Dipsas aparatiritos, Ray & Sánchez-Martínez & Batista & Mulcahy & Sheehy III & Smith & Pyron & Arteaga, 2023

Ray, Julie M., Sanchez-Martinez, Paola, Batista, Abel, Mulcahy, Daniel G., Sheehy III, Coleman M., Smith, Eric N., Pyron, R. Alexander & Arteaga, Alejandro, 2023, A new species of Dipsas (Serpentes, Dipsadidae) from central Panama, ZooKeys 1145, pp. 131-167 : 131

Dipsas aparatiritos sp. nov.

Figs 2 , 3 , 4 , 5 , 6 , 7 , 8

Type material.

Holotype. Panama • ♀; PNGDOTH, ca. 7.5 km N of El Copé de La Pintada, Coclé Province, 8.670383°N, 80.592343°W, 763 m a.s.l.; 30 Jul 2010; S. Gotte, J. Jacobs, D. Mulcahy and R. Reynolds; USNM 579828 (Biol. Survey Field Series 4608) (Figs 3 , 4 ).

Paratype. Panama • ♀; PNGDOTH, ca. 7.5 km N of El Copé de La Pintada, Coclé Province, 8.670383°N, 80.592343°W, 763 m a.s.l.; 30 Jul 2010; S. Gotte, J. Jacobs, D. Mulcahy and R. Reynolds; USNM 579829 (Biol Survey Field Series 4609) (Figs 5 , 6 ).

Diagnosis.

Dipsas aparatiritos sp. nov. is placed in the genus Dipsas based on phylogenetic evidence (Fig. 1 ) and the absence of a labial that is noticeably higher than other labials. The species is diagnosed based on the following combination of characters: (1) 15/15/15 smooth dorsals with enlarged vertebral row (1.5-2.4 × as wide as adjacent rows); (2) loreal and a preocular in contact with orbit; (3) 7 supralabials with 4th and 5th contacting orbit, 1st supralabial fused with nasal scale; (4) 8-9 infralabials with 3rd to 6th in contact with chin shields, first pair of infralabials not in contact behind symphysial due to presence of two postmentals; (5) 191-196 ventrals in males, 177-197 in females; (6) 122-136 divided subcaudals in males, 111-126 in females; (7) dorsal and ventral color consisting of 17-20 dark brown to black white-bordered body bands (10-12 dorsal scales long anteriorly to 3-5 dorsal scales long posteriorly) separated from each other by white to pale yellow (anteriorly) to pale brown (posteriorly) interspaces measuring 2-6 dorsal scales long, ventral surfaces white with encroachment from the dorsal dark blotches and with smaller blackish marks in-between the blotches, dorsal aspect of head dark reddish brown with small blotches on the labial and temporal scales as well as a pale nuchal collar, throat white with small dark brown to blackish markings, iris pale brown with minute black speckles; (8) 310-465 mm SVL in males, 169-424 mm females; (9) 122-260 mm TL in males, 65-247 mm in females.

Description of the holotype.

An adult female; SVL 424 mm; TL 211 mm (49.7% SVL); head broadly distinct from body; head length 13.2 mm (3.10% SVL); head width 7.3 mm (55% head length); snout-orbit distance 3.3 mm; eye diameter 2.5 mm; rostral broader than high, triangular in frontal view, not visible from above; internasals broader than long; prefrontals broader than long and do not enter the orbit; from above, the triangular shape of the top of the preocular is visible; supraocular longer than broad; frontal longer than broad, with a triangular shape in dorsal view; parietals longer than broad; nasal entire and fused with the first supralabial on both sides; loreal longer than high, enters the orbit; one upper preocular; two postoculars; temporals 2+3 left side, 2+2 right side, where the upper primary and secondary scales are fused; 7 supralabials, 4 and 5 contacting orbit (first supralabial is fused with the nasal) symphysial contacting the first pair of chin shields; 9 infralabials; four pairs of irregular chin shields, the first pair is smaller, second pair is longer than broad, the third pair is slightly longer than broad, but its scales are not in contact, the last pair is broader than long. Dorsals smooth in 15-15-15 rows; mid-vertebral scales moderately enlarged; 178 ventral scales; 118 paired subcaudals; cloacal scale single.

