Indo-Australian Muroids (Murinae)

Upon Guy's arrival at the AMNH as a newly minted Archbold Assistant Curator, there already existed a rich collection of mammals from the Indo-Australian region that invited careful research, as well as a mechanism, the Archbold Expeditions, Inc., that encouraged pursuit of museum and field studies relating to them. From this stage, his research focus and publication theme are largely straightforward.

Guy's early years at the AMNH were spent learning the mammals, especially Rodentia, of the region, and assessing the strengths and weaknesses of the collections. This education necessarily required much basic, hands-on curation, bringing a peromyscine yardstick of discrimination to the murine identifications and alpha taxonomies of Archbold and Tate. Guy also invested considerable curatorial effort in the important Indo-Malayan rodent series contained in the U.S. National Museum of Natural History (USNM), the repository of collections generated by W.C. Abbott and H.C. Raven, along with the numerous holotypes and type series of taxa described by Ned Hollister and Gerrit Miller in the early 1900s (e.g., Miller, 1900; Hollister, 1913; Miller and Hollister, 1921). In the late 1960s through early 1970s, Guy worked so often in the USNM, commuting by rail between New York City and Washington, D.C., that the divisional technicians viewed him as the Mammal Division's fourth curator.4 Having improved the identification of material housed in North American collections as a dependable taxonomic resource, travel to European museums was the obvious next step. Those that contained critical series of Indo-Australian rats and mice—the British Museum of Natural History, London (BMNH); Rijksmuseum van Natuurlijke Histoire, Leiden; and the Museum National d'Histoire Naturelle, Paris—were visited in 1969, not as a routine museum trip of days to weeks in duration but a prolonged tour of five months.

Examination of holotypes and associated material, the bases of descriptions by early workers such as Oldfield Thomas, F.A. Jentink, and Alphonse Milne-Edwards, was necessary to resolve explicit nomenclatural problems and enlighten taxonomic suspicions. By the conclusion of the 1969 European trip, he had examined all of the types of rodent taxa known from Sulawesi. A three-month museum trip followed in 1971 to study collections in Indonesia, Malaya, Singapore, and Thailand.

The dividends from this initial phase of museum investigation started to appear in papers produced from 1969 to 1973 (appendix 1). The majority of these focused on taxa described from Sulawesi and most involved reparatory taxonomic and nomenclatural issues: providing diagnoses and comparisons for obscure taxa; resurrecting epithets long buried in Rattus infraspecific taxonomy to valid species; reassigning subjective synonyms among species judged to be valid, especially the allocation of poorly known forms with the correct species of commensal Rattus; emending definitions of taxa based on composite holotypes, designating lectotypes, and restricting type localities. In one exceptionally contorted case (17), the type series of Mus callitrichus Jentink, 1879, proved to be a mixture of five divergent species (Taeromys callitrichus proper plus Bunomys chrysocomus, B. fratorum, Pauromys dominator, and Rattus hoffmani). Only one new taxonomic description appeared in this period (Tateomys rhinogradoides Musser, 1969), but “Results of the Archbold Expeditions. No. 91” was a beefy Novitates (12) that portended the succession of insightful AMNH reports and monographs on Indo-Australian murids. Hooper chuckled that only Guy could write a 41-page article based on a single specimen. Of course, the paper covered much more than an exacting morphological description of Tateomys (which it certainly contained), but it also broadly addressed evolutionary origins and possible relationships among the shrew rats of Sulawesi and the Philippines and began to consolidate the rodent genera endemic to Sulawesi. Those uninitiated to the arcana of murine nomenclature may find such papers tortuous to read, yet together they constituted the building stones of an objective foundation that would impel a fresh look at the diversification of murine rodents across the Indo-Australian region. A crucial aspect of any fresh look would depend upon renewed biological survey.

And three years it was: from June 1973 to September 1976, Guy lived in the forests of Sulawesi and accumulated a superb collection of small mammals, especially rodents. As a Michigan grad student at the time, I kept writing to AMNH to inquire when Musser would return from Sulawesi, only to learn that he had extended his fieldwork for still another six months in view of the exciting discoveries being made. Van Gelder and Sydney Anderson, departmental chairs during those years, didn't seem to mind his prolonged absence in view of the shipments of well-preserved small mammals that periodically emerged from somewhere in the forests of Sulawesi, with runners porting specimens out and carrying supplies in as required, all shipped via Jakarta. Guy purposefully situated his base camps in primary forests of the interior, away from human settlements, and concentrated his field surveys in the central highlands of Sulawesi. Detailed altitudinal transects from lowland evergreen rainforest through upper montane rainforest were regularly established to delimit altitudinal ranges and ecological occurrences (e.g., see Musser and Holden, 1991 [71]: table 18). The value of his Sulawesian collections is enhanced not only by the quality of the specimen preparations but, for the era, their variety—yes, the traditional skins and skulls, but also fluids, skeletons, and chromosomal preparations (“I can now run rats through the chromosome mill and that required a whole different suite of junk that I am unused to taking into the field.”—GGM, in litt., 5 June 1973). Reams of ecological, reproductive, and dietary information were recovered and habitats and live animals were photographed in order to document the natural history of the specimens collected. The latter kinds of data were typically absent from the scanty descriptive literature with which Guy had to contend, but they would be profusely integrated throughout his subsequent generic and specific revisions.

