Showing papers in "Systematic Biology in 1983"

Permutation Tests for Association Between Two Distance Matrices

Abstract: -Systematists and geneticists often wish to compare two pair-wise distance or similarity matrices based on different characters. Conventional correlation tests are not appropriate in such situations because of dependencies among the entries in each matrix. A broad class of permutation tests for association between distance matrices is described. Specific members of the class are discussed and compared using real and simulated data. Statistics resembling Kendall's tau and Spearman's rho are found to have desirable power and invariance properties. [Distance matrices; permutation tests; Mantel test; Spearman's rho; Kendall's tau.] Biologists frequently summarize multivariate data from groups or individuals by computing some measure of generalized distance or similarity between each two groups or individuals. Distances based on genetic, geographic, morphological, and linguistic traits appear in the literature (e.g., Howells, 1966). The problem then becomes the comparison of two pair-wise distance or similarity matrices based on different characters for the same groups or individuals. Problems requiring the comparison of two pair-wise matrices also arise in taxonomic studies. Here each matrix may contain cophenetic values (Sokal and Rohlf, 1962) computed from a dendrogram. Two dendrograms to be compared may be based on different suites of characters or produced by different researchers from different sets of data. Some authors (Howells, 1966; McKechnie et al., 1975; Guries and Ledig, 1982) simply calculate and test for significance the sample correlation coefficient (r) between the pairwise distances. The normality assumption required to test the significance of r is suspect for many distance measures (e.g., see Friedlaender et al., 1971). This difficulty could be overcome by using a distribution-free test for independence. More problematic, however, are dependencies among the pair-wise distances in each matrix which violate the assumptions of normal theory or distribution-free tests. Valid permutation tests for association between distance matrices have been proposed by authors in other fields (Mantel, 1967; Hubert, 1978a), but have been little used by systematists or geneticists (but see Douglas and Endler, 1982). In this paper, I describe the general strategy for constructing such tests and give examples of specific test statistics, illustrating test properties with real and simulated data. Although I use the term "distance matrix" throughout the paper, the matrices to be compared may be similarity or dissimilarity matrices. The two matrices must be obtained from different sets of data for the permutation strategy described here to be appropriate, a point discussed by Hubert and Baker (1977), Hubert (1978a), and Sokal (1979). In particular, these permutation tests cannot be used to compare a matrix representing a dendrogram with the original similarity matrix from which the dendrogram was constructed. Neither should the tests be used to compare two dendrograms constructed by different methods from the same data. In these two situations, the hypothesis of independence between the two matrices is clearly untenable. Note that the test statistics described in this paper can be used as descriptive measures of association in these situations; it is the hypothesis-testing procedure that is inappropriate. TESTS FOR ASSOCIATION Permutation Strategy Let n be the number of "points" (groups or individuals) between which distances have

Phylogeny and Biogeography of the Rana Pipiens Complex: A Biochemical Evaluation

Abstract: -The phylogeny of the Rana pipiens complex as supported by cladistic analysis of the enzymatic products of 50 gene loci is presented. Two broadly sympatric groups within the complex are identified and named the Alpha and Beta divisions. Within both of these divisions, a dichotomy exists between North American and Middle American species. The two groups in the Alpha division are recognized as the R. montezumae species group and the R. areolata species group; the two in the Beta division are referred to the R. pipiens species group and the R. berlandieri species group. Most of the species within a species group are distributed parapatrically; some hybridization may take place within narrow zones of sympatry. Limited hybridization also occurs in the two narrow zones of sympatry that exist between members of different species groups in the same division. However, although sympatry between Alpha division species and Beta division species is extensive, interdivisional hybridization is relatively rare. [Biogeography; cladistics; electrophoresis; phylogeny; Rana pipiens complex.] The systematics of the Rana pipiens complex (leopard frogs and related species) has been a modern biological enigma. Although a dozen species in this complex had been described before the start of the present century, this number was reduced to four through synonymy in association with development of the polytypic species concept during the 1940s and 1950s (Moore, 1944, 1946; Neill, 1957). However, extensive field work in the 1960s and 1970s led to the discovery of several zones of sympatry between different "morphotypes," in which little or no hybridization was evident (Post and Pettus, 1967; Mecham, 1968; Brown and Brown, 1972; Platz, 1972; Platz and Platz, 1973; Dunlap and Kruse, 1976; Frost and Bagnara, 1976, 1977a, b; Lynch, 1978; Hillis, 1981). The realization that these zones of sympatry exist, coupled with detailed morphological (Post and Pettus, 1966; Pace, 1974; Korky, 1978; Hillis, 1982), auditory (Littlejohn and Oldham, 1968; Frost and Bagnara, 1977a, b; Frost, 1982; Frost and Platz, 1983), biochemical (Salthe, 1969; Platz, 1972, 1976; Platz and Platz, 1973; Sage and Selander, 1979), and reproductive studies (Frost and Bagnara, 1977a; Hillis, 1981; Frost and Platz, 1983) has led to a return to the concept of numerous distinct species of leopard frogs (Moore, 1975). Several of these species have recently been described (Mecham et al., 1973; Sanders, 1973; Frost and Bagnara, 1976; Platz and Mecham, 1979), and the descriptions of several others will be forthcoming (Frost and Hillis, unpubl. data). Although each of the described species in the R. pipiens complex can be distinguished morphologically, the complex as a whole is morphologically conservative. The known morphological differences are too few to permit phylogenetic analysis based upon these traits. However, the complex is sufficiently diverse biochemically to lend this group to ready phylogenetic analysis though electrophoresis. Electrophoretic analyses of phylogenies are maximally informative when they are restricted to relatively closely related groups of organisms with known sister groups. Furthermore, because few synapomorphic electromorphs can be identified relative to the number that are autapomorphic, many loci must be examined in order to resolve fully a phylogeny if the group under consideration is highly speciose (Avise et al., 1980b). The R. pipiens complex is an ideal group for electrophoretic analysis of phylogeny be-

