Brasilotyphlus guarantanus, Maciel, Adriano O., Mott, Tami & Hoogmoed, Marinus S., 2009

Maciel, Adriano O., Mott, Tami & Hoogmoed, Marinus S., 2009, A second species of Brasilotyphlus (Amphibia: Gymnophiona: Caeciliidae) from Brazilian Amazonia, Zootaxa 2226, pp. 19-27 : 21-25

Brasilotyphlus guarantanus sp. nov.

Holotype: MPEG 22382, Brazil, state of Mato Grosso, Municipality of Guarantã do Norte, S 9°40’59.44” W 54°57’46.58”, collected on March 13, 2003 by Tami Mott.

Paratypes: Forty-seven specimens from the type locality: CHUNB (30703) March 12, 2003, CHUNB (30704–30707), MPEG (16767, 16768, 22383–22385), UFMT (5008, 5012, 5013, 5015–5017) all collected March 13, 2003; MPEG (22386–22387), UFMT (5571–5578, 5581–5593, 6648–6655) all collected April 12, 2007. All collected by Tami Mott. MPEG (22170) Brazil, state of Pará, Municipality of Parauapebas (S 6°3’ W 50°10’), collected by Carvalho Jr. and Chaves on November 14, 2004.

Diagnosis: A Brasilotyphlus with maximum known total length of 305 mm; 47–76.1 times the width at midbody. Primary folds 151–170, secondary folds 0–2. The first nuchal collar is distinct dorsally and ventrally, the second is partly fused below with the first body collar. Two paired anal papillae may be present either side of midline just anterior of the vent. A weak vertical keel is present on the terminal part of the body of most specimens (in 27 of the type specimens). Maxillary teeth may reach the level of the posterior border of the choanae or extend slightly beyond them. Dermal scales present in folds in the posterior part of the body.

Brasilotyphlus guarantanus differs from B. braziliensis mainly in annular counts, with a higher number of primaries (151–170 versus 142–147) and a lower number of secondaries (0–2 versus 23–36: only three type specimens of B. guarantanus have two, incomplete secondary folds, MPEG 22387 and UFMT 5589, 6648). In B. guarantanus the maxillary teeth either reach the level of the posterior edge of the choanae or extend posteriorly beyond them, while in B. braziliensis the maxillary teeth do not reach the level of the choanae. This was the only notable difference in skull characters found between B. braziliensis and B. guarantanus . In B. guarantanus dermal scales only appear near the end of the body (from the 145th fold of the holotype), while in B. braziliensis they already appear near the 25th fold. Although the number of B. braziliensis specimens available is small for a detailed comparison, B. guarantanus seems to be more slender than B. braziliensis . Comparison of the new species with B. braziliensis is given in Tables 1 and 2 .

Variables B. braziliensis B. guarantanus Types from Taylor 1968 MZUSP 63097 Holotype Description of the holotype: Mature male ( Fig. 2 ). Total length 222 mm. Total length 50.5 times midbody width. Head longer than wide and narrower than body. Eye not visible externally. Snout projects 1 mm beyond the mouth. Tentacles slightly elevated and not visible from above, closer to angle of the mouth (1.4 mm) than to nostril (2 mm). Nostrils visible from above, not from below. First nuchal collar distinct dorsally and ventrally, the second partly fused below with the first body annulus. One dorsal transverse groove present on each collar, that on the first less marked. Primary annuli 159; secondaries absent. Most primary folds are ventrally incomplete, two interrupted by the disc surrounding the vent. Transverse vent with eleven denticulations: five on the anterior margin, six on the posterior margin. No distinct anal papillae. A weak vertical keel is apparent on the end of the body. Dermal scales present in posterior part of body, starting from the 145th annulus; at most two rows of dermal scales per fold. Subdermal scales absent. Premaxillary and maxillary teeth monocuspid, forming a series (10–10 teeth) with little variation in size, posterior maxillary teeth slightly smaller, extending to the level of the posterior border of the choanae. Prevomerine (6–6) and palatine (5–6) series bicuspid, with no apparent variation in size of teeth and a large diastema between these two series; teeth smaller than in premaxillary-maxillary series. Dentary teeth (10–8) monocuspid, approximately same size as premaxillary-maxillary teeth.

