Taxonomic revision of the Brazilian Atlantic Forest Atractus (Reptilia: Serpentes: Dipsadidae) 2364
Author
Passos, Paulo
Author
Fernandes, Ronaldo
Author
Bérnils, Renato S.
Author
De Moura-Leite, Julio C.
text
Zootaxa
2010
2010-02-19
2364
1
1
63
https://biotaxa.org/Zootaxa/article/view/zootaxa.2364.1.1
journal article
10.11646/zootaxa.2364.1.1
11755334
5315506
Atractus francoi
sp. nov.
Figs. 2B–C
,
3C
,
5
Atractus
sp.
–
Marques
, Eterovic & Sazima, 2004
; Snakes of the Brazilian Atlantic Forest: An Illustrate Field Guide for the Serra do Mar. Holos, Ribeirão Preto, 1–205:69.
Holotype
:
Adult
male,
MNRJ 17537
(formerly
DZUFRJ 1742
), collected
17 July 2006
by
M. C. Carlo
, locality
Fazenda Recanto
,
Serra do Piloto
(
22°50’S
,
44°03’W
, ca.
600 m
), municipality of
Mangaratiba
, state of
Rio de Janeiro
,
Brazil
.
Paratypes
:
Six
n specimens: adult male (
IBSP 72654
), municipality of
São José do Barreiro
(
22º38’S
,
44º35’W
, ca.
600 m
), state of
São Paulo
;
an adult male (
IBSP 74724
),
two juvenile
females (
IBSP 53924
,
74723
), and adult female (
IBSP 74648
), collected by
P. A. Hartmann
,
Núcleo SantaVirgínia
,
Parque Estadual da Serra do Mar
, municipality of
São Luís de Paraitinga
(
23º14’S
,
45º20’W
, ca.
770 m
), state of
São Paulo
;
adult female (
MNRJ 17536
), collected on
September 1989
by
R
.
Schasse
, municipality of
Nova Friburgo
(
22º16’S
,
42º32’W
, ca.
915 m
), state of
Rio de Janeiro
.
Diagnosis:
Atractus francoi
is distinguished from all known congeners by the following combination of characters: (1) 17/17/17 smooth dorsal scale rows; (2) two postoculars; (3) moderate loreal; (4) temporals 1+2; (5) usually seven supralabials (six in one side), third and fourth contacting orbit; (6) seven infralabials, first four contacting chinshields; (7) eight or nine maxillary teeth; (8) two to four gular scale rows; (9) three or four preventrals; (10) 156–164 ventrals in females and
162–164 in
males; (11) 14–19 subcaudals in females and
25–30 in
males; (12) dorsum uniformly black in adults and brown with scattered small black dots in juveniles; (13) venter beige anteriorly, becoming gradually black after 15
th
ventral in juveniles and adults; (14) moderate body size, females reaching
473 mm
SVL and males
420 mm
SVL; (15) tail short in females (6.3– 8.6% SVL) and moderate (12.6–13.6% SVL) in males; (16) moderately bilobed, semicapitate, and semicalyculate hemipenis.
Comparisons:
Among congeners,
A. francoi
shares 17 dorsal scale rows, dorsal colour pattern uniformly black in adults, venter dark with posterior margin of ventral scales with pale (beige) pigmentation, seven to ten maxillary teeth, and semicapitate and semicalyculate hemipenis [unknown in
A. caete
] only with
A. caete
,
A. serranus
,
and
A. trihedrurus
.
Atractus francoi
differs from
A. caete
by usually having seven supralabials (six in one side of
one specimen
), eight or nine maxillary teeth, and juveniles dark brown with small black dots dorsally and having venter mostly brown (vs. usually six supralabials, seven maxillary teeth, and juvenile with dorsum uniformly black and venter mostly cream); from
A. serranus
and
A. trihedrurus
by having females attain maturity below
500 mm
SVL, 152–154 ventrals in males and
162–164 in
females, hemipenial lobes smaller than remaining capitulum, asulcate capitulum lacking medial and lobular crests, sulcus spermaticus narrow, basal region of hemipenis lacking moderate hooked spines, and barely distinct ontogenetic change of dorsal colouration (vs. mature females always more than
500 mm
SVL, 141–147 ventrals in males and
150–163 in
females of
A. serranus
and
136–150 in
males and
146–159 in
females of
A. trihedrurus
, hemipenial lobes longer than remaining capitulum, asulcate capitulum with conspicuous medial and lobular crests, sulcus spermaticus expanded laterally, basal region of hemipenial with moderate hooked spines, and juveniles of
A. trihedrurus
with banded colour pattern).