In preservative, dorsal ground color of head uniformly brown except for some small dark-brown blotches on the occipital areas; laterals with small pale brown and dark blotches; white supralabials with evident pale brown and dark blotches; ground color of infralabial and gular region cream colored with dark-brown blotches and pale-brown spots; dorsal color of body pale brown with dark-brown blotches and pale interspaces; on the anterior portion of the body the blotches are dark-brown and long (between 10 and 13 scales) contacting the opposite one in the vertebral row, the interspaces are pale brown with small and scarce dark-brown spots on the dorsal, and white on the lateral; on the middle of the body, the dark-brown blotches diminish their length (between 8 and 9 scales), and they lose the dorsal continuation between them in the vertebral row, the interspaces get a pale-brown color with some small dark-brown spots; on the posterior portion, the blotches are shorter (5-7 scales), rounded, and they are margined by a white edge with many small dark-brown spots; ground color of the belly cream-colored, with irregular blotches of different sizes along the ventral line of the interspaces; tail resembles the body in color pattern; body with 16 blotches, and tail with 12. Color in preservative (70% ethanol) similar to color in life.

Description of the paratype.

An adult female; SVL 328 mm; TL 170 mm (51.8% SVL); head broadly distinct from body; head length 12.2 (3.7% SVL); head width 6.6mm (54% head length); snout-orbit distance 2.9 mm; eye diameter 2.3 mm; rostral broader than high, triangular in frontal view, not visible from above; internasals, broader than long; prefrontals long as wide, no enter the orbit; from above, the triangular shape of the top of the preocular is visible; supraocular longer than broad; frontal longer than broad, with a triangular shape in dorsal view; parietals longer than broad; nasal entire; loreal longer than high, enters the orbit; one upper preocular; two postoculars; temporals 2+3 left side, 3+4 right side; 8 supralabials, 4 and 5 contacting orbit; symphysial contacting the first pair of chin shields; 9 infralabials; three pairs of irregular chin shields, the first pair is the smaller, second pair is longer than broad; the third pair is slightly broader than long. Dorsals smooth in 15-15-15; vertebral scale moderately enlarged; 183 ventral scales; 124 paired subcaudals; cloacal scale single. In preservative, dorsal ground color of head uniformly brown except for some small dark-brown blotches on the occipital areas; laterals with small blotches pale brown and dark; white supralabials with evident pale brown and dark blotches; ground color of infralabial and gular region cream with dark-brown blotches and pale-brown spots; dorsal color of body pale-brown with dark-brown blotches and pale interspaces; on the anterior and middle portion of the body the blotches are dark-brown and long (12-14 scales) contacting the opposite one in the vertebral row, the interspaces are pale brown with small and scarce dark-brown spots on the dorsal, and white on the lateral; on the posterior portion, the blotches are shorter (between 5 and 7 scales), rounded, they are margined by a white edge with many dark-brown small spots, and they lose the dorsal continuation between them in the vertebral row, the interspaces get a pale-brown color with some small dark-brown spots; ground color of the belly cream, with irregular blotches of different sizes along the ventral line of the interspaces; tail resembles the body; body with 19 blotches, and tail with 15. Color in preservative (70% ethanol) similar to color in life.

Referred specimens.

MHCH 2311, juvenile male collected by Sebastian Lotzkat and Andreas Hertz on 18 August 2010 at Cerro Mariposa, Veraguas province, Panama (8.51166°N, 81.12163°W; 940 m), SMF 89551-53, adult males collected by Leonhard Stadler and Nadim Hamad between 8 May and 7 July 2008 at the type locality. SMF 90036, adult male collected by Arcadio Carrizo on 28 July 2008 at Cerro Negro, Veraguas province, Panama (8.56901°N, 81.09894°W; 700 m). SMF 97346, adult male collected by Abel Batista on 25 January 2013 at Donoso, Coclé province, Panama. SMF 89953-54, juvenile and adult of undetermined sex, respectively, collected by Leonhard Stadler and Nadim Hamad on 8 May 2008 at the type locality. SMF 89769, juvenile of undetermined sex collected by Sebastian Lotzkat and Andreas Hertz on 3 April 2009 at Cerro Negro, Veraguas province, Panama (8.56901°N, 81.09894°W; 700 m). MHCH 3123, adult female collected by Marcos Ponce and Roger Morales on 30 May 2018 at Cerro Campana, Panama province, Panama (8.69378°N, 79.92098°W; 730 m).