Consistently High Meristic Counts in Natural Hybrids Between Brook Trout and Bull Trout

Abstract: Detection et hybrides entre Salvelinus confluentus et S. fontinalis dans la riviere Colombia au Montana par etude de 10 loci d'isozyme

Resolving systematic relationships with g-bands: a study of five genera of south american cricetine rodents

Abstract: G- and C-banded chromosomes of Holochilus brasiliensis, Nectomys squamipes, Neaco- mys guianae, Sigmodon hispidus, and 11 species of Oryzomys are compared and cladistically ana- lyzed to document direction, type, and magnitude of chromosomal evolution in these species. Direction of chromosomal evolution was determined from the proposed primitive G-band se- quences for cricetid rodents. Numbers and types of chromosomal rearrangements identified in the largest 12 chromosomes of Oryzomys were 13 Robertsonian translocations (9 of which are polymorphic), 21 other translocations, 8 pericentric inversions, 1 paracentric inversion, and 12 rearrangements whose nature could not be identified from banding sequences. In 11 species of Oryzomys there are about 2.5 times as many euchromatic rearrangements as found in 18 species of Peromyscus. It is concluded that: (1) The early radiation of the peromyscine-neotomine-ory- zomyine lineages was accompanied by little chromosomal evolution. (2) Chromosomal evolu- tion in cricetine rodents does not appear to fit the predictions of the canalization model. (3) None of the currently accepted broadly-based models of chromosomal evolution appears ade- quate to explain the pattern of variation observed in the cricetines (especially the variation within and between Oryzomys and Peromyscus). (4) Nondifferentially stained chromosomes gen- erally will not be a useful predictor of phylogenetic relationships. (5) For some clades, G-banded sequences provide synapomorphies for the development of systematic hypotheses; however, several branching events cannot be resolved with the quality of G-bands available to us. Some of the phylogenetic hypotheses are: (1) that of the five genera of South American cricetids examined, Oryzomys and Holochilus appear to be the most closely related (based on morphology, Holochilus was thought to be more closely related to Sigmodon); (2) that Neacomys, Holochilus, and species of Oryzomys examined shared a common ancestry after diverging from the Nectomys lineage; and (3) chromosomal characters identified by us failed to document that Sigmodon is more closely related to the other South American genera (Oryzomys, Holochilus, Neacomys, and Nectomys) than it is to the North American cricetids (for example, Neotoma and Peromyscus). One example of lack of congruence documents convergence in chromosomal rearrangements. (Chro- mosomes; G-bands; C-bands; oryzomyines; cladistics; South America; canalization model.)

The canalized evolutionary potential: inconsistencies in phylogenetic reasoning

Abstract: Holomorphological similarities can be based on synapomorphies, symplesiomor- phies, convergences, diffuse parallelisms through parallel selection, and underlying synapo- morphies (i.e., close parallelism as a result of inherited factors within a monophyletic group causing incomplete synapomorphy). Two sets of minimum criteria for asserting synapomorphies are given; one does not allow for outside parallelism and secondary reductions, reversals or change, while the other allows for reductions in apomorphic part taxa (subgroups) and outside parallelism in groups which cannot be sister groups. A theoretical scheme of argumentation (cladogram) secured through synapomorphies satisfying the strictest criteria is drawn. Three modifications of synapomorphies satisfying the second set of criteria are discussed and exem- plified. The remaining six hypothetical trends can be explained as underlying synapomorphies, as diffuse parallel selections (including convergence) or as secondary reductions (and reversals). Hypothetical phylogenetic trees with the distribution of character alternatives for each taxon including hypothetical ancestors are given for each alternate explanation, discussed and ex- emplified from chironomid morphology. When the monophyly of every taxon is established, underlying synapomorphy may assert monophyly for the collective taxon. As the underlying synapomorphy consists in the capacity to develop synapomorphy, loss of this capacity can be regarded, under certain circumstances, as a new synapomorphy. There appears to be analogy between species genetics (pleiotropy, polygenes, suppressive genes) and supraspecific phylo- genetics. The canalized evolutionary potential exemplified through underlying synapomorphies corresponds to the potential information classes of Wiley and Brooks (1982). (Evolutionary po- tential; underlying synapomorphy; parallel selection; secondary reduction; Chironomidae.)