Atractus francoi
occurrs sympatrically with
A. zebrinus
along the coastal mountains of the states of
Rio de Janeiro
and
São Paulo
, but differs from it by having the dorsum and venter mostly black (vs. dorsum beige to creamish red with wide transversal black blotches, venter immaculate creamish white).
Description of the
holotype
:
Adult male, SVL
420 mm
, CL
53 mm
(12.6% SVL); body diameter 9.0 mm (2% SVL); head length 18.2 mm (4.3% SVL); head width 10.8 mm (59.3% head length); interorbital distance 6.9 mm; rostro-orbital distance 4.9 mm (70% interorbital distance); naso-orbital distance 3.7 mm; cervical constriction barely distinct; head slightly arched in lateral view, round in dorsal view; snout truncate in lateral view, round in dorsal view; rostral sub-triangular in frontal view, 3.0 mm wide, 1.0 mm high, little visible in dorsal view; internasal 1.3 mm long, as long as wide; internasal suture sinistral with respect to prefrontal suture; prefrontal 2.2 mm long, 3.5 mm wide; supraocular sub-rectangular, 1.9 mm long, 1.3 mm wide; frontal sub-pentagonal, 4.2 mm long, 4.4 mm wide; parietal 7.1 mm long, 4.0 mm wide; nasal divided; nostril located between prenasal and postnasal; prenasal 1.2 mm high, 0.6 mm long; postnasal 1.5 mm high, 0.9 mm long; loreal 2.5 mm long, 1.0 mm high, contacting second and third supralabials; eye diameter 2.0 mm; pupil subelliptical; two postoculars; upper postocular 1.1 mm high, 0.9 mm long, similar in height and slightly longer than lower postocular; temporals 1+2; anterior temporal 3.5 mm long, 1.3 mm high; upper posterior temporal fragmented into small occipital-like scales and elongate (on the left side), 5.1 mm long, 1.9 mm wide; six (left) and seven (rigth) supralabials, third and fourth contacting orbit; second supralabial higher than first and lower than third; sixth supralabial higher and seventh longer than remaining supralabials; symphisial triangular, 2.6 mm wide, 1.2 mm long; seven infralabials, first four contacting chinshields; first pair of infralabials in contact behind symphisial, preventing symphisial/chinshield contact; chinshields 5.1 mm long, 2.1 mm wide; two (left) and three (right) gular scale rows; two preventrals; 152 ventrals; 29 (left) and 30 (right) subcaudals; 17/17/17 smooth dorsal scale rows; dorsals lacking apical pits, supra-anal tubercles, and keels; eight dorsal scale rows at the level of second subcaudal; anal gland three subcaudals long; caudal spine short, robust, and rhomboid; retracted hemipenis extends to the level of 11
th
and bifurcates at 10
th
subcaudal; six prediastemal and two postediastemal teeth; maxillary diastema moderate (
Fig. 5
).
FIGURE 5.
Dorsal (A) and lateral (B) views of head, and lateral view of body (C) of the holotype of
Atractus francoi
sp. nov.
(MNRJ 17535). Scale = 5 mm.
Maxillary arch:
Arched in dorsal view, with six prediastemal and two postdiastemal teeth; prediastemal teeth large, similar in size, curved posteriorly, angular in cross section, robust at base, narrower on the apices; first five teeth generally closely spaced, space between fifth and sixth tooth moderate; maxillary diastema moderate; postdiastemal teeth about half size of prediastemal teeth; lateral process of maxilla moderately developed, lacking posterior projections.
Colour in preservative:
Dorsum of head dark brown, except for pale brown spots on distal portion of prefrontals; head dark brown, except for irregular pale brown dots covering anterior portion of loreal and fourth to sixth supralabials; symphisial and first three infralabials spotted with brown, remaining infralabials, chinshields, and preventrals beige coloured; gulars with dark brown dots; venter uniform beige anteriorly, with brown blotches on lateral portions of ventrals from 15
th
scale; lateral blotches increase progressively in size, collapsing at level of 20
th
ventral; posterior to this point venter becomes uniform brown, with only the posterior margin pale (creamish brown); tail brown with beige dots on posterior suture of subcaudals; dorsum of body uniformly dark brown (
Fig. 2B
).