Additionally, a series of individuals was collected from Parque Nacional General de División Omar Torrijos Herrera between 2006 and 2009 that included 15 females and 12 males. There was variation between sexes and among individuals (Tables 1 - 3 ). A summary of the most commonly measured characteristics includes the range of 173-192 ventrals in females (n = 11) and 187-191 in males (n = 12), subcaudals 116-131 in females (n = 13) and 129-136 in males (n = 8). All individuals had either 7 or 8 supralabials on both sides (n = 26) except one female USNM 579810 with only 6 on the left. Individuals (n = 25) had 8 or 9 left infralabials with two individuals having 10. However, the right infralabials ranged from 7-9 with the same individual as above (USNM 579810) having 6 (Fig. 7 ).

Hemipenial morphology.

Description based on the hemipenes fully everted, but not completely expanded, for the specimen USNM 579815 (Fig. 8 ). Distal end of retractor muscle divided, hemipenis unilobed, unicapitate and unicalyculate; capitulum with papillate and spinulate calyces, it covers approximately the distal half of the organ in the sulcate face, and the distal one-third in the asulcate; the inferior capitular edge of the sulcate face is V-shape, and in the asulcate face the capitular arch is present. In both faces, the hemipenial body is covered by a few small spines, and mostly by medium-sized spines which have curved and robust tips. The base of the organ also is covered by dispersed little spinules on both faces; there is not an evident nude pocket, and there are two spines of similar size on the asulcate side. The sulcus spermaticus bifurcates at the base of the capitulum; both branches diverge and extend diagonally oriented, and end at the distal edge of the lateral face of the organ.

Comparisons.

Dipsas aparatiritos sp. nov. can be distinguished from all other similar or related species by the following combination of characters: 15 dorsal scale rows; one upper preoculars; two or three postoculars; temporals 1+2; seven or eight supralabials, fourth and fifth contacting the orbit; eight or nine infralabials, no infralabials in contact behind mental; vertebral row moderately enlarged; 191-196 ventrals in males, and 177-197 in females; 129-136 subcaudals in males, and 111-131 in females; by the alternating dark brown and tan brown bands running the length of the body, including the tail.

Dipsas aparatiritos sp. nov. differs from the majority of its congeners by having the nasal scale fused with the first supralabial, anterior infralabials separated by a pair of (rarely fused) small postmentals, and temporals usually entering the orbit. Dipsas aparatiritos sp. nov. shares with the other Central American species of the genus the number of dorsal scales rows (15-15-15), except with D. gaigeae Oliver (13-13-13); number of temporals (1+2+ 2); absence of preoculars, except D. brevifacies Cope (1, 2 or 3); and number of postoculars (2,3), except D. temporalis Werner (3,4). The number of infralabials (9-10) is in the range of all Panamanian species, but the infralabial scales in contact behind mental (0) differs from all species, except with D. temporalis . The number of supralabials (7-8) is within the variation found in D. gaigeae (7-8), D. nicholsi (7-9), D. temporalis (6-8), and D. tenuissima Taylor (8), but differs from D. articulata Cope, D. bicolor Günther, D. brevifacies , and D. viguieri Bocourt (9-10); the supralabials scales in contact with the eye (4-5) also are in the variation found in the other species (Table 4 ). The vertebral row is enlarged moderately as in D. nicholsi and D. temporalis , and it different from the other species where it is scarcely enlarged. The number of ventral scales of males and females of Dipsas aparatiritos sp. nov.is larger than D. brevifacies and D. gaigeae and fewer than D. articulata , D. tenuissima and the males of D. temporalis , while overlapping with D. bicolor , D. nicholsi , D. viguieri , and the females of D. temporalis (Table 2 ). The number of subcaudal scales of males and females is larger than D. brevifacies , D. gaigeae , D. nicholsi , and D. tenuissima , while overlapping with D. articulata , D. bicolor , D. temporalis , and D. viguieri (Table 4 ).

