THERYA NOTES 2020, Vol. 1 (1): 34-38 DOI: 10.12933/therya_notes-20-9

Broadening the distribution of the microendemic shrew Cryptotis phillipsii (Eulipotyphla, Soricidae)

Ampliación de la distribución de la musaraña microendémica Cryptotis phillipsii (Eulipotyphla, Soricidae)

Mario C. Lavariega1, Stephanye Mata-González2, Miguel Briones-Salas1, and Lázaro Guevara2*

1Centro Interdisciplinario de Investigación para el Desarrollo Integral Regional, Unidad Oaxaca, Instituto Politécnico Nacional. Calle Hornos 1003, CP. 71230, Santa Cruz Xoxocotlán, Oaxaca, México. Email: mariolavnol@yahoo.com.mx (MCL), mbriones@ipn.mx (MB-S).

2Departamento de Zoología, Instituto de Biología, Universidad Nacional Autónoma de México. Circuito Zona Deportiva s/n, Ciudad Universitaria, CP 04510, Coyoacán, Ciudad de México, México. Email: any.matagz@gmail.com (SM-G), llg@ib.unam.mx (LG).

*Corresponding author

The Phillips´ small-eared shrew, Cryptotis phillipsii (Schaldach, 1966), is geographically restricted to a small patches of montane cloud forests from southern Oaxaca, México. Distributional records and specimens of C. phillipsii are relatively scarce, so it still remains as poorly-known species. Here, we provide 2 new localities based on the analyses of specimens that remained unidentified in a museum. We analyzed 5 specimens from the Sierra Madre del Sur biogeographic province, southwestern Oaxaca, which were collected in 1-liter pitfall traps. We determined the taxonomic identity of the specimens using specialized literature and by comparison with other shrew species potentially inhabiting the region. The external and cranial morphology allowed us to determine that these 2 specimens belong to the species Cryptotis phillipsii. These records extend the known distribution of C. phillipsii by about ca. 60 km west and provide additional information about their habitat preferences. The records presented here extend the range of C. phillipsii and corroborate predictions maps of current potential distributions suggesting the existence of suitable conditions for the species in the region. We urge continuing support and funding for fieldwork and the updating of scientific collections in order to accomplish the urgent task of completing the inventory of species and overcome the lack of their distributional information.

Key words: Cloud forests; inventories; México; museum specimens; taxonomy.

La musaraña de orejas pequeñas de Phillips, Cryptotis phillipsii (Schaldach, 1966), está geográficamente restringida a pequeños parches de bosques de niebla en el sur de Oaxaca, México. Los registros de distribución y los especímenes de C. phillipsii son relativamente escasos, por lo que sigue siendo una especie poco conocida. Proporcionamos 2 nuevas localidades basadas en el análisis de especímenes que permanecieron sin identificar en un museo. Analizamos 5 especímenes de la provincia biogeográfica de Sierra Madre del Sur, en el suroeste de Oaxaca, que fueron recolectados en trampas de caída de 1 litro de capacidad. Determinamos la identidad taxonómica de los especímenes usando literatura especializada y con la comparación con especímenes de otras especies de musarañas que potencialmente habitan la región. La morfología externa y craneal permitió determinar que estos 5 especímenes pertenecen a la especie Cryptotis phillipsii. Estos registros extienden la distribución geográfica conocida de C. phillipsii unos ca. 60 km al oeste y brindan más información sobre sus preferencias de hábitat. Los registros presentados aquí amplían la distribución de C. phillipsii y corroboran las predicciones de mapas de distribuciones potenciales actuales que sugieren la existencia de condiciones adecuadas para la especie en la región. Instamos a continuar el trabajo de campo y la actualización de las colecciones científicas para realizar la tarea urgente de completar el inventario de especies y superar la falta de información de su distribución geográfica.

Palabras clave: Bosques de niebla; especímenes de museos; inventarios; México; taxonomía.

