1 REPTILIA: TESTUDINES: KINOSTERNIDAE Kinosternon abaxillare Catalogue of American Amphibians and combination. Reptiles 927 Kinosternon cruentatum abaxillare: Artner 2003:xix. First use of combination. E. Reyes-Grajales and J. B. Iverson. 2020. Kinosternon scorpioides abaxilare: Acuña and Kinosternon abaxillare. Merchán 2003:31. Lapsus. Kinosternon abaxillare Baur CONTENT. No subspecies are recognized. in Stejneger 1925 Central Chiapas Mud Turtle DESCRIPTION. Kinosternon abaxillare is a medium to large Kinosternon, with males in Kinosternon abaxillare Baur in Stejneger some populations exceeding 156 mm in car- 1925:462. Type locality, “Tuxtla [Gutiér- apace length, and females reaching 160 mm. rez], Chiapas, Mexico.” Holotype, United The carapace is moderately to strongly tricar- States National Museum (USNM; now inate in all but the oldest, largest individuals. Smithonian Institution National Museum The shell is somewhat depressed (shell height of Natural History) 7518, the shell of an averages 35% of carapace length in males, adult male collected by Dr. C. H. Berendt, 38% in females). The first vertebral scute is apparently in 1863 or 1864 (see Smith and wider than long; vertebral scutes 1–4 have Smith 1980). The holotype is lost, but the distinct posterior notches at the midline in all junior author has examined the 11 para- but the oldest, largest individuals. In imma- types (USNM 7519-29; Cochran 1961). ture individuals, the second vertebral shield is Kinosternun abaxillare: Alvarez del Toro the longest, and in mature specimens (of both 1973:20. Lapsus. sexes) the third vertebral shield is the longest; Kinosternon scorpioides abaxillare: Berry in both size classes the fifth vertebral shield is 1979:3186-B (also Ernst and Barbour the shortest. The tenth marginal scute is high- 1989; Smith and Smith 1980). First use of er than the ninth. The shape of the carapace is Figure 1. Male Kinosternon abaxillare from Villa Hidalgo, Chiapas, México. Photograph by Eduardo Reyes-Grajales. 2 Map. Distribution of Kinosternon abaxillare in Chiapas, México, and Huehuetenango, Guatemala. The red dots indicate localities verified by the authors and the blue dots represent localities verified by collaborators (see Acknowledgments). The red triangles designate unverified records. approximately oval (more evident in imma- pletely closes the shell (width of posterior ture individuals and females than in males); plastral lobe averages 47% of maximum car- the margins are distinctly flared outward in apace length in males, 48% in females) with most populations. The carapace is highly adult males having a smaller plastron than variable in color, ranging from light brown to females. Maximum plastron length averages olive to black, with darker seams in all but the 100% of maximum carapace length in males, darkest individuals. and 99% in females (Reyes-Grajales 2019). The plastron has two kinetic hinges, an- The posterior plastral lobe bears only a tiny terior and posterior to the abdominal scutes, posterior notch, or more typically none at and is concave to flat in males but slightly all. Bridge length averages 28% of carapace convex or flat in females. The plastron com- length in males and 31% in females. The in- Account 927 3 Figure 2. Female Kinosternon abaxillare from Villa Hidalgo, Chiapas, México. Photograph by Eduardo Reyes-Grajales. terabdominal seam length averages 30% of skin of other soft parts is gray or brown, usu- carapace length in males and 33% in females. ally with many small, darker spots. There are Axillary scutes are usually absent, although three to four pairs of gular barbels, with the the axillary-abdominal scute seam may be in- anterior pair the largest. Elevated patches of complete in some individuals (<15% in a pop- horny scales (‘clasping organs’ or ‘vinculae’) ulation). For medial length of plastral scutes, are absent from the posterior thigh and leg the most common formula for all class sizes of both males and females. Males have lon- and sexes is interabdominal > interanal > gu- ger, more prehensile tails than do females; the lar > interhumeral > interfemoral > interpec- cloacal aperture is at or posterior to the car- toral. The interabdominal scute seam is long, apace margin in males but is anterior to the averaging 29% of maximum carapace length carapace margin in females. The tails of both (27–33%), and the interpectoral seam is short sexes have terminal spines, but the spines are (3%). The color of the plastron may be yellow, larger in males. orange, brown or black, usually with darker seams. The dorsal head shield is rhomboi- DIAGNOSIS. The body size is medium rel- dal, bell-shaped, or triangular. The maxillary ative to other Kinosternon (to only 170 mm sheaths are weakly to strongly hooked, more carapace