Phylogenies based on combined mitochondrial and nuclear sequences conflict with morphologically defined genera in the eimeriid coccidia (Apicomplexa)

Partial mitochondrial (mt) cytochrome c oxidase subunit I (COI) and near-complete nuclear (nu) 18S rDNA sequences were obtained from various eimeriid coccidia infecting vertebrates. New and published sequences were used in phylogenetic reconstructions based on nu 18S rDNA, mt COI and concatenated sequence datasets. Bayesian analyses of nu 18S rDNA sequences used secondary structure-based alignments with a doublet nucleotide substitution model; the codon nucleotide substitution model was applied to COI sequences. Although alignment of the mt COI sequences was unambiguous, substitution saturation was evident for comparisons of COI sequences between ingroup (eimeriid) and outgroup (sarcocystid) taxa. Consequently, a combined dataset applying partition-specific analytical and alignment improvements was used to generate a robust molecular phylogeny. Most eimeriid parasites that infect closely related definitive hosts were found in close proximity on the resulting tree, frequently in a single clade. Whether this represents coevolution or co-accommodation or a combination remains an open point. Unlike host associations, basic oocyst configuration (number of sporocysts per oocyst and sporozoites per sporocyst) was not correlated with phylogeny. Neither ‘Eimeria-type’ nor ‘Isospora-type’ oocyst morphotypes formed monophyletic groups. In the combined dataset tree (representing only a tiny fraction of described eimeriid coccidia), at least 10 clades of Eimeria spp. would need to be re-assigned to nine distinct genera to resolve their paraphyly. The apparent lack of congruence between morphotype and genotype will require taxonomists to balance nomenclatural stability and diagnostic ease against the ideal of monophyletic genera. For now, recognition of paraphyletic eimeriid genera defined by basic oocyst configuration may be necessary for reasons of taxonomic stability and diagnostic utility. Future taxonomic revisions to produce monophyletic eimeriid genera will ultimately require the identification of reliable phenotypic characters that agree with the molecular phylogeny of these parasites or, less optimally, acceptance that genotyping may be needed to support monophyletic supraspecific taxonomic groups.     

Phylogenetic analyses of marine sponges within the order Verongida: a comparison of morphological and molecular data

Abstract. Because the taxonomy of marine sponges is based primarily on morphological characters that can display a high degree of phenotypic plasticity, current classifications may not always reflect evolutionary relationships. To assess phylogenetic relationships among sponges in the order Verongida, we examined 11 verongid species, representing six genera and four families. We compared the utility of morphological and molecular data in verongid sponge systematics by comparing a phylogeny constructed from a morphological character matrix with a phylogeny based on nuclear ribosomal DNA sequences. The morphological phylogeny was not well resolved below the ordinal level, likely hindered by the paucity of characters available for analysis, and the potential plasticity of these characters. The molecular phylogeny was well resolved and robust from the ordinal to the species level. We also examined the morphology of spongin fibers to assess their reliability in verongid sponge taxonomy. Fiber diameter and pith content were highly variable within and among species. Despite this variability, spongin fiber comparisons were useful at lower taxonomic levels (i.e., among congeneric species); however, these characters are potentially homoplasic at higher taxonomic levels (i.e., between families). Our molecular data provide good support for the current classification of verongid sponges, but suggest a re-examination and potential reclassification of the genera Aiolochroia and Pseudoceratina . The placements of these genera highlight two current issues in morphology-based sponge taxonomy: intermediate character states and undetermined character polarity.     

An Eimeriid origin of isosporoid coccidia with Stieda bodies as shown by phylogenetic analysis of small subunit ribosomal RNA gene sequences

Morphological and life cycle features of the tissue cyst-forming coccidia have been difficult to interpret in devising taxonomic classifications for the various genera. In this study, we amplified the full small subunit rRNA gene sequence of Isospora robini McQuistion and Holmes, 1988, and the partial sequence of Isospora gryphoni Olsen, Gissing, Barta, and Middleton, 1998 by PCR. Both of these species vary from Isospora species of mammals in having Stieda bodies on the sporocysts. The sequences were cloned and sequenced and were incorporated into an alignment with other Isospora species lacking Stieda bodies as well as with other coccidia. Maximum parsimony analysis of these sequences produced a single most parsimonious tree that placed I. robini and I. gryphoni in a clade containing various other eimeriid species. The Isospora species lacking Stieda bodies were in the sarcocystid clade. Similar results were found by maximum likelihood analysis. These findings indicate that the genus Isospora as defined by several authors is polyphyletic. Taxonomic changes to the genus Isospora would have to incorporate the 2 major clades found by molecular phylogenetic analysis. Isospora species with Stieda bodies should be classified in the family Eimeriidae, whereas those without Stieda bodies should remain in the family Sarcocystidae.     

