Typhleotris pauliani Arnoult, 1959

Sparks, John S. & Chakrabarty, Prosanta, 2012, Revision of the Endemic Malagasy Cavefish Genus Typhleotris (Teleostei: Gobiiformes: Milyeringidae), with Discussion of its Phylogenetic Placement and Description of a New Species, American Museum Novitates 2012 (3764), pp. 1-28 : 7-16

Typhleotris pauliani Arnoult, 1959

Figures 4 , 6B , 7B , 8B; table 1

HOLOTYPE: MNHN 1960-0258 , 53.6 mm SL, Grotte d’Andranomaly , region of Andalambezo near Morombe, southwestern coastal Madagascar, coll. R. Paulian.

PARATYPE: MNHN 1960-0259 , 1 ex., 42.8 mm SL, data as for holotype .

NONTYPE COMPARATIVE MATERIALS: AMNH 245646 , 1 ex., 49.2 mm SL, Andranomahiha Cave , southeast of Andalambezo, 22°17′23.6″S, 043°19′21.7″E , southwestern Madagascar, Mad-12-2008, coll. P. Chakrabarty and P.W. Willink, 11 June 2008. AMNH 245647 , 1 ex., 43.7 mm SL , data as for AMNH 245646. AMNH 245648 , 1 ex., 42.6 mm SL , data as for AMNH 245646. AMNH 245649 , 1 ex., 49.8 mm SL, Safora Cave , southeast of Andalambezo, 22°19′18.4″S, 043°19′22.9″E, southwestern Madagascar, Mad-13-2008, coll. P. Chakrabarty and P.W. Willink, 11 June 2008. AMNH 245650 , 1 ex. , 35.0 mm SL, Anona “shallow” cave in town of Andalambezo, 22°19′09.9″S, 043°19′21.4″E, southwestern Madagascar, Mad-14-2008, coll. P. Chakrabarty and P.W. Willink, 11 June 2008. AMNH 245651 , 2 ex. , 59.8–61.4 mm SL, data as for AMNH 245650. AMNH 245652 , 1 ex. , 41.0 mm SL, data as for AMNH 245650. AMNH 245653 , 1 ex. , 60.4 mm SL, Andakatomivola Cave , east of Andalambezo , 22°16′40.6″S, 043°19′02.0″E, southwestern Madagascar, Mad-16-2008, coll. P. Chakrabarty and P.W. Willink, 11 June 2008. AMNH 245654 , 1 ex. , 45.3 mm SL, data as for AMNH 245653. AMNH 245655 , 1 ex. , 44.3 mm SL, data as for AMNH 245653. AMNH 245656 , 1 ex. , 42.8 mm SL, data as for AMNH 245650. AMNH 245657 , 1 ex. , 50.3 mm SL, data as for AMNH 245650. AMNH 245658 , 1 ex. , 43.1 mm SL, data as for AMNH 245650. AMNH 245659 , 1 ex. , 39.7 mm SL, C&S, data as for AMNH 245650. AMNH 245660 , 1 ex. , 66.3 mm SL, Anona “deep” cave in town of Andalambezo, 22°19′09.9″S, 043°19′21.4″E, southwestern Madagascar, Mad-15-2008, coll. P. Chakrabarty and P.W. Willink, 11 June 2008. AMNH 245661 , 1 ex. , 71.2 mm SL, data as for AMNH 245660. AMNH 245662 , 1 ex. , 53.2 mm SL, data as for AMNH 245646. AMNH 245663 , 1 ex. , 47.7 mm SL, data as for AMNH 245646. AMNH 245664 , 1 ex. , 47.3 mm SL, data as for AMNH 245649. AMNH 245665 , 1 ex. , 44.7 mm SL, data as for AMNH 245649. AMNH 245666 , 1 ex. , 43.1 mm SL, data as for AMNH 245649. AMNH 245667 , 1 ex. , 58.6 mm SL, data as for AMNH 245653. AMNH 245668 , 1 ex. , 47.8 mm SL, data as for AMNH 245653. AMNH 245669 , 1 ex. , 41.5 mm SL, data as for AMNH 245653. AMNH 245670, 1 ex., 55.8 mm SL, data as for AMNH 245653. AMNH 245671 , 1 ex., 52.6 mm SL, data as for AMNH 245653. MNHN 1968-0168 , 1 ex., 71.4 mm SL, Tulear (Toliara) (no additional data provided), southwestern Madagascar, coll. A. Kiener.

