Larval Development and Synapomorphies for Species Groups of Hyloscirtus Peters, 1882 (Anura: Hylidae: Cophomantini)
The morphology of the larval oral disc, nostril, skin, and vent tube of tadpoles of Andean stream dwelling Hyloscirtus (Hylidae: Hylinae: Cophomantini) was studied. A wide variation of larval tooth row number is compiled from literature and from observations of Colombian specimens in museums. The marginal papillae are precursors of the tooth rows. The submarginal papillae are organized parallel to the anterior tooth rows and are precursors of the flaps or accessory tooth rows. There is no particular tooth row formula, and no particular marginal papillae arrangement for a species or a recognized species group in the genus. The number of tooth rows and of accessory tooth rows increase with development and size of the tadpole. Two species groups are identified inside Hyloscirtus based on the tooth row formulae, upper jaw sheath morphology, and shape of the nostril of tadpoles. The two groups identified here are different from the three species groups currently recognized for the genus and show well-delimited geographic distributions through the northern Andes. Nostril shape of one species group of Hyloscirtus recognized here is putatively present in all Cophomantini. Spots on the venter associated with neuromasts are present in all the tadpoles of Hyloscirtus studied, and presumably the same as the ones found in some Hypsiboas and Aplastodiscus (Hylidae: Hylinae: Cophomantini). A saccular structure associated with the vent tube covers developing hindlimbs of all tadpoles of Hyloscirtus, and is proposed as a morphological synapomorphy of the genus. Se estudió la morfología del disco oral, narinas, piel, y tubo cloacal en renacuajos andinos de quebrada Hyloscirtus (Hylidae: Hylinae: Cophomantini). Una amplia variación del número de hileras de dientes larvales se recopila y describe a partir de literatura y observaciones en ejemplares de museo colombianos. Las papilas marginales son precursoras de las hileras de dientes, y las papilas submarginales se organizan paralelas a las hileras de dientes anteriores y son precursoras de las hileras de dientes accesorias o flaps. Ninguna especie o grupo de especies reconocidas en el género tiene una fórmula dental larval o un arreglo de papilas marginales particular. El número de hileras de dientes crece a medida que el renacuajo crece y se desarrolla. Se pueden identificar dos grupos de especies dentro de Hyloscirtus usando la fórmula dental, la forma del pico anterior y la forma de las narinas de las larvas. Estos dos grupos son diferentes a los tres grupos de especies actualmente reconocidos dentro del género y muestran una distribución geográfica bien delimitada en el norte de Los Andes. La forma de las narinas de uno de los grupos de especies acá reconocidos está putativamente presente en todos los Cophomantini. Unos puntos redondos en el vientre asociados a neuromastos están presentes en todos los renacuajos de Hyloscirtus estudiados, y presuntamente son los mismos que se encuentran en especies de Hypsiboas y Aplastodiscus (Hylidae: Hylinae: Cophomantini). Una estructura en forma de bolsa cubre las patas traseras en desarrollo de todos los renacuajos de Hyloscirtus, y se propone como sinapomorfía morfológica del género.Abstract
Resumen
(A) Generalized lateral scheme and (B) ventral magnified oral disc of Hyloscirtus showing papillae on the edge of long labia resembling a funnel (arrow). Jaw sheaths not shown on (B). (C) Posterior ventral view of tadpoles of Hyloscirtus. Spots (black arrows) and vent tube bag (white arrow).
Hypothetic larval oral disc, as presented by Altig and MDiarmid (1999:35). Right half shows an oral disc with emargination; left side shows an oral disc with no emargination or submarginal papillae. A1 and A2: first and second anterior or upper tooth rows, respectively. P1, P2, and P3: first, second, and third posterior or lower tooth rows. A2 and P1 gap: medial gap or interruption in the second anterior and first posterior.
