Ceuthomantis smaragdinus, Heinicke, Matthew P., Duellman, William E., Trueb, Linda, Means, Bruce, D, Ross & Hedges, Blair, 2009

Heinicke, Matthew P., Duellman, William E., Trueb, Linda, Means, Bruce, D, Ross & Hedges, Blair, 2009, A new frog family (Anura: Terrarana) from South America and an expanded direct-developing clade revealed by molecular phylogeny, Zootaxa 2211, pp. 1-35 : 7-17

Ceuthomantis smaragdinus new species

Holotype. KU 300000, an adult male, from top of Kamana Falls on Mt. Kopinang, part of the Wokomung Massif, Potaro-Siparuni District, Guyana (05˚00'08" N, 59˚52'47" W, ~ 1540 m elevation), obtained on 18 July 2007 by D. Bruce Means. Field number CPI 10559.

Paratype. KU 315000, a subadult female collected with the holotype.

Referred specimen. ROM 40161, a juvenile, from Mt. Ayanganna, Potaro-Siparuni District, Guyana, 1490 m (05°24' N 59°57' W, 1490 m elevation), obtained on 20 October 2000 by Amy Lathrop and Carter Cox.

Diagnosis. This small frog has: (1) skin on dorsum smooth, that on belly areolate; dorsolateral folds absent; pair of dorsal protrusions in sacral region and small pair in scapular region; discoidal fold not evident; (2) tympanic membrane differentiated; tympanic annulus low, smooth, round, its diameter about 40% length of eye; (3) snout rounded in dorsal view, bluntly rounded in profile; (4) upper eyelid bearing prominent subconical tubercle; width of eyelid slightly less than interorbital distance; cranial crests absent; (5) dentigerous processes of vomers absent; (6) vocal slits present; nuptial excrescences absent; (7) Finger I shorter than Finger II; discs on outer fingers broadly expanded with terminal notch; (8) fingers lacking lateral fringes; (9) ulnar tubercles absent; (10) heel bearing prominent subconical tubercle; row of conical tubercles on outer edge of tarsus; (11) inner metatarsal tubercle elliptical 3x subconical outer metatarsal tubercle; plantar supernumerary tubercles absent; (12) toes lacking lateral fringes; webbing absent; Toe V slightly longer than Toe III; discs about same size as those on fingers; (13) dorsum olive brown with diffuse black markings and prominent bright green (in life) interorbital bar, subcanthal stripe, and diagonal bars in scapular region; venter pale gray with black mottling; (14) SVL in one male 19.8 mm, in one subadult female 19.5 mm.

Ceuthomantis smaragdinus shares a unique combination of five characters with two other species from elevated areas of the Guiana Shield that we tentatively place in Ceuthomantis : C. aracamuni and C. cavernibardus . These characters are notched digital discs, narrow heads, green coloration, and the absence of vomerine teeth and nuptial pads ( Barrio-Amorós & Molina 2006; Myers & Donnelly 1997). Separately, each of these characters is found in other species of terraranans ( Hedges et al. 2008; Lynch 1979; Lynch & Duellman 1997; Duellman & Pramuk 1999), but their combination in species from the same region suggests a close relationship. Nonetheless, C. smaragdinus differs from both in having paired dorsal gland-like protrusions, prominent subconical tubercle on the upper eyelid and the heel, and a row of conical tubercles on the outer edge of the tarsus.

Other terraranans known from the highlands in the southwestern part of the Guiana Highlands are Pristimantis avius ( Myers & Donnelly 1997) and P. memorans ( Myers & Donnelly 1997) . These, like all other Pristimantis known from the highlands, have vomerine teeth and both lack tubercles of the heels. Furthermore, P. a v i u s differs from C. smaragdinus by having weak dorsolateral folds, marginate discs on the digits, no eyelid tubercle, a brown dorsum, and a pale orange or yellow venter. Pristimantis memorans differs from C. smaragdinus by having small tubercles on the eyelid, shallowly indented digital discs, a brown dorsum with dark brown markings, and a gray venter.