Further comment on the coccidian nature of cryptosporidia (Sporozoa: Apicomplexa)

The coccidian nature of the genus Cryptosporidium was undoubtedly accepted by Tyzzer who was the first to describe this sporozoan parasite in 1907. Electron microscopic studies made in 70-90s demonstrated the intracellular, although extracytoplasmic localization of Cryptosporidium spp. The pattern of Cryptosporidium life cycle fits well that of other intestinal homogeneous coccidian genera of the suborder Eimeriina: macro- and microgamonts develop independently, a microgamont gives rise to numerous male gametes, oocysts serving for parasite's spreading in the environment. Along with these characters, Cryptosporidium spp. demonstrate some secondary peculiarities (an endogenous phase of development in microvilli of epithelial surfaces, two morphofunctional types of oocysts, the smallest number of sporozoites per oocyst, a multi-membraneous "feeder" organelle etc.), which may be due presumably to their early acquisition of specialization in the course of evolution. The recent studies based on molecular sequence data (18S rRNA) applied to 8 eimeriid and isosporid coccidian genera (Morrison, Ellis, 1997), suggested that the subclass Coccidia (class, according to Morrison and Ellis) be considered monophylic if Cryptosporidium were excluded, and this genus was regarded as the sister group to the rest of the Apicomplexa, or as the sister to the suborder (class) Hematozoa within the Apicomplexa. Either of these placements of Cryptosporidium definitely conflicts with both the generally accepted taxonomic scheme by Levine (1982) and the phenotypically based phylogeny of the phylum Apicomplexa (Barta e. a., 1990). The author's opinion is that the differences between the examined eimeriid and isosporid coccidia, on the one hand, and Cryptosporidium, on the other hand, provided by molecular sequence data, may testify primarily to the well known morphofunctional dissimilarities between the compared organisms, rather than cast doubt on the coccidian nature of Cryptosporidium. Again, these data can hardly prove that Cryptosporidium does not belong to the coccidia. Thus, the modern molecular sequence data, despite their obvious scientific value, would make sense for phylogeny estimation only, if they are critically analysed and considered in combination with results of the relevant basic research.     

Phylogenetics and evolution of Capitata (Cnidaria: Hydrozoa), and the systematics of Corynidae

Nawrocki, A. M., Schuchert, P. & Cartwright, P. (2009). Phylogenetics and evolution of Capitata (Cnidaria: Hydrozoa), and the systematics of Corynidae.—Zoologica Scripta, 39, 290–304. Generic‐ and family level classifications in Hydrozoa have been historically problematic due to limited morphological characters for phylogenetic analyses and thus taxonomy, as well as disagreement over the relative importance of polyp vs. medusa characters. Within the recently redefined suborder Capitata (Cnidaria: Hydrozoa: Hydroidolina), which includes 15 families and almost 200 valid species, family level relationships based on morphology alone have proven elusive, and there exist numerous conflicting proposals for the relationships of component species. Relationships within the speciose capitate family Corynidae also remain uncertain, for similar reasons. Here, we combine mitochondrial 16S, and nuclear 18S and 28S sequences from capitate hydrozoans representing 12 of the 15 valid capitate families, to examine family level relationships within Capitata. We further sample densely within Corynidae to investigate the validity of several generic‐level classification schemes that rely heavily on the presence/absence of a medusa, a character that has been questioned for its utility in generic‐level classification. We recover largely congruent tree topologies from all three markers, with 28S and the combined dataset providing the most resolution. Our study confirms the monophyly of the redefined Capitata, and provides resolution for family level relationships of most sampled families within the suborder. These analyses reveal Corynidae as paraphyletic and suggest that the limits of the family have been underestimated. Our results contradict all available generic‐level classification schemes for Corynidae. As classification schemes for this family have been largely based on reproductive characters such as the presence/absence of a medusa, our results suggest that these are not valid generic‐level characters for the clade. We suggest a new taxonomic structure for the lineage that includes all members of the newly redefined Corynidae, based on molecular and morphological synapomorphies for recovered clades within the group.     

