Pteronura Gray, 1837

Noonan, Paula, Prout, Siobhan & Hayssen, Virginia, 2017, Pteronura brasiliensis (Carnivora: Mustelidae), Mammalian Species 49 (953), pp. 97-108 : 97-101

Pteronura Gray, 1837

Lutra Zimmermann, 1777:485 . Type species Lutra brasiliensis Ray, 1693 . Saricoviene Zimmermann, 1777:485. Type species Lutra brasiliensis Ray, 1693 . Mustela Gmelin, 1788:93 . Type species Mustela lutris brasiliensis ( Ray, 1693) . Saricovienne Schinz, 1821:213. Type species Lutra brasiliensis Ray, 1693 . Pteronùra Gray, 1837:580 . Type species Pteronùra sambachii . Pterura Wiegmann, 1839a:285 . Type species Pteronùra [ sambachii ] Gray, 1837. Pteronurus Lesson, 1842:72. Unjustified emendation of

Fig. 1. —Adult Pteronura brasiliensis from Karanambu-Rupununi,

Pteronura Gray, 1837 .

Guyana (© Pete Oxford/naturepl.com).

Saricovia Lesson, 1842:72 . Type species Lutra brasiliensis Ray, 1693 . Lontra Gray, 1843:70 . Type species Lutra brasiliensis Ray, 1693 . Pteroneura Sanderson, 1949:774 . Unjustified emendation of correspondiente al estado de Alagoas ” Brazil by Cabrera Pteronura Gray, 1837 . (1958:274).

Lutra nigricans Barrère, 1749:155 . No type locality; refers to a

CONTEXT AND CONTENT. Order Carnivora , family Mustelidae ,

composite specimen.

subfamily Lutrinae . Pteronura is monotypic.

Lutra atri coloris Brisson, 1762:278 . Type locality “ Brésil.”

Lutra ( brasiliensis ) Zimmermann, 1780:316. First legitimate use

Pteronura brasiliensis after 1758. Parentheses in original.

( Zimmermann, 1780) [ Mustela lutris ] brasiliensis: Gmelin, 1788:93 . Name combination.

Giant Otter Lutra brasiliana Shaw 1800:446 . Unjustified emendation of

Lutra brasiliensis Ray, 1693:189 . No type locality given; stated brasiliensis Ray, 1693 .

Lutra paraguaensis Schinz, 1821:213 . No type locality.

Lutra paranensis Rengger, 1830:128 . Type locality “ Paraguay.”

Pteronùra sambàchii Gray, 1837:580 . Type locality “ Demerara.”

Pteronura sanbachii Gray, 1839 :Plate XIV. Unjustified emendation of sambachii Gray, 1837 .

Pteronurus sandbackii Lesson, 1842:72 . Unjustified emendation of sambachii Gray 1837 .

Lutra sandbackii: Lesson, 1842:72 . Name combination.

Saricovia brasiliensis: Lesson, 1842:72 . Name combination.

Mustela brasiliensis: Lesson, 1842:72 . Name combination.

Lontra brasiliensis: Gray, 1843:70 . Name combination.

Pterura sandbachii: Gray, 1869:114 . Name combination attributed to Wiegmann, 1839b:392.

Pteronura sandbachii kappleri Gray, 1869:114 . Type locality “ Surinam.”

Pteronura brasiliensis: Thomas, 1908:390 . First use of current name combination.

[ Pteronura ] sambacchii Pohle 1919 (1920):115. Unjustified emendation of sambachii Gray, 1837 .

P [teronura]. b [rasiliensis]. lupina: Pohle 1919 (1920):117. Name combination.

P [teronura]. b [rasiliensis]. paranensis: Pohle 1919 (1920) :117. Name combination.

Pteroneura braziliensis Sanderson, 1949:774 . Unjustified emendation of brasiliensis Ray, 1693 .

CONTEXT AND CONTENT. Context as for genus. Historically a northern and southern subspecies have been named but genetic data do not support this distinction ( Garcia et al. 2007). Thus, the species is monotypic.

