Global trends and biases in new mammal species discoveries

2007·18.5 MB·English

by  Deeann M Reeder

TEXAS TECH UNIVERSITY
Natural Science Research Laboratory
Occasional Papers
Museum of Texas Tech University Number 269 8 October 2007
Global Trends and Biases in New
Mammal Species Discoveries
DeeAnnM. Reeder, Kristofer M. Helgen, and Don E. Wilson
Abstract
Contrary to common perception, the number of living mammal species and the relationship
of those species with one another are incompletely understood. Taxonomic revisions within
mammals are frequent and are often motivated by the discovery of new species. In fact, an
analysis of patterns of discovery suggests that complete alpha-taxonomic characterization of
living mammals remains a far-off goal. Examination of chronological, geographical, and taxo¬
nomic trends in new species discoveries reveals interesting trends, telling biases, and priorities
for further study. An average of 223 new valid species have been described per decade since
the birth of modern taxonomic nomenclature in 1758, and this rate is increasing. Over 300
new mammal species are expected to be described this decade and some estimates suggest that
7,000+ living species of mammals will eventually be recognized. An analysis of 341 recently
described species indicates that the great majority of them are restricted to threatened areas of
high endemism—reiterating the biotic richness of these regions, but also indicating that most
new species and the regions in which they occur require urgent conservation attention. That
the global mammal fauna remains so incompletely characterized reflects the woeful state of
knowledge of global biodiversity.
Key words: biodiversity, conservation, mammals, new species discoveries, taxonomy
Introduction
The science of taxonomy provides the essential pinnings for all of biology (Wilson 1992,2004,2005).
means for documenting the magnitude and distribution Despite its fundamental nature, scientific interest and
of biological diversity (Wilson 1992), and ultimately for investment in taxonomy appear to be waning (Wheeler
prioritizing global and regional conservation initiatives 2004; Wilson 2004,2005; Schmidly 2005), even as evi¬
aimed at preserving that diversity (Wilson 1992; Myers dence continues to mount that a large proportion of all
et al. 2000; Brooks et al. 2005). Indeed, in discerning living organisms remain uncharacterized by biologists
the identity and evolutionary relationships of organ¬ (Wilson 2004, 2005). However, startling taxonomic
isms, taxonomy ultimately provides the practical under¬ ignorance afflicts not only megadiverse animal groups
2 Occasional Papers, Museum of Texas Tech University
such as insects, nematodes, and marine invertebrates. goal was to quantify just how many species are being
Even in “flagship” groups like mammals, assumed by newly described, and to compare this with historical
many biologists to be well understood taxonomically, rates. Furthermore, as has been demonstrated in other
a complete understanding of the diversity of living taxonomic groups or in subsets of mammals (Patterson
species remains a far-off goal. This is in part because 2000, 2001; Collen et al. 2004), we predict that new
new mammals, even large and relatively conspicuous species discoveries will be biased both in terms of
species, continue to be discovered and described by which species are described and from what regions.
field biologists and taxonomists at a rapid rate. Our
Materials and Methods
The analysis of mammal species description rates Wilson and Reeder (2005), regardless of subsequent
per decade was performed with a database created from developments, and have not evaluated the validity of
the third edition of Mammal Species of the World (Wil¬ subsequently introduced names. For example, the new¬
son and Reeder 2005). This database contains informa¬ ly-described carnivore Viverra tainguensis Sokolov,
tion on 5,339 extant (or presumably extant) mammals Rozhnov and Pham Trong 1997 was synonymized with
recognized as valid species (as of 1 January 2004, V zibetha by Walston and Veron (2001) and Wozencraft
when Mammal Species of the World went to press), (2005) and is excluded from our table. Balaenoptera
as well as the names of 6,351 recognized subspecies omurai Wada, Oishi, and Omada 2003 was included
and an additional 15,881 species-level synonyms. To in the synonymy of B. edeni by Mead and Brownell
these data, we added the records of an additional 82 (2005), and thus is not included in our table, despite
species that were described between 2004 and 1 July subsequent arguments (Sasaki et al. 2006). Our table
2006. Figure 1 illustrates two things: 1) the number includes some new names since identified as synonyms
of species described per decade; and 2) the rise in the of earlier names (such as Pteropus banakrisi, argued
total number of species recognized over time (along to be a junior synonym of P. alecto (Helgen 2004)),
with a linear regression analysis of this rise). It should because of their inclusion in Wilson and Reeder (2005).