DIAGNOSIS: Distinguished from congeners by the absence of scales on the head, less the operculum (a scaled operculum is common to all species of Typhleotris ), the presence of single and feeble leading spines in both the second dorsal and anal fins (vs. soft rays in T. madagascariensis and T. mararybe ), a pelvic formula of I, 4 (vs. I, 5 in T. madagascariensis and T. mararybe ), the presence of an enlarged, bony operculum, and an overall more robust and heavier body, particularly in adults. Typhleotris pauliani is further distinguished from the new species by the absence of pigment on the body and a longer prepelvic length (34.1%–40.4% vs. 33.0%– 33.9% SL in T. mararybe ), and from T. madagascariensis by the absence of ctenoid scales on the flank and dorsum (ctenoid scales present only on operculum in T. pauliani ), except for a few weak ctenoid scales midflank in some individuals, more or less along the lateral midline.

DESCRIPTION: Selected proportional measurements and meristic data presented in table 1. A robust and deep-bodied (BD> 26% SL) species of Typhleotris , growing to roughly similar adult size (> 70 mm SL) as T. madagascariensis . Body wide anteriorly, particularly posterior to snout, and head dorsoventrally compressed, particularly rostrally. Operculum prominent and angular, yet head overall appearing more fleshy than congeners. Back (spine) appears arched in larger specimens. Snout and anterior portion of head markedly elongate and shovellike (more so than congeners, creating a duck-billed look). Body becoming progressively laterally compressed posteriorly. Caudal peduncle laterally compressed and elongate. No eyes present; however, significant fat deposits present anteriorly over neurocranium, including orbital region. Anterior nostril relatively short, wide, and tubular, located just posterior to upper lip; posterior nostril very short and tubular, not slitlike. Lacrimal small, greatly reduced in size. Palatine elongate and very thin. Numerous deep grooves present on dorsal and ventral side of head; grooves lined with small pores.

Mouth large, and gape moderately wide. Oral jaw teeth small, conical, and moderately recurved; teeth numerous and arrayed in six to eight closely set and irregular rows along anterior portion of jaws, and tapering to fewer rows of somewhat smaller teeth posteriorly, as well as medially proximal to synthesis, where tooth rows become noticeably reduced and constricted, in both upper and lower jaws. Teeth present along full length of premaxillary arcade and dentary. Basihyal large, triangular, and fan shaped.

Gill rakers on lower limb of first arch somewhat thin, elongate, denticulate medially, and tapering distally, yet noticeably more robust and triangular than in T. madagascariensis , numbering 10 to 13. Two or three epibranchial rakers of similar morphology present on first arch. Gill rakers on arches 2–4 short, robust, and strongly denticulate dorsally; covered apically with short conical teeth. Fifth ceratobranchial elements separate, and densely toothed, as are upper pharyngobranchial toothplates. Fifth ceratobranchial and upper pharyngeal toothplates covered with small, robust conical teeth.

Head asquamate, except for presence of scales dorsally on posterior portion of neurocranium (figs. 4, 6B, 7B, 8B). Scales extending anteriorly approximately to posterior margin of frontals, and also onto operculum. Scales on opercle and subopercle strongly ctenoid, all others on body cycloid, including posterior roof of neurocranium, except for occasional weakly ctenoid scale on midflank (about at midline). Otherwise, body fully scaled to caudal fin, including along ventrum anterior of pelvic fin and on fleshy base of pectoral fin. Scales on ventrum cycloid, not well ossified and strongly embedded; difficult to visualize on whole alcohol-preserved specimens, but can easily be seen in C&S specimen (AMNH 245659, 39.7 mm SL). Pectoral-fin axil asquamate.

It is worth noting that as for T. madagascariensis , there is some intraspecific variation in head squamation in T. pauliani . The large individual from MNHN 1968-168 (71.4 mm SL, region: Toliara, locality: Tulear [no additional data provided]), also collected by Kiener, has cycloid scales extending anterior of the operculum and onto the cheek in two to four columns, whereas in all other available material, anterior lateral squamation is restricted to the operculum. Unfortunately, collection locality information for this lot is also lacking, indicating only Tulear (Toliara), the largest city in the general region. This individual may simply be aberrant in terms of scale morphology on the head, or this variation could be unique to an isolated population; however, we have no way of verifying given the limited information available for this lot.

Two dorsal fins. First dorsal fin with five weakly developed spines and second dorsal fin with one weak spine and seven or eight segmented, branched rays. Anal fin with one weak spine and seven or eight rays. First dorsal fin small, rays feeble, origin at vertical about 2/3 distance of adducted pelvic fin. Second dorsal-fin origin located at about midpoint of distance between posterior insertion of urogenital papilla and anal-fin origin. Pelvic formula I, 4. Pelvic-fin origin slightly posterior to vertical through dorsal margin of pectoral-fin insertion. Pectoral-fin origin slightly anterior to vertical through posterior margin of opercle. Pectoral base well developed, portion with proximal radials projects considerably from body as fleshy appendage. Pectoral rays 13 or 14. Urogenital papilla robust, relatively short and tubular, not reaching anal fin when adducted in smaller specimens, reaching anal-fin origin in larger specimens (> ca. 55 mm SL). Pelvic and pectoral fins elongate and produced, with filamentous trailing rays, particularly in larger individuals. Caudal fin short and moderately rounded on distal end; in larger specimens (> ~ 60 mm SL) caudal becoming more lanceolate in appearance (e.g., fig. 3C). Vertebral count 24 or 25.

