases of coomani
synonym of Livolia, this problem is eliminated and Carolina.
immediately; this is discussed below. Scherer (1974) [6] changed the name of his L.
Carolina: This species was described by Chujo serraticollis to impressiceps because ofhomonymy;
(1943) [31] as a memberofEpithrix (—Epitrix). If that is, the name was preoccupied by Samuelson
we regard this species as a memberofLivolia, this (1965) [24] as a name for one of three species of
means that some species have been mixed in Micrepitrix from New Guinea. Such homonymy
Epitrix. Gressitt (1955) [22] treated this species as producesaquiteconfusinghistorythat seemstobe
a memberofMicrepitrix. Therefore, as in the case mysterious for workers of other fields of biology.
of coomani, at least some species which should The authors summarize above items as follows.
belong to Livolia have been mixed in Micrepitrix. In analyzing Scherer's (1971) [21] opinion, the
Here, we experience the following two derived systematic relationships between three genera
problems: (1) what kind ofsystematic relationship (Crepidodera, Epitrix and Micrepitrix) and Livolia
is there between Epitrix and Livolia and (2) how are: (1) in the first two genera, only some species
should we treat the systematic position ofCarolina. belongingto Livoliahad been mixed; so that, their
For the first problem, one possible answer may be systematic assignment to a genus needed to be
that ifMicrepitrixshould be regardedasasynonym changedand; (2) Micrepitrixshould be regarded as
of Livolia, we have to consider systematic treat- asynonym ofLivolia; sothat, allspeciesdescribed
ment of Epitrix separately; that is, because Epitrix as members ofMicrepitrix should be automatically
What Is a Classification? 1119
transferred to Livolia. After all these changes, from Orthaltica in the strict sense (Orthaltica (s.
Scherer (1974, 1982b) [6, 29] ultimately regarded str.)) only at the subgeneric level as Orthaltica
Livolia as a synonym of Orthaltica. (Livolia). In the case ofOrthaltica, ifone makes a
2. Leptotrichaltica: classification based on Scherer's broadened con-
Concerning the systematic treatment of this cept, he would be considered a "lumper" (i.e.
genus, we completely agree with Scherer's opinion joining groups together); in contrast to this, many
that it should be regarded as a synonym ofOrthal- systematists are "splitters" (i.e., dividing groups
tica. That is, Leptotrix (=Leptotrichaltica) recti- apart). Occasionally the distinction between the
collis described by Horn (1889) [10] can be treated so-called "lumper" and "splitter" has been discus-
asamemberofOrthalticaaccordingtotheoriginal sed in systematics; it is, of course, a somewhat
description. relative and subjective matter.
3. Micrepitrix: The authors would like to point out the follow-
Sherer (1971) [20] synonymized this genus with ing two problems. First, Scherer (1973, 1982,
Livolia. Samuelson (1973) [36] followed his opin- 1988) [38, 29, 37] suggests that taxonomists use a
ion. Because ofseveral reasons mentioned below, broadened interpretation of the genus by "lump-
the authors would like to treat Livolia and Micre- ing" subunitswhich share commonecologyand/or
pitrix as independent genera, not as synonyms. historic-zoogeography into subgenera rather than
4. Serraticollis: "splitting" them into several genera. Although
This genus was treated by Arnett (1963) [13] Scherer agrees that the genus should include spe-
(following Wilcox's opinin) as a synonym of cies of common ancestry (monophyletic), he con-
Orthaltica. The authors agree that White's (1942) siders that interpretation of the "gap" separating
[25] original description ofthis genus can be com- higher categories is a critical aspect of defining
pletely adopted into Orthaltica. generic level ranks (i.e. genera or subgenera).
However, even as Scherer partially admits, the
Genus vs. Subgenus/Lumping vs. Splitting. information (e.g. ecology, historic-zoogeography,
Scherer (1971, 1974, 1982, 1988) [20, 6, 29, 37] etc.) necessary to define a genus is not always
synonymized Livolia andMicrepitrixwith Orthalti- available for many groups; on the contrary, it is
ca. The first two genera have a symmetrical often quite limited. Although the authorsagree in
aedeagus, whereas Orthaltica as an asymmetrical principle with Scherer's (1973) [38] definition of
one, which is extremely rare in the Alticinae. Of the genus concept, we suggest that some of his
course, Scherer recognized this fact and main- examples ofgenera (especially Orthaltica) are too
tained that such differences should be regarded as broadlydefined ("lumped") andmaybeasdifficult
the charactersofasubgenuslevel. The basisofhis to interpret evolutionarily aswith generawhich he
assertion seems to be his special concept of a claims are over-split.