Panbiogeography and Vicariance Cladistics: Are They Truly Different?

Abstract: It has been claimed that the ideas contained in the panbiogeographic methodology and synthesis of Croizat (1952-1964) have been "greatly extended" to result in the vicariance cladistic approach to the study of historical biogeography (Sneath, 1982:213; also Patterson, 1981a, b). Both Craw (1982) and Croizat (1982) have argued that panbiogeography and vicariance cladistics are distinctive and rival research programs. A recent insightful analysis of the nature of branching diagrams or cladograms (Nelson and Platnick, 1981) offers a means of comparing these contradictory views.

A Phylogenetic Analysis of the Caminalcules. I. the Data Base

Abstract: les caminalcules sont un groupe «d'organisme» cree artificiellement selon des principes ressemblant aux organismes reels

Contact Zones and the Genetics of Differentiation in the Pocket Gopher Thomomys Bottae (Rodentia: Geomyidae)

Abstract: -The genetic interaction between clinally varying populations of pocket gophers (Thomomys bottae) along the eastern flank of the Sangre de Cristo Mountains in Colorado and New Mexico is examined by comparative karyology, electromorphic analysis of proteins, and colorimetric and morphometric analyses of morphology. Diploid number varies clinally along the transected populations from 76 in the south to 88 in the north. The karyotypic change is unaccompanied by electromorphic divergence as all populations studied share greater than 95% similarity, although similar clines in pelage brightness and mean morphometric coefficient of variation are evident. Individuals with intermediate diploid numbers suffer no apparent fitness deficit. The patterns of genetic interaction at the Sangre de Cristo contact are compared with four other T. bottae "contact zones" previously investigated. These five situations include differentiated parental forms which span the range of known genetic (karyological and electromorphic) divergence in the T. bottae species group, and involve both instances of reproductive isolation and extensive introgressive hybridization. Cline widths for T. bottae zones vary from approximately 1 km to 200 km, with the nature of the environmental setting at a contact being more predictive of cline width than gross measures of genetic differentiation (e.g., electromorphic distance values and chromosome numbers). [Pocket gophers; Thomomys; hybridization; chromosomes; electrophoresis; morphometrics; cline models.] During the past 15 years, we have gathered information on the dynamics of genetic, phenetic, and ecologic interactions in hybrid zones of pocket gophers of the Thomomys bottae group (Fig. 1). The philosophy behind these studies has rested on the view that detailed analyses of character variation, at geographic sites where phenotypically and/or genetically differentiated populations are in contact, provide the best means to evaluate the types of changes that may be involved in speciation in the group. Thus, the Patagonia Mountains contact (for review see Patton, 1973), where the species T. bottae and T. umbrinus hybridize but produce only F1, largely sterile offspring, emphasized the potential role of meiotic imbalance in mediating hybrid success in chromosomally differentiated forms. Other parapatric zones within T. bottae, involving both chromosomal and electromorphic differentiation (White-Sacramento Mts. [Patton et al., 1979]; Rio Grande [Smith et al., 1983]) or solely electromorphic differences (Colorado River [Smith and Patton, 1980]), emphasize that not all types of chromosomal changes will affect reproductive performance of hybrids, that hybridization potential is unrelated to the level of electromorphic differentiation, and that genic introgression may reflect only the local ecology and physiography of given regions (reviewed by Patton, 1981). In this study genetic and morphologic information are evaluated for T. bottae character clines along a narrow peninsular distribution abutting the Sangre de Cristo Mountains of Colorado and New Mexico (Fig. 1). This situation involves the addition of up to 12 extra chromosomal elements to the diploid number, yet population samples lack electromorphic differentiation. This is an unusual system of cytological differentiation,

Frogs of the Eleutherodactylus Rugulosus Group: A Cladistic Study of Allozyme, Morphological, and Karyological Data

Abstract: Le groupe Eleutherodactylus rugulosus de Savage (1975) renferme 11 especes nominales de grenouilles distribuees au Mexique et en Amerique centrale. Trois sous-groupes sont reconnus. Le sous-groupe E. fleischmanni renferme E.angelicus, E.escoces, E.fleishmanni et E. punctariolus alors que le sous-groupe E. rugulosus comprend E. azveroensis, E. berkenbuschii, E.brocchi, E.rugulosus, E.taurus et E.viscalis. Le dernier sous-groupe E.merendonensis est monotypique

Preliminary chemosystematics of the andrenidae and exocrine lipid evolution of the short-tongued bees (hymenoptera: apoidea)