At a girth of merely 69 pages, the Chiropodomys revision (35) would prove to be only a dwarf Godzilla compared with the monographic monsters that were soon to hatch. The continuing dissemination of results from Guy's museum sleuthing, now supplemented by the abundant new material collected during his Sulawesian expedition, would yield a fertile second phase of publication on murine systematics (1979–1987; appendix 1, fig. 1). The majority of his murine descriptions, 11 genera and 20 species, appeared during this period (table 1), which included five substantial Bulletins, many weighty Novitates, and some of the longest “notes” ever published in Journal of Mammalogy before the journal abandoned that subdivision of articles. Such numbers of taxa new to science pale against the lifetime output of a C. Hart Merriam (U.S. Biological Survey) or Oldfield Thomas (BMNH), but one must appreciate that Guy's mammalian discoveries transpired in the latter 1900s, a century after the inception of directed survey collecting and correlative eruption of taxonomic description (e.g., Kohler, 2006). For someone whose command of the Eurasian and Indo-Australian murid faunas was now so expert, new species or genera were relatively simple to spot in a drawer of specimens (though proper documentation of those novelties was never a simple task). More taxonomically complicated and excruciating to document were the many groups extricated from the nebulous construct and bloated synonymy of Indo-Australian Rattus that prevailed in the middle 1900s (e.g., Chasen, 1940; Ellerman, 1941, 1961; Simpson, 1945; Ellerman and Morrison-Scott, 1951; Tate, 1951; Laurie and Hill, 1954). Genera such as Limnomys (34), Maxomys (37), Leopoldamys and Niviventer (40), Apomys (46), and Berylmys, Bullimus, and Bunomys (52) had to be differentiated from Rattus and from one another, their morphological diagnoses recrafted, and their specific contents and distributions redefined.

Guy's contributions to the systematics of Indo-Australian murines have steadily continued from 1990 onward (appendix 1), but not with the concentrated flourishes that characterized the two earlier periods. Preoccupation with new research interests competed for his time and energy. Noteworthy over this latter period was the 1992 monograph of Musser and Heaney on native Philippine murines (74). Though not a quantitative phyletic analysis per se, the authors systematized the character variation among the 18 native genera as evidence of three major divisions and developed phylogenetic and biogeographic hypotheses to account those divisions. A recent molecular study (Jansa et al., 2006) has broadly supported their ideas, particularly with regard to Old Endemic and New Endemic groupings, although disagreeing (naturally) over details. Guy twice returned to the field in the Indo-Australian region, in 1998 and 2004, after a lapse of 22 years since the productive expedition to Sulawesi. Field trips of 1–2 months duration were conducted to Vietnam, under the auspices of the AMNH Center for Biodiversity and Conservation, and uncovered new species of shrews and a new genus and species of rodent (96, 99, 104; table 1). Guy coordinated the first Vietnam trip, but Darrin Lunde, a frequent collaborator and AMNH Collection Manager of Mammals, handled all logistics for the second, with Guy tagging along as earnest field hand (fig. 2).

Figure 2

Twenty-two years after his fieldwork in Sulawesi (see frontispiece), Guy returned to fieldwork in Indo-Malayan forests, this time for shorter surveys conducted in Vietnam in 1998 and 2004. Guy is pictured here with a live individual of the new genus and species Tonkinomys daovantieni Musser, Lunde, and Son, 2006 (photograph by Darrin P. Lunde, 2004). When a live animal was captured, Guy often retained it in the trap in order to observe its behavior and to test reactions to various foodstuffs.

Guy's studies of Indo-Australian murines feature twin subtexts that are threaded among the bare bones of his taxonomic findings and amended synonymies. One was the need to disentangle truly indigenous species from those forms associated with human peregrinations and agricultural activities. Credible identification of the latter (commensal) species was hindered by an overburden of scientific names, particularly for Rattus, and the consequent nomenclatural morass obscured real biogeographic commonalities or differences among the murine faunas of Sulawesi, the Philippines, and Sunda Shelf (fig. 3). The 1973 paper on Rattus argentiventer (28), the ricefield rat once considered to be an ecological subspecies of R. rattus, signaled his emerging perception of the microdistributional dichotomy between indigenous murines (mainly confined to pristine environments) and introduced species (limited to anthropogenic settings), and other reports followed to solidify this pattern (33, 52, 63, 71). Other researchers had appreciated such a division, albeit on a local basis (e.g., Barbehenn et al., 1972–1973, for the Philippines). Guy grounded his morphological understanding of commensal species through actual examination of type specimens; periodically updated the growing list of synonyms, many described and long disguised as endemic species (especially see 33, 52); and achieved a fresh picture of their distributions throughout the Indo-Australian region. These dogged efforts revealed a surprisingly diverse suite of species that are never encountered in primary forest (apart from the usual triumvirate of Rattus rattus, R. norvegicus, and Mus musculus), and whose presence on the Sunda Shelf or across Indo-Australian island groups had resulted from human-mediated introductions (i.e., R. argentiventer, R. exulans, R. nitidus, R. tanezumi, Bandicota indica, B. bengalensis, Mus caroli, M. cervicolor, and M. terricolor). Coincidentally, the degree of endemism recorded for indigenous rodents was substantially enhanced at both specific and generic ranks. The taxonomic lists and endemism tallies for various Indo-Malayan island groups presented in a recent article on the “Diversity, distribution, and conservation of endemic island rodents” readily attest to the magnitude of Guy's alpha-taxonomic labors (Amori et al., 2008; also see, Corbet and Hill, 1992).