genus. In his 1973 paper [38], Schererpointed out Secondly, several items that may lead to diffe-
"how reliance on topological criteria and over- rent systematic treatment should be considered.
rankingoflesserunitscandestroythephylogenetic Synonymyzing ofgenus A with genus B will result
image of a genus." He also regretted that many in automatic transfer ofthe species members ofA
systematists are likely to treat closely related spe- to B. This also means automatic extension of
cies groups as independent genera based only on category A. In the present case, if Livolia and
morphological characters. According to Scherer, Micrepitrix are synonymized with Orthaltica, this
Livolia and Micrepitrix should not be separated automaticallyextends Orthalticainto havingavery
from one another (the latter, which was estab- wide geographical range. On the contrary, if we
lished more recently than the former, is regarded regard these three as independent genera, we
as ajunior synonym) and neither should be distin- understand theirdistribution as follows: Orthaltica
guished from Orthaltica at genus level. Thus, this from North America, Livolia from Africa, and
Livolia-Micrepitrix complex is regarded as a Micrepitrix from Southwest Asia to Pacific. Of
synonym ofOrthaltica and shouldbe distinguished course, comprehension ofsuch facts are important
1120 K. Suzuki and D. G. Furth
for us and although some may considerthat such a In the phylogenetic sense ofcladistics, it is impor-
dividedtreatmentofrankinginataxonisessential- tant to establish that each genus has evolved from
ly not important, this demonstrates a gross mis- asingle ancestral lineage orclade, i.e. monophyle-
understanding. For example, when we consider tic. The aboveexamination oftheproblematicand
phylogenetic relationships at the genus level, from complex situation ofthe genus Orthaltica has gra-
the lumper's viewpoint (Scherer, 1974, 1988) [6, dually unfolded to the authors and based on it we
37] the differences among these three groups now begin to approach the core of GA Problem.
(Orthaltica, Livolia, Micrepitrix) may be regarded Concerning the higher systematic position of
as intra-generic variation, whereas forthe splitters Orthaltica, there is a difference of opinion among
they maybeviewed attheinter-genericlevel. This some chrysomelid systematists, i.e. even its sub-
may be deduced by an ordinary comparative family placement (Furth, 1985, 1988 [41, 42];
method. Suzuki (1984, 1989a) [39, 40] haspointed Reid, 1990, 1992 [43, 44]).
out that the ranking of any taxon must strongly
influence the phylogenetic consideration of that Recognition of Higher Taxa in Chrysomeloidea.
group. Mainlybasedonextensivecomparativemorpho-
Lumping and splitting have both good and bad logical study of the internal reproductive systems
points. Actually, one should judge individual of both sexes, Suzuki (1988) [45] pointed out that
cases oftaxon ranking accordingto thedifferences the family Chrysomelidae cannot be regarded as a
in the effect on the understanding ofthe groups in monophyletic group in relation to the two other
question. Our conclusion about this problem is familesCerambycidae and Bruchidae ofthe super-
that in a group for which there is a wealth of family Chrysomeloidea. Suzuki's first essential
information, Scherer's (1973) [38] broadened question aboutchrysomeloidphylogenyconcerned
treatmentofthe genus (usingsubgenera) mayhelp the fact that, surprisingly, the Chrysomelidae
the evolutionary understanding; however, in cases (Leaf Beetles) cannot always be clearly distin-
where there is not much information about the guished from the Cerambycidae (Long-horned
group in question, Scherer's lumping treatment Beetles) andBruchidae (SeedBeetles); henatural-
can have a negative effect on the evolutionary ly assumed that there must be greater differences
understanding. Unlike some systematists the au- among higher categories than among lower ones.
thors do not think that splitting is an improper Theclassification atsubfamilial level in these three
systematic practice. Rather we recognize the na- familieshasbeenconsiderablywellestablishedand
ture of each of the groups which we study and consistent, although there are still differing opin-
preferto enhance the knowledge ofeach group by ions. There are, however, relatively few obvious
finding and analyzing differences between/among differences that separate these three familes from
them. Essentialcharacteristicsandrelationshipsof each other.