be noted that the first and the last decade illustrated on We also include names that postdate Wilson and Reeder
this figure are incomplete. The formal scientifically (2005) but are probably synonymous with earlier names
recognized description of mammal species began with (such as Cebus queirozi, a junior synonym of C.fiavia
Linnaeus’s Systerna Naturae in 1758, thus, the first (de Oliveira and Langguth 2006)). We leave it to future
decade column represents a shortened period and the reviewers to cement these and other nomenclatural
last decade column, representing the 2000s, is still on¬ updates.
going. It also should be noted that Figure 1 represents
those species described in each decade that are cur¬ The analysis of potential biases in newly de¬
rently accepted as valid (on average, for each species scribed taxa was performed with data from 341 newly
described, there are three other names that currently described extant mammal species, each of which was
are considered synonyms or subspecies (Wilson and formally described between July 1992 and June 2006.
Reeder 2005)). As the field progresses, and more new The July 1992 starting point was chosen because it
mammals are described, some reorganization should represents the cut off of the second edition of Mam¬
be expected, and some “new” species will undoubtedly mal Species of the World (Wilson and Reeder 1993),
be synonymized with older, previously known species which was nearly universally accepted during the past
(Alroy 2002). Although often not perceived in this way, decade as the standard checklist for mammal species.
the description of a new species is a hypothesis that, The 341 new species include those species reviewed by
like all other scientific hypotheses, should be subject the authors of the most recent, third edition of Mammal
to further studies and thus to rejection or confirmation Species of the World (Wilson and Reeder 2005) and
(Baker et al. 2004). It is not our intention to address accepted by these authorities as being valid new spe¬
any taxonomic controversies anew in this paper. We cies (259 new extant species described and accepted
have relied on taxonomic assessments defended in as valid by other experts in the field between 1992 and
Reeder et al.-New Mammals Continue to be Discovered 3
6000
5000 CmA
u
o
Q.
(f)
4000
O
3000 >
3
E
3
2000
o
1000
0
Figure 1. Cumulative and decadal descriptions of taxonomically valid extant mammal species.
2004) as well as the 82 newly described species refer¬ particular taxonomic group with the number of new
enced above. Global coordinates of the type locality species that would be expected (given the total num¬
(site of collection of the type specimen(s)) for each ber of new species and the relative size of that group
species were obtained from their original descriptions compared to other taxonomic groups). For example,
or calculated from other sources, such as documenta¬ one new species was described in the Order Carnivora.
tion of the location of known field sites. Species were Given that carnivores account for 5.5% of all mammal
categorized as being continental, insular, or marine species (281 extant carnivores [not including the new
and data are provided in Table 1. The type locality species] out of a total of 5,080 extant mammals), one
for each species was plotted onto a base map indicat¬ would expect that 5.5% of the 341 new species, or 19
ing currently recognized regions of high threat and species, would be carnivores (see Table 2). Across all
irreplaceability (Brooks et al. 2005). Variable levels mammal orders, the fit between observed frequencies
of shading indicate the number of global biodiversity of new species and expected frequencies was tested
conservation templates that prioritize the region. The with a Chi-square goodness of fit test. To meet the
six templates include Biodiversity Hotspots, Crisis requirements of Chi-square analysis, all eutherian or¬
Ecoregions, Endemic Bird Areas, Centers of Plant ders with less than 20 species were lumped together,
Diversity, Megadiversity Countries, and Global 200 the ungulates (Perissodactyla and Artiodactyla) were
Ecoregions (Brooks et al. 2005). lumped together, and the monotremes and the seven
marsupial orders were lumped together.
Potential taxonomic biases were calculated by
comparing the observed number of new species in a
4
Occasional Papers, Museum of Texas Tech University
Table 1.—Information for the 341 new species used in the analysis. Locality, Latitude, and Longitude represent where the type specimen for each
new species was collected. Higher classification and order of species follows Wilson and Reeder (2005).