NOMENCLATURAL NOTES. Lutra brasiliensis Ray, 1693 and Lutra nigricans Barrère, 1749 predate the formal start of binomial nomenclature. In addition, Barrère’s description refers to a composite of P. brasiliensis and Eira barbara identified as Carigueya brasilienebus by Marcgraf 1648:222. Saricoviene was used by Zimmermann (1777:485) in reference to the giant otter but Saricovienne was used by Shaw (1800:447) for a cat-sized otter and thus not Pteronura . Gray (1869:114) attributes Pterura sandbachii to “Wiegmann’s Arch. iv. p392, 1838 (published 1839)” but Wiegmann refers only to the genus and does not give a species name. Confusion regarding nomenclature arose from early descriptions confounding the sea otter ( Enhydra lutris ) and Pteronura brasiliensis (extensive details in Harris 1968; Husson 1978).

Common names include hwana-dagu ( Sanderson 1949), lontra ( Gray 1843), margin-tailed otter ( Thomas 1908), and Surinam otter ( Gray 1868). Other common names are Guiana flat-tailed otter, winged-tailed otter, grote waterhond, grote visotter, platstaart otter, and watradogoe ( Husson 1978), as well as ariranha, lobito de cola ancha, lobo del río, lobo corbata, londra, lobo del río grande, lontra gigante, onça-d’água, and perro de água (Carter and Rosas 1997; Rodrigues et al. 2013). Local names in Argentina include lobo gargantilla, arirai, and nutria gigante ( Chehèbar 1991); in Guyana, water dog, turara, saaru, eniabu peru, and turáclá (van der Waal 2012).

DIAGNOSIS

Pteronura brasiliensis is longer (maximum total length: up to 1,800 [intact]– 2,440 mm [skin] versus 1,200 mm) and heavier (23–32 kg versus 5–15 kg) than the Neotropical otter, Lontra longicaudis (formerly, Lutra enudris — Harris 1968; Larivière 1999; Rosas et al. 2009a). The webbing on the feet of P. brasiliensis extends to the claws, but that of the Neotropical otter does not ( Husson 1978). The tail of P. brasiliensis is flattened, while that of the Neotropical otter is cylindrical ( Husson 1978). The Neotropical otter lacks the white patches on the throat ( Duplaix 1980).

GENERAL CHARACTERS

Pteronura brasiliensis (Fig. 1) has fawn, reddish, dark grayish, or chestnut brown fur with white or cream patches on the throat ( Harris 1968; Husson 1978). Individuals can be identified by their throat patterns ( Duplaix 1980; Schenck and Staib 1998). Rarely, individuals (3 out of 294) have no throat marking ( Groenendijk et al. 2014).

For 11 captive males from the Amazon River basin, the maximum total length was 1,630 mm, and the maximum mass 22.5 kg; 4 females had a maximum length of 1,620 mm and mass of 28.8 kg ( Rosas et al. 2009a). The mass–length relationship did not reveal significant sex differences and is expressed by W (kg) = 1.48 × 10 −5 L (cm) 2.81 ( Rosas et al. 2009a). Compiled from over 15 sources from 1817 to 1978 and using diverse techniques including measurements of skins, historical ranges for total length for males were 1,500 –1,800 mm and for females 1,500 –1,700 mm; the weight range for females (22–26 kg) was lower than that for males (26–32 kg — Duplaix 1980). External measurements (mm) for an adult male from Suriname were: head-body length, 1,050; tail length, 573; length of hind foot with claw, 175 ( Sanderson 1949). Measurements (mm) for an adult male and female from the Araguaia River in Brazil were: head circumference, 325, 330; neck circumference, 325, 365; head length, 220, 190; head-body length: 1,070, 970; tail length, 650, 555; ear length, 22, 22; ear width, 20, 20; length of hind foot, 210, 190; height, 330, 280 ( Silveira et al. 2011). Mean total length (mm) and mass (kg) of 6 captive males in Brazil, but of unknown origin, were: 1,556.67 and 21.25, respectively ( de Oliveira et al. 2011). Mean measurements (mm; parenthetical n) for males and females, respectively, from unspecified locations were: head-body length, 948.33 (2), 1,045, (2); tail length, 492.67 (3), 555 (2); total length, 1,441 (3), 1,615 (3— Rengger 1830; Nehring 1899 [1900]; Allen 1910; Vieira 1952). Mean lengths (mm; parenthetical n) of animals of unknown sex and location were: head-body length, 1,007.83 (6); tail length, 552.83 (6); total length, 1,480.1 (10— Schomburgk 1840; Gervais 1855; Gray 1869; Burmeister 1879; Waterton 1879; Quelch 1901; Fountain 1902; Santos 1945; Burton 1962). Masses (kg) for 3 animals of unknown sex were: 31.8, 34.2, 24.0 ( Fountain 1902; Sanderson 1949). Measurements (mm) for a subadult female were: head-body length, 770; tail length, 500; and total length, 1,270 ( Nehring 1899 [1900]). The skeleton of a 4-month-old P. brasiliensis had a head-body length of 324 mm, tail length of 191 mm, and a total length of 515 mm ( Rengger 1830). A 3- to 4-month-old male cub from Brazil weighed 4 kg; total length was 1,140 mm, tail length 330 mm, and hind foot length 130 mm (Lima and Marmontel 2011). Four (2 males and 2 females) 3-day-old cubs weighed 198, 177, 192, and 172 g, respectively; total lengths were 327, 325, 318, and 324 mm; tail lengths 121, 120, 118, and 123 mm; hind foot lengths 39, 37.5, 37.6, and 39 mm; and ear lengths 4.6, 4.5, 4.8, and 4.6 mm (Hantke and Kitchener 2015).