Figure 3

The Indo-Australian region formed the dramatic geographic backdrop to Guy G. Musser's systematic studies of Murinae. Sulawesi, where Guy spent three years in the field (1973–1976), was the centerpiece of his contributions to murine systematics, but substantial research was necessarily devoted to nearby islands, archipelagos, and Indochina to clarify the taxonomy, evolutionary relationships, and biogeography of rats and mice that inhabit the region (numbers in parentheses next to island groups or geographic feature signify the number of publications that principally address taxa in those areas). Color inset: Sommeromys macrorhinus Musser and Durden (2002), one of the many endemics described from Sulawesi (drawing by Patricia Wynne). (Figure adapted from Musser, 1981[40].)

The second interwoven subtext concerned the need for a morphologically credible, monophyletic construct of the genus Rattus. The heterogeneous, waste-basket composition of the genus handed down from the era of Chasen, Ellerman, and Simpson defied objective diagnosis, and its apparently expansive occurrence across the Indo-Australian region posed distributional enigmas that misled past zoogeographers. Misonne (1969) began to unravel this view of Rattus by excluding genera endemic to Africa, but little headway had been accomplished with Indo-Malayan rodents when Guy started to work with the Archbold collections. His approach to the problem was direct and methodical: sorting out clearly definable, morphological clusters; describing new genera (table 1) or resurrecting genus-group taxa uncritically lumped under Rattus (e.g., 37, 39, 52); and contrasting all of these with regional forms of true Rattus. Most generic changes were accompanied by detailed enumerations of differentiating traits and/or tabulations of primitive versus derived character states (such as, 39, 52, 71, 74). By the close of his second phase of murine investigations in 1987, Guy could record that the indigenous murines on Sulawesi consisted of 14 genera and 36 species, four of them in Rattus (63); in contrast, Laurie and Hill (1954) had recognized six genera and 35 species, 29 of them in Rattus. Although the process was operationally phenetic, the ultimate goal was phylogenetic. His taxonomic amendments typically raised evolutionary questions that invite testing and identified explicit means to reject or accept his proposals. Recent molecular studies of murine phylogeny appear to offer broad support for his redrawn limits of genera and notions of relationship vis-à-vis Rattus (e.g., Steppan et al., 2005; Jansa et al., 2006; Lecompte et al., 2008; Rowe et al., 2008). Forms such as Apomys, Maxomys, and Sundamys decidedly fall outside the clade of Rattus proper, and the polyphyletic burden of the genus sensu Ellerman and others has been appreciably and irrevocably reduced. Throughout his ongoing murine investigations, Guy had obviously formulated a working diagnosis of Rattus sensu strico and intended one day to punctuate his many alpha-taxonomic projects with a proper phylogenetic delineation of the genus. As sometimes happens, one's ambitions run out of lifetime to fulfill them.

Guy would not style himself as a biogeographer, but his research arguably holds its greatest relevance within the arena of Indo-Australian biogeography. Still, encamping for three years in the forests of Sulawesi speaks an awareness of biogeographic insights that could unfold from intense fieldwork there. Sulawesi is a large island found immediately east of Wallace's line (fig. 3), where so many abrupt faunal and floral changes are recorded compared with islands of the Sunda Shelf and the Philippines, and is situated at the nexus of colliding tectonic plates and complex geomorphic changes. The study group of choice, murine rodents, also conveys a deliberate calculation in view of their low vagility, the ample opportunities for fine-grained speciation across such a geologically volatile region, and the general want of rigorous revision since the descriptive era. Yet only a couple of his papers overtly address murine biogeography of the region (33, 63). Instead, most remarks on the topic are relayed incidentally within his revisions and descriptions, which also consider the biogeographic ramifications of the proposed taxonomic changes and summarize the altered picture of faunal associations and endemism patterns. A noteworthy example was the description of Rattus osgoodi from southern Vietnam (56), a paper that highlighted the Annamite Mountains as an area of endemism before the biogeographic excitement they sparked apropos the discovery of new ungulates (Dung et al., 1993; Giao et al., 1998). His studies of fossil and subfossil murines (late Pliocene–Holocene) from Sulawesi and various Lesser Sunda Islands have supplied another important window to understanding the paleogeography of the region (40, 48, 53, 90, 91).