Abstract: The complex arrays of lipids secreted from the exocrine Dufour's glands of short- tongued bees (Colletidae, Halictidae, Oxaeidae, Andrenidae, Melittidae) reflect both (1) occa- sional evolutionary origins of novel chemical structures, and (2) frequent re-orchestrations of suites of ancestrally derived components. Despite the rarity of unique lipid constituents, cla- distic analyses of the combinations of these diverse esters, aldehydes, lactones, hydrocarbons and carboxylic acids yield rooted phylogenies that are often either congruent with well-defined taxa or decisive for otherwise ambiguous taxonomic relationships. The short-tongued bees are chemosystematically divisable by their Dufour's gland lipids into two lineages: the "lactone-producing" bees (Colletidae, Oxaeidae, Halictinae, Nomiinae) and an andrenid-melittid-dufoureine group. Bee taxa that are soundly defined by morphological criteria-such as Perdita, Melitta, Protandrena, and the Calliopsis-Nomadopsis-Hypomacrotera group ("paraffin bees")-also appear to be monophyletic using the lipid characters. The Dufour's gland lipid products of previously unrepresented genera of the Panurginae (16 spp.), Dasypodinae (1 sp.), and Melittinae (1 sp.) are described, as are a new representative each of Andrena, Dufourea, and Melitta. (Chemosystematics; Apoidea; Andrenidae; Melittidae; lipids; Dufour's gland; bees.)

A Phylogenetic Analysis of the Caminalcules. II. Estimating the True Cladogram

Abstract: -The ability of numerical methods to estimate the true cladogram is examined, using the Caminalcules as an example. This group of "organisms" was generated artificially according to principles believed to resemble those operating in real organisms. Estimated cladograms obtained by numerical methods are only moderately good estimates of the true cladogeny. Of the various models applied in numerical cladistics, the closeness of approximation to the true cladogeny is in the following order: best-Wagner parsimony and Camin-Sokal parsimony; second-polymorphism parsimony; third-character compatibility and Fitch's nonsequential method; fourth-UPGMA phenograms; worst-Dollo parsimony. Since the data matrix contains NC (no comparison) states, numerical cladistic algorithms that take account of these states give better results than those that do not. For distance Wagner algorithms, there is little difference in the outcome between midpoint rooting and rooting with a zero vector or with the true ancestor. By separate permutations of the order of the OTUs that are input to the numerical algorithm, trees of varying length were obtained from which the shortest could be chosen. Shortest trees, computed globally over all OTUs or separately for each Caminalcule genus, are not necessarily those that best estimate the true cladogeny. Numerical cladistic estimates separately computed for genera are poorer than those based on the entire taxon. The effects of homoplasy and divergence on the results of phenetic and cladistic algorithms are investigated in general and employed to explain in detail the differences among the true cladogram, the phenogram, and the estimated cladogram. The agreements observed are all in cases where given taxa diverge greatly from ancestral stems. Discrepancies are due to (A) parallelisms in the cladogeny affecting phenetic similarities and (B) divergence of cladistically close relatives increasing the relative phenetic similarity of cladistically more distant relatives. These two cases are about equally frequent. [Phenetic classifications; cladistic classifications; estimated cladograms; homoplasy; Wagner trees; Caminalcules; numerical taxonomy.] The availability of the true cladogeny of the Caminalcules, a group of artificially created organisms, has presented an opportunity for examining various principles and practices of current interest to systematists. In a previous paper (Sokal, 1983a), I presented for the first time the images of all 77 Recent and fossil Caminalcules, definitions of their characters, and the data matrix employed in this study, as well as a cladogram of their true phylogeny. A new standard phenogram was also featured. The current study investigates the accuracy of numerical estimates of the true cladogram from an assemblage of Recent species and examines the reasons for the departure of numerical phenetic and cladistic dendrograms from the correct genealogy. The following two sets of related questions are examined in this paper. (1) How reliable are various numerical approaches for estimating the true cladogeny? Can reasons be found for their varying degrees of success? How does the nonnumerical, traditional Hennigian method compare with numerical approaches? (2) How does Hennigian classification based on the true cladogeny compare with a classification based on numerical phenetic procedures applied to the images of the Caminalcules? What evolutionary phenomena are responsible for the observed discrepancies between the phenetic classification and that based on the true cladogeny? The question of the relevance of the Caminalcules to the study of real taxonomic organisms has been discussed in Sokal (1983a) and need not be repeated here. For relevant parameters, the Recent and fossil Caminalcules provide values that resemble those resulting from data sets of real organisms. Consequently, questions raised by the Cam-

Evolutionary and Systematic Significance of Temporal Variation in the Fox Sparrow