Skull ( Fig. 2 ) measurements (mm) for 1 female and 4 males, respectively, from Suriname were: condylobasal length: 153.6, 143.1, 145.8, 155.8, 154.9; palatal length: 76.3, 71.5, 75.0, 77.8, 76.0; zygomatic breadth: 92.0, 85.0, 94.3, 94.9, 97.2; interorbital constriction: 17.1, 17.5, 15.8, 16.7, 17.4; postorbital constriction: 17.6, 18.1, 16.1, 16.7, 17.3; length of postorbital constriction: 35, 27, 32, 41, 35; mastoid breadth: 82.4, 76.0, 79.4, 87.4, 81.1; length of upper toothrow C–M1: 48.0, 45.8, 47.6, 50.0, 49.6; length of upper carnassial: 18.3, 16.8, 17.3, 17.8, 17.4; greatest diameter of upper molar: 16.7, 15.5, 15.5. 15.4, 16.1; width across canines: 35.0, 31.8, 31.8, 31.8, 34.0; length of mandible: 99.5, 95.9, 100.1, 104.1, 103.9; length of lower carnassial: 19.6, 19.0, 18.0, 18.7, 19.5 ( Husson 1978). Skull measurements (mm) for 3 females were: condylobasal length: 148.0, 154.0, 164.0; basal length: 135.0, 142.0, —; width across postorbital processes: 31.0, 24.6, —; interorbital breadth: 19.3, 18.4, —; intertemporal length: 37.0, 34.0, —; mastoid breadth: 97.7, 85.2, —; zygomatic width: 97.4, 97.9; 98.0; length of mandible: —, —, 105.0; total length: —, —, 165.0 ( Pohle 1919 (1920); Vieira 1952). Skull measurements (mm) for 2 males were: condylobasal length: —, 149.0; basilar length: 142.0, —; zygomatic width: 99.0, 98.0; width of mastoid process: 88.0, —; length of mandible: —, 105.0; height of forehead (including lower jaw): 74.0, —; total length: 157.0, 150.0 ( Nehring 1899 [1900]; Vieira 1952). Skull measurements (mm) for 2 adults of unknown sex were: condylobasal length: 147.1, 147.5; basal length: 136.5, 135.? [sic]; interorbital breadth: 18.6, 16.2; width across postorbital processes: 23.8, 19.2; intertemporal length: 32.0, 27.0; mastoid breadth: 75.3, 77.3; zygomatic width: 93.7, 92.1 ( Pohle 1919 (1920)).

Limb measurements (mm) from 1 specimen (AMNH [American Museum of Natural History] 30190) were: scapula—maximum length of head, 22.7, maximum width of head, 14.2, length of neck, 20.2, width of neck, 9.6; humerus—length, 113.6, proximal width, 26.3, distal width, 33.3; radius—length, 74.9, proximal width, 14.6, proximal depth, 11.3, distal width, 20.5, distal depth, 14.8; scapholunar—length, 9.6, width, 9.4, depth, 12.5; cuneiform—length, 5.4, width, 9.4, depth, 12.2; metacarpal—length, II, 35.6, III, 40.7; femur—length, 102.0, proximal width, 33.3, midshaft width, 13.9, midshaft depth, 10.7, distal width, 30.1, distal depth, 25.6; tibia—length, 116.2, proximal width, 29.9, distal width, 23.2, distal depth, 15.2; astragalus—length, 26.7, width, 17.5; calcaneum—length, 40.9, width, 21.3; navicular—width, 20.0, depth, 10.7; cuboid—length, 14.6, width, 11.6; ectocuneiform—length 10.2, width, 10.0, depth, 16.2; metatarsal—length I, 32.4, II, 47.2, III, 56.9, IV, 60.1 ( Bjork 1970).

