Sorex ibarrai Matson and McCarthy, 2005

Matson, John O. & Ordóñez-Garza, Nicté, 2017, The taxonomic status of Long-tailed shrews (Mammalia: genus Sorex) from Nuclear Central America, Zootaxa 4236 (3), pp. 461-483 : 478-479

Sorex ibarrai Matson and McCarthy, 2005

Ibarra’s Shrew

Sorex veraepacis ibarrai Matson And McCarthy, 2005: 68 . Type locality: “ Guatemala, Departamento de El Progreso, Municipio San Augustín Acasaguastlan [sic], Reserva de Biosfera Sierra de las Minas, Cerro Pinalón, Camino de las Torres, 2700 m; 15 ° 4'54" N, 89 ° 55'59" W.

Holotype. Adult, female, skin, skull, and partial postcranial skeleton; CMNH No. 113283, collected 3 May 1998 by John O. Matson and field party (original number JOM 6823, M685), the animal was lactating.

Distribution. Known from mountains south and southeast of Cobán, in Alta Verapaz, Baja Verapaz, and El Progreso, Guatemala.

Diagnosis. Sorex ibarrai is a member of the Sorex veraepacis species group. It is the largest member of this species group ( Table 1 and Figure 5 ) and one of the largest New World Sorex . U3 is usually <U4, but in some individuals U3 Ĺ U4. Pelage color of the adult female holotype was reported as Clove Brown above, scarcely paler below, by Matson and McCarthy (2005) . Upon reassessment, we now regard the color as being Chaetura Black. Specimens of S. ibarrai from the Sierra de las Minas are the darkest of the S. veraepacis species group. Some specimens have white tipped guard hairs on the dorsum. The tail is slightly bicolor. Specimens from other populations (Biotopo Quetzal, Chelemhá, Finca Chinaux, and El Limo) are essentially of the same coloration. Sorex ibarrai averages larger in all body and skull measurements than any Sorex southeast of the Isthmus of Tehuantepec ( Table 1 and Figure 5 ), except for length of unicuspid toothrow, which less than in S. chiapensis , S. veraepacis , and the new Sierra Madre species.

Description. Sorex ibarrai differs from S. veraepacis by averaging larger in most measurements; it has a shorter mandible relative to skull length; and, its braincase is less inflated. Compared to S. chiapensis and the undescribed species from the Sierra Madre, it is absolutely larger in all measurements. It is the darkest of the S. veraepacis species group.

Ecology. Found in cloud forests of the mountains south and southeast of Cobán, in Alta Verapaz, Baja Verapaz, and El Progreso, Guatemala ( Matson & McCarthy 2005 ; Woodman 2011b; Matson et al. 2014). Dominant cloud forest trees that make up the habitat include Persea sessilis , Persea verticulata, Quercus sapoteifolia, tree ferns ( Cyathea sp.), Podocarpus oleifolius , and various other conifers ( Matson & McCarthy 2005 ; Woodman et al. 2012). Known altitudinal range is 1475 m to 2800 m. Woodman et al. (2012) summarized data on reproduction in S. ibarrai . Essentially, most reproduction (pregnant or lactating individuals) occurs in the wet season (April through July), with limited reproduction in the drier months. This same pattern has been found in many cloud forest small mammals ( Rickart 1977; Vásquez et al. 2000; Matson et al. 2012). Small mammal associates include Cryptotis goodwini , Habromys lophurus, Handleyomys rhabdops, Heteromys desmarestianus, Marmosa mexicana, Microtus guatemalensis, Nyctomys sumichrasti , Peromyscus grandis , P. oaxacensis , Reithrodontomys microdon , R. sumichrasti , R. tenuirostris , and Microtus guatemalensis ( Matson & McCarthy 2005 ; Matson et al. 2014).

Specimens examined (146). Guatemala, Alta Verapaz, Chelemhá , 2100 m ( CM 120111 120123; USNM 569840, 569841 , 569855, 569860, 569892, 569907, 569908, 569923, 569929, 569942, 569950, 569973–569976) ; Alta Verapaz, Finca Chinaux , 2040–2190 m ( CM 120125 – 120144) ; Baja Verapaz, Biotopo del Quetzal , ( USAC 71–73, 75 , 78, 79, 80, 4043) ; Baja Verapaz, Salamá , ( USAC 70 ) ; El Progreso, Cerro Pinalón , 2560–2800 m ( CM 113277 –113294; USAC 3735, 3736 , uncatalogued USAC [NS 28; JOM 6860; TJM 9705, 9709; SGP 300, 400, 401, 426, 438, 714, 715, 724; M 708, 718]); El Progresso, 3 km W Pinalón Reserva de Biosfera Sierra de las Minas ( MVZ 223391 ) ; Zacapa, 6 km NNW San Lorenzo , 2200 m ( CM 113295 –113317; USAC 28–31 , uncatalogued, USAC [JOM 6743, 6744, 6745, 6773, 6774; SGP 430, 477–480, 488, 499, 501–503, 508, 509, 684, 696]) ; Zacapa, El Limo , 1475 m ( USNM 570021, 570026 , 570027, 570050, 570051, 570069, 570070).

Figures

FIGURE 5. Plot of the Principal Component scores on the first two axes based on 8 log-transformed skull variables for specimens identified as Sorex veraepacis including the type specimen (see Table 5).