In the context of assessing rates of extinction and colonization in southeastern Asia, Heaney (1986) pleaded “for research of the most fundamental sort. All of these [biogeographic] studies are predicated on the availability of accurate taxonomic data, and yet the distributions and systematic relations of many, if not most, insular mammals are poorly known, especially in the tropics. Theoretical advances in island biogeography are currently impeded by insufficient empirical data.” In effect, Guy's career of thoughtfully crafted systematic essays was undertaken with just those inadequacies foremost in mind. Looking back, the conceptual landscape that existed when Guy initiated his researches on Indo-Australian rodents resembled, in geographic and taxonomic scale, the state of sigmodontine taxonomy as direly assessed by Ellerman (1941: 327): “But directly Panama is passed, an enormous list of names described for the most part binomially, and in appalling chaos, is reached.” If one rephrased this as “But directly the Malay Peninsula is passed,” Ellerman's words would capture the systematic confusion that greeted the young Archbold Assistant Curator in 1966.

New World Muroids (Neotominae and Sigmodontinae)

Among the small mammals collected in the Tushar Mountains of southwestern Utah, Guy was certainly drawn to the variety of native muroid rodents (Neotominae) and intrigued by the difficulties in supplying specific determinations. He developed a fondness for woodrats and fleetingly considered Neotoma as a research focus, but the move to UMMZ cemented his interest in the systematics of Peromyscus. Presented with the opportunity to work with an eminent “peromyscologist,” how could it have happened otherwise? When not hunting for tree squirrels in southern Mexico (1963–1965), Guy managed to set and run traplines, yielding catches of interesting Peromyscus. These specimens provided the impetus for important reports on the taxonomy and distribution of a wide array of Neotropical groups, notably those of P. (Megadontomys) thomasi (6), P. (Osgoodomys) banderanus (10), the P. (Habromys) lepturus complex (10, 32), and the P. mexicanus group (6, 10, 20). Undoubtedly the most influential of his Peromyscus researches was the 1964 collaboration with his major professor (5). “Notes on Classification” expanded upon Hooper's (1958) application of male reproductive anatomy to evaluate interspecific relationships and formal groupings within the genus, and together they conceived the most substantive reclassification into species groups and subgenera (some newly described; see table 1) since Osgood's (1909) classic work. The 1964 paper set the stage for Hooper's (1968) deft review of Peromyscus classification, and together they have animated four decades of fruitful and penetrating research, drawing upon a variety of data, analytical tools, and research methodologies (e.g., see many articles cited in Carleton, 1989, and in Musser and Carleton, 2005 [103]). To judge from recent issues of Journal of Mammalogy, the discussion continues (Bradley et al., 2007; Miller and Engstrom, 2008).

The unrelenting tug to first complete his Indo-Australian projects effectively stifled such passing yearnings for a taxonomic first love.

However, Guy's research sights did turn once more to New World rodents, this time drawn to the impressive radiation of South American cricetids (Sigmodontinae). Besides presenting the opportunity to work with a valued colleague, the description of a new ichthyomyine species (31) with Al Gardner dovetailed with Guy's planned revision of the ichthyomyine group, a project earlier initiated by Hooper and continued by Guy when he relocated to the AMNH. Aware that he could never finish a thorough review as his Indo-Australian projects proliferated, Guy returned his ichthyomyine loans in 1977. Another UMMZ student of a successive generation would carry forth investigation of the group and resoundingly close a circle of sorts (Voss, 1988). More taxonomic attention was devoted to another tribe of Sigmodontinae, the Oryzomyini (55, 64, 65, 85, 89, 107). The genesis of these papers stemmed from basic curation of the large oryzomyine holdings in the AMNH and USNM, a task that exposed the glaring inadequacies of species definitions and generic limits as then recognized (notably, Goldman, 1918; Hershkovitz, 1960; Cabrera, 1961; Handley, 1976). The impediments to improve understanding of oryzomyine diversity somewhat paralleled the situation that Guy encountered when first grappling with Indo-Australian murines: an abundance of names used inconsistently for decades and lack of a phylogenetic diagnosis of Oryzomys sensu stricto. The deconstruction of the polyphyletic mishmash that so long characterized Oryzomys was precipitated by the watershed karyotypic paper of Gardner and Patton (1976), advanced by the studies of Carleton and Musser (1989 [65]) and Musser et al. (1998 [89]), and completed by the syncretistic investigations of Weksler (2006; Weksler et al., 2006). During the years of reidentifying oryzomyine specimens, Guy predictably called upon those same discriminatory abilities acquired through his early Peromyscus examinations, as exemplified by his remarks on researching the Oligoryzomys addendum to our Microryzomys revision (65).