The medullary cone apex was close to the L4 vertebra on 2 specimens and between the L3 and L4 vertebrae on a 3rd specimen ( Machado et al. 2009). The medullary cone length was 55 mm for all 3 ( Machado et al. 2009).

DISTRIBUTION

Pteronura brasiliensis ( Fig. 3 ) lives on major river systems in South America from the Guianas to Uruguay ( Harris 1968) up to elevations of about 1,000 m ( Groenendijk et al. 2015). In Bolivia, the minimum population estimate is 350 individuals, mostly within national parks ( van Damme et al. 2002). It has disappeared from the southern portion of Brazil, except for isolated populations in the Amazon basin ( Chehébar 1990); 80 otters were sited near the Jauaperi River (Evangelista and Rosas 2011b). Colombia, Guyana, and Suriname have the strongest populations ( Chehébar 1990; Barnett et al. 2000); in the Orinoquia region of Colombia, a group of 8 individuals was observed (Díaz and Sánchez 2002). In Ecuador, P. brasiliensis was found in isolated areas ( Chehébar 1990). In French Guiana, it may live in the interior ( Chehébar 1990). In Bolivia, small populations of P. brasiliensis are present in national parks (Carter and Rosas 1997). In Ecuador and Peru, P. brasiliensis lives east of the Andes, with populations in isolated Amazon tributaries (Carter and Rosas 1997); 8 otters were sited near the Tapiche River ( Tramm 2014). In Paraguay, populations lived on the Paraguay and Prana rivers, with remnant populations elsewhere (Carter and Rosas 1997). P. brasiliensis is probably extinct in Uruguay (Carter and Rosas 1997) and Argentina ( Parera 1992). In Venezuela, small populations exist in protected areas ( Chehébar 1990). A decades old skull was recovered from Corrientes Province, Argentina (Beccaceci and Waller 2000).

FOSSIL RECORD

The extinct Pliocene Satherium piscinaria may be an ancestor to Pteronura brasiliensis , based on comparisons of skull, dental, and skeletal measures ( Bjork 1970). A fossil specimen of P. brasiliensis , the first to be found in Argentina, was also determined to be the oldest of existing records, at 125,000–130,000 years ago (Prevosti and Ferrero 2008). The body was larger than current specimens and showed minor differences in the skull and dentition (Prevosti and Ferrero 2008). Analysis of 21 P. brasiliensis skins from the upper Amazon and the Orinoco basin determined that 2 clades diverged about 37,000 years ago, and divergence within those clades was between 10,000 and 20,000 years ago ( de Thoisy et al. 2013).

FORM AND FUNCTION

Form. — The iris is pale green-yellow ochre ( Sanderson 1949). The nose is hairy ( Gray 1868). Pteronura brasiliensis has long mysticial, supraciliary, and gular virbrissae ( Duplaix 1980). Outside each ankle is a large tuft of hair ( Gray 1868). Anal glands are 40 mm with 5-mm diameter, black openings, on either side of the anus ( Sanderson 1949). The secretions of the anal gland are a cream color, can be forcibly ejected, and have a fishy smell ( Sanderson 1949). The tail is furred, thick, and rounded with a ridge on each side ( Gray 1868). The plantigrade feet have 5 webbed digits with claws ( Duplaix 1980).

The pars intermedia of the hair shafts exhibit an irregular mosaic pattern (Kuhn and Meyer 2010). The primary hairs (mm, mean ± SD) are short and parallel, 11 ± 0.6; the secondary hairs are 5 ± 0.2 (Kuhn and Meyer 2010). The width of the primary hairs is 0.097 ± 0.0099 (Kuhn and Meyer 2010).