Males Females

Variables Range, mean ± SD and N Range, Mean ± SD and N ANOVA Primary folds 153–170; 160.48 ± 4.04; 27 151–167; 159.9 ± 3.76; 20 F = 0.252 P = 0.618 Total length 199–283; 237.54 ± 21.5; 27 165.2–305; 233.7 ± 33.3; 20 F = 0.228 P = 0.635 Head height at jaw articulation 2.1–3.3; 2.58 ± 0.39; 23 1.5–3.35; 2.39 ± 0.43; 18 F = 2.257 P = 0.141

ANCOVA

Snout projection beyond mouth 0.8–1.5; 1.21 ± 0.17; 27 0.9–1.4; 1.1 ± 0.14; 20 F = 0.423 P = 0.519 Head width at jaw articulation 3.2–4.2; 3.67 ± 0.28; 27 2.5–4.1; 3.26 ± 0.39; 20 F = 31.069 P = 0.000 Head length 3.8–6.2; 5.11 ± 0.49; 27 4–5.3; 4.72 ± 0.35; 20 F = 10.876 P = 0.002 Body height at midbody 3–4.2; 3.51 ± 0.28; 20 2.7–4.26; 3.45 ± 0.43; 15 F = 0.142 P = 0.708 Body width at midbody 3.5–4.7; 4.21 ± 0.29; 23 3.3–4.9; 4.08 ± 0.47; 17 F = 0.637 P = 0.417 Body width at five folds anterior to vent 3.27–4.7; 3.98 ± 0.37; 25 2.9–4.6; 3.72 ± 0.54; 18 F = 1.938 P = 0.172 Color of the type specimens: In life, B. guarantanus is lavender and there are two patterns of body coloration. In one the body is dark lavender and gradually paler towards the head. In the other the body is entirely pale lavender ( Fig. 4 ), this difference is not sexually dimorphic. Preserved specimens are grayish or brownish. The venter and the lateral surface are slightly paler than the dorsum along the entire body. The area surrounding the vent is less pigmented, as are the mandible and part of the head. A very thin longitudinal ventral line appears in the posterior half of the body of some specimens.

Variation: There is little external variation, except in annular counts, the presence or absence of a terminal keel and of a dorsal transverse fold on the first nuchal collar. One pair of anal papillae is present beside the vent of one male specimen (UFMT 5591). External sexual dimorphism is evident only for head width and head length, males having wider and longer head than females ( Table 3). At most there are two rows of dermal scales per fold near the posterior edge. The museum number, the dimensions of the major scale found (width x length in mm), and the annulus where the scales begin to appear in each of three paratype specimens analyzed are: UFMT 6648, 0.28 x 0.46, 154th annulus; UFMT 5015, 0.27 x 0.86, 160th annulus; MPEG 22384, 0.42 x 0.92, 155th annulus.

Etymology: The name of the species refers to the type-locality, Guarantã do Norte, state of Mato Grosso, Brazil.

Remarks: Dunn (1945) and Taylor (1968) did not mention the condition of the cusps of the teeth of B. braziliensis . In all specimens of B. guarantanus observed, the prevomerine and palatine teeth are bicuspid, all other teeth are monocuspid. The unique specimen (collected 1986) of B. braziliensis from Reserva do Gavião INPA-WWF, near Manaus (MZUSP 63097) studied by us shows this same condition of the teeth which was also mentioned by Nussbaum & Hinkel (1994) in their table of character states. Thus this character condition has been added to the revised diagnosis of Brasilotyphlus . Further we counted 36 secondary annuli in MZUSP 63097, which increases the upper range limit from 27 to 36 in B. braziliensis . Comparing the skulls of the two species, no significant differences were found, except that the maxillary teeth extend slightly posteriorly of the choanae in B. guarantanus whereas in B. braziliensis they may at most reach the level of the anterior border of the choanae, as observed in MZUSP 63097.