The new species is sister to Dipsas temporalis , from which it differs on the following characters of coloration and lepidosis. In D. aparatiritos sp. nov., the first dorsal band extends far onto the ventrals (restricted to the dorsum or barely entering ventrals in D. temporalis ) and the posterior body bands form elliptical blotches usually broken along the vertebral line (bands complete over dorsum or elliptical blotches joined along the vertebral line in D. temporalis ). The color of the anterior interspaces is white or bright pale yellow in D. aparatiritos sp. nov. and pale brown in D. temporalis . Overall, D. temporalis compared to D. aparatiritos sp. nov. have a greater number of ventral scales in males (x̄ = 198) vs. (x̄ = 192) and females (x̄ = 192) vs. (x̄ = 184) respectively, although there is overlap in the counts (Table 5 , Fig. 10 ).

Etymology.

The species name is an adjective formed from the Greek word aparatíritos (απαρατήρητος), which means unnoticed. The snake has hidden in plain sight for more than forty years at a very well-studied field site for herpetological research. We suggest the common name "Hidden Snail-eater" ("Caracolera Escondida" in Spanish).

Distribution.

Dipsas aparatiritos sp. nov. is found in both the Atlantic and Pacific slopes of the Cordillera Central in western Panama, with an additional population on the Parque Nacional Chagres. The species occurs over an estimated 9,630 km2 area and has been recorded at elevations 597-1002 m above sea level, which makes it the most wide-spread species of Dipsas in Panama. A series of individuals were collected from PNGDOTH. This is a mid-elevation, premontane cloud-forest with mature secondary forest and many streams branching from Río Guabal ( McCaffery and Lips 2013). The mean annual rainfall is 3500 mm and mean annual temperature range is 19-31 °C ( Lips et al. 2006). Two localities (Donoso, Colón province, and Quebrada Las Tres Honeras, Panama province) are in valleys 134-197 m above sea level. Since these localities are much lower in elevation than all other reported localities, it is likely that the specimens collected there (SMF 97346 and MCZ 50214) were actually found in the neighboring mountain ridges (Fig. 9 ).

Natural history notes.

The holotype was encountered at 21:58 h in mature secondary (40+ years) premontane forest on the Atlantic versant, but only ca. 100 m from the Continental Divide. The trail is known as "the old logging road" as described by Myers et al. (2007). The Tropical Amphibian Declines in Streams (TADS) project, which has been working in the area since 1997, refers to the trail as "Rocky Road," while the park calls it "La Salida" to Sendero La Rana. The snake was elongate and crawling on small tree 0.75 m off the ground. The paratype was encountered at 2159h in mature secondary (40+ years) premontane forest on the Atlantic versant, but only ca. 100 m from the Continental Divide on the same trail as the holotype. The snake was elongate and crawling on small tree 0.75 m off the ground. Lotzkat (2015) found specimens of Dipsas aparatiritos sp. nov. foraging at night on vegetation 30-200 cm above the ground. JMR found this species to be more common in forest and along streams rather than around ponds. In PNGDOTH, JMR examined the fecal samples of this species and found that one (2% of the sample) contained the operculum of a snail and 49 (98%) contained oligochaete chaetae.

Despite being a new species, it is relatively common at the PNGDOTH site and has been documented for years, thus providing much data on the natural history. Specimens have been found in vegetation, at times over one meter in height, but at other times just centimeters off the ground where it blended in well with leaf litter, as proven by one individual found on the ground (Fig. 2 ). Gravid females were found in all months except February, March, October, and December with the highest frequency in June and July (JMR pers. obs.). Females had either one or two ova. Breeding events were not observed, although one night four different Dipsas aparatiritos sp. nov. were observed intertwined on a single branch (Fig. 11 ).

Near the area where the holotype of Dipsas aparatiritos sp. nov. was found in PNGDOTH, JMR has recorded the following species of amphibians and reptiles: salamanders including Oedipina collaris (Stejneger, 1907), and Bolitoglossa colonnea (Dunn, 1924), frogs, including Diasporus diastema (Cope, 1875), Espadarana prosoblepon (Boettger, 1892), lizards including Anolis humilis Peters, 1863, and Enyalioides heterolepis (Bocourt, 1874), and snakes including Bothrops asper (Garman, 1883), Bothriechis schlegelii (Berthold, 1846), D. nicholsi , Imantodes cenchoa (Linnaeus, 1758), Oxybelis brevirostris (Cope, 1861), Sibon annulatus , and S. nebulatus (Linnaeus, 1758).