length). In addition to its localized strongly hooked in older males than in fe- geographic distribution, the most important males or younger individuals. Head markings character distinguishing Kinosternon abax- consist of yellow, cream, or pale gray dots or illare from congeners is the lack of axillary reticulations on a gray or olive background. scutes; however, some individuals (< 10%) The jaw sheaths are cream to yellow (more have full or partial axillary scutes (Iverson evident in adult females) with darker vertical 2008; Reyes-Grajales 2019). streaks most conspicuous in older males. The 4 Figure 3. Details of the carapace (top row) and plastron (bottom row) of an adult female (left column) and an adult male (right column) of Kinosternon abaxillare from Villa Hidalgo, Chiapas, México. Photo- graphs by Eduardo Reyes-Grajales. PHYLOGENETIC RELATIONSHIPS. The (1960, 1973, 1982), Berry (1978, 1979), Ber- relationships among the species of the genus ry and Iverson (2001), Bonin et al. (2006a, Kinosternon are still uncertain. A tree based 2006b), Legler and Vogt (2013), Reyes-Gra- on combined mtDNA + nuDNA presented by jales (2018a, 2018b), Smith and Smith (1980), Iverson et al. (2013) contained a clade with and Stejneger (1925). Specific descriptions Kinosternon abaxillare and Kinosternon oaxa- include comparisons with other Kinosternon cae as sister species, then most closely related (Kinosternon chimalhuaca, Kinosternon hirti- to a clade comprising Kinosternon scorpioi- pes, Kinosternon integrum, Kinosternon oaxa- des cruentatum and Kinosternon scorpioides cae, Kinosternon scorpioides and Kinosternon scorpioides. A subsequent phylogenetic anal- sonoriense; Reyes-Grajales 2019); shell shape ysis of the family Kinosternidae (Spinks et al. and morphometrics (Iverson, 2008, 2010; 2014) did not include Kinosternon abaxillare, Reyes-Grajales et al. 2020; Sánchez-M. et al. but the sister species identified in the analysis 2000), and lack of cloacal bursae (Smith and by Iverson et al. (2013), Kinosternon oaxacae, James 1958). was most closely aligned with Kinosternon in- tegrum and Kinosternon sonoriense. ILLUSTRATIONS. Color photographs were published by Alvarez del Toro (1960, 1973, CONSERVATION STATUS. Not evaluated. 1982; dorsal views), Arai (1998; general pro- file), Legler and Vogt (2013; dorsal and ven- PUBLISHED DESCRIPTIONS. General de- tral views of male and female), Reyes-Graja- scriptions were provided by Alvarez del Toro les (2019; general, ventral, dorsal, head views Account 927 5 Figure 4. Dorsal (left column) and ventral (right column) views of adult, juvenile, and neonate (top to bottom) of Kinosternon abaxillare from Villaflores, Chiapas, México. Photographs by Eduardo Reyes-Gra- jales. of neonates, juveniles, males and females), and medium elevations across its range. The Turtle Taxonomy Working Group (2017; gen- general distribution was described by Turtle eral profile), and Vetter (2005; general profile, Taxonomy Working Group (2017). Addition- the plastron, the side of the head, and the al distributional information is available for bridge). Black-and-white photographs were México (Alvarez del Toro 1960, 1973, 1982; presented by Alderton (1988a, 1988b), Berry Bannikov 1969; Bonin et al. 1998, 2006a, (1978; dorsal, ventral, head and bridge area), 2006b; Bour 2004; Darevskiy and Orlov 1988; Freiberg (1972; general profile), and Pritchard Ferri 1999, 2002; Fotolulu 2018; Fritz and Ha- (1979a; general profile and plastron). vaš 2007; Iverson 1985, 1986, 1992; Johnson 1989; Nelson and Nickerson 1966; Rhodin et DISTRIBUTION. Kinosternon abaxillare is al. 2008; Smith and Smith 1980; Turtle Taxon- endemic to the Grijalva River basin in the omy Working Group 2007, 2009, 2010, 2011, Central Depression of Chiapas and north- 2012, 2014). west Guatemala (Reyes-Grajales et al. 2020; Sánchez-M. et al. 2000). Our personal data FOSSIL RECORD. None. and information presented by Rogner (1996) suggest that Kinosternon abaxillare occurs at PERTINENT LITERATURE. General re- altitudes of 300 to 860 m. This taxon occurs in views were published by Alvarez del Toro a variety of permanent, semipermanent, and (1960, 1973, 1982), Berry (1978, 1979), Ber- temporary aquatic habitats, primarily at low ry and Iverson (2001), Casas Andreu (1965, 6 2019; Reyes-Grajales et al. 2020, in review; Sánchez-M. et al. 2000), feeding (Reyes-Gra- jales 2018a, 2018b; Sánchez-M. et al. 2000), habitat (Alvarez del Toro 1960, 1973, 1982), longevity (Mertens 1970; Nöllert 1992; Slavens 1981, 1982, 1987, 1988; Slavens and Slavens 1991, 2000), morphology (Berlant and Stayton 2017; Casas Andreu 1965, 1967; Gijzen and Wermuth 1958a, 1958b; Iverson 1984; Kilias 1957; Smith and Smith 1980), Figure 5. Presence of axillary scutes in a juve- parasites