Schematic drawing of hypothetic larval oral discs and their labial tooth row formulae. (A) LTRF: 2(2)/3(1), (B) LTRF: 3(1,3)/4), (C) LTRF: 2(2)/4(1–3), (D) LTRF 2(2)/3(1). Uni.: uniserial marginal papillae. Em.: oral disc emargination. D. gap: gap on the anterior labium marginal papillae, or dorsal gap. Uni-bi.: Uniserial marginal papillae, with alternating direction and their bases aligned. Bi.: biserial marginal papillae. Mult.: multi serial papillae, not properly aligned in clearly identifiable rows. Bi-mult.: marginal papillae ambiguously defined as aligned or not. Int.: Interruptions on tooth rows. Submarginal papillae are obviously more abundant in (B) left. Jaw sheath not shown in B, C, and D.
(A) Schematic illustration of an Hyloscirtus oral disc in the beginning of development with LTRF: 4(1,2,4)/5(1). (B) Anterior tooth row addition. Development from bottom to top. Top left shows morphology after completion of development of distal anterior tooth rows with medial gap (group B). Top right shows morphology after completion of development of distal anterior tooth rows with no medial gap (group A). Last anterior tooth row not shown and interrupted in groups A and B. (C) Posterior tooth row addition. Development from top to bottom. (D) Development of submarginal papillae and accessory tooth rows. Development from top to bottom.
Tadpole narial ornamentation. (A) Crown around left naris (arrow) in tadpoles of group B; (B) is magnified image. (C) Triangular projection on inner margin of right naris (arrow) in tadpoles of group A; (D) is magnified image. (E) Triangular projection on inner margin of right naris (arrow) of Hypsiboas geographicus and (F) Hypsiboas crepitans. (G) Development of ornamentation around naris in Hyloscirtus group B (left) and group A (right) from bottom (stage 25) to top (stage 42).
Jaw sheaths of tadpole of Hyloscirtus. (A) Small serrations (small arrow) in narrow sheath with wide shelf (large arrow) of Hyloscirtus group A. (B) Large serrations and wide anterior jaw sheath with no evident shelf in Hyloscirtus group B.
Map of the three Cordilleras or mountain ridges in Colombia, South America with 1000 m and 3000 m contours: (A) Western Cordillera, (B) Central Cordillera, (C) Eastern Cordillera. White dots indicate species of group B. Black dots indicate species of group A.
Number of anterior and posterior tooth rows of individual tadpoles in four lots. Developmental stage or tadpole total length is shown on the x axis. Pairs of dots aligned vertically correspond to numbers of anterior (black dots) and posterior (white dots) tooth rows of an individual tadpole in each stage or total length.
Hyloscirtus tooth row development. All tadpoles oriented anterior (up) to posterior (down) end. (A) H. caucanus, row of papillae aligned parallel to margin and tooth rows in posterior labium (arrow; see Fig. 4-C1, 4-C2, 4-C3) ICNMHN 12142. (B) H. caucanus, papillae aligned (short arrow) with a section of a tooth row in posterior labium (long arrow; see Fig. 4-C4) ICNMHN 12142. (C) Hyloscirtus sp. group A, segments of tooth rows (long arrows) and papillae aligned with tooth row segments (short arrows) and larger teeth on tooth rows proximal to jaw sheath in anterior labium (see Fig. 4-B3, 4-B4) ICNMHN 15569. (D, E) Short tooth row segments (arrows) on H. denticulentus posterior labium (see Fig. 4-C3, 4-C4) ICNMHN 32496. (F) H. bogotensis posterior labium with last posterior segmented tooth row (arrow; see Fig. 4-C4, 4-C5) ICNMHN 32105. (G) H. denticulentus general view of submarginal papillae (arrows) aligned, and with teeth ICNMHN 6365. Tip of snout is top left. H and I are close ups of the same individual (see Fig. 4-D1, 4-D2, 4-D3, 4-D4).
Contributor Notes
Associate Editor: J. F. Webb.