Function. —Hemoglobin values (mean ± SD) of 6 captive individuals (3 male, 3 female) were 16.36 ± 2.81 g /dl; mean packed cell volume was 50.66 ± 7.77% ( Rosas et al. 2008a). Red blood cell counts were 6.82 ± 1.64 106 /mm 3 for females, 5.860 ± 0.59 106 /mm 3 for males. White blood cell counts were 6.325 ± 1.52 103 /mm 3 for females, 4.77 ± 1.66 103 /mm 3 for males ( Rosas et al. 2008a). Other hematology values (not separated by sex) were: mean corpuscular value, 74.63 fl; mean corpuscular hemoglobin, 24.58 pg; mean corpuscular hemoglobin concentration 33.05 g /dl; red cell distribution width, 14.54%; platelets, 401.81 103 /mm 3; platelet distribution width, 14.28%; basophils, 0.30%; eosinophils, 0.87%; segmented neutrophils, 80.03%; lymphocytes, 16.24%; monocytes, 1.10%. Mean biochemistry values were: glucose, 100.67 mg /dl; uric acid, 1.33 mg /dl; urea, 221.50 mg /dl; creatinine, 1.80 mg /dl; cholesterol, 314.33 mg / dl; triglycerides, 19.50 mg /dl; aspartate aminotransferase, 183.67 U/l; alanine aminotransferase, 114.33 U/l; total bilirubin, 0.20 mg /dl; alkaline phosphates, 53.33 U/l; lactic dehydrogenase, 1226.33 mg /dl; gamma GT, 17.67 U/l; amylase, 9.33 U/l; calcium 9.57 mg /dl; phosphorus, 5.80 mg /dl; magnesium, 3.73 mg /dl; total protein, 7.00 g/dl; albumin, 3.60 g /dl; globulin, 3.70 g /dl ( Rosas et al. 2008a).

Dentition is i 3/3, c 1/1, p 4/3, m 1/2, total 36, with the lower premolar sometimes absent ( Husson 1978; Duplaix 1980). Infrared thermography shows heat dissipation from the entire body and tail due to its relatively short and thin hair, although the coldest parts of the body are the feet and tail (Kuhn and Meyer 2009, 2010).

ONTOGENY AND REPRODUCTION

Gestation is 52–70 days ( Hayssen et al. 1993; Carter and Rosas 1997). In a captive population of Pteronura brasiliensis , the mean interval between births was 180–214 days (n = 3—Londoño and Muñoz 2006). Litter size is 1–5 young with an average of 2 ( Hayssen et al. 1993; Carter and Rosas 1997; Groenendijk et al. 2014). Pseudopregnancies may last as long as a normal pregnancy (Londoño and Muñoz 2006).

Neonatal mass is 0.20 kg (Carter and Rosas 1997). The sex of cubs as young as 3 days old can be determined by comparing the distance between the genital and anal openings, with the distance for male cubs about 8 times longer than that of females (Hantke and Kitchener 2015). By 2 weeks, cubs can float and swim but with the tail in the air and superficial immersion (Evangelista and Rosas 2011a). Eyes open at 1 month (Carter and Rosas 1997). By 6–8 weeks, pups are able to swim independently (Londono and Munoz 2006; Evangelista and Rosas 2011a). Initial attempts at hunting begin around 2.5 months (Evangelista and Rosas 2011a). Weaning and autonomy occurs at 4–9 months ( Hayssen et al. 1993; Carter and Rosas 1997; Evangelista and Rosas 2011a). Subadults usually swim in the middle of a group ( Duplaix 1980). Growth layers in canines can be used to age P. brasiliensis ( de Oliveira et al. 2007) .

An analysis of 6 P. brasiliensis males that died in captivity in Brazil showed a ratio of testes mass to body mass of 0.046 ± 0.0071% (SD — de Oliveira et al. 2011). Mean diameter (μm ± SD) of the seminiferous tubules was 126.3 ± 13.37; for epididymal tubules, 198.8 ± 31.39 ( de Oliveira et al. 2011). The length and width (cm ± SD) of the testes were 2.76 ± 0.15 and 1.46 ± 0.09, respectively ( de Oliveira et al. 2011). The presence of spermatozoa indicated that 2-year-old P. brasiliensis are sexually mature ( de Oliveira et al. 2011).

Figures

Fig. 2.—Dorsal, ventral, and lateral views of skull and lateral view of mandible of an adult male specimen AMNH (American Museum of Natural History) 71858. Greatest length of skull is 147.25 mm.

Fig. 3.—Geographic distribution of Pteronura brasiliensis. Modified from the International Union for Conservation of Nature and Natural Resources Red List of Threatened Species (2015).