放线菌的分子分类

在放线菌分类学研究中,最初是根据形态特征、生理生化特征等表观分类学特征进行研究。随着分子生物学的飞速发展,放线菌的分类鉴定亦从传统的表型分类进入到各种基因型分类水平。分子分类在放线菌分类研究中起到越来越重要的作用,目前放线菌的分子分类研究主要包括:G Cmol%测定、DNA杂交、核酸结构分析以及DNA指纹图谱分析等方面。     

When taxonomy meets genomics: lessons from a common songbird

Taxonomy is being increasingly informed by genomics. Traditionally, taxonomy has relied extensively on phenotypic traits for the identification and delimitation of species, though with a growing influence from molecular phylogenetics in recent decades. Now, genomics opens up new and more powerful tools for analysing the evolutionary history and relatedness among species, as well as understanding the genetic basis for phenotypic traits and their role in reproductive isolation. New insights gained from genomics will therefore have major effects on taxonomic classifications and species delimitation. How a genomics approach can inform a flawed taxonomy is nicely exemplified by Mason & Taylor ( 2015 ) in this issue of Molecular Ecology. They studied redpolls, which comprise a genus (Acanthis) of fringillid finches with a wide distribution in the Holarctic region, and whose species taxonomy has been a matter of much controversy for decades (Fig.  1 ). Current authoritative checklists classify them into one, two or three species, and five or six subspecies, based largely on geographical differences in phenotypic traits. Previous studies, including a recent one of the subspecies on Iceland (Amouret et al. 2015 ), have found no evidence of differentiation between these taxa in conventional molecular markers. The lack of genetic structure has been interpreted as incomplete lineage sorting among rapidly evolving lineages. Now Mason & Taylor ( 2015 ), using a large data set of genomewide SNPs, verify that they all belong to a single gene pool with a common evolutionary history, and with little or no geographical structuring. They also show that phenotypic traits used in taxonomic classifications (plumage and bill morphology) are closely associated with polygenic patterns of gene expression, presumably driven by ecological selection on a few regulatory genes. Several lessons can be learned from this study. Perhaps the most important one for taxonomy is the risk of taxonomic inflation resulting from overemphasizing phenotypic traits under local adaptation and ignoring a lack of phylogenetic signal in molecular markers.     

A Model for Taxonomic Work on Homoxenous Coccidia: Redescription, Host Specificity, and Molecular Phylogeny of Eimeria ranae Dobell, 1909, with a Review of Anuran-Host Eimeria (Apicomplexa: Eimeriorina)

ABSTRACT. We attempt to extend knowledge of anuran Eimeria , and to provide a model for a complex approach to studies on coccidia. New host and geographic records of coccidia in European Anura are provided. In the second part, Eimeria ranae Dobell, 1909 is redescribed from European terrestrial frogs of the genus Rana based on light microscopic and ultrastructural data on both exogenous and endogenous developmental stages, host specificity, and molecular phylogenetic data. Results of experimental transmissions show for the first time that the host specificity of E. ranae is restricted to the genus Rana and that isolates from tadpoles and adults are conspecific. Disappearance of infection during metamorphosis was confirmed experimentally, suggesting that infections in adults result from reinfections. Poikilotherm-host Eimeria species possessing a Stieda body (SB) are for the first time included in a molecular phylogenetic analysis. Eimeria ranae and Eimeria arnyi from a colubrid snake form together a well-supported clade, basal to other SB-bearing coccidia. The other analysed reptile–host eimerians, Eimeria tropidura and Choleoeimeria sp., which possess bivalved sporocysts and lack a SB, represent a distinct basal lineage of the eimeriid clade. The third part of the article reviews anuran-host Eimeria . Three distinct oocyst morphotypes, apparently correlating with the character of endogenous development, are recognized and characterized among anuran eimeriids.     

A preliminary phylogenetic study of late Palaeozoic spiriferoid brachiopods using cladistic and Bayesian approaches

The brachiopod Superfamily Spiriferoidea diversified greatly and was widely distributed in the late Palaeozoic (Carboniferous–Permian), and yet its phylogeny has been seldom investigated with analytical methods. This is reflected in the current flux of very different classification schemes for this superfamily. This paper provides the first attempt to investigate the phylogenetic relationships of spiriferoid brachiopods through both cladistic and Bayesian analyses involving 24 discrete and continuous characters. The continuous characters, from morphometric data, have been separately discretized using the gap weighting method, and the ‘as such’ option in TNT. Our results highlight the potential significance of continuous characters in reconstructing and elucidating phylogenies, as much as qualitative characters. Building on the outcomes of the analyses, we also briefly evaluate existing classification schemes of Spiriferoidea. We found that none of the existing classifications fully reflect the phylogeny properly; major families within the superfamily, such as Spiriferidae, Choristitidae, and Trigonotretidae, turned out to be polyphyletic. Although this study is considered preliminary, due to the selection of and restriction to certain taxa, combined with the use of a relatively small number of characters, it nevertheless demonstrates that potentially the true phylogenetic relationships of spiriferoid taxa sharply contrast with any of the existing classification schemes. This highlights the need to develop an alternative scheme that takes into account a more comprehensive range of phylogenetic variables.     