Abstract: Morphometric variation was studied among samples of fox sparrows taken in 1926- 1927 and 1978-1980 at seven sites in California. Samples of males were taken at two of the seven sites in both 1978 and 1979, and five samples of males were measured a second time to assess measurement error. Thus, 21 groups of males (14 "main" samples, 2 samples one year apart, and 5 remeasured samples) and 14 groups of females were used in this study. Thirty-one measurements of skeletal characters were taken on 317 males and 142 females, plus on the 101 males that were remeasured. The main objective was to determine if phenotypic change had occurred over a half century, and to quantify the extent of such temporal change relative to levels and patterns of geographic variation. In the temporal samples, an average of 2.2 (7.1%) significant character differences per site was observed. Hence, most characters showed no signif- icant differences over 50 years. Character differences between remeasured, temporal, and geo- graphic samples were quantified by computing average percentage differences between char- acter means. Taxonomic distances were computed between all pairs of samples (sexes separate). Ten characters were excluded from analyses due to relatively high levels of measurement error. Percentage differences for the remaining 21 character means for remeasured samples averaged 0.33 ? SD of 0.31% and resulted in an average taxonomic distance between replicates of 0.25. Average percentage differences in character means over 50 years (0.98 ? 0.79%) were similar to geographic differences (1.14 ? 0.88%) among samples taken during the same time period. Av- erage taxonomic distance between samples taken 50 years apart (0.71 ? 0.21) was somewhat less than that between temporally comparable samples from different sites (0.84 ? 0.16). However, samples taken 50 years apart at a site can be as different as those from sites 100 to 200 km apart and assigned to different subspecies. Multivariate analysis of variance revealed that temporal samples at two (of seven) sites differed significantly, and generalized discriminant analysis obtained significant differences between temporal samples at two additional sites. Temporal phenotypic stability was evident in that the same two groupings of samples were obtained in analyses of both old and new samples. However, patterns of variation in the two time periods, within these two main groupings of samples, are not concordant because of phe- notypic change over time. That is, temporal change altered geographic patterns. Males and females showed different patterns of variation. No clear temporal trends in morphological change were identified, either in individual characters across sites, or in suites of characters within population samples. Characters with the largest relative differences over 50 years did not tend to show large geographic differences. The average taxonomic distance among old samples did not differ from that computed between recent samples; therefore, the populations at these sites are not diverging phenetically. Although the genetic basis of the phenotypic variation measured here is unknown, temporal variation could be adaptive either through phe- notypic response to environmental change or by maintaining a store of morphological vari- ability. (Sparrows; morphometrics; measurement error; temporal variation; geographic variation; microevolution.)

A Phylogenetic Analysis of the Caminalcules. IV. Congruence and Character Stability

Abstract: -The taxonomic congruence of phenetic and cladistic classifications is tested, as is the closeness of estimated cladograms to the true cladogram as a function of the number of characters employed, using the Caminalcules as an example. This group of "organisms" was generated artificially according to principles believed to resemble those operating in real organ-

Biochemical Variation in the Frog Eleutherodactylus Bransfordii: Geographic Patterns and Cryptic Species

Abstract: Eleutherodactylus bransfordii (Cope, 1886) is a highly polymorphic species of frog with a complex and interesting taxonomic history. This taxon was originally divided into mul- tiple species which were later synonymized because the morphological data did not support any unique and defining characters. The present study evaluates the current taxonomic status of E. bransfordii based on an electrophoretic comparison of six Costa Rican localities. The allo- zyme data were analyzed cladistically and geographically for patterns of relationship and ge- netic differentiation. These samples could be clustered into three distinct geographic compo- nents representing separate evolutionary lineages. The geographic and electrophoretic data suggest that at least two of these components constitute separate species reflecting different biogeographic regions. One form sampled in the Golfo Dulcean region is therefore resurrected as Eleutherodactylus stejnegerianus (Cope, 1893), and the taxon E. bransfordii is restricted to popu- lations represented by Cahuita, Cascajal, La Selva, and Monteverde. Formal taxonomic recog- nition of a second sympatric form found in the Golfo Dulcean region awaits further study. (Eleutherodactylus bransfordii; E. stejnegerianus; Costa Rica; phylogenetic relationships; geographic differentiation; cryptic species; allozymes; transformation series analysis.)

Can baptism alone save a species

Abstract: To maintain that the names of biological species are purely denotative proper names which cannot be defined is to maintain, in effect, that a biological species is confined to the actual world which is to maintain, in turn, that every property of a species is essential to it. The consequence of such a view is to render impossible the explanation of the origin and coherence of named chunks of the genealogical nexus. (Species names; essential properties; origin of species.)

Morphological and Allozymic Variation in the Stichaeid Fish Anoplarchus Purpurescens

Abstract: Morphological and allozymic variation in the stichaeid fish Anoplarchus purpurescens was compared among samples collected from open-coast localities from Alaska to California and from inner-coastal localities in Washington. We evaluated the possibility that fish from southern California (Monterey Bay southward) are genetically distinct from fish from more northern areas, which has bearing on the relevance of allozymic data from southern California fish in interpreting patterns of allozymic variation in A. purpurescens elsewhere in its geographical range. Examination of three morphological characters and 12 enzyme loci indicated the lack of genetic distinctiveness of southern California populations from more northern ones, which is consistent with the suggestion that current-mediated transport of the planktonic larvae pro- motes genetic dispersal and/or mixing among populations. The lack of genetic distinctiveness argues against the validity of a separate southern California subspecies (A. p. archolepis; Hubbs, 1927), but more importantly allows us to use the geographical pattern of muscle lactate dehy- drogenase (LDH-A) variation in California to refute the hypothesis that the A' allele is directly favored by elevated environmental temperature. Allelic frequencies in Alaska populations provide a second test of, and similarly refute, the hypothesis that elevated temperature per se selectively favors individuals with the A' allele. Although several alternative hypotheses on the evolutionary significance of LDH-A variation in A. purpurescens can be envisioned, presently a plausible one is that heterozygosity at the LDH-A locus is selectively favored by increased environmental thermal variation. This hypoth- esis is consistent not only with the geographical pattern of variation within Washington inner- coastal waters (Johnson, 1971), but also with observed changes in allelic frequencies along the outer coast both to the south (California) and to the north (Alaska). We found no significant correlation between the amount of allozymic variation (at the LDH-A and PGM loci) and morphological variation present within localities, and heterozygous fish were no more variable for meristic traits than were homozygous fish. There was no clear and consistent pattern of association between particular genotypes and morphological charac- ters. The lack of a significant relationship between enzyme and morphological traits probably is due to appreciable environmental (non-genetic) influences on the morphological characters examined, which may obscure whatever enzyme-morphological covariation exists. (Allozymes; Anoplarchus purpurescens; clines; meristic variation; natural selection; Stichaeidae.)