Figures

FIGURE 2. Brasilotyphlus guarantanus sp. nov. holotype MPEG 22382; anterior (left) and posterior (right) ends in lateral, dorsal and ventral views; scale bar represents 4 mm.

FIGURE 4. Photograph of a live specimen of B. guarantanus from the type locality.

Tables

TABLE 1. Variation in meristic and morphometric (mm) data of Brasilotyphlus braziliensis and B. guarantanus sp. nov.

Variables	B. braziliensis	B. guarantanus
	Range; mean ± SD; n	Range; mean ± SD; n
Total length	147–260; 204 ± 41.5; 5	165.2–305; 235.9 ± 26.6; 48
Head width at jaw articulation	2.7–5.1; 4 ± 0; 5	2.5–4.25; 3.49 ± 0.38; 48
Head width at level of nostrils	X	1.28–2.04; 1.59 ± 0.17; 47
Head length	X	3.8–6.2; 4.95 ± 0.47; 48
Head height at level of jaw articulation	X	1.5–3.35; 2.51 ± 0.42; 42
Snout projection beyond mouth	X	0.83–1.5; 1.16 ± 0.16; 48
Body width at midbody	3–6; 4.5 ± 1.29; 5	3.3–4.9; 4.17 ± 0.38; 41
Body width at five folds anterior to vent	X	2.92–4.7; 3.87 ± 0.45; 44
Body height at midbody	X	2.71–4.26; 3.48 ± 0.35; 35
Distance between nostrils	X	0.88–1.5; 1.26 ± 0.13; 48
Distance nostril-margin of the mouth	X	0.6–1.24; 0.93 ± 0.14
Tentacle to nostril distance	1.5–2.6; 1.96 ± 0.4; 5	1.5–2.4; 1.82 ± 0.23; 48
Distance tentacle-margin of the mouth	X	0.22–0.52; 0.34 ± 0.06; 46
Distance tentacle-angle jaw	X	0.8–1.57; 1.17 ± 0.14; 48
Primary annuli	142–147; 145 ± 2; 5	151–170; 160 ± 3.8; 48
Secondary annuli	23–36; 27 ± 5; 5	0–2; 0.12 ± 0; 48
Complete secondary folds	4–7; 6 ± 1.3; 5	Absent
Annuli interrupted by vent	X	0–3; 1.82 ± 0.67; 46
Premaxillary–maxillary teeth	15–25; 20.2 ± 4.1; 4	17–24; 21 ± 1.95; 27
Prevomerine teeth	8–12; 10.6 ± 1.94; 5	8–13; 10 ± 1.45; 25
Palatine teeth	10–14; 11.8 ± 1.8; 4	8–14; 10.6 ± 1.43; 25
Dentary teeth	15–18; 15.8 ± 1.9; 5	13–21; 17.2 ± 2.2; 26
Midbody width in total length	43–48.7; 46.14 ± 2.5; 5	47–76; 56.9 ± 6.2; 41

TABLE 2. Comparison of the types and a new specimen of Brasilotyphlus braziliensis with the holotype of B. guarantanus sp. nov. Measurements in mm.

Total length 191–260	147	222
Head width at jaw articulation 4–5.1	2.7	3.7
Head width at level of nostrils X	1.5	1.7
Head length X	4.5	4.3
Head height at level of jaw articulation X	2	X
Snout projection beyond mouth X	1.2	1
Body width at midbody 4–6	3	4.4
Body width at five folds anterior to vent X	3.1	4.2
Body height at midbody X	2.8	3.2
Distance between nostrils X	1.2	1.4
Distance nostril-margin of the mouth X	0.7	0.9
Tentacle to nostril distance 1.8–2.6	1.5	1.9
Distance tentacle-margin of the mouth X	0.2	0.2
Distance tentacle-jaw angle X	0.8	1.4
Primary annuli 142–147	146	159
Secondary annuli 23–27	36	0
Complete secondary folds 4–7	5	0
Annuli interrupted by vent X	2	2
Premaxillary–maxillary teeth 20–25	15	22
Prevomerine teeth 8–12	9	12
Palatine teeth 5–14	10	11
Dentary teeth 13–18	15	18
Mid body width in total length 43–48	48.7	50.5