© 2020 Asociación Mexicana de Mastozoología, www.mastozoologiamexicana.org

The lack of geographic information on species distributions (i.e., the Wallacean shortfall; Whittaker et al. 2005) hinders our ability to adequately manage and conserve the natural resources of the planet. Although the scientific interest in the study of mammals has grown over the time, baseline data on the diversity and distribution of some taxonomic groups are far from well known, because biological explorations are insufficient, especially in tropical mountain regions (Guevara and Sánchez-Cordero 2018; Mayén-Zaragoza et al. 2019). On the other hand, it has been observed that specimens representing new records (or even new species) have already been obtained but remain unidentified or misidentified in natural history collections (Kemp 2015). Thus, it is necessary to work from several fronts to achieve a minimal knowledge on the geographical distribution of species, particularly those secretive, elusive or rare species, for which the use of inappropriate collecting methods, poor sampling effort, and problems in taxonomic identification prevent the completeness of inventories (Carraway 2007; Lobo et al. 2018).

One of these groups are the shrews (Eulipotyphla, Soricidae), which comprise small-sized mammals that occupy various ecological niches and modes of life (Berman et al. 2007). In México and the United States of America, where the greatest diversity of shrews in the Americas occurs, the discovery and description of new species, rediscoveries, and range extensions within this family are yet common (Cervantes et al. 2008; Lorenzo et al. 2019). Of the 5 extant genera of shrews in the Americas, small-eared shrews of the genus Cryptotis have the widest distribution extending from eastern North America to the north of South America (Woodman 2019). The genus attains its greatest diversity in the northern tropics of southern México, particularly in the State of Oaxaca, including the presence of sympatric and syntopic species (Guevara and Cervantes 2017). Most of the species of Cryptotis in Oaxaca are relatively homogeneous in external and cranial morphology (Choate 1970; Guevara and Cervantes 2017). It is therefore not unusual to find species to be morphologically almost indistinguishable, and for which some specimens could remain unidentified or misidentified in museums (Woodman and Timm 2000; Guevara and Sánchez-Cordero 2018).

Long-term field inventories of small mammals in the Sierra Madre del Sur biogeographic province, southwestern Oaxaca, have yielded various specimens of the genus Cryptotis collected in 1-liter capacity pitfall traps (collecting permit FAUT-0037, SEMARNAT). However, some specimens have remained unidentified. Therefore, we revised five specimens from two localities to clarify their taxonomic status using specialized literature (Carraway 2007; Woodman and Timm 2000) and by comparison with specimens of C. goldmani machetes, C. phillipsii, and C. pueblensis, which correspond to shrew species potentially inhabiting the same region (see Appendix I). The five specimens examined have a broad zygomatic plate and a well-developed lower third molar compared to C. pueblensis; they are also relatively smaller in head-and-body length and exhibit narrower foreclaws compared to C. goldmani machetes. The external and cranial morphology of the specimens examined allowed us to determine that these belong to the species Cryptotis phillipsii (Figure 1).

Two specimens (Mammal Collection of the CIIDIR-Oaxaca, OAX.MA 4268, 4269) were collected along a stream surrounding by montane cloud forest and coffee plantations at 914 m in the municipality of San Agustín Chayuco, whereas other 3 specimens (OAX.MA 4262, 4263, and 4264) were collected in a very wet slope of cloud forests with arborescent ferns at 1,654 m in the municipality of San Miguel Panixtlahuaca (Figure 2). In the same area where C. phillipsii was collected in San Agustín Chayuco, some specimens of Peromyscus aztecus were also obtained. In San Miguel Panixtlahuaca, also P. aztecus, plus P. melanurus, P. mexicanus, Oryzomys fulgens, and Heteromys pictus were collected and deposited at the OAX.MA.