Author and
Classification Species*, ** Description Date Citation Locality+ Latitude^ Longitude
Order Monotremata
Family Zaglossus Flannery and Mammalia
Tachyglossidae attenboroughi Groves 1998 62:387 I -2.53 140.63
Order Didelphimorphia Diaz, Flores,
Family Gracilinanus and Barquez J. Mammal.
Didelphidae ignitus 2002 83:825 C -23.63 -64.47
Fieldiana
Hyladelphys (Hershkovitz Zool., n.s.,
kalinowskii**,AA 1992) 70:37 C -13.50 -70.92
Marmosops Voss, Tarifa, and Am. Mus.
creightoni Yensen 2004 Novit. 3466:11 c -16.12 -68.08
Mem. Fund. La
Monodelphis Lew and Perez- Salle Cienc.
reigi Hernandez 2004 Nat. 159-160:9 c 5.97 -61.42
Monodelphis Mamm. Biol.
ronaldi Solari 2004 69:146 c -11.93 -71.28
Lew, Perez-
Philander Hernandez, and J. Mammal.
deltae Ventura 2006 87:224 c 10.00 -62.82
Lew, Perez-
Philander Hernandez, and J. Mammal.
mondolfii Ventura 2006 87:229 c 8.00 -61.50
Order Paucituberculata
Family Caenolestes Albuja and J. Mammal.
Caenolestidae condorensis Patterson 1996 77:42 c -2.27 -78.73
Order Dasyuromorphia
Family Myoictis Rec. Aust.
Dasyuridae leucura Woolley 2005 Mus. 57:334 I -6.28 142.75
Pseudantechinus Cooper, Aplin Rec. W. Aust.
roryi and Adams 2000 Mus. 20:125 c -21.61 118.00
Dickman,
Antechinus Parnaby, Crowther Aust. J. Zool.
agilis and King 1998 46:5 c -22.19 148.84
Antechinus Van Dyck and Mem. Qld.
subtropicus Crowther 2000 Mus. 45:613 c -28.22 152.42
Van Dyck,
Sminthopsis Woinarski Mem. Qld.
bindi and Press 1994 Mus. 37:312 c -14.50 132.75
Crowther,
Sminthopsis Dickman and Aust. J. Zool.
boullangerensis Lynam1999 47:220 I -30.30 115.03
Reeder et al.-New Mammals Continue to be Discovered 5
Table 1 (cont.).
Author and
Classification Species*, ** Description Date Citation Locality+ Latitude ++- Longitude
Order Peramelemorphia
Family Microperoryctes Helgen and J. Zool.
Peramelidae aplini Flannery 2004 264:117 I -1.38 133.97
Order Diprotodontia
Family Phalanger Flannery and Aust. Mammal.
Phalangeridae alexandrae Boeadi 1995 18:42 I -0.08 129.42
Phalanger Flannery and Aust. Mammal.
matabiru Boeadi 1995 18:40 I 0.83 127.30
Spilocuscus Helgen and J. Mammal.
wilsoni Flannery 2004 85:826 1 -0.87 135.00
Lindemayer,
Trichosurus Dubach and Aust. J. Zool.
cunninghami Viggers 2002 50:17 ( -37.33 145.53
Family Flannery,
Macropodidae Dendrolagus Boeadi and Mammalia
mbaiso Szalay 1995 59:66 I -4.08 137.10
Petrogale Eldredge and Aust. J. Zool.
coenensis Close 1992 40:621 ( -13.78 143.07
Petrogale Eldredge and Aust. J. Zool.
mareeba Close 1992 40:619 ( -17.10 144.38
Petrogale Eldredge and Aust. J. Zool.
sharmani Close 1992 40:618 ( -18.87 145.73
Thylogale Aust. Mammal.
calabyi Flanneiy 1992 15:18 I -8.41 147.38
Order Afrosoricida
Family Jenkins,
Tenrecidae Microgale Rax worthy and Bull. Am. Mus.
fotsifotsy Nussbaum 1997 Nat. Hist. 63:2 I -12.48 49.17
Jenkins,
Microgale Goodman and Fieldiana Zool.
gymnorhyncha Raxworthy 1996 n.s. 85:211 1 -22.19 46.97
Microgale Goodman and Proc. Biol. Soc.
jenkinsae Soarimalala 2004 Wash. 117:253 1 -22.77 43.52
Microgale Goodman and Fieldiana Zool.
monticola Jenkins 1998 n.s. 90:149 I -14.73 49.43
Bull. Nat. Hist.