COLORATION AND PIGMENTATION PATTERN IN LIFE AND ALCOHOL (fig. 4): Body without pigment and uniformly white in coloration in all recently collected individuals. In life, body is relatively translucent, whereas translucency is lost and body becomes opaque white in alcohol. As reported above for T. madagascariensis , it is worth noting that although all recently collected material is entirely lacking in pigment (e.g., fig. 4C), some historical specimens (MNHN 1968168, 1 ex., 71.4 mm SL) appear to exhibit a grayish or light grayish-brown coloration in alcohol. Unfortunately, it is impossible to know whether this faint pigmentation was visible in life or is simply an artifact of preservation. The fact that pigmentation is not mentioned in the original description of either T. pauliani or T. madagascariensis is certainly telling, but inconclusive.

ETYMOLOGY: Named in honor of the prominent French entomologist and former deputy director of the Institut de Recherche Scientifique de Madagascar, Renaud Paulian, who collected the specimens on which the original description is based and who did much seminal work on western Indian Ocean biogeography ( Aberlenc, 2008).

DISTRIBUTION AND HABITAT (figs. 1, 5): Restricted to subterranean habitats in coastal regions to the south of Morombe in the vicinity of Andalambezo, extending from about 22°19′S northward to 22°16′S. Typhleotris pauliani is restricted to caves and sinkholes to the north of the large Onilahy River drainage. The type locality listed by Arnoult (1959a, 1959b) is “ Madagascar Sud Ouest: Morombe, plateau de la baie des Assassins, grottes d’Andranomaly.” Goodman and colleagues (personal commun.) have determined the location of the cave that Paulian (1959) explored at Andalambezo (22°16′S; 43°17′E, cave at 15 m), and from which the type series was collected. Recently, additional specimens, presumably of T. pauliani based on digital images, have been collected from caves inland and just south of Andavadoaka (22°04′S) (S. Barley, personal commun.). Based on historical records, the geographic range of T. pauliani is considerably more restricted than that of T. madagascariensis ; however, these new records extend the northern limit of the range of T. pauliani , suggesting that the species is more widely distributed.

REMARKS AND COMPARISONS: Typhleotris pauliani can be distinguished from T. madagascariensis by the absence of scales extending onto the anterior portions of the head and snout ( T. pauliani and T. mararybe have scales extending anteriorly only up to the roof of the neurocranium, not extending onto the cheek [suspensorium], except a few rows in rare individuals, or more anterior portions of the head [e.g., snout, orbital region, or anterior portion of frontal bones]; T. madagascariensis has a fully scaled head) (figs. 2, 4, 6–7), and by the presence of cycloid scales covering the flank, roof of the neurocranium, dorsum, and posterior portion of ventrum (vs. ctenoid in T. madagascariensis ). In addition to the lack of pigmentation, Typhleotris pauliani can further be distinguished from T. mararybe by the presence of a more or less smooth outline of the snout and anterior portion of the head in dorsal view (fig. 7B), versus the head appearing greatly constricted in the orbital region due to enlarged and projecting lateral skull elements (i.e., posteriorly the pterotic and sphenotic, and anteriorly the lateral ethmoid) and a strongly sunken, concave orbital region (fig. 7C). In addition, large individuals of T. pauliani (> ~ 60 mm SL) can be distinguished from congeners by more elongate second dorsal and anal fins, and to a lesser degree, caudal fin, with produced and filamentous trailing rays.

Figures

FIGURE 4. Typhleotris pauliani:A. Lateral view of holotype, MNHN 1960-0258, 53.6 mm SL; Grotte d’Andranomaly, Andalambezo region near Morombe, southwestern Madagascar. B. Paratype, MNHN 1960-0259, 42.8 mm SL; data as for holotype. C. Recently collected specimen, AMNH 245651, 61.4 mm SL; Anona “shallow” cave in town of Andalambezo.

FIGURE 6. Illustration of A. Typhleotris madagascariensis and B. T. pauliani after Arnoult (1959b), showing general body and fin shape, as well as differences in extent of head squamation between species.

FIGURE 7. Dorsal view of the anterior portion of the head in the three described species of Typhleotris: A. T. madagascariensis, AMNH 245603; B. T. pauliani, AMNH 245651; C. T. mararybe, AMNH 245601, holotype.