Description of the holotype. Small frog with head much longer than wide, head length 40.9% SVL, head width 33.3% SVL; head narrower than body; snout moderately long, rounded in dorsal view ( Fig. 1 ), bluntly rounded in profile; eye-nostril distance 80.0% length of eye; loreal region concave; nostrils barely protruding, directed laterally at level well behind anterior margin of lower lip; canthus rostralis slightly curved, rounded in section; lips rounded; width of upper eyelid 85.7% interorbital distance; side of head vertical. One rounded postrictal tubercle posteroventral to tympanum; supratympanic fold weak, barely obscuring posterodorsal edge of tympanum; tympanic membrane differentiated; tympanic annulus low, smooth, round, its diameter 40.0% length of eye; tympanum separated from eye by distance about twice diameter of tympanum.

Skin smooth on dorsum, weakly granular on throat, areolate on belly; discoidal fold not evident; cloacal sheath short, not bordered laterally by fold or tubercles. Prominent subconical tubercle on upper eyelid and heel; row of conical tubercles on outer edge of tarsus; inner tarsal fold absent; inner metatarsal tubercle ovoid, elliptical, three times size of subconical outer metatarsal tubercle; ulnar tubercles absent; thenar tubercle elliptical, slightly elevated, much larger that low, bifid palmar tubercle; plantar supernumerary tubercles absent; subarticular tubercles low, rounded; nuptial excrescences absent; pairs of what appear to be small glandular structures in the post-temporal and sacral regions ( Fig. 1 ).

Finger I shorter than Finger II; Finger III very long; relative lengths of fingers: I <II <IV <III; discs on outer fingers broadly expanded, rounded with terminal notch ( Fig. 1 ), lacking lateral fringes; circumferential grooves present; Toe V slightly longer than Toe III; Toe IV very long; discs on toes expanded, rounded with terminal notch, about equal in size to those on fingers; toes not webbed, lacking lateral fringes; relative lengths of toes: I <II <III <V <IV; tip of Toe V extending to base of penultimate subarticular tubercle of Toe IV; tip of Toe III extending to point midway between antepenultimate and penultimate subarticular tubercles on Toe IV. When hind limbs flexed perpendicular to axis of body, heels broadly overlap; shank 59.6% SVL; foot length 40.1% SVL.

Vocal slits and single, median, subgular vocal sac present; vocal slits extending from midlateral base of tongue to point about two-thirds distance to angle of jaw; tongue ovoid, broadest posteriorly, not notched behind, free posteriorly for nearly half of its length; choanae ovoid, not obscured by palatal shelf of maxillary; cranial crests and dentigerous processes of vomers absent.

In life, dorsum dull olive-brown with diffuse black markings on body; black transverse bars on limbs; black longitudinal stripe on inner surface of forearm; black labial bars; broad black canthal stripe; bright, almost phosphorescent green interorbital bar; pair of diagonal marks in scapular region; spot on anterior surfaces of upper arm; distinct green bar below black canthal stripe ( Fig. 2 A); dorsal surfaces of discs on fingers white; dorsal surfaces of toe pads creamy white with black suffusion in terminal notch; venter creamy gray, heavily mottled in black; throat nearly entirely black ( Fig. 2 B); belly mottled black and gray; iris greenish bronze heavily flecked with black.

In preservative, dorsum tan with irregular paravertebral marks extending from occiput to sacrum; bright green marks in life now pale gray; limbs tan with brown transverse bars; posterior surfaces of thighs brown; belly cream with irregular brown spots; throat black; ventral surfaces of hind limbs brown with cream spots; palmar and plantar surfaces black.

Character KU 300000 KU 315000 ROM 40161 Measurements of holotype. Measurements and proportions of the three known specimens are given in Table 1 .

Variation. Both adults (KU 300000 and 315000) and the one juvenile (ROM 40161) are alike structurally, except that glandlike protrusions are less pronounced in the juvenile. The dorsal color pattern is the same in all specimens; the bright green markings are distinct not only in adults but also in the juvenile. The throat in the female and in the juvenile are mottled like the belly, not black as in the male.

The holotype (KU 300000) and female paratype (KU 315000) both bear what appear to be small glandular structures in the post-temporal and sacral regions ( Fig. 1 ). Close examination reveals the skin to be slightly elevated and to lack melanophores. A section through the structure in KU 315000 shows a disassociation between the connective tissue and the overlying unpigmented skin, whereas the surrounding skin is loosely connected to the underlying muscles by the connective tissue. It is possible that the “bubble” of unpigmented skin might have been filled with adipose cells, which have dissolved in preservative.