Microgale Jenkins and Mus. Lond.
nasoloi Goodman 1999 (Zool.) 65:156 I -22.46 44.84
Microgale Am. Mus.
soricoides Jenkins 1993 Novit. 3067:2 I -18.85 48.45
Family Amblysomus Mammalia
Chrysochloridae robustus Bronner 2000 64:42 ( -25.30 30.13
6 Occasional Papers, Museum of Texas Tech University
Table 1 (cont.).
Author and
Classification Species*, ** Description Date Citation Locality+ Latitude^ Longitude
Order Cingulata
Family Dasypus Mastozool.
Dasypodidae yepesi Vizcaino 1995 Trap. 2:7 C -23.07 -64.92
Order Pilosa
Family Bradypus Anderson and Proc. Biol. Soc.
Bradypodidae pygmaeus Handley 2001 Wash. 114:17 I 9.10 -81.55
Order Primates
Family Cheirogaleus Int. J. Primatol.
Cheirogaleidae minusculus Groves 2000 21:960 I -20.52 47.32
Cheirogaleus Int. J. Primatol.
ravus Groves 2000 21:960 I -18.16 49.38
Rasoloarison,
Microcebus Goodman and Int. J. Primatol.
berthae Ganzhom 2000 21:1001 I -22.07 44.65
Microcebus Int. J. Primatol.
jollyae Louis et al. 2006 27:382 I -21.38 47.87
Microcebus Int. J. Primatol.
mittermeieri Louis et al. 2006 27:381 I -14.80 49.47
Zimmermann,
Ehresmann,
Zietemann,
Radespiel,
Randrianambinina,
Microcebus and Rakotoarison Primate Eye
ravelobensis 1997 63:26 I -16.58 46.87
Rasoloarison,
Microcebus Goodman and Int. J. Primatol.
sambiranensis Ganzhorn 2000 21:982 1 -14.03 48.27
Microcebus Louis et al. Int. J. Primatol.
simmoni 2006 27:383 I -17.93 49.20
Rasoloarison,
Microcebus Goodman and Int. J. Primatol.
tavaratra Ganzhorn 2000 21:977 I -13.08 49.10
Kappeler and Primate Report
Mirza zaza Roos 2005 71:18 I -13.67 48.25
Family BMC Evolutionary
Lepilemuridae Biology 6(17)
Lepilemur Andriaholinirina epub, page not
aeclis et al. 2006 available I -16.05 45.91
BMC Evolutionary
Biology 6(17)
Lepilemur Andriaholinirina epub, page not
randrianasoli et al. 2006 available I -19.47 44.29
Reeder et al.-New Mammals Continue to be Discovered 7
Table 1 (cont.).
Author and
Classification Species*, ** Description Date Citation Locality+ Latitude^ Longitude'1*
BMC Evolutionary
Biology 6(17)
Lepilemur Andriaholinirina epub, page not
sahamalazensis et al. 2006 available I -14.37 47.75
Family Thalmann and Am. J. Primatol.
Indridae Avahi cleesei Geissmann 2005 67:373 I -18.98 44.75
Thalmann and Int. J. Primatol.
Avahi unicolor Geissmann 2000 21:934 I -13.58 47.95
Family Anthropol. Pap.
Lorisidae Pseudopotto Amer. Mus. Nat.
martini**, A Schwartz 1996 Hist. 78:8 C unknown unknown
Family In Kingdon,
Galagidae Kingdon Field
Galago Guide to African
rondoensis Honess 1997 Mammals, p. 106 C -10.12 39.38
Family Tarsius Merker and Int. J. Primatol.