醋酸菌多相分类研究进展

醋酸菌是一大群革兰氏染色阴性、绝对好氧的细菌的总称, 能将乙醇或糖类不完全氧化为有机酸。醋酸菌的分类在近30年经历了很大变化, 早期的分类系统主要以表型和生化特征为基础。如今, 大多采用结合表型、化学分类法和基因型数据的多相分类法对醋酸菌进行分类。本文综述了醋酸菌的多相分类研究进展, 主要介绍了醋酸菌的现行分类情况及表型分类、化学分类和基因分型等方法在醋酸菌分类中的应用。     

中国白蛉亚科数值分类研究（双翅目: 毛蠓科）

【目的】 对中国白蛉亚科（Phlebotominae）昆虫进行数值分类研究, 探索其在系统发育过程中的亲缘关系。【方法】 选取中国白蛉40个蛉种作为分类单元以及白蛉的68项形态特征为分类指标, 进行系统聚类分析。【结果】 聚类分析结果与传统属级及白蛉属Phlebotomus的亚属级分类一致。司蛉属Sergentomyia的亚属分类与传统分类有一些区别, 聚类分析将司蛉属分为8类, 其中尼克组nicnic group与司蛉亚属subgenus Sergentomyia和传统分类一致; 泉州司蛉S. quanzhouensis和唐氏司蛉S. tangi聚入帕蛉亚属subgenus Parrotomyia; 尹氏司蛉S. yini聚入新蛉亚属subgenus Neophlebotomus, 应氏司蛉S. iyengari、马来司蛉S. malayensis、吐鲁番司蛉S. turfanensis、兰州司蛉S. lanzhouensis和南京司蛉S. nankingensis聚为一类; 歌乐山司蛉S. koloshanensis、方亮司蛉S. fanglianensis和云南司蛉S. yunnanensis与尼克组nicnic group聚成一类, 此类群和此属中其他蛉种系统发育关系距离远。【结论】 中国白蛉亚科昆虫的聚类分析结果与传统分类基本一致, 验证了传统分类系统的可靠性, 并揭示了传统分类中一些蛉种不确定分类问题。司蛉属聚类分析结果与传统分类有差别, 提示有个别蛉种需重新考虑其分类地位。     

Phylogenetic significance of morphological characters in the taxonomy of Pestalotiopsis species

There has been considerable disagreement regarding the relationships among Pestalotiopsis species and their delimitations. A molecular phylogenetic analysis was conducted on 32 species of Pestalotiopsis in order to evaluate the utility of morphological characters currently used in their taxonomy. Phylogenetic relationships were inferred from nucleotide sequences in the ITS regions and 5.8S gene of the rDNA under four optimality criteria: maximum parsimony, weighted parsimony, maximum likelihood, and neighbor joining. Phylogenies estimated from all analyses yielded trees of essentially similar topology and revealed 3 major groups that correspond with morphology-based classification systems. Molecular data indicated that the genus contains two distinct lineages based on pigmentation of median cells and four distinct groupings based on morphology of apical appendages. The analyses did not support reliability of other phenotypic characters of this genus, such as spore dimensions. Characters with particular phylogenetic significance are discussed in relation to the taxonomy of Pestalotiopsis.     

Molecular phylogeny of the other tissue coccidia: Lankesterella and Caryospora

Nearly complete sequences were obtained from the 18S rDNA genes of Eimeria falciformis (the type species of the genus), Caryospora bigenetica, and Lankesterella minima. Two clones of the rDNA gene from C. higenetica varied slightly in primary structure. Parsimony-based and maximum likelihood phylogenetic reconstructions with a number of other apicomplexan taxa support 2 major clades within the Eucoccidiorida, i.e., the isosporoid coccidia (consisting of Toxoplasma, Neospora, Isospora [in part], and Sarcocystis spp.) and a second clade containing Lankesterella and Caryospora spp., as well as the eimeriid coccidia (Cyclospora, Isospora [in part], and Eimeria spp.). Our observations suggest that Caryospora spp. may not belong in the family Eimeriidae but rather may be allied with the family Lankesterellidae with which they share molecular and life history similarities. This may be a third lineage of coccidian parasites that has independently evolved a unique heteroxenous transmission strategy.     

