Sumaterana, Arifin, Umilaela, Smart, Utpal, Hertwig, Stefan T., Smith, Eric N., Iskandar, Djoko T. & Alexander Haas,, 2018

Arifin, Umilaela, Smart, Utpal, Hertwig, Stefan T., Smith, Eric N., Iskandar, Djoko T. & Alexander Haas,, 2018, Molecular phylogenetic analysis of a taxonomically unstable ranid from Sumatra, Indonesia, reveals a new genus with gastromyzophorous tadpoles and two new species, Zoosystematics and Evolution 94 (1), pp. 163-193 : 169

Sumaterana gen. n. Fig. 5 a–c

Type species.

Rana crassiovis Boulenger, 1920, Syntypes: two adult females, BMNH1947.2.3.99 and BMNH1947.2.4.1.

Diagnosis.

Sumaterana gen. n. belongs to a group of ranid torrent frogs, along with Huia and Meristogenys that possess gastromyzophorous larvae ( Inger 1966, Inger and Gritis 1983, Inger 1986, Yang 1991). Sumaterana gen. n. species can be diagnosed by a combination of: (1) gastromyzophorous tadpole; (2) larval upper jaw sheaths thick, smooth, broadly arched, with thinner medial section; (3) lower jaw sheaths undivided, smooth, and V-shaped; (4) Labial Tooth Row Formula (LTRF): 8(5-9)/8(1) to 9(5-9)/9(1); (5) infraorbital and postorbital gland clusters present; (6) adult frogs medium sized (SVL males = 27.94-48.87 mm; females = 40.98-83.99 mm); (7) dorsum finely granulated, with or without scattered tubercles; (8) supratympanic fold present (skin fold above the tympanum, starting behind the eye); (9) posttympanic fold absent (vertical skin fold immediately posterior to tympanum); (10) dorsolateral fold absent or present; (11) tibia length 58.08-79.67% SVL; (12) outer metatarsal tubercle absent; (13) inner metatarsal tubercle present; (14) Finger I relatively shorter or subequal to Finger II; (15) width of finger discs larger or subequal to width of toe discs; (16) vocal sacs and nuptial pads present; (17) humeral gland absent.

Comparison.

Sumaterana gen. n., Huia , Meristogenys , and Amolops can be distinguish from Chalcorana , Clinotarsus , Hydrophylax , Hylarana , Odorrana , and all other ranids (except, Rana sauteri , Kuramoto et al. 1984) by having gastromyzophorous tadpoles. Although R. sauteri has gastromyzophorous tadpoles ( Kuramoto et al. 1984), Gan et al. (2015) pointed out that R. sauteri larvae differs from the gastromyzophorous tadpole of Huia and Meristogenys in significant features of the sucker (see below). Amolops and R. sauteri seem only distantly related to Huia and Meristogenys ( Pyron and Wiens 2011; this study), and independent evolution in gastromyzophorous tadpoles must be assumed. We corroborate and expand the conclusion of Manthey and Denzer (2014) that the tadpoles of Sumaterana gen. n., Amolops , Huia , and Meristogenys can be distinguished by the shape of their jaw sheaths. The jaw sheath of Sumaterana gen. n. is characterized by (followed by Amolops ; Huia ; Meristogenys features in parantheses): the upper jaw sheath thick, broadly arched, with thinner medial section (thick, broadly arched, without the medial thinning; M-shaped or ˄-shaped; divided; Yang 1991, Manthey and Denzer 2014); lower jaw sheath V-shaped (V-shaped; V-shaped; divided or undivided; Yang 1991, Manthey and Denzer 2014). The number of keratodont rows on the lower lip is eight to nine in Sumaterana gen. n. (three to five rows in Amolops , except for A. cremnobatus with six rows ( Inger and Kottelat 1998); six rows or more in Huia ( Manthey and Denzer 2014); four rows or more in Meristogenys ( Inger and Stuebing 2009, Manthey and Denzer 2014, Shimada et al. 2015). Sumaterana gen. n. has two glandular clusters, infraorbital and postorbital (postorbital and abdominal clusters in Amolops ( Yang 1991, Inger and Kottelat 1998, Liu et al. 2000, Matsui and Nabhitabhata 2006, Ngo et al. 2006), except for A. cremnobatus , postorbital and midlateral clusters ( Inger and Kottelat 1998); a combination of infraorbital, postorbital, prespiracular, midlateral, and variably caudal/fin clusters in Meristogenys (e.g., Yang 1991, Matsui et al. 2010, Shimada et al. 2011, Shimada et al. 2015); and a combination of caudal/fin, postorbital, midlateral, and infraorbital clusters in Huia ( Yang 1991; UA pers. observ.).