Character Transformations in Phenetic Studies Using Continuous Morphometric Variables

Abstract: La classification phenetique basee sur des donnees morphometriques C, mesure du squelette chez des oiseaux, 17 especes de Ciconiidae, 13 especes de Gruinae et 9 especes des genres Zonotrichia, Passerella et Melospiza) est utilisee

A Phylogenetic Analysis of the Caminalcules. III. Fossils and Classification

Abstract: -The consequences of introducing fossil species into a numerical taxonomic data, set are examined, using the Caminalcules as an example. This group of "organisms" was generated artificially according to principles believed to resemble those operating in real organisms. Inclusion of fossils into the phenetic classification introduces some nonconvex taxa at higher phenetic levels, but unites phenetically homogeneous groups of mixed Recent and fossil composition. There is good correspondence of phenetics with phylogenetic sequences. The taxonomic relationships of the phenetic classification of Recent plus fossil forms can be explained by the amount of evolutionary change known to have occurred in given internodes. All but one of the mutually closest pairs in the phenogram are ancestor-descendant pairs. Gingerich's stratophenetic method yields a reasonably good estimated cladogram, but is misled by the occurrence of homoplasy in portions of the tree. Adding fossils improves estimates of the true cladogram based on the distance Wagner method but not estimates based on the Wagner parsimony algorithm. Estimated cladograms approach the true cladogram more closely than phenograms do, yet even the best estimate including the fossils has a strict consensus index no higher than 0.667. There are 10 characters that define genera. Their removal from the data base affects phenetic classifications slightly, cladistic classifications somewhat more. A cladistic classification of the Recent Caminalcules unnecessarily raises the ranks of some taxa. The less speciose and more symmetrical taxa emerge at lower taxonomic ranks than more speciose and asymmetrical taxa. Adding fossils to the Caminalcules requires a greater number of ranks for a cladistic than for a phenetic classification. [Phenetic classifications; cladistic classifications; classification of fossils; stratophenetics; Caminalcules; numerical taxonomy.] The availability of the true cladogeny of the Caminalcules, a group of artificially created organisms, has presented an opportunity for examining various principles and practices of current interest to systematists. In an earlier paper (Sokal, 1983a), I presented the images of all 77 Recent and fossil Caminalcules, definitions of their characters and the data matrix employed in this study, as well as a cladogram of their true phylogeny. A new standard phenogram was also featured. In a second paper (Sokal, 1983b), I examined the efficacy of numerical cladistic methods for finding the true cladogram from an assemblage of Recent species and examined the reasons for the departure of numerical phenetic and cladistic dendrograms from the correct genealogy. The current study deals with the consequences of introducing fossil species into a taxonomic data set, using the Caminalcules as a test case. It is of interest to compare the classifications obtained by numerical phenetic and numerical cladistic techniques in such a data set. Does introduction of fossil species simplify or complicate phenetic classifications, will it improve or worsen estimated cladograms, and does it widen or narrow the discrepancy between the two kinds of dendrograms? Knowing the true cladogram, including all fossils and the evolution of characters upon it, permits investigations of some additional taxonomic and evolutionary questions. I have already reported on various types of tree statistics and evolutionary rates (Sokal, 1983a). Here I examine whether a hierarchy of taxonomic characters can be said to exist. Furthermore, I look into the classifications that result when the Caminalcules are classified on the basis of phenograms or of cladograms, with or without the fossils. The Caminalcules are unusual as taxonomic objects in that they include all fossil members of the taxon up to and including their most recent common ancestor. The presence of fossils among the OTUs of a data set create prob-