Osteology. The head is widest anterior to angle of jaw at the level of the articulation of the quadratojugal and maxilla, at which level, the medial head length is 98% the head width. The overall width of the head diminishes gradually in the orbital region, being 86% of the greatest width (HWG of Trueb 1977) at the midorbit level and 76% of this measure at the anterior margin of the orbit. The rostrum seems especially massive, with its medial length composing 25% of the length of the skull (HLM of Trueb 1977), and its posterior and anterior widths, composing 68% and 27%, respectively, of the greatest width of the skull ( Fig. 3 A).

The braincase is poorly ossified. Sphenethmoid ossification is limited to a narrow girdle of bone in the anterolateral walls of the braincase; the anterior limit of the bone is the orbitonasal canal, which has a complete margin in bone. There is an asymmetrical structure apparent dorsomedially that probably represents mineralization of ethmoidal cartilage. The prootic forms the bony anterior, anterodorsal, and anteroventral walls of the otic capsule; the bony posterior walls are formed by the exoccipital. These bones are so poorly ossified that epiotic eminences, as well as most of the lateral parts of the otic capsule, remain cartilaginous. The stapes are exceedingly delicate and small, but there is a large, bony operculum. The bony parts of the exoccipitals and prootics are widely separated from one another and their counter members.

The massive frontoparietals completely roof the central braincase from the anterior level of the orbit to the tectum synoticum posteriorly. The lamina perpendicularis is particularly well developed along the entire orbital margin of the frontoparietal. In the posterior part of the orbit, there is a small, knoblike orbital process on the frontoparietal. In lateral profile, a ventral process extends into the orbital fenestra from the lamina perpendicularis at the same level. Posterolaterally, the frontoparietal expands to form a flangelike process that extends dorsally along the anteromedial margin of the anterior epiotic eminence.

The parasphenoid floors the braincase ( Fig. 3 B). The long, narrow cultriform process extends from the anterior margin of the sphenethmoid to the otic capsules posteriorly. The alae completely floor the otic capsules and are approximately perpendicular to the cultriform process. The posteromedial process of the parasphenoid is broadly acuminate and does not reach the margin of the foramen magnum.

The nasal region is remarkable for its lack of bony armament. The small, slender nasals are broadly separated—apparently poised along the anterolateral margins of the olfactory capsules leaving the central portions of the capsules exposed in cartilage. Ventrally, the vomers are revealed as a pair of L-shaped bones that seem to lack a dorsal flange. The vomers seem to consist only of pre- and postchoanal bony process to support the internal choana. The paired septomaxillae are minute and lie dorsal to the partes palatinae and the articulation between the maxilla and premaxilla.

In contrast to the seemingly weak construction of the endocranium, the suspensory apparatus, maxillary arcade, and its support is robust. The otic and ventral rami of the squamosal are especially well developed, with the otic ramus seeming to extend along the entire lateral margin of the cartilaginous crista parotica. The zyogmatic ramus is short and acuiminate in lateral profile. The quadratojugal is particularly robust and bears a broadly overlapping articulation with the maxilla. The maxillae and premaxillae bear teeth, and both have moderately well developed partes palatinae; that of the premaxilla is medially notched to produce prominent medial and lateral flanges. The pars facialis of the maxilla is well developed and bears a large, acuminate preorbital process that extends nearly to the ventral margin of the nasal lateral to the planum antorbitale at the anterior margin of the eye. Anteriorly, the pars facialis overlaps the lateral margin of the pars dentalis of the premaxilla slightly. The pterygoid is a stout, triradiate element. The anterior ramus extends toward the braincase from the maxilla at the mid-orbit level and braces against the anteroventral margin of the otic capsule via the short medial ramus. The posterolateral ramus lies in the same plane as the anterior ramus and is about half its length; it provides support for the palatoquadrate cartilage and the jaw articulation. One of the most extraordinary features of the skull is the massive neopalatine, which seems to have encased completely the planum antorbitale and extends from the sphenethmoid laterally to the lingual margin of the maxilla.