Muroid Rodent Classification and Relationships

Guy's interest in relationships among muroid lineages was whetted by his experience as research assistant to Hooper in the early 1960s. Their morphological survey of “The glans penis in Neotropical cricetines” formed a framework for reassessing relationship, in this case higher levels of kinship among neotomine-peromyscines (Neotominae), South American cricetines (Sigmodontinae), and major assemblages of Muroidea (4). The 1964 study of Hooper and Musser immediately drew sharp criticism from Hershkovitz (1966) for recklessly drawing broad phylogenetic conclusions based on a single organ (Karl Koopman occasionally tweaked Guy by reciting one of Hershkovitz's more colorful lines—namely, that their study was “insistently and unremittingly phallic and typological,” a quotation punctuated by Karl's peals of laughter). Notwithstanding Hershkovitz's caustic disapproval, the 1964 report (4) has stimulated vigorous and abundant follow-up research, including taxonomically broad surveys of other organ systems (Carleton, 1973; Voss and Linzey, 1981) and phylogenetic studies using morphological characters (Carleton, 1980; Steppan, 1995). In particular, their diagrams of possible relationships, at the generic and family level (e.g., see fig. 4), were sufficiently explicit to provoke testing by that new information base for phylogenetic inference, DNA sequences (e.g., Engel et al., 1998; Smith and Patton, 1999, Michaux et al., 2001; D'Elía 2003; Bradley et al., 2004; Jansa and Weksler, 2004; Steppan et al., 2004). True, Hooper and Musser did not supply an OTU by character-state matrix, branch-support statistics, or consensus trees, but their diagrams did depict evolutionary lines of descent and hierarchies of relationship. Viewed against the long sweep of muroid classifications, from Gill (1872) to Musser and Carleton (2005 [103]), the innovative studies of Hooper and Musser (4, 5) served as conceptual stepping stones between the evolutionary taxonomy of Mayr and Simpson and the phylogenetic systematics of Hennig and its various quantitative phyletic applications.

Figure 4

Two diagrams of possible relationships developed by Hooper and Musser as based on their morphological surveys of the glans penis in various assemblages of muroids. Top, hypothesized phyletic affinity among genera of neotomine-peromyscines (Neotominae); bottom, hypothesized relationships among several groups (subfamilies) of Muroidea (after Hooper and Musser, 1964[4]: figs. 8 and 9). Such clearly depicted lines of descent precipitated vibrant waves of systematic study using successively more sophisticated methods and information bases for judging relationship and inferring phylogenies.

The 1984 review of muroid rodents (54) unfolded from Anderson's appeal to Guy for recommendations of authors who could assume responsibility for orphaned chapters from the first edition (Anderson and Jones, 1967). Although our collaboration was faulted for equivocation over the issue of Cricetidae versus Muridae (Hershkovitz, 1993), a reclassification of Muroidea was never the chapter's purpose (Carleton and Musser, 1984 [54]: 300): “Consequently … our arrangement of the groups as equivalent subfamilies of Muridae reflects not our conviction that this is the preferred nomenclature, but rather our uncertainty of the hierarchical pattern and our desire to focus upon the distinctive and richly varied geographic and biological properties of the groups comprising the Muroidea.” Based on extensive specimen examination and literature search, traits used to diagnose muroid groups were evaluated as primitive versus derived character states, amplified, and discussed in terms of the evidence for monophyly, patterns of relationship, and support for past classifications. With regard to these more modest aims, the chapter succeeded and provided the family-group rationale adopted in Guy's subsequent contributions on the superfamily (78, 87).

When Don Wilson became Chair of the American Society of Mammalogists Checklist Committee in 1990, he initiated important format changes for preparation of the next editions of Mammal Species of the World (Wilson and Reeder, 1993, 2005). Foremost, it was agreed that individual authors would be recognized for each family, rather than buried among some 150 contributors in a forgotten preface as was done for the first edition (Honacki et al., 1982). This change appealed to Guy's preference for personal accountability for one's ideas and control (more or less) over content and secured his involvement in our next joint ventures with the superfamily (78, 103). In preparing the 1993 chapter and especially its 2005 successor, we were staggered by the voluminous literature that had appeared since Honacki et al. (1982), particularly because many specific and generic accounts were informed not simply by literature compilation but also through specimen examination, insofar as possible (availability of specimens) or practical (availability of time). For example, the specific and generic accounts of African murines and assorted “archaic” muroids were extensively upgraded, compared with contemporary standards (Misonne, 1974; Honacki et al., 1982; Corbet and Hill, 1991), based on inspection of the large African series in the AMNH and USNM, supplemented by trips to or loans from the Field Museum of Natural History and Museum of Comparative Zoology, and nomenclaturally grounded on Guy's prior studies of BMNH types. I thought that we had pushed the envelope on the amount of specimen examination in researching the 1993 edition, but museum documentation, as cited within distributions and comments, grew appreciably in the 2005 edition (as appreciated by Solari and Baker, 2007, in their review). As I reviewed Guy's first drafts of various murines, one reason for the difference became apparent: with retirement fast approaching, the third edition of MSW represented the last opportunity to record incidental results accumulated during his many years of specimen examination in European and Asian museums. Whereas the 1984 and 1993 muroid contributions were never intended to be formal family-group classifications, the six-family arrangement presented in the 2005 chapter was, and it broke with the recent classificatory habit to place all subfamilies under one huge Family Muridae (e.g, Corbet and Hill, 1991; Musser and Carleton, 1993 [78]; McKenna and Bell, 1997). The 2005 classification drew upon our 1984 synthesis of morphological and paleontological information (54), historically influential arrangements of the superfamily, and the fresh insight to those past classifications supplied by the rapidly proliferating, taxonomically broad molecular investigations (that of Michaux et al., 2001, was pivotal). During the years of composing the 1993 and 2005 contributions, a lively correspondence transpired, as much to bolster one another's sagging enthusiasm to persevere as to exchange ideas.

