Paretroplus polyactis Bleeker, 1878
Sparks, J. S., 2008, Phylogeny Of The Cichlid Subfamily Etroplinae And Taxonomic Revision Of The Malagasy Cichlid Genus Paretroplus (Teleostei: Cichlidae), Bulletin of the American Museum of Natural History 2008 (314), pp. 1-151: 63-72
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|Paretroplus polyactis Bleeker, 1878|
Paretroplus polyactis Bleeker, 1878 Figures 30–33; plate 1B; table 3
NOTES ON SYNTYPES AND TYPE LOCALI- TY: Bleeker (1878) included two specimens (67 and 89 mm [presumably] TL) in his original description of P. polyactis . No catalog numbers for these syntypes accompany the description, which is consistent for that time period. Bleeker (1878: 196) reported that the type specimens were collected from rivers in eastern Madagascar near the town of ‘‘Manahare’’ (‘‘ Madagascar orientalis (Manahare); in fluviis’’); however, I am unable to locate any town with that exact spelling in eastern coastal Madagascar. It has generally been assumed that Bleeker was referring to the large town of Mananara (P. Loiselle, personal commun.), located near the mouth of Antongil Bay in the northeast (and between Maroansetra and Toamasina), and that ‘‘Manahare’’ was simply a phonetic misspelling. The type series was collected by J.-P. Audebert, a German naturalist who collected along Madagascar’s eastern coast from 1876 to 1880, and who presumably spent 1876 collecting in northeastern coastal localities from Antongil Bay southward to Toamasina (Tamatave) ( Carleton and Schmidt, 1990: 18). As Carleton and Schmidt (1990) point out, ‘‘Audebert’s orthographic renditions of Malagasy place names, howev- er, have challenged attempts to associate them with conventional geographic spellings and created considerable uncertainly about the distribution of the taxa he collected’’. Carleton and Schmidt (1990) indicate ‘‘Mananare’’ is probably simply a phonetic misspelling of Mananara (as many other localities reported by Audebert contain similar phonetic misspellings). It is not a stretch to assume that Bleeker (1878) added to the confusion with his phonetic interpretation (‘‘Manahare’’). Nevertheless, in a detailed journal of his travels in northern Madagascar, the Rev. Kestell Cornish (unpubl. journal, 1876) mentions a coastal town by the name of Manahara, which is located north of the Masoala Peninsula, between the towns of Manakana and Bemarivo, and which is closer in spelling to ‘‘Manahare’’. Both Paretroplus polyactis and members of Paratilapia (the other freshwater species described by Bleeker (1878) was Paracara [now Paratilapia ] typus ) occur in this far northern region of the island where Audebert also collected, and the possibility remains that this more northerly location could represent the type locality. The type specimen of Paracara typus is in terrible condition and the illustration of Paretroplus polyactis lacks sufficient details that would permit one to associate these specimens to a particular geographic population. Given that P. polyactis occurs along nearly the entire eastern coastal region of Madagascar, and that differences between various populations spanning the geographic range of the species are subtle, the specific type locality is somewhat irrelevant given that a single species is recognized herein under the concept of P. polyactis (but see Discussion and Relationships below regarding intraspecific variation).
Eschmeyer (2006) reports that there are two syntypes for P. polyactis , one corresponding to RMNH 4478; the other is not provided an RMNH catalog number. An examination of RMNH 4478 shows that this specimen is a juvenile P. damii , and there is reason to believe that this individual is probably a syntype of that species (see Notes on Type Series above for P. damii ). The other putative syntype could not be located at RMNH and is presumed lost. Given Bleeker’s (1878) detailed description and accompanying illustration, it is clear that he was not describing an amalgam of two different species (i.e., P. polyactis and P. damii ), and it is unclear why Eschmeyer associated RMNH 4478 with P. polyactis . The distinctive lateral barring pattern in combination with dark scale margins and body shape of the specimen illustrated ( Bleeker, 1878: fig. 2) are significantly different from that of P. damii . Also, the dorsal- (XVI spines and 17–19 rays) and anal-fin (13–16 rays) counts and lateral line scale count (32 or 33) provided for P. polyactis by Bleeker (1878) all fall outside the range of P. damii (table 2; also see Bleeker, 1868). Moreover, an old label in the jar with RMNH 4478 states ‘‘type’’ under the species name of ‘‘ Paretroplus dami ’’. Thus, both of the syntypes of P. polyactis described by Bleeker must be presumed lost.