a given group can be obscured by the lumping The assignment of a given species to any of the
treatment. three families is automatically determined by the
Concerning the Livolia-Micrepitrix-Orthaltica fact that the species belongs to a particular sub-
problem discussed in this paper, unfortunately family within them; a kind of inverted funnel
there is currently only limited information about system. Suzuki (1984, 1989a) [39, 40] pointed out
them. A lumping treatment of these genera into that this type of problem is one of essential weak
Orthaltica would indicate their general similarity points in the Linnaean hierarchical classification
but the individual characteristics anddifferencesof system and its concomitant hierarchic system of
each ofthree groups would be hidden. Therefore, category names. In most entomology textbooks,
at this relatively initial stage, based on differences one can find some characteristics to separate these
in the aedeagus and geography and in the interest three families, and actually one can classify most
of clarify of these entities for future evolutionary specimens/taxa into families, but there are several
analysis, the authors prefer to treat Livolia, Micr- exceptions. In a recent popular book. White
epitix, and Orthaltica as three independent genera. (1983) [46] mentioned that "(the family Chry-
What Is a Classification? 1121
somelidae) cannot be readily characterized; family
members are very diverse and have no distinctive
characters in common." This is a very basic
statement, but if true, how should we answer the
question "what is a Leaf Beetle or a Long-horned
Beetle oraSeed Beetle?" Actuallybeetleworkers
have not really answered this question. For the
phylogenetic relationships in this superfamily, the
first author will give a general interpretation else-
GA
where (Suzuki, in press [47]). The present
Problem is a smaller version of the same kind of
GA
problems mentioned above; that is, Problem
involves the questions "what is Galerucinae?" or
"what is Alticinae?" or "how can one separate the
Galerucinae and Alticinae from each other?".
There are probably similar situations in many Fig. 1. The MS organ (Metafemoral Spring) ofNonar-
groups; however, in thiscaseourcurrentsystemof thra postfasciatum (Fairmaire, 1889) (Coleoptera,
recognition for these two subfamily groups is rel- lCohfrtylseogmeilnicdluadei,ngAltthieciMnaSe).orga(na,) P(obs)teErniloarrgveidewMoSf
atively advanced.
organ. Scale: 0.5mm. Taken from Suzuki and
Furth (1990b) [49].
Relationship of the Galerucinae and Alticinae,
and the MS Organ.
Howe have we separated the Galerucinae and to the Galerucinae (Furth, 1985, 1988, 1989) [41,
Alticinae so far? Actually there is a diagnostic 42, 50].
character, as indicated by the name "flea beetle," Before proceeding, the authors would like to
themembersoftheAlticinaecanjumpusingawell point out the following facts:
developed hind leg. They have a special jumping 1. Besides Orthaltica, both Livolia and Micr-
organ, whichhasbeen known asMaulik'sorganor epitrix also lack the MS organ (Furth & Suzuki, in
metafemoral spring (MS) (Furth, 1982) [48] in preparation).
their hind femora (Fig. 1, [49]). In fact, the 2. The genus Eubaptus, the only member of
scientificname ofthe typegenus (AfricaFabricius) thesubfamilyEubaptinae (Bruchidae), hasthe MS
is derived from the Greek 'haltikos' which means organ (Teran, 1964, 1967) [51, 52]; the authors
good at jumping (Furth, 1988) [42]. Most chry- have also confirmed this fact. The authors ex-
somelidsystematistshaveregardedthepresenceof aminedmanyotherbruchidsbutcouldnotfindthis
this MS organ as a diagnostic character by which organ in any other groups (Suzuki & Furth, 1990b
theycan separate the Alticinae from the Galeruci- [49]). In addition, the authors have examined
nae. However, there are several potential excep- some Sagrinae species (Chrysomelidae), which
tions to which this rule cannot be applied. The have been occasionally considered as close rel-
genus Orthaltica representsjustsuchanexception- atives of the Bruchidae, and the genus Rhaebus
algroup, becauseit lackstheMS organ inthehind (Bruchidae, Rhaebinae), which has been treated
femora. The authors confirmed this fact in the as a group of the Sagrinae, but has been transfer-
three North American species. If we follow the red to the Bruchidae (Crowson, 1946 [53]; King-
&
rule strictly, the genus Orthaltica should belong to solver Pfaffenberger, 1980 [54]; Borowiec, 1987
the Galerucinae. BasedonthisfactScherer(1974) [55]); the authors could not find the MS organ in
[6] and J. A. Wilcox (personal communication) either group.