Although my prejudice is justifiably suspect, I thought that we did it the “right way,” or as right as one could achieve for Mammalia's richest clade, from the species to family ranks, with due attribution of the classic and recent literature on extant and extinct muroids, and constrained to the format of a “species checklist.”

Research Approach

“Sorting” is a fundamental method mentioned in many of Guy's papers, usually in the context of defining the taxonomic problem, as in: “I have sorted the specimens into five lots, each defined and distinguished from the others by a combination of features … I judge that each lot represents a species” (Musser, 1979 [35]: 388); or, “Sorting and studying museum specimens … has allowed us to document the morphological and distributional limits of 10 Neotropical species” (Musser et al., 1998 [89]: 5). To sort, according to the sense intended here, is to “arrange systematically or according to type, class, etc.; separate and put into different sorts” (Oxford English Dictionary, II 6). The dictionary definition intimates that “types” and “classes” are somehow preexisting, that the activity is little more than a casual shuffling of specimens into already defined groups based on self-evident characteristics. To the contrary, sorting is an investigational tool in its own right, an objective means to discern natural units of meaningful biological significance, or as the method was aptly characterized by Kohler (2006: 227): “The act of sorting and categorizing is as theoretically creative as any scientific act.” In a storage cabinet in the UMMZ mammal range, Hooper maintained a stack of specimen examination boards, cut from eighth-inch masonite sheets into various rectangular sizes, from ca. 8 × 12 to 12 × 20 inches, and spray-painted a flat black to accentuate the osseous white of mammal skulls. Generic identifications of a new collections accession could be reliably ascertained based on features of the skin, but when specific determinations in problematic genera such as Peromyscus or Reithrodontomys were required, out came the examination boards. Skulls were first aligned by occipitonasal length, dorsal side up, to uncover possible assortment of gender with size and to judge interorbital configuration, zygomatic spread, and rostral proportion in relation to size. Skulls would then be flipped over, ventral side up, to appreciate possible correspondence of molar wear (age) to increasing size and to view conformation of incisive foramina, robustness of molar rows, and relative bullar inflation. Series of specimens of known species from nearby localities might be arrayed on the examination boards, together with the unknowns, and extensive comparisons, dorsal and ventral, would be repeated. This iterative routine, patiently and skillfully applied, was keenly sensitive to appraising subtle variational patterns in cranial size and shape and to disclosing specific gaps in those patterns. Sorting, as practiced by the best of our predecessors, was essentially a forerunner of multivariate factor analysis, minus the digital data, covariance matrices, and variable loading coefficients. Guy was—is—among the best, so it is little wonder that species and genera of the unrevised Indo-Australian murid fauna would, for him, “sort out like nuts and bolts” (“I still hear his [Hooper's] voice in my ear and feel his presence over my shoulder every time I lay out a string of skulls.”—GGM, in litt., 2 August 1992). With the advent of molecular bar-coding as the first approximation of specific identification, sorting of specimens, like the “-ology” courses, may pass into obscurity.

The extended field sabbatical in Sulawesi (1973–1976), following years of studying specimens in museums, conforms to a recurring theme of Guy's systematic approach, the interplay of field versus museum perspectives and the reciprocal illumination that each brings to the other. A tropical forest can be bewildering to comprehend, with its infinite variety and immense complexity, but a rodent caught in a trap deliberately placed by the investigator supplies a concrete bit of information—the first hypothesis tested. The requisite next question to ask is what scientific name should be applied to the specimen, an antithetical hypothesis elaborated through recourse to the comparative material and type specimens contained in the world's museums. Guy variously highlighted the contrapuntal theses of forest and museum in conveying his taxonomic conclusions, such as: “My experiences in the forests of Celebes gave reality to a picture that I had formed while I was working in museums” (Musser, 1977 [33]: 1); or, “Our report represents only a beginning, an understanding in the museum of the first lesson in the forest” (Musser et al., 1998 [89]: 324). The length of Guy's fieldwork in Sulawesi, three years, also underscores key aspects of his work habits: a drive to get it right and pertinacity to resolve as many taxonomic questions as possible, without regard to the practical time constraints that truncate the research aspirations of most of us. Guy is relentlessly methodical and thorough, which are useful compulsions for good scientific research in general, but his uncompromising adherence to these qualities is exceptional and surpassed by few other mammalogists in my experience. His papers decidedly evince a preference for working at a tangible empirical level and eschew abstract theorizing. He does not dither over species concepts from paper to paper; instead his specific descriptions and amendments are abundantly accompanied by enumeration and illustration of differentiating traits. Primary source materials, vouchered specimens and the distributional data associated with them, form the core of his taxonomic studies and anchor any commentary on biogeography and phylogeny.