Adult Sumaterana gen. n. can be distinguished from Huia , Meristogenys , and Amolops by: lacking posttympanic fold (present in Huia , Meristogenys and Amolops ; Yang1991; UA unpubl. data); the disc of Finger III wider or almost equal to that of Toe IV (subequal in Huia , less or equal to in Meristogenys , wider in Amolops ; Yang 1991); Finger I length shorter or subequal to that of Finger II (Finger I ≥ Finger II in Huia , Finger I> Finger II in Meristogenys , Finger I ≤ Finger II in Amolops ; Yang 1991); lacking an outer metatarsal tubercle (present in Huia except for H. cavitympanum , present in Meristogenys except for M. kinabaluensis ; Yang 1991); tibia length relative to SVL 58.08-78.39% (> 70% in Huia and in Meristogenys ; Yang 1991); furthermore, Sumaterana gen. n. differs from Huia by having a translucent but non-transparent tympanum; tympanum not encased by dark Π-shaped marking ( Manthey and Denzer 2014); and dorsolateral folds less distinct or absent. Sumaterana gen. n. differs from Amolops by having diamond-shaped finger and toe tips (rounded in Amolops ) and relatively smaller fingers and toe discs.

Etymology.

Sumaterana is a compound generic epithet created from the Indonesian proper noun Sumatera, the Indonesian name for the island of Sumatra, and rana , the feminin Latin word for frog. Sumatera itself is named after the kingdom of Samudra Pasai, which was located along the coast of Aceh, Sumatra from the 13th to the 16th centuries CE. Samudra is a sanskrit word that means gathering of the seas, a place where the Andaman, Java, and South China seas meet the Indian Ocean. Rana , was also the very first generic name to be assigned to a member of the S. crassiovis group, endemic to the island of Sumatra.

Common name.

Sumatran Cascade Frogs (English) and Katak Jeram Sumatra (Bahasa Indonesia).

Phylogenetic definition and content.

Sumaterana gen. n. is a node-based genus that consists of three known species: Sumaterana crassiovis comb. n. (Fig. 2 Clade A, Fig. 5a), S. montana sp. n. (Fig. 2 Clade B, Fig. 5c), and S. dabulescens sp. n. (Fig. 2 Clade C, Fig. 5b), and their most recent common ancestor. Chalcorana kampeni is considered a junior synonym of S. crassiovis comb. n. based on Inger and Iskandar (2005) and the new molecular evidence. The monophyletic clade of Sumaterana gen. n. is restricted to the island of Sumatra, Indonesia. Our phylogenetic analyses and morphological examination supports these taxonomic recognitions (uncorrected p-distances in Suppl. materials 3).

Distribution and habitat.

Species of Sumaterana gen. n. inhabit riparian habitats in primary or secondary forest in Sumatra, Indonesia. Inhabited streams are typically fast flowing, 5 m wide or less, dominated by big rocks (diameter> 1 m). The known elevational range is from 314-2033 m a.s.l.. Adult frogs of these genus usually perched on rocks or vegetation at the stream. Tadpoles of these frogs can be found in groups attached to the top or sides of rocks in fast moving water.