The main component of the mandible is the stout angulosplenial, which is weakly sigmoid, bears scarcely no coronoid flange, and extends nearly to the mentomecklian bone anteriorly. The dentary is fused to the mentomecklian anteriorly and extends along the lateral surface of the mandible to terminate in the posterior part of the orbit. The only part of the hyoid revealed are the posteromedial processes, which are long, slender elements that are slightly expanded proximally and distally; the proximal expansion is slightly greater than the distal expansion. There is no mineralization in the hyoid corpus.

The vertebral column is composed of eight nonimbricate, procoelous vertebrae. The atlantal cotylar arrangement is stalked and Type I of Lynch (1973). The tranverse processes are short and not expanded. There is little variation in the overall width of vertebrae with the vertebral profile being as follows: III> Sacrum> II> IV> VII> V VI> VIII> I. The neural arches are well developed and bear neural spines that are most prominent on Presacrals I–IV; however, the neural arches are exceedingly narrow, with the result that much of the spinal column is exposed dorsally. The short, round sacral diapophyses are nearly uniform in width and directly slightly posterolaterally. The sacrum has a bicondylar articulation with the urostyle. The urostyle is short, being only 84% of the length of the presacral vertebral column. It bears a well-developed dorsal crest and one pair of nerve foramina; there is no other evidence of postsacral vertebrae.

The pectoral girdle likely is arciferal. The clavicles are robust, curved, and moderately broadly separated from one another medially; the bones are separated from the adjacent scapulae and coracoids by cartilage. The posterior margin of the stout coracoid is straight, whereas the anterior margin is convex; the long axis of the coracoid is nearly perpendicular to the longitudinal axis of the body. The glenoid and sternal ends of the coracoid are about equally expanded and slightly more than twice as wide as the midshaft width of the bone. A distinct notch separates the pars acromialis from the pars glenoidalis of the scapula, which is long and slender, with shallowly concave anterior and posterior margins. The suprascapular margin is about twice the width of the narrowest part of the bone, and the length is slightly more than three times the width of the suprascapular margin. The cleithrum is a dagger-shaped element; there is no indication of mineralization of the suprascapular cartilage. Ossified or mineralized pre- and postzonal elements are absent.

The head of the humerus is cartilaginous. There is a moderate crista ventralis or deltoid crest extending along the proximal third of the bone. The cristae medialis and lateralis are not evident, but the eminentia capitata and ulnar and radial condyles are relatively well developed. The radio-ulna has a low olecranon and shallow sulcus intermedius; the epiphyses of the ulna and radius are cartilaginous. All carpal elements and the prepollex, if it is present, are cartilaginous.

The phalangeal formula is 2-2-3-3, and the relative lengths of the digits in increasing order is: II> III> V> IV. Concerning the phalangeal formula: fingers are numbered preaxially to postaxially from II– V, in consistency with the hypothesis that Digit I was lost in anurans ( Alberch & Gale 1985; Fabrezi & Alberch 1996; Shubin & Alberch 1986); the reader is cautioned that in older accounts, fingers are numbered from I to IV. The relative lengths of the metacarpals in increasing order is: II> V> III> IV. The phalangeal elements are well ossified with cartilaginous epiphyses. The terminal phalanges are stout, thick elements that are almost hourglass-shaped, with T-shaped distal ends ( Fig. 1 C–D).

The postsacral trunk region is short and narrow. The dorsal width of the pelvis at the sacrum is 57% of its overall length, and the angle of expansion is about 33˚. The internal margin of the pelvis in dorsal view describes a narrow U-shape. The ilial shaft is smooth and bears a scant indication of low, rounded dorsal ridge that terminates posteriorly in a low knob of a posterior prominence. The preacetabular angle is about 90˚. The pubes are lightly mineralized. The ischium is well ossified. The acetabulum is round; about two thirds of it is formed in bone by equal contributions of the ilium and ischium.