The diagnostic traits of a Musser publication—replete historical and biological context, detailed morphological description, exhaustive taxonomic comparison, and elegant illustration—coalesced during Guy's second phase of murine publications (1979–1987). The AMNH has always liberally supported the illustrational needs of its scientists, and Guy just as liberally availed himself of those artistic talents and funds. He has an artful knack for judging the illustrational needs required to tell a paper's story. Assembling the figures, maps, and tables is, for him, just as critical to communicating results of one's study as is composing the text (“I really see the need to have illustrations and a simple diagram of terms. I can picture the tooth in my head but readers will have a tough time.”—GGM, in litt., 12 December 1988). Although some may find the description overmuch and the illustration excessive, Guy's reason for this approach is difficult to assail: to consolidate at one time and place the involved nomenclatural histories, empirical specimen-based data scattered amongst the world's museums, and all character information on which his own taxonomic results are based. An overarching motivation has been to spare future systematists the time and effort that he was forced to expend in trying to comprehend the taxonomic pronouncements of his predecessors. He reflected on these points as an aside when reviewing one of my papers.

His words may sound like banal truisms measured by today's standards of systematic research (though not always the practice). However, the quotation must be understood from the perspective of a new Archbold Assistant Curator, grappling with a daunting body of systematic literature set forth by luminaries such as Thomas, Miller, and Ellerman, and judged against the meagre documentation that accompanied the far-reaching biogeographic and phylogenetic implications of their specific and generic taxonomies.

Chairman and Collection Duties

When Guy joined the AMNH Department of Mammalogy in 1966, his responsibility was mostly confined to research, as departmental roles were delineated by Van Gelder. Promotions to Archbold Associate Curator (1970) and Archbold Curator (1976) followed mainly in recognition of his research output and extensive fieldwork. Guy was early on immersed in collections curation, although such activities were then related to his immediate research projects—foremost Indo-Australian murids of the Archbold collections, to a lesser degree the extensive holdings of South American cricetids acquired by Anthony and Tate in the early 1900s. Inside-the-case experiences with the latter gave Guy a sobering glimse of the curatorial needs of the department as a whole.

Guy became chairman of the department in 1981, following the terms of Van Gelder (1959–1974) and Anderson (1975–1981), and launched a long (1981–1993), concerted program to upgrade the physical storage and curatorial order of the entire mammal holdings, which had been sadly neglected for decades. Guy was successful in securing several NSF collection support grants (1981–1990), which allowed purchase of new cases for decompression of overcrowded cases and wholesale reorganization of large, heavily utilized orders, such as marsupials, carnivores, and primates. The dust-covered, unidentified jars of fluid specimens were removed from the back stairwells and arranged taxonomically within a new alcohol range that featured compactor shelving. Ungulate skeletons scattered throughout attics and other wings of the museum were consolidated and recurated to become again accessible to visitors. Storage and arrangement of large, tanned skins were improved. Attention was also devoted to upgrading the physical plant, including plastering and painting of the ranges and offices and the installation of air conditioners to exclude the dust and soot that permeated the collections when windows were opened during the summer months. Guy's involvement in these improvements included supervisory oversight as well as much hands-on curation, verifying identifications so that groups could be properly rearranged into new trays and cases. At the halfway point of his chairmanship, Guy assessed the status of the collections as follows.

The curatorial achievements owed much to a dedicated support staff, in particular Helmut Sommer, who long worked (1959–1997) as technician in the Mammalogy Department. Rescued from the museum's defunct taxidermic unit, Helmut was delighted and inspired to see the multifaceted attention being devoted to the mammal collections after Guy became chairman. The two developed an effective working bond and collaborated to correct specimen identifications uncovered during Helmut's curation of marsupials (72). Guy considered him to be a museum-based member of the Archbold Sulawesi Expedition and acknowledged his reliance on Helmut's wide-ranging capabilities in naming a new genus of Sulawesi rodent (Sommeromys Musser and Durden, 2002). Another focus of recuration was the type collection, along with revision of the type catalog, which projects Guy entrusted to Marie Lawrence. The two amended a taxonomic oversight discovered during Marie's curation (66), and after her unexpected death in 1992, Guy assumed the final editing chores that brought her first draft of the type catalog to publishable form (Lawrence, 1993). Any long-term user of the AMNH mammal collections readily appreciates the many and vast improvements he effected during his tenure as chairman.

