Paracanthopoma vampyra, Pinna & Dagosta, 2022

Pinna, Mário de & Dagosta, Fernando Cesar Paiva, 2022, A taxonomic review of the vampire catfish genus Paracanthopoma Giltay, 1935 (Siluriformes, Trichomycteridae), with descriptions of nine new species and a revised diagnosis of the genus, Papéis Avulsos de Zoologia 62, pp. 1-90 : 70-74

Paracanthopoma vampyra , new species ( Fig. 42 )

Holotype: MZUSP 86953 , 14.6 mm SL, Brazil, Amazonas , Rio Preto da Eva , Igarapé Sucuriju (trib. to rio Preto da Eva) (approx. 02°44′S, 59°33′W), col., M. de Pinna, L. PyDaniel & L. Sousa, 14 Aug 2004.

Paratypes: All from Brazil: MZUSP 100137 , 4 ex, 14.3-18.1 mm SL, Amazonas , Rio Preto da Eva , Igarapé Sucuriju , ao lado do Sítio Bom Jesus, estrada Francisca Mendes, km 13 (02°45′15.8″S, 59°37′29.6″W), col., O. Oyakawa et al., 04 Jul 2003 ; MZUSP 100138 , 3 ex, 20.8-22.7 mm SL, Amazonas , Rio Preto da Eva , stream tributary to rio Preto da Eva, after the Encanto da Mata beach complex (02°37′10.2″S, 59°44′30.5″W), col., MZUSP team, 09 Jul 2003 ; MZUSP 103049 , 11 ex (2 c&s), 12.8-14.7 mm SL, collected with holotype .

Non-type specimens: BRAZIL: INPA 28601 , 6 ex (1 c&s, 1 ex decapitated), 16.6-17.7 mm SL, Amazonas, Rio Preto da Eva , unnamed creek at km 10 of Ramal Francisca Mendes ; INPA 29572 , 5 ex (1 c&s) 13.1-16.0 mm SL, Pará, Porto Trombetas, Igarapé at Platô Aviso ( rio Trombetas drainage) ; INPA 31306 , 15 ex (2 c&s), 13.1-17.0 mm SL, Pará, Porto Trombetas, rio Trombetas at Araticum, col., INPA team, 10 Aug 2008 ; INPA 31551 , 9 ex (2 c&s, 1 head SEM), 14.4-16.9mm SL, Amazonas, Presidente Figueiredo, stream crossing "Ramal da Morena″ (a local dirt road) ( rio Uatumã drainage), col., INPA team, 13 Dec 2007 ; LIRP 7410 , 3 ex, 13.4-14.6 mm SL, Roraima, Boa Vista, Igarapé Au-Au (trib. to rio Cauamá , rio Branco drainage), under bridge of road RR-205 (02°56′19″N, 61°03′03″W), col., M. Carvalho & A. Datovo, 12 Feb 2007 ; LIRP 12693 , 26 ex, 10.3-16.9 mm SL, Roraima, Caracaraí, Igarapé Água Boa , under bridge on road BR-210 (01°57′01″N, 61°14′38″W), col., A. Datovo & M. Carvalho, 22 Feb 2007 ; MCP 36220 , 14 ex, 11.4-16.0 mm SL, Amazonas, rio Traíra (rio Madeira drainage), ca. 35 km E of rio Madeira by Transamazônica road (07°35′33″S, 62°44′45″W), col., R. Reis et al., 27 Jul 2004 ; MZUSP 105740 , 2 ex, 15.0- 15.3 mm SL, Pará, village of Igarapé Miri, Igarapé Macajateua (trib. to rio Moju ) (01°57′51″S, 48°54′18″W), col., M.M.F. Marinho and D.A. Bastos, 09 Apr 2010 ; MZUSP 117521 , 1 ex, 12.6 mm SL, Amazonas, Tributary of rio Aripuanã, Apuí (07°11′10.1″S, 59°50′01.4″W) . VENEZUELA: MBUCV-V 29226 , 3 ex, 16.1-20.3 mm SL, Amazonas, río Corocoro (tribut. to río Ventuari, Orinoco system), beach on río Corocoro , 30 min downstream from Yutaje (05°37′N, 66°08′W). col., S. Schaefer and S. Provenzano, 27 Apr 1999 ; MBUCV-V 29351 , 1 ex, 18.8 mm SL, Amazonas, río Corocoro (tribut. to río Ventuari, Orinoco system), río Corocoro at campamiento Yutaje, col., S. Schaefer and F. Provenzano, 28 Apr 1999 .