Juvenile colouration in preservative:
Dorsum of body dark brown with small (one scale long) black dots concentrated on paravertebral region, occasionally in a fragmented barely distinct vertebral black line; first four scale rows lacking marks on both sides of body; venter similar to adults with slightly paler colour.
Juvenile colouration in life:
Dorsum of head almost black, with reddish brown blotches concentrated on anterolateral portion of prefrontals and temporal region; lower margins of supralabials beige; dorsal ground colour of body and tail dark reddish brown with small fragmented black dots (
Fig. 3C
).
Hemipenis morphology (everted organs
n
= 2):
Retracted organ bifurcates at level of eighth and extends to level of ninth subcaudal. Everted hemipenis moderately bilobed, semicapitate, semicalyculate; lobes distinct and restricted to distal portion of capitulum; lobes sub-cylindrical, of similar size, with round apices; lobes slightly centrifugally oriented, with length similar to remaining capitulum; lobes and capitulum covered with small papillate calyces; vertical walls of calyces well defined, not arranged in distinct calyculate flounces on both sides of organ; asulcate side of capitulum with irregular calyces lacking lobular and medial crests; capitular groove indistinct on the sulcate side and well defined on the asulcate side of hemipenis; capitulum located just above sulcus spermaticus bifurcation and slightly smaller than hemipenial body; sulcus spermaticus bifurcates at about middle of organ; sulcus spermaticus branches centrifugally oriented, running to tip of lobes; margins of sulcus spermaticus stout and narrow, bordered with papillae from the base to the apices of lobes; hemipenial body sub-cylindrical, covered with moderate hooked spines on laterodistal region of the sulcate side of hemipenis; basal portion of the hemipenial body with small spines only, lacking moderate hooked spines; basal naked pocket restricted to basal portion of hemipenial body; proximal region of hemipenis with an evident constriction with uniformly scattered longitudinal plicae and diffuse spinules (
Fig. 6A
).
Variation:
Largest male
420 mm
SVL,
53 mm
CL; largest female
475 mm
SVL,
40 mm
CL; tail 12.6– 13.6% (
n
= 2) SVL in males, 6.3–8.6% (
x¯
= 7.6; SD = 3.5;
n
= 4) SVL in females; 152–154 (
n
= 2) ventrals in males, 162–164 (
x¯
= 161; SD = 1;
n
= 3) in females; 25–30 (
x¯
= 27.2; SD = 2.1;
n
= 3) subcaudals in males, 14–19 (
x¯
= 16.9; SD = 2.1;
n
= 4) in females; 6 (
n
= 1 side) or 7 (
n
= 13 sides) supralabials; 2 (
n
= 2 sides), 3 (
n
= 8 sides), or 4 (
n
= 3 sides) gular scale rows; 2 (
n
= 1) or 3 (
n
= 6) preventrals; 8 (
n
= 6 sides) or 9 (
n
= 2 sides) maxillary teeth; 8–10 (
x¯
= 8.9; SD = 0.7;
n
= 14 sides) dorsal scale rows at the level of second subcaudal; 7.2–9.2 mm (
x¯
= 8.6; SD = 0.9;
n
= 4) body diameter; hemipenis bifurcates at level of seventh to 10
th
and extends to level of eighth to 11
th
(
n
= 2) subcaudal.
Etymology:
This species is dedicated to our friend Dr. Francisco Luís Franco, Curator of Herpetology at Instituto Butantan in
Brazil
, for his contribution to the systematics of South American snakes, and also for calling our attention to this undescribed species.
Distribution:
Highlands of the Serra da
Bocaina
and Serra dos Órgãos, in Southeastern
Brazil
between the states of
Rio de Janeiro
and
São Paulo
, ranging from Nova Friburgo to São Luís do Paraitinga.
Atractus francoi
inhabits Lower Montane Rainforest between
600–1000 m
elevation (
Fig. 7
).
Remarks:
Marques
et al
. (2004)
identified and illustrate a juvenile female of
A. francoi
(IBSP 74723, actually
paratype
) as possibly an undescribed species (=
Atractus
sp.
). A female (MNRJ
17536, 473 mm
SVL, CL
30 mm
) layed
six eggs
in captivity (R. Fernandes pers. observ.), which corroborates that females of
A. francoi
attain maturity below
500 mm
SVL.