The Phillips´ small-eared shrew, Cryptotis phillipsii (Schaldach, 1966), is one of the less-known species in México. Initially described as Notiosorex phillipsii, was later included as a population of C. mexicana peregrina (or most recently as C. peregrinus); however, a morphological and molecular revision supports its status as species separated from C. peregrinus, a similar but not closely related species (Woodman and Timm 2000). The revised specimens of southwestern Oaxaca increase the number of specimens known of C. phillipsii available in natural history museums, from 55 to 60 specimens, of which just over half (51.6 %) are housed in Mexican museums (Table 1). Cryptotis phillipsii inhabits tropical montane cloud forests over an altitudinal range of 900 to 2,500 m, being geographically restricted to only 6,000 km2 in the Sierra Madre del Sur biogeographic province, within the state of Oaxaca (Álvarez-Castañeda et al. 2018). The records presented here fall in this habitat and elevational range. Further research is necessary to assess how coffee plantations affect their populations, in particular in San Agustín Chayuco. A search in databases and literature indicates that this species has been collected throughout the year (Table 1; Sánchez-Cordero and Guevara 2016; Woodman and Timm 2000).

The two new localities presented here extend the distribution by ca. 60 km to the west of the nearest localities in the Sierra de Miahuatlán (Figure 2; Woodman and Timm 2000). In particular, the records of San Agustín Chayuco are notables because they are located crossing Río Verde, a large watercourse running in northern-southern direction that break the continuity of the mountains in the Sierra Madre del Sur. Maps of current potential distributions have suggested the existence of suitable conditions for cloud forest shrews in that region, but so far there were no records that corroborate its presence (Guevara et al. 2015; Guevara and Sánchez-Cordero 2018). Therefore, the records analyzed here contribute to the value of these studies by corroborating their predictions. Due to its estimated area of occupancy and environmental threats within its distribution area, it is cataloged as vulnerable according to the International Union for Conservation of Nature (Álvarez-Castañeda et al. 2018); however, it has not been considered of priority protection by the Mexican government (SEMARNAT 2010, 2019).

It is feasible that the lack of more records of C. phillipsii in other predicted regions, such as southern Guerrero, is due to insufficient fieldwork. We then invite the scientific community to continue long-term surveys in under-sampled regions using proper methods for small mammals. In the case of shrews from northern Neotropics, pitfall traps have proven be highly efficient (Umetsu et al. 2006). On the other hand, it is also possible that, as shown in this work, specimens have already been collected but remain forgotten or ignored in the drawers of the collections (Kemp 2015). Therefore, we urge the constant updating of scientific collections, as well as the databases associated with voucher specimens. Collaborative work between curators and specialist taxonomists should be the norm in order to accomplish the task of completing the inventory of species and overcome the lack of distributional information (Johnson 2012). This accumulated knowledge will provide crucial information for a better understanding of the evolutionary history and conservation status of poorly-known species.

Acknowledgements

We thank students and staff of the mammalian collection of the Centro Interdisciplinario de Investigación para el Desarrollo Integral Regional Unidad Oaxaca of the Instituto Politécnico Nacional for support during biological exploration in southern Oaxaca. We especially thank to people from San Agustín Chayuco and San Miguel Panixtlahuaca for all the logistic support and hospitality in the field. We dedicate this note to the memory of Eugui Roy, a biology student, environmental advocate, and passionate lover of Oaxacan cloud forests.

Literature cited

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Associated editor: Tamara M. Rioja-Paradela

Submitted: March 19, 2020; Reviewed: May 15, 2020.

Accepted: May 30, 2020; Published on line: June 9, 2020.

Appendix I

Specimens examined

Cryptotis pueblensis (17). México: Oaxaca; 1.5 km NE Santa Rosa, Santiago Jamiltepec (CNMA 44691, 44693, 44694, 44698, 44701); km 193 Oaxaca-Puerto Escondido Road, 2.25 km NE San Gabriel Mixtepec (CNMA 44704, 44705, 44707–44709, 44711, 44713, 44715–44717); 20 mi S, 5 mi E Sola de Vega (KU 99547); 27 km (by road) S Juchatengo, 1850 m (KU 121662).