Tarsiidae lariang Groves 2006 27:465 I -1.63 120.03
Family M. van Roosmalen,
Cebidae T. van Roosmalen,
Callithrix Mittermeier and Neotropical
acariensis Rylands 2000 Primates 8:7 c -5.12 -60.02
M. van Roosmalen,
T. van Roosmalen,
Callithrix Mittermeier and Goeldiana
humilis de Fonseca 1998 Zoologia 22:8 c -5.52 -60.42
M. van Roosmalen,
T. van Roosmalen,
Callithrix Mittermeier and Neotropical
manicorensis Rylands 2000 Primates 8:3 c -5.84 -61.31
Bol. Mus. Para.
Callithrix Emilio Goeldi,
marcai Alperin 1993 ser. Zool. 9:325 c -7.00 -60.95
Mittermeier,
Callithrix M. Schwarz Goeldiana
mauesi and Ayres 1992 Zoologia 14:6 c -3.38 -57.77
Callithrix Ferrari and Goeldiana
nigriceps Lopes 1992 Zoologia 12:4 c -7.52 -62.87
Callithrix Silva and Goeldiana
saterei Noronha 1998 Zoologia 21:6 c -4.00 -59.09
Cebus Goeldiana
kaapori Queiroz 1992 Zoologia 15:4 c -0.50 -47.50
Cebus Mendes Pontes Zootaxa
queirozi and Malta 2006 1200:2 c -8.40 -35.07
8 Occasional Papers, Museum of Texas Tech University
Table 1 (cont.).
Author and
Classification Species*, ** Description Date Citation Locality+ Latitude++ Longitude
Family M. van Roosmalen,
Pitheciidae T. van Roosmalen Neotropical
Callicebus and Mittermeier Primates 10
bernhardi 2002 (Suppl.):24 C -5.52 -60.42
Callicebus Kobayashi and Rev. Bras.
coimbrai Langguth 1999 Zool. 16:534 C -10.53 -36.68
M. van Roosmalen,
T. van Roosmalen Neotropical
Callicebus and Mittermeier Primates 10
stephennashi 2002 (Suppl.):15 C -3.75 -59.00
Family Ehardt, Butynski, In Jones et al..
Cercopithecidae Lophocebus Jones, and Science
kipunji Davenport 2005 308:1161 C -9.15 33.83
Sinha, Datta, Int. J.
Macaca Madhusudan, Primatol
munzala and Mishra 2005 26:980 C 27.70 91.72
Macaca Fuentes and Asian
siberu Olson 1995 Primates 4:1 I -1.35 98.92
Kingdon
Field Guide to
African
Miopithecus Mammals,
ogouensis Kingdon 1997 p. 55 C 1.50 10.00
Pygathrix Zool. Garten
cinerea Nadler 1997 NF 67:165 C 13.98 108.00
Raffles Bulletin
Trachypithecus Brandon-Jones of Zoology
ebenus 1995 43:15 C 22.50 103.83
Order Rodentia
Suborder Sciuromorpha
Family Dryomys Bonn. Zool.
Gliridae niethammeri Holden 1996 Beitr. 46:116 C 30.38 67.72
Suborder Castorimorpha
Family Heteromys Anderson and Am. Mus.
Heteromyidae nubicolens Timm 2006 Novit. 3509:7 C 10.30 -84.80
Heteromys Am. Mus.
oasicus Anderson 2003 Novit. 3396:9 C 11.83 -69.95
Heteromys Anderson and Am. Mus.
teleus Jarrin-V. 2002 Novit. 3382:6 C -1.83 -80.73
Suborder Myomorpha
Family Adaptive
Spalacidae Nevo, Radiation
Ivanitskaya, of Blind
Spalax and Beiles Subterranean
carmeli 2001 Mole Rats, p. 23 C 32.80 34.98
Reeder et al.-New Mammals Continue to be Discovered 9
Table 1 (cont.).