Conservation.

We consider Dipsas aparatiritos sp. nov. to be included in the Near Threatened category following the IUCN Red List categories and criteria, v. 3.1, second edition ( IUCN 2012) because, although the species’ estimated extent of occurrence is less than 10,000 km2 and nearly 44% of this area has already been deforested ( CATHALAC 2011), the species occurs in at least four major national parks (Santa Fe, PNGDOTH, Altos de Campana, and Chagres) and satellite images show that there is forest connectivity between populations. At PNGDOTH, the occurrence rate of D. aparatiritos sp. nov. has actually increased by a factor of three in the period between 2006 and 2012 ( Zipkin et al. 2020). Also, the body condition of the individuals in this locality increased following the collapse of amphibian populations due to chytridiomycosis ( Zipkin et al. 2020). However, the causes for these changes are enigmatic given that amphibians presumably do not comprise an important part of the diet of this species. The status and trend of other populations should be evaluated carefully given that D. aparatiritos sp. nov. is endemic to Panama and probably highly dependent on old-growth forests.

Other Dipsas species at the site.

In addition to the new species there are two other species of Dipsas known from the site: Dipsas nicholsi ( Myers et al. 2007 [see edit to proof]) and Dipsas articulata ( Vecchiet et al. 2014). This adds one more confirmed species, bringing the total to three. Furthermore, also known to occur at the site are at least four species of Sibon ( S. argus , S. canopy , S. longifrenis , and S. nebulatus ), which are closely related phylogenetically ( Peters 1960; Sheehy 2012) and ecologically ( Ray et al. 2011). Sibon lamari also may be present at the site (JMR unpubl. data). Dipsas aparatiritos sp. nov. was found throughout the general survey area, both on metered-transects and within the adjacent forest between transects.

Figures

Figure 1. Phylogeny of 20 species of Dipsas using the best ML tree. Black circles denote strong nodal support (≥ 0.95 PP and ≥ 0.70 ML bootstrap). See Sheehy (2012) for further details on the outgroup taxa.

Figure 2. Live individual of Dipsas aparatiritos sp. nov. in Parque Nacional General de Division Omar Torrijos Herrera photographed in the wild and not collected. Photography by Kevin Enge.

Figure 3. Holotype (USNM 579828) of Dipsas aparatiritos sp. nov. showing a dorsum and b venter. Ruler units in cm. Photographs by James Poindexter.

Figure 4. Holotype (USNM 579828) of Dipsas aparatiritos sp. nov. showing a dorsum of head and b chin shields and c lateral view. Ruler notches denote mm. Photographs by James Poindexter.

Figure 5. Paratype (USNM 579829) of Dipsas aparatiritos sp. nov. showing a dorsum and b venter. Ruler units in cm. Photographs by James Poindexter.

Figure 6. Paratype (USNM 579829) of Dipsas aparatiritos sp. nov. showing a dorsum of head and b chin shields and c lateral view. Ruler notches denote mm. Photographs by James Poindexter.

Figure 7. Illustration of the head scales of a Dipsas aparatiritos sp. nov. (USNM 579810). Drawings by Shannon Bowley Christensen.

Figure 8. Hemipenes of Dipsas aparatiritos sp. nov. USNM 579815 a sulcate face b, d lateral faces c asulcate face. Photographs by James Poindexter.

Figure 9. Map of locality data for Dipsas aparatiritos sp. nov. (red showing range, circles marking specimens included in this paper) and updated range data for D. temporalis (yellow showing range, triangles marking specimens included in this paper).

Figure 10. Photographs of species of Dipsas previously subsumed under D. temporalis a D. aparatiritos sp. nov. from Cerro Gaital, Anton, Cocle province, Panama b D. temporalis ZSFQ 5063 from Durango, Esmeraldas province, Ecuador c D. temporalis ZSFQ 5062 from Durango, Esmeraldas province, Ecuador.

Figure 11. Four individuals of Dipsas aparatiritos sp. nov. intertwined on one plant at Parque Nacional General de Division Omar Torrijos Herrera. Photograph by Noah Carl.