Cryptotis goldmani machetes (14). México: Oaxaca; Campamento Río Molino, 2 km SSW San Miguel Suchixtepec (CNMA 44675-44681, 44683-44689).

Figure 1. Specimen of the Phillips´ small-eared shrew, Cryptotis phillipsii, collected in San Miguel Panixtlahuaca, Oaxaca (OAX.MA 4263). Bar indicates 5 mm.

Figure 2. Map showing historical (dots) and new records (star, San Miguel Panixtlahuaca; square, San Agustín Chayuco) of the Phillips´ small-eared shrew, Cryptotis phillipsii, in Oaxaca, southern México. New records extend its geographic range ca. 60 km to the west.

Table 1. Records of the Phillips´ small-eared shrew, Cryptotis phillipsii, in Oaxaca, México, indicating the month and year of collecting. American Museum of Natural History, New York, New York (AMNH); California Academy of Sciences, San Francisco, California (CAS); Colección Nacional de Mamíferos, México City (CNMA); Escuela Nacional de Ciencias Biológicas, México City, (ENCB); The University of Kansas Natural History Museum, Lawrence, Kansas (KU); Louisiana State University, Baton Rouge, Louisiana (LSUMZ); University of Michigan, Museum of Zoology, Ann Arbor, Michigan (UMMZ); Colección Mastozoológica del CIIDIR-Oaxaca, IPN (OAXMA).

Records

Month

Year

Locality

AMNH 178739

August

1957

San Andres Lovene, San Juan Ozolotepec

UMMZ 112572

July

1963

Near Campamento Río Molino (Hwy 175), 7300 ft

CNMA 8444-8446, 8447; AMNH 213758-213759; 214152, 214803-214805; KU 114226

December

1964

Río Molino

KU 121661

December

1969

Río Molino

KU 124298-124299

April

1970

Río Molino

LSUMZ 11915

July

1969

Río Molino

KU 98728

July

1964

20 mi S, 5 mi E Sola De Vega

CAS 14940-14941

March

1965

Sinai, 10 km E Nopala

AMNH 214806, 214808

October

1967

San Miguel Suchixtepec

CAS 14069, 14071-14072 CNMA 26552

April

1968

Km 178, Rio Jalatengo, Puerto Angel Rd.

CAS 15475

January

1970

Rio Jalatengo, Puerto Angel Rd.

ENCB 3413-3414

January

1968

16 km SW San Miguel Suchixtepec

CAS 14068

April

1968

Km 153, Rio Molino, Puerto Angel Rd.

KU 124295-124296

November

1969

27.8 Km (By Road) N of San Gabriel Mixtepec

CNMA 27517-27518

June

1970

Puerto Ángel Road, Km 158

CNMA 26551

January

1970

Km 195 Oaxaca-Puerto Ángel Rd.

CAS 15478

January

1970

Lumber Camp, Km 158, Puerto Angel Rd.

CAS 15476

January

1970

Km 195 Puerto Escondido Rd.

CAS 15474

January

1970

Km 193 Puerto Escondido Rd.

CAS 15473

January

1970

La Cima, Km 184-1/2 Puerto Escondido Rd.

KU 124294

May

1970

36 Km (By Road) N San Gabriel Mixtepec

CNMA 44682, 44724-44736

October

2006

Campamento Río Molino, 2 km SSW San Miguel Suchixtepec

CNMA 44723

October

2006

3.25 Km NE San Juan Lachao

CNMA 44699

October

2006

Santa Rosa, 1.5 km NE San Juan Lachao

OAXMA 4262-4264

March

2009

5.08 km S, 3.32 km W San Miguel Panixtlahuaca

OAXMA 4268-4269

February

2009

9 km E San Agustín Chayuco