There is nothing particularly remarkable in the hind limb except for the lack of ossification (but presence of scattered mineralization) of the epiphyses of the femur, tibiofibula, and tibiale and fibulare. The tibiale and fibulare seem especially long, being about 58% of the length of the tibiofibula. Tarsal elements and a prehallux, if present, are cartilaginous. The phalangeal formula is 2-2-3-4-3, and the relative lengths of the digits in increasing order is: I> II> III = V> IV. The relative lengths of the metacarpals in increasing order is: I> II> III = V> IV. The phalangeal elements are well ossified with cartilaginous epiphyses. The terminal phalanges are stout, thick elements that are almost hourglass-shaped, with T-shaped distal ends ( Fig. 7 C–D).

Distribution and ecology. Ceuthomantis smaragdinus is known from two of the easternmost mountains in the Guiana Shield, Mt. Ayanganna and Mt. Kopinang in the Wokomung Massif ( Fig. 4 ). These mountains are separated by 37 km of uplands that support lower montane forest ( Huber et al 1995). At the type locality, the forest consists of shrubs, including Melastomataceae (Myrtales) , broad-leafed trees about 12 m high, and a few small tree ferns (Cyatheales); the trunks, boles, and limbs of all are festooned with epiphytes, especially dense olive-green moss and many bromeliads. The ground is deep organic peat covered with the same moss and bromeliads as on the trees. The holotype and paratype were collected after dark in cloud forest at an elevation of about 1540 m. The holotype was sitting on a leaf 1.5 m above the ground about 5 m from a cascading stream ( Fig. 5 A); another leaf sheltered it from a heavy rain. The paratype was found 30 min later during a light rain. It was perched on a leaf about 10 m away from the stream slightly to the left of the middle of Figure 5 B. The juvenile from Mt. Ayanganna was collected at night amidst leaf litter on the ground in dense low-canopy forest at an elevation of 1490 m.

At the type locality 18 other species of anurans were found— Oreophrynella cf. macconnelli Boulenger , Anomaloglossus beebei (Noble) , A. kaiei (Kok, Sambhu, Roopsind, Lenglet & Bourne) , Pristimantis saltissimus Means and Savage , P. dendrobatoides Means and Savage , Pristimantis sp., Leptodactylus lutzi Heyer , Stefania ayangannae MacCulloch and Lathrop , S. coxi MacCulloch and Lathrop , S. roraimae Duellman and Hoogmoed , Vitreorana gorzulae (Ayarzagüena) , Hypsiboas sibleszi (Rivero) , Myersiohyla kanaima (Goin and Woodley) , Osteocephalus cf. cabrerai (Cochran and Goin) , O. cf. exophthalmus (Smith and Noonan) , Otophryne steyermarki Rivero , and two species of “ Bufo .” Only six of these are represented in the other 16 species that were found at 1490 m on Mt. Ayanganna— Anomaloglossus beebei (Noble) , A. tepuyensis (La Marca) , Oreophrynella dendronastes Lathrop and MacCulloch , Stefania ackawaio MacCulloch and Lathrop , S. ayangannae MacCulloch and Lathrop , S. coxi MacCulloch and Lathrop , S. roraimae Duellman and Hoogmoed , “ Hyla ” warreni Duellman and Hoogmoed, Hypsiboas roraima (Duellman and Hoogmoed) , Myersiohyla kanaima (Goin and Woodley) , Osteocephalus phasmatus MacCulloch and Lathrop , Leptodactylus lutzi Heyer , Pristimantis inguinalis (Parker) , P. jester Means and Savage , P. marmoratus (Boulenger) and P. pulvinatus (Rivero) .

Etymology. The specific name ( smaragdinus ) is a Latin adjective meaning emerald green and refers to the distinctive marks on the head and body.

Remarks. We refer Pristimantis aracamuni and P. cavernibardus to Ceuthomantis based on their sharing, with Ceuthomantis smaragdinus , a unique combination of five characters (cited above). However, we consider this arrangement to be tentative because genetic data are unavailable for either species and both lack the paired dorsal gland-like structures of C. smaragdinus . An unusual behavioral trait (for terraranans)— diurnal calling—may be shared by these three species. Ceuthomantis aracamuni were found during the day on moss and rocks in a small creek ( Barrio-Amorós & Molina 2006), and C. cavernibardus were calling during the day in caves formed by granite boulders or on roots and moss ( Myers & Donnelly 1997). At the type locality of C. smaragdinus , frogs of an unknown species (perhaps C. smaragdinus ) were calling vociferously during the day from a site where a small stream emerged amongst large boulders. Barrio-Amoros and Brewer- Carias (2008) reported hearing P. cf. cavernibardus calling during rainy or cloudy days on Sarisariñama.

Barrio-Amorós and Brewer-Carías (2008) reported “ Pristimantis ” cf. cavernibardus from elevations of 1100–1375 m of Sarisariñama Tepui, which is about 380 km NNE of Cerro Aracamuni and Sierra Tapirapecó. Their color photograph (Fig. 13) shows a narrow nearly phosphorescent interorbital bar like that in Ceuthomantis smaragdinus . The tepuis in extreme southern Venezuela and in Guyana seem to harbor a biota that is distinct from the tepuis on the northern part of the Guiana Highlands in Venezuela ( McDiarmid & Donnelly 2005).

Ceuthomantis cavernibardus has large, unpigmented eggs ( Myers & Donnelly 1997); these are typical of direct-developing species of terraranans. The only female of C. smaragdinus is a subadult with small, unpigmented eggs in the ovaries. Consequently, direct development of terrestrial eggs on C. smaragdinus can only be assumed. Large, unpigmented eggs also are associated with frogs that have nonfeeding tadpoles, including hemiphractids (Duellman 2007; Wells 2007); consequently, additional data are needed to confirm the reproductive mode of Ceuthomantis .

Inasmuch as the osteological data for Ceuthomantis smaragdinus were obtained from a tomograph, the only direct comparisons are made with representatives of the other four families of Terrarana for which tomographs exist. These are Ischnocnema guentheri (Steindachner) of the Brachycephalidae , Haddadus binotatus (Spix) of the Craugastoridae , Eleutherodactylus gossei Dunn of the Eleutherodactylidae , and Pristimantis pulvinatus (Rivero) of the Strabomantidae ( Figs. 6 and 7 ).

Comparison of the taxa reveals several rather striking differences. Ischnocnema , Eleutherodactylus , and Pristimantis have rather well-ossified skeletons in contrast to that of C. smaragdinus . As a result, note that the anterolateral part of the braincase is complete, although the sphenethmoid may be marginally ossified dorsally ( E. gossei ); likewise, the exooccipitals are synostotically united to one another and to the prootics so as to produce well-developed otic regions. The nasals are large; ventrally, vomers and robust pterygoids are present. The neural arches of Presacrals I and II are fused. The epiphyses of the long bones are uniformly mineralized and ossification of the carpal and tarsal elements is clearly evident.

The shape of the head (dorsal/ventral profiles) of Ceuthomantis is distinctly different from that of Pristimantis , Ischnocnema , and Eleutherodactylus , which one could reasonably interpret as being more “typical” of terraranans, with their broadly arced jaws and almost triangular heads. In contrast, the head of Ceuthomantis , with its narrow otic region and wide preorbital region, has an overall shape somewhat reminiscent of a quadrangular caudate skull. Note the disproportionately large rostrum in contrast to that of Pristimantis , and the shape of the mandible in ventral view; it is strongly sigmoid in Ischnocnema , Eleutherodactylus , and Pristimantis , and only weakly so in Ceuthomantis . The transverse processes of the presacral vertebrae of Ceuthomantis are much shorter than those of Ischnocnema , Eleutherodactylus , and Pristimantis , and the sacral diapophyses are less robustly developed. Ceuthomantis lacks well-developed preacetabular ilium, whereas Ischnocnema , Eleutherodactylus , Haddadus , and Pristimantis possesses distinct, well-developed preacetabular ilia. The terminal phalanges are small, knobby expansions in Ischnocnema , Eleutherodactylus , and Haddadus , whereas they are larger and have a distinctive hourglass shape in Ceuthomantis and a broadly expanded, gracile T-shape in Pristimantis .

Of the four genera and families available for comparison with Ceuthomantis , it bears a few features in common with the craugastorid, Haddadus . In Haddadus binotatus , the anterior braincase (sphenethmoid) is scarcely ossified and the otic capsule is very poorly developed. The neural arches of Presacrals I and II are not fused, and the transverse processes of the presacrals are short, resembling those of Ceuthomantis . Despite the reduced ossification of Haddadus , the carpal and tarsal elements are mineralized in contrast to those in Ceuthomantis .