Hooper was a student of Grinnell and reverently absorbed his professor's short commentary (1922) on “The Museum Conscience.” Hooper observed Grinnell's dual essentials of a scientific museum—order and accuracy—in his assiduous care and curation of the UMMZ mammal collection, standards of excellence that were surely impressed upon Guy during his graduate years at Michigan. In closing his essay, Grinnell (1922: 63) remarked that “My visits to the larger museums have left me with the unpleasant and very distinct conviction that a large portion of the vertebrate collections in this country … are in far from satisfactory condition with respect to the matters here emphasized.” Reading between the lines, it seems probable that his remarks on “larger museums” were directed, in part, at the AMNH and USNM. That a second-generation, academic descendent of Grinnell would begin to redress unsatisfactory conditions of the AMNH mammal collection was somehow fitting.

In spite of the substantial progress in collection improvement, Guy considered that his most important accomplishment as chair was to give Karl Koopman free rein to concentrate soley on his bat research. Under previous chairs, Karl was the curatorial specialist of Chiroptera, which, in addition to research, involved such tasks as pulling specimens for loans and answering information requests. Among the curators in the Mammalogy Department when Guy arrived, he and Karl developed a special friendship although they seldom collaborated on scientific matters (49, 83). Guy twice acknowledged Karl's intellectual breadth and contributions to systematic biology in describing new murine species (Chiropodomys karlkoopmani Musser 1979; Rattus koopmani Musser and Holden 1991) and regularly sought his input as reviewer of presubmission drafts. When Karl started to mutter about the unseemly increase of murid genera and species, Guy would thereafter present a manuscript along with a tray of rat skins and skulls so that Karl could verify the traits mentioned in diagnoses and comparisons. The muttering stopped.

Other Professional Activities and Honors

Guy has had little formal involvement in academia and the matriculation of future mammalogists, partly given his position in an independent museum and partly due to his conviction that research and curation in a huge collection are by themselves fulltime endeavors. Nevertheless, Guy has influenced many graduate students through his curatorial efforts to make the AMNH mammal collections accessible for their research, sponsorship of short-term visitor awards, and encouragement of collection internships under which graduate students could simultaneously conduct their own specimen examinations and recurate a portion of the mammal collection. He regularly participated in the Susan Greenwall Foundation, administered by the AMNH, and involved graduate students as collaborators in his own research projects (52, 56, 59, 61). Guy has shown especial willingness to review the manuscripts of graduate students or younger colleagues and has volunteered detailed and thoughtful, sometimes hard-nosed but always constructive, advice on how to write a systematic paper, frame a species description, or develop a taxonomic revision (“You need more illustrations!” was a familiar urging). In this informal capacity, his involvement in the education of systematic mammalogists has been generous and substantial, benefiting the professional development of most contributors to this volume among many others.

Guy's professional activities in the American Society of Mammalogists (ASM) included turns as editor for General Notes (1971) and editor for Feature Articles (1972–1973) for the society's journal and membership on various standing committees (Bibliography Committee, 1978–1980, which compiled the now-discontinued Recent Literature sections of the journal; Nomenclature Committee, 1978–1982; and the Checklist Committee, 1983–present, essentially responsible for producing revised editions of Mammal Species of the World). Guy is by nature a private individual, tends to shun gregarious settings like scientific meetings, and is uninterested in the prestige of holding societal offices. Given the usual constraints of budgets and time, he has preferred writing papers over giving talks, visiting museums over attending meetings. Notwithstanding his infrequent attendance at annual meetings, the ASM has bestowed two of its highest honors upon Guy. In 1992, he received the C. Hart Merriam Award, established primarily to give recognition to mammalogists with a stellar record in scientific research and singling out “his seminal contributions to understanding the systematics of murid rodents and because he is internationally recognized as an outstanding systematist.” In 2004, two years into retirement, he was elected to honorary membership in the ASM, an esteemed honor bequeathed for a distinguished record of achievement in the science of mammalogy.

Several mammalian species have been named to honor Guy, including a shrew (Crocidura musseri Ruedi, 1995) and, naturally, several species of muroid rodents (Microhydromys musseri Flannery, 1989; Archboldomys musseri Rickart, Heaney, Tabaranza, and Balete, 1998; Neacomys musseri Patton, da Silva, and Malcolm, 2000; Coryphomys musseri Aplin and Helgen, in press). A surprising number of invertebrate patronyms have been named, reflecting Guy's encouragement of such researchers to use the Sulawesian collections and glean parasites (fleas—Neopsylla musseri Beaucournu and Durden 1999; a suckling louse—Hoplopleura musseri Durden 1990; a fur mite—Listrophoroides musseri Bochkov and OConnor 2005; and a nematode—Heligmonoides musseri Hasegawa and Syafruddin 1994); the collegiality formed with one of those specialists, Lance A. Durden, led to their fruitful collaborations on suckling ice of Murinae (70, 73, 80, 81, 93). The present volume appropriately continues this honorific mode: Crocidura guy Jenkins, Lunde, and Moncrieff; Reithrodontomys musseri Gardner and Carleton; and Musseromys Heaney, Balete, Rickart, Veluz, and Jansa.