Diagnosis: Distinguished form all congeners except Pc. alleynei by four to six scalpelloid teeth (decreasing in size laterally) stacked in parallel at the distal end of the premaxilla (vs. scalpelloid teeth one or two, equal in size when two); by the presence of one or two conical teeth on the premaxilla (inserted basally relative to distal scalpelloid teeth) (vs. no conical teeth on premaxilla); by the long and ventrally-flat, almost spatulate, snout (vs. snout not pronouncedly spatulate); and by the presence of 11 median premaxillary teeth (vs. either three to nine or 13 and more). Distinguished from Pc. alleynei by the truncate or convex caudal fin (vs. bilobed or concave); by the more numerous procurrent caudal-fin rays (22 to 27 dorsal and 21 to 25 ventral) forming prominent expansions along most of caudal peduncle which as a consequence is spatulate in shape (vs. 14 to 19 procurrent rays dorsally and ventrally, forming inconspicuous expansions only on posterior half of caudal peduncle); by the pectoral fin pointedly triangular in specimens 15 mm SL or larger, with rays steeply decreasing in size posteriorly (vs. fin broadly triangular, with rays approximately with same size, or only slightly longer anteriorly); by the angulate mesethmoid cornua (vs. mostly round); by the shorter and thicker distal ramus of the premaxilla, shorter than the proximal ramus (vs. distal ramus longer than the proximal one; cf., Figs. 4L , 43 ); by the median premaxilla broader than long (vs. as broad as long); by the shorter snout (35.3-37.6% HL, vs. 39.3-43.1); by the presence of 40-42 vertebrae (vs. 38 or 39); and by the fewer principal caudal-fin rays (5 + 6 or 6 + 6; vs 6 + 7).

Description: Morphometric data for the holotype and paratypes are provided in Table 13 . Body moderately elongate (HL 5 to 5.3 times in SL). Cross-section of body slightly broader than deep at pectoral-fin insertion and increasingly compressed posterior to that point, tapering to caudal fin. Dorsal profile of body gently convex from head to origin of dorsal fin ( Fig. 42 ). Dorsal and ventral profiles of caudal peduncle strongly convex posterior to dorsal and anal fins, spatulate, expanded by procurrent caudal-fin rays. Ventral profile of body straight at pectoral-fin base and then gently convex until pelvic-fin origin, with some specimens with greatly distented abdomens due to gut contents. Myotomes and longitudinal skeletogenous septum clearly visible through thin integument along whole body. Axillary gland very large, elongate in shape, protruding markedly on surface of body when full with secretion. Anterior end of gland surrounding dorsoposterior, ventral and posterior margins of muscular pectoral-fin base, as thick corselet, extending posteriorly to beyond margin of adpressed pectoral fin. Gland tapering to fine posterior tip, extending along limit between hypaxial musculature and abdominal cavity, its large round or oval pore located at its anterior portion, approximately at vertical through anterior third of pectoral- fin length. Condition of gland posterior to pore evidently related to amount of secretion stored.

Dorsal profile of head continuous with that of dorsum,its origin sometimes indicated by slight constriction of anterior end of epaxial musculature ( Fig.42 ).Head longer than broad,snout broad, parabolic with a continuous round anterior margin. Head muscles not entering skull roof. Head depressed (head depth approximately 58% of head width) with dorsal profile gently convex, nearly straight, to tip of snout. Ventral profile of head straight, flattened. Eye large ( Fig. 42 ), without free orbital rim, located dorsolaterally on head and directed dorsolaterally, with pronounced lateral component. Integument over eye thin and transparent. Middle of eye slightly anterior to middle of HL, interorbital width approximately 70% of longitudinal diameter of eye. Eyelens large, constricted by iris only marginally, with large round or oval pupil, in specimens examined. Anterior nostril small, surrounded by short tubule of integument produced posteriorly into small pointed process, with double elastin cores. Anterior internarial width slightly larger than interorbital. Posterior naris slightly larger than anterior one, roundish or triangular in shape, adjacent to mesial margin of eye and partly occluded by anterior flap of integument. Anterior margin of posterior naris posterior to transverse line through anterior margin of eyes. Posterior internarial width narrower than interorbital and slightly larger than diameter of one nostril.

Opercular odontodophore medium-sized and elongate, dorsolaterally located on head, on dorsal half of head depth in lateral view, anterodorsally to pectoral-fin base. Opercular odontodes 10 or 11, closely positioned in four irregular vertical rows of two to four. Main axis of opercular odontodes oriented horizontally in lateral view, with distal portions of larger posterior ones curved dorsoposteriorly. Two or three caps of replacement odontodes interspersed with mature ones. Opercular periodontodal fold well-differentiated but small, extending shortly beyond tips of odontodes. Interopercular odontodophore slightly larger than opercular one, located ventrolaterally on head, immediately ventral to horizontal through origin of pectoral fin, with 8 or 9 odontodes closely positioned in two irregular, partly imbricating, rows. Interopercular odontodes progressiely larger posteriorly. Interopercular odontodophore approximately equidistant between opercular one and eye. Interopercular periodontodal fold of integument well-developed but narrow, roundish, extending shortly beyond tips of odontodes. Epiodontodeal velum thin and transparent, entirely covering odontodes.

Mouth inferior (ventral), strongly flattened ventrally. