Irregular Rows Research Articles

A new species of the Cyrtodactylus irregularis complex (Squamata: Gekkonidae) from Gia Lai Province, Central Highlands of Vietnam.

We describe a new species of the genus Cyrtodactylus from Gia Lai Province, Central Highlands of Vietnam based on morphological and molecular differences. Cyrtodactylus gialaiensis sp. nov. is differentiated from other congeners by a unique combination of the following characters: Size small, maximum known SVL reaching 62.8 mm; dorsal pattern consisting of six or seven dark transverse bands between limb insertions; intersupranasals two or three; dorsal tubercles at midbody in 16-21 irregular rows, strongly developed on flanks; lateral folds poorly defined with interspersed tubercles; ventral scales between ventrolateral folds 38-45; precloacal pores nine or 10 in males, eight pitted scales in the adult female, in a continuous row; femoral pores absent; enlarged femoral scales present; postcloacal tubercles two or three; dorsal tubercles present to half of tail; subcaudal scales not enlarged. In molecular analyses, the new species is weakly supported as a member of the Cyrtodactylus irregularis species group with a minimum pairwise genetic distance of 13.7% from others within the group.

On the oviposition and egg masses of Conus regius (Neogastropoda: Conidae) from northeastern Brazil

Abstract Characteristics of the egg masses of Conus regius Gmelin, 1791 are described and figured for the first time for the coast of Brazil based on a female specimen found in the process of oviposition during the day in the state of Bahia, northeastern Brazil. Two clusters of egg masses were found in the subtidal zone of Itapuã beach attached to rocky substrate in a completely unprotected site. Oviposition likely began at least one day earlier, since the specimen had already affixed an entire egg mass and was ovipositing a second cluster at the time it was found. The egg masses were arranged in short, irregular rows of three to nine closely spaced capsules in parallel and facing the same direction. One egg mass cluster consisted of 34 capsules. Conus regius capsules are semi-transparent, vasiform in side view, higher than broad and have flattened to slightly convex sides with slight wrinkles constituted by transversal ridges. Conus regius is on the IUCN Red List of Threatened Species, but is still intensively collected in the study area and surrounding coastal environment by fishermen for the purposes of selling shells and as a food source.

New record of the golden grouper Saloptia powelli (Perciformes: Serranidae) from North Sulawesi, Indonesia

One specimen (300 mm in standard length) of Saloptia powelli, belonging to the family Serranidae, was newly collected in a local fish market in Manado, North Sulawesi, constituting a new record for the species in the Indonesian archipelago. This species was diagnosed by the following morphological traits: dorsal rays VIII—11, anal rays III—8, well-defined opercular spines, pelvic fins below pectoral fins, caudal fin emarginate, mouth moderate in size, supplemental maxillary present, fine teeth in irregular rows on vomer and palatines. Head, body, and fins yellow in color. We suggest “kerapu emas”, a translation of its existing common name “golden grouper”, for the Indonesian species names.

Morphology of immature stages of flesh flies, Boettcherisca nathani and Lioproctia pattoni (Diptera: Sarcophagidae)

The flesh flies are medically-important because the larvae found in the human corpses can provide evidence in forensic investigations through larva identification and their developmental rate. Firstly, we thoroughly described the larval morphology of Boettcherisca nathani and Lioproctia pattoni, using scanning electron microscopy (SEM). The third instar of the two species differed markedly in two characters: (1) spines between the prothorax and mesothorax−B. nathani has more or less slender triangular spines, with those at the posterior region more slender than the anterior region; whereas L. pattoni has stout triangular spines with one or two tips anteriorly, with smaller and tapered triangular shape, grouped two to four laterally in the posterior end, and (2) morphology of the peristigmatic tufts at the posterior spiracle−B. nathani has extensively branched long, fine hairs, whereas tufts in L. pattoni have moderately branched long, fine hairs. The anterior spiracle displayed similarity; B. nathani has two irregular rows of 21–27 papillae, while L. pattoni has a single irregular row of 20–28 papillae. Secondly, we use light microscopy to compare morphology of the third instar of the two species and additional three species, i.e., Bercaea africa, Parasarcophaga dux and Liopygia ruficornis. Particular attention was paid to the features of anterior spiracle, spines between prothorax and mesothorax and posterior spiracle. These results are useful in species identification and estimation of age of larvae found associated with corpses.

A new species of Trichomycterus (Siluriformes: Trichomycteridae) from the upper río Magdalena basin, Colombia

Trichomycterus tetuanensis, new species, is described from the río Tetuan, upper río Magdalena basin in Colombia. The new species is distinguished by its margin of caudal fin conspicuously emarginate, in combination with a high number of opercular odontodes (21-39), reflected externally in the large size of the opercular patch of odontodes, 3 irregular rows of conic teeth in the upper jaw, 42-52 interopercular odontodes, 8 branchiostegal rays, 37 post Weberian vertebrae, 7 branched pectoral-fin rays, hypural 3 separated from hypural plate 4+5, and background coloration light brown with darker dots uniformly sparse on dorsum and sides of trunk. Some apomorphic characters informative for the phylogenetic affinities of the new species within Trichomycterus are discussed.

A new species of karst-dwelling bent-toed gecko (Squamata: Gekkonidae)from Khammouane Province, central Laos.

We describe a new species of the genus Cyrtodactylus from Khammouane Province, central Laos based on morphological features and molecular data. Morphologically, Cyrtodactylus bansocensis sp. nov. is differentiated from other congeners by a unique combination of the following characters: medium size, SVL reaching 74.0 mm; dorsal pattern consisting of four light transverse bands between limb insertions; supranasals in contact with each other; dorsal tubercles at midbody in 14-15 irregular rows; lateral folds present without interspersed tubercles; ventral scales between ventrolateral folds 34-35; precloacal and femoral pores in males 34, separated by four poreless scales in the male holotype and in a continuous row in the male paratype; enlarged femoral and precloacal scales present; postcloacal tubercles 5-7 on each side; dorsal tubercles present at tail base; and subcaudal scales transversely enlarged. Molecular analyses revealed the new species to be closely related to Cyrtodactylus rufford, which is also found in Khammouane Province.

Prologue as Part of the Body

Prologue as Part of the Body Anna Journey (bio) "Guess how I spent my Halloween?" Captain Morgan asked me over the telephone. I hadn't heard his voice in nearly five years. He spoke as fast as one of his humming tattoo guns. "I spent it in a graveyard," he said, "in Salem, Massachusetts, drinking wine beside a pond with a Croatian witch!" I told him I wasn't surprised to hear it. The last time we'd talked, Captain Morgan had sent me the text message, "Thinking of you," beneath a photograph of a granite headstone engraved with my own last name. Five years ago, a nineteenth-century graveyard in Richmond, Virginia, had brought us together. He: an artist about to leave Richmond to open a tattoo parlor in Nashville. Me: a poet fleeing a breakup in Houston and a falling out with a close friend, Lee. I believed returning to Richmond—the city in which I'd lived for most of my twenties—and renting an apartment on the grounds of my favorite cemetery would help me recover. I could get by on funds from a recent literary grant and write poems all day, I thought, gazing into a landscape of rest. Captain Morgan had posted an ad online for the one-bedroom he needed to abandon due to his new plans: a spacious ground-floor unit in the cemetery's former caretaker's house—that grand lavender Victorian trimmed in ivory paint just inside Hollywood Cemetery's wrought-iron front gate. As I scrolled through the rental listings, I recognized the house immediately. Amid the thorny evergreens and leaning headstones, the mansion resembled an iconic haunted house, replete with gothic spires, bay windows, scarlet drapes, and wraparound porch. When Captain Morgan opened the door of the apartment to give me a tour, his arms and neck poked from his T-shirt. My eyes moved over his tattooed skin swirled in dense sleeves of ink. _______ I lived for three years with Carrick in our narrow brick row house on South Cherry Street, three blocks away from Hollywood Cemetery. The [End Page 112] graveyard, designed in 1847 and landscaped in the "rural style," rises on one side of the James River in a sprawl of grassy hills and foot paths clustered with its namesake's deep green holly trees, gnarl-kneed magnolias, bark-sloughing sycamores, and three-story cedars that smell like cookie dough after the rains. Between trees tilt irregular rows of ivy-draped headstones: grey or rose-pink granite and strange white soap-stones carved to mimic vine-shrouded oak stumps. My favorite graves: a pair of horizontal ledger slabs marking a married couple, Jonathan and Winnifred (I called them "Johnny and Winnie"), enclosed by a low brick wall at the steep riverside edge of the cemetery. The enclave formed a rhombus-shaped balcony overlooking the parallel lines of the railroad tracks below and the James River beyond. I'd nod to Johnny and Winnie, saying hello if no one else was around, and then hoist myself up to perch on the far wall and watch a coal train that idled beneath my feet or peer at clusters of sunbathers sprawled on flat rocks on Belle Isle across the river. Sometimes the wallop of bongo drums pulsed downwind. Hollywood Cemetery houses an eclectic mix of regional skeletons, including a number of major figures of the Civil War-era South: Jefferson Davis, President of the Confederacy; twenty-five Confederate generals, such as J.E.B. Stuart; a number of victims of the November 1918 influenza epidemic; Virginius Dabney, editor of the Richmond Times Dispatch (now nicknamed the Richmond Times Disgrace), who wore sharkskin trousers and won a Pulitzer for his work championing civil rights; the suffragette Lila Meade Valentine; James Monroe, the fifth president of the United States, whose tomb juts up from the middle of a sort of gazebo-sized, iron birdcage; and the Irish schoolteacher William Burke, who tutored the teenaged and not yet famous Edgar Allan Poe. In the middle of the graveyard sit several horseshoe-shaped "whispering benches" of cool white marble designed with concave backs that amplify and channel echoes. This way...

Multi-period activity, the European Marine Science Park, Dunstaffnage, Argyll

Excavation in advance of development of the European Marine Science Park at Dunstaffnage in Argyll (NGR: NM 87878 34063) revealed multi-phased activity from the Neolithic into the Early Historic period. An irregular row of firepits, interpreted as funerary pyres, was orientated east–west and incorporated an infant inhumation and a cobble path. Dating of charcoal revealed that the fire-pits were probably in use for a number of generations during the Late Iron Age. The fire-pits were located on the edge of wet ground and it is postulated that these were deliberately located on what may have been perceived as a liminal boundary to aid passage into the afterlife. Activity shifted to the drier ground in the Early Historic period, late 7th to 9th century, in the form of an extended farmstead within which barley and oats were being dried in a kiln. Evidence for possible barns and/or houses survives in the form of a post-hole structure, a post-built wattle and daub structure, at least one basket pit boiler and a number of cobble hearths. One pit contained ten metal artefacts thought to be derived from agricultural implements or a dismantled structure. The duration of use of the farmstead appears to have been relatively short and it may have been seasonally occupied.

A new species of Cyrtodactylus (Squamata: Gekkonidae) from the limestone forest of Khammouane Province, central Laos.

We describe a new species of the genus Cyrtodactylus on the basis of three specimens from Khammouane Province, Laos. Cyrtodactylus soudthichaki sp. nov. is distinguished from the remaining congeners by the combination of the following characters: adult SVL 69.2-70.0 mm; dorsal head and neck with dark blotches; nuchal loop present; dorsum with five brown bands between limb insertions; 19 or 20 irregular rows of dorsal tubercles; 32 or 33 ventral scale rows; ventrolateral folds present, with distinct tubercles; dorsal surface of hind limbs with tubercles; 29 precloacal and femoral pores in a continuous row in males, precloacal pores absent in the female; enlarged femoral and precloacal scales present; 4 or 5 postcloacal tubercles; and subcaudals transversely enlarged. The new species most closely resembles Cyrtodactylus jaegeri and Cyrtodactylus roesleri in overall coloration and pattern. However, they can be clearly distinguished from each other in the number of dorsal tubercle rows, ventral scales, and femoral and precloacal pores. Cyrtodactylus soudthichaki is the 16th species of Cyrtodactylus known from Laos.

Lithobius (Ezembius) laevidentata sp. n., a new species (Chilopoda: Lithobiomorpha: Lithobiidae) from the Northwest region of China

Abstract Lithobius (Ezembius) laevidentata sp. n. (Lithobiomorpha: Lithobiidae), discovered from Barkol Kazak Autonomous County, Hami City, Xinjiang Uygur Autonomous Region, Northwest region of China, is described. Morphologically it resembles L. (E.) bilineatus Pei, Ma, Zhu & Gai, 2014. from Guangxi Zhuang Autonomous Region, China, but can be readily distinguished from the latter by 8–10 ocelli arranged in 3 irregular rows, Tömösváry’s organ subequal in size to the adjoining ocelli, female gonopods with 3–4 spurs, and the terminal claw of the third article of female gonopods simple. A key to Chinese Lithobius (Ezembius) species is presented.

A New Species of Phoenicopsis Subgenus Windwardia (Florin) Samylina (Czekanowskiales) from the Middle Jurassic of Inner Mongolia, China

AbstractA new species of Phoenicopsis subgenus Windwardia (Florin) Samylina, Phoenicopsis neimengguensis sp.nov., is recognized from the Middle Jurassic Zhaogou Formation in the Shiguai Basin, a Jurassic coal‐bearing sedimentary basin in Inner Mongolia, China. Linear leaves are in bundles of six to eight and are attached on a short shoot. The leaf is amphistomatic with one or two irregular rows of longitudinally oriented stomata in each intercostal zone on the upper epidermis and three or four (occasionally six) rows of stomata in each intercostal zone on the lower epidermis. Each stomata is surrounded by four to six subsidiary cells with unevenly developed papillae. The anticlinal walls of epidermal cells are straight. Cuticular thickenings or papillae are present on the outer surface of the periclinal walls. This is the first time that Phoenicopsis subgenus Windwardia (Florin) Samylina is recognized from the Middle Jurassic of Inner Mongolia, China. The occurrence of the new species is noteworthy because it extends the geological and geographic distribution of Phoenicopsis subg. Windwardia in China and Eurasia. The discovery is significant as it increases our knowledge of Phoenicopsis subg. Windwardia by providing new data on morphological and epidermal features.

Three new monotypic genera of Trichopolydesmidae from Croatia, Balkan Peninsula (Diplopoda, Polydesmida).

Three new monotypic genera are described from underground habitats in Croatia: Balkanodesmus biokovensis gen. n., sp. n., Solentanodesmus insularis gen. n., sp. n. and Velebitodesmus cavernicolus gen. n., sp. n. In all three new genera the prefemoral part of the gonopods is orientated transversely to the main body axis, and all three new genera possess numerous metatergal setae arranged in a few transverse irregular rows, a condition observed in several European trichopolydesmids. These three new genera are very close to the genus Verhoeffodesmus. A distribution map and a brief discussion about the relationship with congeners are provided.

Parapercis nigrodorsalis (Perciformes: Pinguipedidae), a new species of sandperch from northern New Zealand and the Norfolk Ridge, Tasman Sea and remarks on P. binivirgata (Waite, 1904).

A new species of pinguipedid fish, Parapercis nigrodorsalis, is described from 17 specimens collected off the North Island of New Zealand and Wanganella Bank, Norfolk Ridge, Tasman Sea, in depths of 56-280 m. The species has also been photographed underwater off the Poor Knights Islands Reserve and Burgess Island, Mokohinau Group, in New Zealand. It is most similar to Parapercis binivirgata (Waite, 1904) in morphology, coloration and meristic values, but is unique among the genus in having a combination of dorsal-fin rays V, 23, anal-fin rays I, 19, lateral-line scales 57-63, vomer with 1-2 irregular rows of robust conical teeth, palatines with 1-2 rows of small teeth, angle of subopercle smooth, 10 abdominal and 22 caudal vertebrae, and coloration, including seven broad reddish-brown bands on the upper body between the spinous dorsal-fin and the caudal peduncle, most bands bifurcated into close-set double bars with black smudge-like blotches below, and membrane of the spinous dorsal fin black. Comparison of the mitochondrial cytochrome c oxidase subunit 1 (CO 1) genetic marker utilised in DNA barcoding produced a genetic divergence of 5.38% and 7.63% between the new species and its two closest sampled congeners. The holotype of P. binivirgata is identified from two specimens previously regarded as syntypes, some revisions are made to meristic data in the original description of the latter, and a detailed description of the revised geographic range of P. binivirgata is provided.

Morphology and phylogenetic analysis of two oxytrichid soil ciliates from China, Oxytricha paragranulifera n. sp. and Oxytricha granulifera Foissner and Adam, 1983 (Protista, Ciliophora, Hypotrichia).

The morphology and infraciliature of two hypotrichous ciliates, Oxytricha paragranulifera n. sp. and Oxytricha granulifera Foissner and Adam, 1983, collected respectively from the surface of a sandy soil in the Huguang mangrove forest, Zhanjiang, China, and the surface of soil in a forest beside Ziwu Road, Xian, north-west China, were examined. O. paragranulifera n. sp. is characterized by an elongate body with slightly tapered anterior end, two macronuclear nodules and two micronuclei, paroral and endoral in Stylonychia-pattern, colourless cortical granules distributed in clusters or irregular short rows, adoral zone occupying 37 % of the body length, marginal rows almost confluent posteriorly, six dorsal kineties and three caudal cirri, caudal cirri and dorsal bristles almost indistinguishable when viewed in vivo. The well-known O. granulifera Foissner and Adam, 1983 was also redescribed and can be separated from the novel species by having cortical granules arranged along dorsal kineties and marginal rows on both sides (vs grouped in clusters as well as in short irregular rows), paroral and endoral in Oxytricha-pattern (vs in Stylonychia-pattern), macronuclear nodules obviously detached (vs adjacent) and a non-saline terrestrial habitat (vs saline terrestrial). The separation of these two taxa is also firmly supported by the molecular data, which show a significant difference between the two in their SSU rRNA gene sequences (similarity 97.1 %). Phylogenetic analyses based on SSU rRNA gene sequence data suggest a close relationship within the Oxytrichidae assemblage between O. paragranulifera n. sp. and O. granulifera.

A new species of Lithobius (Ezembius) Chamberlin (Lithobiomorpha: Lithobiidae) from China

A new species of centipede Lithobius (Ezembius) bilineatus sp. nov. (Lithobiomorpha) from Guangxi Zhuang Nationality Autonomous Region, China, is described. Although this new species resembles Lithobius (Ezembius) chekianus Chamberlin and Wang, it can be distinguished in its ocelli situated in two irregular rows versus in three rows, the terminal two ocelli comparatively large versus only the posterior most ocellus large, and in the 15th legs’ plectrotaxy. A key to the species of the subgenus from the Oriental region of China is given. Type material is deposited with the Department of Life Sciences, Hengshui University, Hengshui, China.

Potamotrygon limai, sp. nov., a new species of freshwater stingray from the upper Madeira River system, Amazon basin (Chondrichthyes: Potamotrygonidae).

Potamotrygon limai, sp. nov., is described from the Jamari River, upper Madeira River system (Amazon basin), state of Rondônia, Brazil. This new species differs from congeners by presenting unique polygonal or concentric patterns formed by small whitish spots better defined over the posterior disc and tail-base regions. Potamotrygon limai, sp. nov., can be further distinguished from congeners in the same basin by other characters in combination, such as two to three rows of midtail spines converging to a single irregular row at level of caudal sting origin, proportions of head, tail and disc, patterns of dermal denticles on rostral, cranial and tail regions, among other features discussed herein. Potamotrygon limai, sp. nov., is most similar to, and occurs sympatrically with, P. scobina, and is distinguished from it by lacking ocellated spots on disc, by its characteristic polygonal pattern on posterior disc, a comparatively much shorter and broader tail, greater intensity of denticles on disc, more midtail spine rows at tail-base, and other features including size at maturity and meristic characters. Potamotrygon limai, sp. nov., is also distinguished from other species of Potamotrygon occurring in the Amazon region, except P. scobina, by presenting three angular cartilages (vs. two or one). This new species was discovered during a detailed taxonomic and morphological revision of the closely related species P. scobina, and highlights the necessity for thorough and all-embracing taxonomic studies, particularly in groups with pronounced endemism and morphological variability.

A third new Cyrtodactylus (Squamata: Gekkonidae) from Ba Den Mountain,Tay Ninh Province, southern Vietnam.

We describe the third new species of the genus Cyrtodactylus from Ba Den Mountain, Tay Ninh Province, southern Vietnam based on a type series consisting of eleven specimens. Cyrtodactylus thuongae sp. nov. is distinguished from the remaining Indochinese Bent-toed Geckos by a combination of the following morphological characters: size medium, with a maximum SVL of 77.6 mm; dorsal pattern consisting of blotches between limbs and on occiput and a sometimes medially opened nuchal loop; dorsal tubercles in 16-18 irregular rows; ventrals in 29-44 longitudinal rows at midbody; lateral skin folds present, lacking tubercles; femoral pore series separated from precloacal pore series in males, 0-3 on each side; precloacal pores in males absent or only one; enlarged femoral scales and precloacal scales present, separated by a series of 15-16 smaller scales; postcloacal spurs two or three; subcaudal scales slightly enlarged. This is the 32^nd described Cyrtodactylus species from Vietnam.

A new species of Cyrtodactylus (Squamata: Gekkonidae) from Khammouane Province, Laos.

We describe a new species of the genus Cyrtodactylus based on two adult specimens from Khammouane Province, Laos. Cyrtodactylus jaegeri sp. nov. is distinguished from the remaining Indochinese bent-toed geckos by a combination of the following characters: a moderately sized Cyrtodactylus with a maximum SVL reaching 68.5 mm; dorsal pattern consisting of a dark nuchal loop and four narrow brown body bands between limb insertions; dorsal tubercles in 15-17 irregular rows; ventrals in 31-32 longitudinal rows at midbody; lateral skin folds present with interspersed tubercles; precloacal-femoral pores 44 in the male, in a continuous series; enlarged femoral scales and precloacal scales present; postcloacal tubercles 3-6; subcaudals transversely enlarged. Cyrtodactylus jaegeri sp. nov. is the ninth species of Cyrtodactylus known from Laos.

The genus Rhadinorhynchus (Acanthocephala: Rhadinorhynchidae) from marine fish in Australia with the description of four new species.

Species of Rhadinorhynchus, collected from Australian waters were examined. Specimens of Rhadinorhynchus from Scorpis aequipinnis, Girella tricuspidata, Johnius australis and Grammatobothus polyophthalmus could not be identified further. New host and locality records are reported for R. bicircumspinus found in Trachurus declivis and Rexea solandri from the east coast of Tasmania; R. carangis found in Trachinotus bailonii and T. copperingi from Queensland and Western Australian coasts; R. polynemi from Queensland; R. seriolae found in Seriola lalandi from the east coast of Australia. An immature female specimen of R. johnstoni provided no additional data on the species. Rhadinorhynchus biformis sp. nov., described from Pelates quadrilineatus and a trumpeter from Moreton Bay, Queensland differs from all its congeners in the pattern of the trunk spines, a single field of numerous small spines ventro-laterally, overlapping with irregular rows and circles of larger spines extending posteriorly. Rhadinorhynchus pichelinae sp. nov. described from Upeneichthys vlamingi from Point Peron, Western Australia differs from all its congeners in having proboscis armature of 10 longitudinal rows of 24-28, usually 26-27 hooks up to 87 long and a single field of 21-24 irregular circles of spines on the anterior trunk, with the posterior circles incomplete dorsally. Rhadinorhynchus polydactyli sp. nov. described from Polydactylus sp. from Moreton Bay is differentiated from all congenerics by the elongated neck of the females and having a proboscis armature of up to 34 hooks in 10 longitudinal rows. Rhadinorhynchus pomatomi sp. nov. found in Pomotomus saltrix differs from its most similar congeners, those without dorsal trunk spines, in having a proboscis armature of 12-15 rows of 20-22 hooks up to 73.5-80.5 long. Rhadinorhynchus bicircumspinus, R. biformis, R. pichelinae, R. polydactyli and R. pomatomi are known only from Australian waters while R. carangis and R. seriolae are also known from Japanese waters, R. johnstoni from the western Pacific and R. polynemi from the Indian coast.

A New Species ofArapaima(Osteoglossomorpha: Osteoglossidae) from the Solimões River, Amazonas State, Brazil

A new species of Arapaima has been discovered from the central Amazon of Brazil. This new taxon is readily distinguished from all other Arapaima by the following three characters: 1) dorsalmost lateralis sensory cavity on preopercle extremely slender (vs. broadly oval or nearly rectangular in other nominal taxa); 2) ventrolateral margin of head where third infraorbital meets anterior limb of preopercle strongly angled such that ventral surface of head is almost flat (vs. ventrolateral margin of head relatively rounded); and 3) anterior third of dorsal-fin base covered with an enlarged, thickened sheath that hides anterior dorsal-fin rays when adpressed (vs. no thickened sheath on anterior base of dorsal fin and anterior dorsal-fin rays visible when adpressed). Distinguished from all other Arapaima except A. agassizii by having extremely long fourth infraorbital. Distinguished from A. arapaima and all other examined non-type specimens by notably slender body (the holotypes of A. gigas, A. mapae, and A. agassizii also have slender bodies). Further distinguished from A. mapae and A. agassizii by having relatively deep caudal peduncle (6.0% SL, vs. ∼4.0% in latter two taxa), and from A. gigas by having dentary teeth in a single row (vs. dentary teeth in 2–2.5 irregular rows). This species was collected near the confluence of the Solimões and Purus rivers in Amazonas State, Brazil. It is the first new species of Arapaima to be described since 1847, and comparisons with Arapaima from Mamirauá Reserve demonstrate that there are at least two species of Arapaima present in Amazonas State.