Author and
Classification Species*, ** Description Date Citation Locality+ Latitude^ Longitude
Adaptive
Nevo, Radiation
Ivanitskaya, of Blind
Spalax and Beiles Subterranean
galili 2001 Mole Rats, p. 23 C 33.00 35.50
Adaptive
Nevo, Radiation
Ivanitskaya, of Blind
Spalax and Beiles Subterranean
golani 2001 Mole Rats, p. 23 C 33.13 35.82
Adaptive
Nevo, Radiation
Ivanitskaya, of Blind
Spalax and Beiles Subterranean
judaei 2001 Mole Rats, p. 23 C 31.38 34.87
Zoology in
Spalax the Middle
munzuriAA (Coskun 2004) East 33:157 C 39.73 39.28
Family Carleton,
Nesomyidae Goodman, and Proc. Biol.
Eliurus Rakotondravony Soc. Wash.
antsingy 2001 114:974 I -19.13 44.82
Eliurus Am. Mus.
ellermani Carleton 1994 Novit. 3087:39 1 -15.50 49.93
Eliurus Carleton and Fieldiana Zool.
grandidieri Goodman 1998 n.s. 90:165 I -14.74 49.46
Am. Mus.
Eliurus petteri Carleton 1994 Novit. 3087:37 I -18.92 48.57
Goodman and Proc. Biol.
Macrotar somys Soarimalala Soc. Wash.
petteri 2005 118:453 I -22.27 43.47
Monticolomys Carleton and Fieldiana Zool.
koopmani** Goodman 1996 n.s. 85:235 I -19.30 47.43
Goodman,
Rakotondravony,
Randriamanantsoa,
and Rakotomalala- Proc. Biol.
Voalavo Razanahoera Soc. Wash.
antsahabensis* 2005 118:866 I -18.42 47.94
Voalavo Carleton and Fieldiana Zool.
gymnocaudus* Goodman 1998 n.s. 85:182 I -14.75 49.43
Family Microtus Krystufek and Bonn. Zool.
Cricetidae anatolicus Kefelioglu 2002 Beitr. 50:8 c 37.87 32.48
Microtus Kefelioglu and J. Nat. Hist.
dogramacii Krystufek 1999 33:301 c 41.67 35.6
10 Occasional Papers, Museum of Texas Tech University
Table 1 (cont.).
Author and
Classification Species*,** Description Date Citation Locality+ Latitude++ Longitude^
Microtus Golenishchev Russian J.
qazvinensis 2003 Theriol. 1:118 C 35.65 49.97
Carleton,
Sanchez,
Habromys and Urbano Proc. Biol. Soc.
delicatulus Vidales 2002 Wash. 115:491 C 19.93 -99.50
Bradley,
Carroll, Haynie,
Martinez,
Peromyscus Hamilton, and J. Mammal.
schmidlyi Kilpatrick 2004 85:1190 c 24.25 -104.70
Bradley,
Mendez-
Harclerode, Occ. Pap. Mus.
Reithrodontomys Hamilton, and Texas Tech.
bakeri Ceballos 2004 Univ. 23 l:i, 7 c 17.65 -99.84
Ochoa G.,
Aguilera,
Aepeomys Pacheco, and Mamm. Biol.
reigi Soriano 2001 66:230 c 9.67 -69.62
Diaz, Barquez,
Akodon Braun, and J. Mammal.
aliqnantulus Mares 1999 80:788 c -26.70 -65.37
Akodon Hershkovitz Bonn. Zool.
mystax 1998 Beitr. 47:220 c -20.43 -41.78
Akodon Braun, Mares, Z. Saugetierk.
oenos and Ojeda 2000 65:218 c -32.80 -68.67
Christoff,
Fagundes,
Sbalqueiro,
Mattevi, and
Akodon Yonenaga- J. Mammal.
paranaensis Yassuda 2000 81:844 c -25.52 -49.05
Pardinas,
D’Elia,
Akodon Cirignoll, and J. Mammal.
philipmyersi Suarez 2005 86:465 c -27.53 -55.87
Gonzalez, Comun. Zool.
Langguth, Hist. Nat. Mus.
and Oliveira Montevideo
Akodon reigi 1998 12:2 c -34.00 -54.67
In Malygin
et al.,
Amphinectomys Zool. Zhur.
savamis** Malygin 1994 73:203 c -4.92 -73.75
Andalgalomys Mares and J. Mammal.
roigi Braun 1996 77:929 c -36.21 -66.66