maintained that Orthalticawas an exceptional alti- 3. There are species of the Rhynchaeninae
cine genus lacking MS organ. But Furth opposes (superfamily Curculionoidea, family Curculioni-
this point and has asserted that the genus belongs dae) that have the MS organ. Maulik (1929) [56]
1122 K. Suzuki and D. G. Furth
mentioned that the metafemoral organ existed in Alticinae, thetransverse spermathecalfoldsonthe
one species of the genus Rhynchaenus but that it spermathecal capsule are quite consistant in the
differed from that in the Alticinae. Pomorski Galerucinae but variable in the Alticinae and the
(1978) [57] first described this metafemoral organ bending of the basal part of the spermathecal
for another species of Rhynchaenus. Furth has capsule (cf. Suzuki, 1988) [45] isdistinctiveinmost
recognized a considerable intrasubfamilial (in- of the alticine genera.
tergeneric) morphological variation and disco- Wilcox (1965) [62] mentioned that: "the Altici-
vered seven different MS morpho-groups in the nae can be distinguished from Galerucinae by the
Alticinae genera (Furth, 1980, 1982, 1985, 1988) sclerotized extensor apodeme [=MS organ] in the
[58, 48, 41, 42]. The MSorgan in the Rhynchaeni- posterior femora of the former. Orthaltica and
nae is quite similar to that in the Eubaptus and to Leptotrichaltica from the United States, Micrepi-
the most simple morpho-group in the Alticinae trix Laboissiere from the Oriental Region, and
(Furth & Suzuki, 1992 [59]). Micrantipha Blackburn from Australia seem to be
The above facts indicate that the MS organ has the only exceptions to the rule. They appearto be
evolved independently in three phylogenetically flea beetles which lack the extensor apodeme."
separated groups. Furth and Suzuki (1992) [59] Wilcox (1975) [63] also listed many genera, long
have discovered that it also exists in other coleo- treated as the members ofthe Galerucinae, which
pterous groups. This suggests that these groups he claimed should be transferred to the Alticinae.
may not have acquired this organ in their hind He considered the MS as the only character to
femora in the same way, i.e., evolution of this distinguish the Alticinae from the Galerucinae. It
organ may have been regulated by the same de- should be mentioned here that recently Reid
velopmental constraints but under different selec- (1990) [43] synomymized Micrantiphawith Orthal-
tive pressures. At the same time we must also tica as a subgenus of the latter. Reid included all
contemplate the reason why the MS organ did not species of Livolia into Micrantipha {Micrantipha
develop in othergroups. In fact, there are various was described in 1896 and, therefore, its name
coleopterous groups which have a developed takes precedence over Livolia described in 1903).
jumping ability in different ways (cf. Pomorski, However, even more recently Reid (1992) [44]
1983 [57], Furth & Suzuki, 1992 [59]). The MS suggests that his 1990 Micrantipha subgenus (in-
organ evolved from the sclerotization of the cluding the former Livolia andMicrepitrix) should
metafemoraltibialextensortendon (Furth& Suzu- be restored to generic status. This is consistent
ki, 1990b) [61]. There are several non-jumping with the principles of the current paper as stated
beetle groups with well developed (swollen) hind above and previously (Suzuki & Furth, 1990a,
femora (Furth & Suzuki, 1990b) [61]; therefore, 1990b) [64, 49].
the enlargement of hind femora is not always Suzuki (1988, 1989b) [45, 65] emphasized char-
concerned with a jumping function. The authors acter correlation among the phylogenetically im-
have examined comparatively many insect orders portant morphological charactesr. Ifwe adopt the
as well as beetles with enlarged hind femora from MS organ as the only character to separate the
the viewpoint ofleg morphology (Furth & Suzuki, Galerucinae and Alticinae, at least the following
1990a, 1990b) [60, 61]. three assumptions should be valid:
The Galerucinae and Alticinae have long been 1. The Galerucinae and Alticinae are each
treated as independent subfamilies. Suzuki (1988) monophyletic groups, we use this term in a cladis-
[45] pointed out that there are few essential differ- tic sense to show phylogenetic relationships.
ences between them concerning much of their 2. The MS organ was acquired in the alticine
internal reproductive systems; however, there are lineage after they diverged from the common
some general differences between them in the ancestor of the galerucine and alticine lineages.
aedeagus (male) and the spermathecae (female). 3. In the alticine lineages species did not lose
Forexample, the aedeagus is usually asymmetrical the MS organ secondarily and similarly in the
in Galerucinae and almost always symmetrical in galerucine lineages no species acquired the organ