On the phylogeny of the glossophaginae and the proper use of outgroup analysis

Abstract: In two recent papers on the phylogeny of phyllostomid bats, Hood and Smith (1982) and Haiduk and Baker (1982) commented unfavorably on my recent cladistic analysis of the New World nectar-feeding bats (Griffiths, 1982). Both pairs of authors suggested that (1) my outgroup comparisons were incorrect, and (2) my character analysis was incorrectly performed. Haiduk and Baker (1982) went so far as to redo the character analysis and claimed that my hyoid/tongue morphology data better supported the branching sequence suggested by them than the one I presented (Griffiths, 1982). Despite the alleged errors in my analysis, both Hood and Smith (1982) and Haiduk and Baker (1982) admitted that at least parts of my conclusions seemed to be correct. Neither paper mentioned that for the first time in the 15 years the nectar-feeding bat problem has been intensively examined, two phylogenies-produced independently and based on unrelated data sets-are remarkably congruent (Baker et al. [1981] and Haiduk and Baker [1982] using biochemical and karyotypic data; Griffiths [1982] using hyoid/ tongue morphology data). Except for very minor differences in the exact relationship of Hylonycteris and Choeroniscus and a minor disagreement on the relationships of the three "brachyphylline" genera, the only difference in the two cladograms produced is in the treatment of the genera Lonchophylla and Lionycteris. Haiduk and Baker (1982) indicated that the two genera are relatively derived members of the subfamily Glossophaginae. On the other hand, I suggested (Griffiths, 1982) that the two genera evolved nectivory independently of the "true" glossophagines. I indicated further that no synapomorphous character state was known that united Lonchophylla and Lionycteris with the "true" glossophagines and, until such a character state was found, Lonchophylla and Lionycteris (along with Platalina which Haiduk and Baker did not karyotype) might best be placed in a separate subfamily, the Lonchophyllinae. In this note, I respond to the allegations that my outgroup comparisons were incorrect. In addition, I show that Haiduk and Baker (1982) are quite incorrect in their assertion that my hyoid/tongue data support the placement of Lonchophylla and Lionycteris as relatively derived glossophagine bat genera. Outgroup comparisons are made to determine correct character polarity within the group one is studying and, most especially, to determine which character states are synapomorphies, which are autapomorphies, and which are symplesiomorphies. When studying the relationships of the genera within the taxonomic group A, it is obviously important to study also outgroup representatives from all closely related sister groups (B and C), as well as representatives from more primitive groups (D) that are thought to be derived from the direct ancestor of A, B, and C. Without so doing, the systematist fails to get an accurate idea of the polarity of characters and of the uniqueness of the synapomorphies in the group (A) in question. Unitl recently, in a study of the relationships within the taxon Glossophaginae, there was no way of determining which other groups were closely-related sister groups (B and C) and which were modern representatives of ancestral groups (D). This was because no study had been done that showed the relationships of the Glossophaginae to other bat taxa. In the absence -of a definitive study, Haiduk and Baker (1982) are entitled to their opinion of the proper outgroups to use, as am I. Such a definitive study (Hood and Smith, 1982) has now been done,

Irreversibility: A Comment on Macbeth's Interpretations

Abstract: Macbeth (1980), writing about irreversibility, found a conflict between Lande (1978) and Wright's (1968) views and those of Simpson (1953) and Laurent (1964), although he stated from the beginning that the authors concern themselves with two different phenomena. The first is that "evolution never goes into reverse in a big way"; the second that "evolution frequently goes into reverse in a small way." I think the purported conflict does not really exist. Lande's model actually belongs to the second category of simple reversibilities. Indeed, complex organs may well reappear sometimes, if their former disappearance resulted from the action of a suppressor regulatory gene(s), that in turn disappears. The catch is that the structure had not really disappeared; it was still there, genetically. Two herpetological examples can be mentioned in this respect. Frogs and toads have no teeth on the lower jaw. However, some have odontoids, which is in line with Dollo's law. More unexpected is the case of Amphignathodon, a genus of marsupial frogs, which has real teeth, in spite of its close relationships with some species of Gastrotheca like G. cornuta. The most likely explanation is the lifting of a very old inhibition. According to Walls' (1942) theory of the origin of snakes, the eyes have been atrophied in their fossorial ancestors, only to reappear, although somewhat different in the flourishing descendants. Again, the suppression of a suppressor is a likely explanation. When it comes to the really big irreversibility-"the unreeling of a movie film"which is a far cry from the reappearance of a lost organ (however complex), I can only reassert its high degree of improbability. An original limb structure can reappear without posing an intractable problem, but a return from Equus to Hyracotherium through Pliohippus, Merychippus, Miohippus, Mesohippus, Epihippus and Orohippus is a practical impossibility, whether the mechanisms are neatly genetic or hazily epigenetic.

Karyotypic megaevolution and phylogenetic analysis: new world nectar-feeding bats revisited