MATERIAL EXAMINED: AMNH 88016 View Materials , 19 ex., 112.9–191.8 mm SL ; eastern Madagascar: Fianarantsoa Province: Mananjary: estuary of Mananjary River behind marketplace, ca. 1 km from sea: 21 ° 05 9 S, 48 ° 27 9 E GoogleMaps ; local fishermen, M. L. J. Stiassny, and P. N. Reinthal, 30-VI-1988. AMNH 88040 View Materials , 3 ex., 124.5–152.5 mm SL ; Fianarantsoa Province: Mananjary River , 1km from sea: 21 ° 05 9 S, 48 ° 27 9 E GoogleMaps ; M. L. J. Stiassny and P. N. Reinthal, 2-VII-1988. AMNH 88078 View Materials , 1 ex., 132.6 mm SL ; eastern Madagascar: Toamasina Province: ferry at Marosiky : 19 ° 40 9 S, 48 ° 50 9 E GoogleMaps ; M. L. J. Stiassny and P. N. Reinthal, 8-VII-1988. AMNH 88091 View Materials , 10 ex., 72.3–149.7 mm SL ; eastern Madagascar: Toamasina Province: Pangalanes Canal north of Mangoro River, Mahanoro town behind Hotel de la Pangalane: 19 ° 55 9 S, 48 ° 50 9 E GoogleMaps ; M. L. J. Stiassny and P. N. Reinthal, 8-VII-1988. AMNH 88116 View Materials , 9 ex., 48.5–188.8 mm SL ; eastern Madagascar: Toamasina Province: Toamasina, main marketplace in town center, caught nearby: 18 ° 10 9 S, 49 ° 25 9 E GoogleMaps ; local fishermen, M. L. J. Stiassny, and P. N. Reinthal, 15-VII-1988. AMNH 88135 View Materials , 4 ex., 97.0–155.9 mm SL ; eastern Madagascar: Toamasina Province: Ivoloina River at large bridge on Toamasina to Fenoarivo road, estuary: 18 ° 00 9 S, 49 ° 25 9 E GoogleMaps ; M. L. J. Stiassny and P. N. Reinthal, 15-VII- 1988. AMNH 88139 View Materials , 1 ex., 41.2 mm SL ; eastern Madagascar: Toamasina Province: bridge over Canal de Pangalanes on Toamasina to Fenoarivo road, ca. 25km north of
TABLE 3 Morphometric and meristic data for Paretroplus polyactis . For meristics, numerals in parentheses indicate number of specimens examined with that count. Syntypes for P. polyactis are presumed lost (see text).
Toamasina : 18 ° 00 9 S, 49 ° 25 9 E GoogleMaps ; M. L. J. Stiassny and P. N. Reinthal, 16-VII-1988. AMNH 88152 View Materials , 1 ex., 95.4 mm SL ; eastern Madagascar: Toamasina (5 Tamatave) Province: Canal de Pangalanes on Toamasina to Fenoarivo (5 Fenerive ) road, ca. 100 m from outflow to sea: 18 ° 00 9 S, 49 ° 25 9 E GoogleMaps ; M. L. J. Stiassny and P. N. Reinthal, 17-VII- 1988. AMNH 97003 View Materials , 2 ex., 79–104 mm SL ; eastern Madagascar: Toamasina Province: east of road by Salehy village, 1 km south of turnoff from Marolambo-Mananjary road: bay lake behind first dune about 100 m from sea: 19 ° 55 9 S, 48 ° 50 9 E GoogleMaps ; M. L. J. Stiassny, P. N. Reinthal, and G. J. P. Naylor, 16-IX-1990. AMNH 97006 View Materials , 1 ex., 49.0 mm SL ; data as for AMNH 97003. AMNH 97013 View Materials , 7 ex., 71.5–103.2 mm SL ; eastern Madagascar: Toamasina Province: Mahanoro market behind Hotel de la Pangalane: 19 ° 55 9 S, 48 ° 50 9 E GoogleMaps ; local fishermen, M. L. J. Stiassny, and P. N. Reinthal, 16-IX-1990. AMNH 97031 View Materials , 2 ex., 52–55 mm SL ; eastern Madagascar: Toamasina Province: mouth of Mangoro River opposite camp by Salehy village : 19 ° 55 9 S, 48 ° 50 9 E GoogleMaps ; M. L. J. Stiassny, P. N. Reinthal, and G. J. P. Naylor, 17-IX-1990. AMNH 97054 View Materials , 1 ex., 109 mm SL ; eastern Madagascar: Toamasina Province: Mangoro River drainage: Savalany River (small stream) by Ambodisovoka village at bridge over road to Marolambo ; M. L. J. Stiassny, P. N. Reinthal, and G. J. P. Naylor, 18-IX- 1990. AMNH 98171 View Materials , 3 ex., 2 ex. C&S, 65.5– 113.8 mm SL ; eastern Madagascar: Toamasina Province: east of road by Salehy village, 1 km south of turnoff from Marolambo- Mananjary road: bay lake behind first dune about 100 m from sea: 19 ° 55 9 S, 48 ° 50 9 E GoogleMaps ; M. L. J. Stiassny, P. N. Reinthal, and G. J. P. Naylor, 17-IX-1990. AMNH 231359 View Materials , 7 ex., 41.0–84.0 mm SL ; northeastern Madagascar: Antsiranana Province: Sambava-Andapa Region: Lake Andohabeobe: ca. 7 km south of Sambava ; PVL-99-01; P. V. Loiselle, 20-X- 1999. AMNH 233656 View Materials , 4 ex., 87.8–97.8 mm SL ; northeastern Madagascar: Antsiranana Province: Andranory River: main channel of small coastal river just south of the airport at Antalaha; PVL-03-05; P. V. Loiselle. AMNH 238558 View Materials , 3 ex., 128.5–185.0 mm SL ; northeastern Madagascar: Toamasina Province: Antainambalana River : north (upriver) of town of Maroansetra: 15 ° 25 9 5.4 0 S, 49 ° 40 9 17.4 0 E ; JSS 2-2003; local fishermen, J. S. Sparks, W. L. Smith, and K. L. Tang, 8- XI-2003. AMNH 238569 View Materials , 7 ex., 1 ex. C&S, 100.0–130.0 mm SL ; northeastern Madagascar: Toamasina Province: Maroansetra market: 15 ° 25 9 60 0 S, 49 ° 43 9 60 0 E GoogleMaps ; JSS 26-2003; J. S. Sparks, W. L. Smith, and K. L. Tang, 24- 26-XI-2003. UMMZ 199407 View Materials , 3 ex. (formerly MNHN 60-222 View Materials ), 84–116 mm SL ; Madagascar. UMMZ 235015 View Materials , 8 ex., 104–215 mm SL ; southeastern Madagascar: Fianarantsoa Province: Mananjary market and port: 21 ° 13 9 0 0 S, 48 ° 19 9 60.0 0 E ; JSS 94-26; J. S. Sparks and K. J. Riseng, 23-VIII-1994. UMMZ 235016 View Materials , 18 ex., 3 ex. C&S, 46– 220 mm SL ; southeastern Madagascar: Fianarantsoa Province: Farafangana market: 22 ° 49 9 0 0 S, 47 ° 49 9 60.0 0 E ; JSS 96-3; J. S. Sparks and K. J. Riseng, 1996. UMMZ 235017 View Materials , 22 ex., 1 ex. C&S, 68–197 mm SL ; southeastern Madagascar: Fianarantsoa Province: south of Farafangana: Manombo Special Reserve : 22 ° 57 9 S to 23 ° 08 9 S, 47 ° 36 9 E to 47 ° 48 9 E GoogleMaps ; PNR 96-2; P. N. Reinthal, 1996. UMMZ 236593 View Materials , 1 ex., 84 mm SL ; northeastern Madagascar: Antsiranana Province: east coast of Masoala Peninsula: Projet Masoala site 1006: mangrove swamp near Lalona river : 15 ° 23 9 11.0 0 S, 50 ° 26 9 24.0 0 E ; JSS 94-49; J. S. Sparks and K. J. Riseng, 4-X-1994. UMMZ 238459 View Materials , 7 ex., 1 ex. S, 95–190 mm SL ; southeastern Madagascar: Fianarantsoa Province: Farafangana market: 22 ° 49 9 0 0 S, 47 ° 49 9 60.0 0 E ; JSS 94-MKT-2-2; J. S. Sparks, K. J. Riseng, and P. N. Reinthal, 1994. UMMZ 238475 View Materials , 1 ex., 108 mm SL ; southeastern Madagascar: Fianarantsoa Province ; JSS 94-MKT-4-1; J. S. Sparks and K. J. Riseng, 1994. UMMZ 238477 View Materials , 1 ex., 84 mm SL ; southeastern Madagascar: Fianarantsoa Province ; JSS 94-MKT-1-1; J. S. Sparks, K. J. Riseng, and P. N. Reinthal, 1994. UMMZ 239527 View Materials , 5 ex., 1 ex. C&S, 45.5–124.0 mm SL ; southeastern Madagascar: Fianarantsoa Province: Andriambondro River (tributary of Rienana River): 6 km north of Karianga at town of Mahavelo: 22 ° 21 9 47.0 0 S, 47 ° 22 9 5.0 0 E: alt. 234.7m a.s.l .; JSS 96-5; J. S. Sparks and K. J. Riseng, 17-VI-1996. UMMZ 239528 View Materials , 4 ex., 84–114 mm SL ; northeastern Madagascar: Toamasina Province: Maroansetra market: 15 ° 26 9 3.0 0 S, 49 ° 44 9 29.0 0 E ; JSS 94-39; J. S. Sparks and K. J. Riseng, 21-IX-1994. UMMZ 239529 View Materials , 4 ex., 127–167 mm SL ; southeastern Madagascar: Fianarantsoa Province: Farafangana market: 22 ° 49 9 0 0 S, 47 ° 49 9 60.0 0 E ; JSS 94- MKT-5; J. S. Sparks, K. J. Riseng, and P. N. Reinthal, 18-VI-1994. UMMZ 239563 View Materials , 3 ex., 102–154 mm SL ; southeastern Madagascar: Fianarantsoa Province: south of Farafangana: Manombo Special Reserve : 22 ° 57 9 S to 23 ° 08 9 S, 47 ° 36 9 E to 47 ° 48 9 E GoogleMaps ; PNR 96-3; P. N. Reinthal, 1996.
DIAGNOSIS: Paretroplus polyactis is distinguished from congeners by a unique chainlink (diamond mesh) pigmentation pattern, owing to contrasting dark scale margins and light centers over the entire flank and portions of the head. It is also the only member of the genus in which the entire series of lateral bars is both strongly pigmented and spotted (not solid), due to more darkly pigmented scale margins than centers, regardless of size (e.g., vs. bars prominent and solid in P. maromandia ). In life, P. polyactis is unique among deep-bodied members of the genus (Clade I) in possessing a bright red iris, a feature shared only with the elongate P. lamenabe (Clade F).
DESCRIPTION: Morphometric and meristic data presented in table 3. Morphological characteristics and general pigmentation pattern in life and preservative can be observed in fig. 24A and 30–32. A deep-bodied, laterally compressed Paretroplus belonging to Clade I, which comprises all deep-bodied and more or less disk-shaped members of Paretroplus (also including P. dambabe , P. maculatus , P. maromandia , P. menarambo , and P. petiti ) (fig. 1). Head shape ranges from pointed, not blunt, and only moderately steeply sloping in lateral view, to relatively blunt and somewhat steeply sloping (see Discussion and Relationships below). Snout ranges from mostly straight to moderately convex in lateral view. Specimens with convex snout characterized by indentation posterior to premaxillary pedicels, which may be quite pronounced. Predorsal profile mostly straight to moderately rounded. Caudal peduncle short, deep, and laterally compressed. No sexually dimorphic characters apparent, although unpaired fins of males slightly more elongate and pointed distally than females of comparative standard length.
Total vertebral count 31–33 (mode 32), with formulae of: 15 + 16, 15 + 17, 15 + 18 precaudal and caudal vertebrae, respectively.
Jaws isognathous. Single row of spatulate unicuspid teeth in both upper and lower jaws. Teeth laterally expanded, flattened at crown, and procumbently implanted. In upper jaw, tooth on either side of premaxillary symphysis greatly enlarged, remaining upper-jaw teeth graded in size laterally. Lower-jaw teeth at symphysis not enlarged, and only slightly reduced in size compared to adjacent lateral teeth, presumably to accommodate enlarged upper symphyseal teeth. Teeth in upper jaw usually number five to eight on each side, and total 11–15. Teeth in lower jaw number four or five on each side, and total eight or nine. Upper- and lower-jaw teeth generally widely set and regularly spaced, although some teeth may be irregularly spaced and closely set.
Upper and lower pharyngeal tooth plates well developed and dentition robust. Dentition on lower pharyngeal tooth plates (5 lower pharyngeal jaws [LPJ] or fifth ceratobranchial tooth plates) hooked and bicuspid both laterally and anteriorly, becoming progressively enlarged medially; robust molariform teeth present posteromedially. LPJ well sutured, with numerous interdigitating sutures on posteroventral margin. Seven to nine robust tooth plates cover majority of dorsal surface of fourth ceratobranchial bones. In some specimens, bases of tooth plates becoming confluent or fused. Tooth plates not confluent with outer-row gill rakers of fourth ceratobranchial elements. Dentition on fourth ceratobranchial tooth plates unicuspid or weakly hooked and bicuspid laterally, hooked and bicuspid medially (similar to lateral LPJ dentition). Dentition on third upper pharyngobranchial tooth plates molariform posteromedially, hooked and bicuspid laterally and anteromedially. Anteromedial teeth on third pharyngobranchial tooth plates enlarged and robust, but not becoming molariform. Dentition on second pharyngobranchial tooth plates hooked and bicuspid and arrayed in two or three rows.
Eleven to 13 (mode 12) elongate, triangular gill rakers arrayed along lower limb of first gill arch. These rakers range from weakly to strongly denticulate, with few to many conical teeth dorsomedially. All other lower-limb rakers (i.e., those on gill arches 2– 4) short, spherical, and strongly denticulate dorsally. Teeth on rakers of gill arches 2–4 elongate, conical and curved near crown, and as long or longer than raker bases. Epibranchial rakers on first gill arch elongate, numbering 10–13.
Body covered with large, regularly imbricate, cycloid scales. Well-developed ridges of scales (5 scale sheathing) present along dorsal- and anal-fin bases. Scale ridges free from both spiny and soft portions of dorsal and anal fins. Pelvic axillary scale present and well developed (fig. 23A). Interpelvic scale series well developed, terminal scale in series robust, elongate, and pointed distally. Lateral-line scales number 31–36 (mode 33). Chest scales somewhat smaller than other body scales, but not greatly reduced in size except anteroventrally. Anteroventral chest scales markedly reduced in size and embedded. Belly scales along ventral midline also markedly reduced in size and embedded. Four to six rows of scales on cheek. Opercle, subopercle, and interopercle scaled. Snout, lacrimal, and anterior portion of interorbital region asquamate. Scales on caudal fin reduced in size and extending posteriorly 2/ 3 to 3/4 length of fin on dorsal and ventral lobes, and 1/4 to 1/3 length of fin medially.
Dorsal with XVI–XVIII spines, 15–18 soft rays. Anal with VII–X spines, 13–15 soft rays. Origin of dorsal fin ranges from about level of to slightly posterior to vertical through pectoral-fin insertion. Caudal fin emarginate, trailing margins of upper and lower lobes weakly produced (compared to other deep-bodied members of genus) in larger individuals. Pectoral fin broad and rounded at distal margin. Distal margins of soft dorsal and anal fins produced and pointed in larger specimens. Pelvic fin extending just to anal-fin origin in smaller specimens, and in larger individuals pelvic fin ranging from not quite reaching anal-fin origin to extending well beyond origin when adducted.
MISCELLANEOUS OSTEOLOGY AND ANAT- OMY: Large, well-developed exoccipital excavations present. Paired anterior gas bladder bullae with tough, thickened tunica externa and narrow tubular connections (5 diverticula) to main gas bladder chamber (fig. 20B). Anteriormost chambers firmly lodged in exoccipital recesses. Prominent excavation (5 supraoccipital notch of Stiassny et al., 2001) along posterior margin of supraoccipital (fig. 20B). Supraoccipital extending anteriorly over median frontal pores of neurocranium (nlf 0 of Barel et al., 1977). Two distinct and well-separated proximal premaxillary-maxillary ligaments present (rostral ligament unique to Paretroplus within Cichlidae ). An additional, fully ossified, anal- and dorsal-fin pterygiophore, not associated with any fin rays, present terminally in both fins. Modified ‘‘prezygopophyses’’ present on anterior neural arches (fig. 18D).
COLORATION IN LIFE: Base body coloration pale yellow, olive, or golden brown, and becoming pale salmon in sexually active individuals. Body pale yellow to pale olive ventrally. Strong chain-link (diamond mesh) pigmentation pattern on flanks and dorsoposterior portion of head, owing to contrasting dark scale margins and light centers (see de Rham and Nourissat, 2004: 84–87). Seven to nine prominent black vertical bars present on flank from posterior margin of opercle to caudal-fin base. Populations from Mananjary northward possess eight or nine lateral bars, whereas those along the southeastern coast and inland from about Karianga and Farafangana (22 ° S) southward have seven lateral bars. Head region generally darker than flanks, but with same pale yellow, olive, or golden brown coloration. Opercle and cheek frequently with some iridescent bright golden patches. Upper lip, interorbital region, lacrimal, and snout grayish brown to uniform dark brown. Iris of eye bright red, which gives species its Malagasy name masovoatoaka, which translates as ‘‘eyes bloodshot from drinking (rum)’’. Lower lip, gular region, anterior chest, belly, interopercle, and ventral cheek white, pale yellow, or light olive. Unpaired fins dark gray, charcoal, or black, with dark red margins. Pectoral fins range from hyaline to translucent brown or black. Pelvic fins dark gray to black, with light gray to whitish leading edge. Juveniles to about 60 mm SL with well-differentiated lateral bars that extend vertically over entire flank. Although still prominent, lateral bars become wider and less well differentiated in adults.
COLORATION IN PRESERVATIVE: Base body coloration ranges from pale yellow, to olive, to dark brown. Seven to nine prominent dark brown or charcoal vertical bars present on flank from posterior margin of opercle to caudal-fin base. In general, populations from Mananjary northward have eight or nine lateral bars (figs. 24A and 31), whereas those from about Karianga and Farafangana (about 22 ° S) southward have only seven lateral bars (fig. 30). Pigmentation pattern of dark scale margins and lighter centers, including scales on lateral bars, creates chain-link pattern over entire flank and portion of head. Body generally somewhat lighter overall dorsally. Interorbital region, lacrimal, and snout pale grayish yellow to uniform dark brown. Upper lip charcoal to dark grayish brown, and lower lip pale yellow to golden brown. Gular region, anterior chest, belly, interopercle, and ventral cheek grayish yellow to golden brown. Dorsal and anal fins range from dark brown, to dark grayish brown, to gray distally and black terminally. Caudal fin ranges from pale yellow anteriorly and charcoal posteriorly, to dark brown or dark grayish brown. Pectoral fins pale yellow, olive, or light brown. Pelvic fins range from pale yellow anteriorly and charcoal posteriorly, to dark grayish brown. Juveniles to about 60 mm SL with distinctive narrow and well-separated bars that extend vertically over entire flank (fig. 32); in adults bars remain prominent, but becoming less well differentiated and more broad, as well as less strongly pigmented ventrally.
DISTRIBUTION AND HABITATS: Paretroplus polyactis exhibits an extensive latitudinal range spanning nearly the entire eastern coast of Madagascar (fig. 33). The known range for the species extends from somewhat north of the Masoala Peninsula, the Lokoho River at Ambatoloaka (de Rham and Nourissat, 2004: 84), southward to the Manampanihy River, located 20 km inland of Fort Dauphin. Interestingly, although P. polyactis is primarily a coastal species throughout most of its range, frequently inhabiting estuarine and brackish habitats and generally not straying far inland, de Rham and Nourissat (2004: 85) report that the species is absent from coastal areas at the southern limit of its range near Fort Dauphin, where it is restricted to the upper reaches of the Manampanihy River. The most southern coastal populations of P. polyactis known occur at Manombo (including rivers and streams within Manombo Special Reserve) and Vangaindrano, which are located to the south of Farafangana. The species has also been collected about 60 km inland from the sea in the Andriambondro River (tributary of Rienana River) just to the north of Karianga (22 ° 21 9 47 0 S, 47 ° 22 9 05 0 E) (J. Sparks, personal obs.). Of the other endemic cichlid species, only Ptychochromis grandidieri exhibits a latitudinally extensive north-south geographic range, although the species does not extend nearly as far north (restricted to the south of the Makira Protected Area) as P. polyactis , whereas its southern range limit remains uncertain (see Stiassny and Sparks, 2006: fig. 1).
Considering the extensive latitudinal range of P. polyactis and that the species can tolerate brackish conditions, the species does not appear to be in immediate danger of extinction. Nevertheless, it is important to note that this species is highly prized as a food fish by the Malagasy, commanding a high price in markets, and is heavily targeted by fishermen throughout eastern Madagascar. Anecdotally, over the past decade many researchers, including our group, our Malagasy colleague Noramalala Raminosoa (University of Antananarivo), Paul Loiselle (WCS/NY Aquarium), and de Rham and Nourissat (2004), have noticed both a decline in abundance as well as a decline in size of P. polyactis offered for sale in markets throughout eastern Madagascar. Of all the species of Paretroplus , with the possible exception of P. damii , which is widely distributed throughout northwestern and northern Madagascar, P. polyactis currently appears to be the least threatened (see Relationships and Discussion below). It is frequently found in quite degraded habitats and I have even observed the species swimming in seawater off of mangrove swamps during high tide. If the current rate of habitat destruction throughout eastern Madagascar is not slowed, the status of P. polyactis could rapidly change.
LOCAL NAME: The iris of the eye is bright red in P. polyactis . Masovoatoaka, which translates as ‘‘eyes bloodshot from drinking (rum)’’, is the Malagasy name used to refer to P. polyactis throughout its range.
ETYMOLOGY: The specific name polyactis derives from poly- (Greek: polus, meaning ‘‘many’’) and actis (Greek: ‘‘ray, sunbeam, beam of light’’), most likely in reference to the reddish, orange, and brown coloration of the species, which is quite striking in life.
RELATIONSHIPS AND DISCUSSION: Paretroplus polyactis is a member of Clade I, comprising all of the deep-bodied members of Paretroplus (also including P. dambabe , P. maculatus , P. maromandia , P. menarambo , and P. petiti ) (fig. 1), which is supported by three unambiguously optimized morphological features, the first two of which are unique and unreversed: a deep and essentially disk-shaped body (fig. 24A), lateral ridges of scales (‘‘scale sheathing’’) along the bases of the soft dorsal and anal fins that are free from the fin membranes over their entire length, and the presence of seven to nine prominent lateral bars (figs. 30–32).
Paretroplus polyactis is recovered as the sister taxon to Clade J, which includes all deep-bodied members of the genus with distributions restricted to western basins ( P. dambabe , P. maculatus , P. maromandia , P. menarambo , and P. petiti ) (fig. 1). Paretroplus polyactis lacks the following derived anatomical features that unite members of Clade J: a blunt snout, with a steeply sloping profile in lateral view, and a distinctive lateral striping pattern of alternating light and dark horizontal stripes extending from the anterior margin of the orbit to origin of the caudal fin. A recent study using only nucleotide characters from multiple mitochondrial and nuclear genes recovered P. polyactis in a slightly different position, as the sister taxon to a clade comprising P. kieneri and Clade J ( P. dambabe , P. maculatus , P. maromandia , P. menarambo , and P. petiti ) ( Sparks and Smith, 2004: fig. 1).
In addition to its unique chain-link pigmentation pattern, P. polyactis is distinguished from all congeners, except P. lamenabe , by the presence of a bright red iris in life. However, the iris is not nearly as bright red in P. lamenabe . It is the only member of Paretroplus in which the lower-jaw teeth at the symphysis of the left and right dentaries are only slightly reduced in size (all other species exhibit symphyseal teeth greatly reduced in size). Paretroplus polyactis can usually be distinguished from other members of Clade I by the number of gill rakers on the lower limb of the first arch (11–13 [mode 12] in P. polyactis vs. 9–10 in other members of Clade I; two individuals of P. maculatus were examined with 11 lower-limb gill rakers). In addition, P. polyactis can generally be distinguished from other deep-bodied Paretroplus (Clade I) by the distribution of accessory parapophyses on the caudal vertebral centra. Paretroplus polyactis usually has accessory parapophyses restricted to the first two caudal vertebral centra, but these structures are occasionally also present on the third caudal centra, whereas all other deepbodied members of the genus always have parapophyses on at least the first three caudal vertebral centra (e.g., P. dambabe has parapophyses on the first three or four caudal vertebral centra, and P. maromandia , P. maculatus , and P. menarambo on the first four or five caudal vertebral centra). These accessory parapophyses directly support the upper wall of the paired posterior gas bladder chambers.
Interestingly, variation in nucleotide sequences between populations of P. polyactis from Mananjary along the southeastern coast and Maroansetra in the northeast is about the same as between other pairs of Paretroplus that are recognized as distinct species (e.g., Paretroplus dambabe and P. maculatus ) and even greater than that observed between P. nourissati and P. tsimoly ( Sparks and Smith, 2004) . Nevertheless, I am unable to find consistent (invariable) morphological features within any of the populations of P. polyactis spanning the eastern coast of Madagascar (from north of the Masoala Peninsula to the far south of the island) that would indicate the presence of more than a single species.
For example, in general populations from Mananjary (southeast coast) northward have eight or nine lateral bars (figs. 24A and 31), whereas those from approximately Karianga and Farafangana southward (i.e., from about 22 ° S) have only seven lateral bars (fig. 30). Northern populations seem to differ from central and southern populations in head shape, with northern populations (Maroansetra and northward) exhibiting a more blunt head and less pointed snout (and generally more rounded and disk-shaped body) (fig. 31). The head is noticeably more pointed in populations south of Maroansetra and the Masoala Peninsula (fig. 30). In these populations the snout is generally convex, and there is a prominent indentation posterior to the premaxillary pedicels. In other words, if one looks across the range of P. polyactis anatomical differences between various populations are evident (in both juveniles and adults); however, there is no clear geographic break where the various morphotypes align. Clearly more data (in particular molecular phylogenetic studies) are needed regarding population structure of P. polyactis throughout its extensive range along the eastern coast of Madagascar before any hypotheses of species boundaries can be tested.
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