Concepts of rational taxonomy

The problems are discussed related to development of concepts of rational taxonomy and rational classifications (taxonomic systems) in biology. Rational taxonomy is based on the assumption that the key characteristic of rationality is deductive inference of certain partial judgments about reality under study from other judgments taken as more general and a priory true. Respectively, two forms of rationality are discriminated--ontological and epistemological ones. The former implies inference of classifications properties from general (essential) properties of the reality being investigated. The latter implies inference of the partial rules of judgments about classifications from more general (formal) rules. The following principal concepts of ontologically rational biological taxonomy are considered: "crystallographic" approach, inference of the orderliness of organismal diversity from general laws of Nature, inference of the above orderliness from the orderliness of ontogenetic development programs, based on the concept of natural kind and Cassirer's series theory, based on the systemic concept, based on the idea of periodic systems. Various concepts of ontologically rational taxonomy can be generalized by an idea of the causal taxonomy, according to which any biologically sound classification is founded on a contentwise model of biological diversity that includes explicit indication of general causes responsible for that diversity. It is asserted that each category of general causation and respective background model may serve as a basis for a particular ontologically rational taxonomy as a distinctive research program. Concepts of epistemologically rational taxonomy and classifications (taxonomic systems) can be interpreted in terms of application of certain epistemological criteria of substantiation of scientific status of taxonomy in general and of taxonomic systems in particular. These concepts include: consideration of taxonomy consistency from the standpoint of inductive and hypothetico-deductive argumentation schemes and such fundamental criteria of classifications naturalness as their prognostic capabilities; foundation of a theory of "general taxonomy" as a "general logic", including elements of the axiomatic method. The latter concept constitutes a core of the program of general classiology; it is inconsistent due to absence of anything like "general logic". It is asserted that elaboration of a theory of taxonomy as a biological discipline based on the formal principles of epistemological rationality is not feasible. Instead, it is to be elaborated as ontologically rational one based on biologically sound metatheories about biological diversity causes.     