Abstract: The phylogenetic relationships among the genera of the New World nectar-feeding bats, subfamilies Glossophaginae sensu lato and Brachyphyllinae of the Phyllostomidae (see Handley [1980] for justification of this family name), have been disputed for over 15 years (see review in Griffiths, 1982). Most recently, Haiduk and Baker (1982) published a hypothesis of "glossophagine" relationships based on a cladistic analysis of chromosomal G-band patterns. Their paper is clearly a reply to Griffiths' (1982) hypothesis based on an analysis of hyoid and lingual morphology of these nectar-feeding bats. The use of multiple data sets provides a powerful tool for developing robust phylogenetic hypotheses, but it also complicates the process as discordances often arise (Straney, 1980; Arnold et al., 1982). Resolution of discordances is a necessary adjunct of the process of hypothesis building. While Haiduk and Baker (1982) claimed a reanalysis of Griffiths' data indicates that the most "parsimonious" cladogram consistent with the morphological information is identical to their cladogram based on chromosomal data, this is not necessarily true, as I will document below. Additionally, I amplify the underlying assumptions of Haiduk and Bakers' analysis and discuss some of the alternative interpretations of the several sets of data now available which bear on the issue of "glossophagine" relationships. The basic premise of phylogenetic reconstructions based on chromosomal preparations is that homologous elements can be identified among karyotypes and, thus, synapomorphic rearrangements can be discerned; homology, in this case, is assessed by visual appraisal of similarity in banding pattern (including number), relative staining intensity of bands, and relative spacing between bands. This further assumes that chromosomal rearrangements are generally unique events (i.e., homoplasy is rare; I will presume this to be true although it is not necessarily so). An additional assumption relied on by Haiduk and Baker (1982) is that the primitive karyotype for the Phyllostomidae is like that of Macrotus. Although I have doubts about identifying a karyotype as plesiomorphic for the whole family, since outgroup comparison cannot be performed (see Baker and Bickham, 1980), one can tentatively allow this assumption. I am not convinced, however, that they, or anyone else, can unambiguously identify a sufficient number of chromosomal homologies in the karyotypes of "glossophagine"' bats to support the cladogram they present. For instance, the major difference between Haiduk and Bakers' (1982) and Griffiths' (1982) cladograms are the positions of Lonchophylla, Lionycteris, and Platalina (compare Figs. la and lb). There are only two chromosomal synapomorphies that would place these three genera within the glossophagine (sensu stricto) clade, a 13/2 fusion and the presence of arm E. Unfortunately, a karyotype indicating the numbering system for chromosomal arms they used was not presented in Haiduk and Baker (1982), nor was it referenced; this information is in Baker (1979) and Baker and Bass (1979). A 13/2 fusion would require a minimum of three rearrangements from the supposed primitive karyotype of the group, that of Glossophaga (Baker and Bass, 1979). These rearrangements are a 13/28 fission, a 2/18 fission, and then a 13/2 fusion (alternatively, a 13/2 chromosome could result from a reciprocal translocation). Based upon the chromosomal spreads presented in Baker and Bass (1979) and Haiduk and Baker (1982), I cannot see a clear basis for distinguishing between a "13/2" chromosome, a " 13/18" chromosome, or a "2/28"

Chromosomal and Genic Divergence in Mammals

Abstract: -The relationship between genic and chromosomal distance was examined for 11 sets of mammalian taxa using a matrix regression procedure. Nine of the 11 comparisons were statistically significant, indicating a lack of independence between genic and chromosomal evolution, but not necessarily a causal relationship. The covariation of genic and chromosomal distance may be related to population structure. Genic and chromosomal evolution would be affected in a similar way by a population structure that is sensitive to the influence of genetic drift and inbreeding. [Chromosomal evolution; genic evolution; population structure; genetic drift; divergence time.] Genetic differentiation is the basis of evolutionary change. Even closely related species usually differ in karyotype and have differences in structural genes as shown by electrophoresis. Numerous studies have documented genic and karyotypic differences between taxa; however, the concordance between genic and chromosomal change during and subsequent to speciation is poorly understood. For example, fish species of the speciose family Centrarchidae show considerable genic divergence, but almost all of the species in the family have the same diploid and fundamental number of chromosomes (Avise et al., 1977; Avise and Gold, 1977). On the other hand, Baccus et al. (1983) reported fairly high associations between measures of genic and chromosomal divergence within a group of artiodactylid species and within populations of a pocket gopher, Thomomys talpoides. Schnell and Selander (1981) summarized recent data of electrophoretic and karyotypic patterns of variation in mammals and concluded that karyotypic and genic evolution proceed more or less independently. However, their support for the independence of genic and chromosomal evolution is based upon only a few examples, and to date a more detailed study comparing genic and chromosomal divergence of a variety of taxa has not been undertaken. The purpose of our study was to examine statistically the relationship between measures of genic and chromosomal differentiation in a number of mammalian taxa in order to test more rigorously the relationship between genic and karyotypic evolution.

Archetypes and Ancestors-Palaeontology in Victorian London 1850-1875.

Abstract: \"The social construction of scientific knowledge, clearly one of the most exciting trends in the history of science in the 1890's, has made a solid stride forward with the publication of \"Archetypes and Ancestors.\" . . . Adrian Desmond set out to determine how much light might be shed on the mid-Victorian controversies over fossil reconstruction by an investigation of the ideological commitments and political programs of London paleontologists. The answer is: a great deal of light. The resulting book is thoroughly fascinating.\" Philip Rehbock, \"American Historical Review\" \"A sophisticated study of the colonization of scientific territory specifically of rival attempts to design the dinosaur and of the constructive (not just obstructive) role of social pressures in the making of 'lasting contributions' to science. Not least it is a joy to read, perkily irreverent at times and full of nice vignettes and memorable turns of phrase.\" Roy Porter, \"Times Higher Education Supplement \"\