There is a brief osteological description for one other species included in Ceuthomantis , C. cavernibardus ( Myers & Donnelly 1997). The authors noted that in this species the skull is a “little wider than long,” and that the nasals are “moderate, not in medial contact, well separated from frontoparietals by sphenethmoid.” These comments suggest that C. cavernibardus has larger nasals and that the sphenethmoid is ossified dorsally, in contrast to C. smaragdinus . Likewise, C. cavernibardus has vomers, whereas C. smaragdinus lacks them. Both taxa have widely separated occipital condyles on short stalks, similar parasphenoids, squamosals, and pterygoids. Likewise, as described by Myers and Donnelly (1997), the configurations of the axial column, and pectoral and pelvic girdles seem to resemble one another; however, based on their comments about the tarsal elements and the skeleton in general, it is evident that the skeleton of C. cavernibardus is more completely ossified than is that of C. smaragdinus .

Figures

FIGURE 1. Dorsal view of female paratype of Ceuthomantis smaragdinus, KU 315000 SVL 19.5 mm. Arrows point to the dorsal glandlike structures. The third finger of the right hand is enlarged to show the notched anterior margin of the disc. Photographs by A. Campbell.

FIGURE 2. Dorsal (A) and ventral (B) views of the holotype of Ceuthomantis smaragdinus (KU 300000) in life. Photographs by D. B. Means.

FIGURE 3. High-resolution tomographs of Centhomantis smaragdinus, KU 315000. A dorsal, B. ventral. Scale bar = 5 mm.

FIGURE 4. Distribution of the family Ceuthomantidae. Lowlands are indicated by green and uplands by brown. Known localities of the new family are indicated in the northeastern and southwestern portions of elevated areas on the Guiana Shield, in Venezuela, Brazil, and Guyana. (1) Mt. Kopinang, Guyana (C. smaragdinus, type locality), (2) Mt. Ayanganna, Guyana C. smaragdinus, referred specimen), (3) Pico Tamacuari, Venezuela and Brazil (C. cavernibardus), (4) Cerro Aracamuni, Venezuela (C. aracamuni), and (5) Sarisariñama Tepui, Venezuela (C. cf. cavernibardus).

FIGURE 5. Habitat of Ceuthomantis smaragdinus at 1540 m on Mt. Kopinang, Guyana. The holotype was found about 5 m from the stream in the foreground in Figure 5 A; the paratype was found on a leaf about 10 m away from the other side of the stream slightly to the left of the middle of Figure 5 B. Photographs by D. B. Means.

FIGURE 6. High-resolution tomographs of terraranan frogs representing two families (left, dorsal view; right, ventral view). (A – B) Brachycephalidae, Ischnocnema guentheri (KU 92816); (C – D) Craugastoridae, Haddadus binotatus (KU 92808). Scale bars = 5 mm.

FIGURE 7. High-resolution tomographs of terraranan frogs representing two families (left, dorsal view; right, ventral view). (A – B) Eleutherodactylidae, Eleutherodactylus gossei (SBH 266440; and (C – D) Strabomantidae, Pristimantis pulvinatus (KU 166368). Scale bars = 5 mm.

Tables

TABLE 1. Measurements and proportions of Ceuthomantis smaragdinus.

(Male)	(Female)	(Juvenile)
Snout-vent length 19.8	19.5	14.8
Shank length 11.8	11.7	8.2
Foot length 8.9	9.1	7.1
Head length 8.1	7.8	6.1
Head width 6.6	6.3	4.5
Interorbital distance 2.1	2.0	1.3
Eyelid width 1.8	1.8	1.1
Internarial distance 1.6	1.6	1.2
Eye length 2.5	2.4	2.0
Eye-nostril distance 2.0	1.9	1.5
Tympanum diameter 1.0	1.0	0.8
Head length/SVL 40.9%	40.0%	41.2%
Head width/SVL 33.3%	32.3%	30.4%
Eyelid/IOD 85.7%	90.0%	84.6%
Tympanum/Eye 40.0%	41.7%	40.0%
Shank/SVL 59.6%	60.0%	55.4%
Foot/SVL 40.1%	40.0%	47.9%