L'analyse et la synthèse en systématique végétale

Analysis and synthesis have been widely used in systematics since, at least, the XIXth Century. Even now, the four major authors (Cronquist, Dahlgren, Takhtajan, Thorne) of angiosperm systems use “synthetic” to qualify their classifications. This word — synthetic or synthesis — has many different meanings that can create ambiguity. Among these meanings, is there one that can be justifiably used to define biological classifications? Although much more than the following applications can be found in the botanical literature, this paper will mainly deal with six meanings which are still in use in contemporary systematics. A synthetic classification has been understood as a classification built upward, from the lower to the higher categories. If we define synthesis as the operation that starts with elements and proceeds to a whole, then upward classification could be viewed as a synthesis in which the concept of hierarchy plays a primordial role, a role that is not initially a part of synthesis. Moreover, synthesis cannot replace all classificatory processes, and other criteria of taxa must be used in addition to synthesis Historically, synthesis has replaced analysis; the latter being employed by Linnaeus in his sexual system. Indeed, Linnaeus used a divisive method in producing his classification; and since division was seen as synonymous to analysis and recognized as a method that led to artificial taxa, leading French taxonomists Adanson, Lamarck and A.-L. de Jussieu among others, rejected analysis and viewed their classifications as synthetic, i.e., based on the natural method. Therefore, a system of value took place: natural was better than artificial, synthesis better than analysis. Reinforcing the importance of synthesis was the belief in a concept widely accepted at the end of the XVIIIth Century: that of continuity. Linking groups and forming a continuum was a procedure eminently synthetic. Such a procedure, known as “chaining”, produced series or sequences of taxa. Analysis was used solely to express the idea of dichotomous or analytical keys, a Lamarckian innovation that enabled taxonomists to identify plants. But whether classifications are built from lower to higher categories (a synthesis of taxa) or from higher to lower categories (an analysis of taxa), another simultaneous, concomitant movement is implied: with the latter, a synthesis of characters, with the former, an analysis of characters. Therefore, a synthetic classification is nevertheless an analytical classification.Basing groups on resemblance instead of difference, results in yet another application of synthesis. This application is probably due to the analogy with “composition”. Already, a separation between resemblance and difference among characters is an analysis. More important, still, is that at a certain rank some characters are used to join whereas, at another rank, they separate. Thus, depending on ranks and taxa, characters are applied in a synthetic or analytical procedure. Here also, other criteria are needed to support group delimitation.In connection with the upward (synthetic) movement in classifying taxa, the use of a great number of characters was also considered to be synthesis. This has been a recurring theme in taxonomy over the last two centuries and was sometimes seen as the Gilmourian approach to classification. When would we be justified to talk about synthesis? After how many characters? In fact, it is not the number of characters that matters but how characters are handled. The use of many characters has been closely linked to the idea of natural groups and its joining with synthesis seems to derive from the association of “natural” and “synthetic”.Synthetic classifications equally imply the common idea that they must represent a résumé of information stemming from all biological fields or disciplines. If classifications portray evolution, as many systematists suggest, then it cannot be just a résumé. And one must first decide what classifications are about: a controversial subject among different schools of thought in taxonomy. This explains another meaning attached to synthesis. Biological classifications have been said to be a synthesis or résumé of two types of information: that of similarity and that of phylogeny. Anagenesis is sometimes viewed as incremental to classification and makes up for a third type of information. Even though taxonomists would (for once!) agree that a classification should be based on phenetic, cladogenetic and anagenetic data, such a classification cannot qualify as a synthesis since it is not a composition and does not meet the definition given above (an operation that starts with elements and goes on to a whole). It is impossible to represent these three types of data together in one classification scheme; they express three, sometimes irreducible, points of view. For such a classification, the word “eclectic” is preferable and closer to reality.The use of synthesis as one term of the dialectical movement has made hesitant steps in taxonomy. Indeed, the two opposed theses that evolve into the synthesis are hardly met in classification and the “dialectical” synthesis promulgated by a few taxonomists can be referred back to synthesis as a résumé.Is classification synthetic because it appears to be based on inductive procedures, as it is sometimes implied by different authors who link deduction and analysis (stemming from downward classification)? In logic, synthesis is sometimes (and questionably so) associated with deduction. Moreover, synthesis cannot follow from induction which deals, for example, with the universality of characters. In that sense, there is no composition and so no synthesis. Thus, although induction has been part of classification, it is not a synthetic method.Apart from the ambiguity originating from the multiple meanings of the word “synthesis” in the context of taxonomy, synthetic classifications do not fully express all the complexity and procedures that lead to it. Actually, a classification is as much a synthesis as an analysis. Both methods are complementary, and should not be opposed as is sometimes the case. This opposition was implicit in the debate between Linneans and Jussieans, surrounding the development of the natural method. If one wants to use “synthetic”, then one should be explicit about its meaning. Taxonomists should also be aware of the incompleteness of synthesis in constructing a classification and should be careful not to create a system of value based upon philosophical ground. They should always prefer a complementary mode of thinking when feasible, instead of an “either-or” approach.     

Taxonomic Implications of a Field Study of Morphotypes of Hanuman Langurs (<Emphasis Type="Italic">Semnopithecus entellus</Emphasis>) in Peninsular India

The Hanuman langur is one of the most widely distributed and morphologically variable non-human primates in South Asia. Even though it has been extensively studied, the taxonomic status of this species remains unresolved due to incongruence between various classification schemes. This incongruence, we believe, is largely due to the use of plastic morphological characters such as coat color in classification. Additionally these classification schemes were largely based on reanalysis of the same set of museum specimens. To bring greater resolution in Hanuman langur taxonomy we undertook a field survey to study variation in external morphological characters among Hanuman langurs. The primary objective of this study is to ascertain the number of morphologically recognizable units (morphotypes) of Hanuman langur in peninsular India and to compare our field observations with published classification schemes. We typed five color-independent characters for multiple adults from various populations in South India. We used the presence-absence matrix of these characters to derive the pair-wise distance between individuals and used this to construct a neighbor-joining (NJ) tree. The resulting NJ tree retrieved six distinct clusters, which we assigned to different morphotypes. These morphotypes can be identified in the field by using a combination of five diagnostic characters. We determined the approximate distributions of these morphotypes by plotting the sampling locations of each morphotype on a map using GIS software. Our field observations are largely concordant with some of the earliest classification schemes, but are incongruent with recent classification schemes. Based on these results we recommend Hill (Ceylon Journal of Science, Colombo 21:277-305, 1939) and Pocock (Primates and carnivora (in part) (pp. 97–163). London: Taylor and Francis, 1939) classification schemes for future studies on Hanuman langurs.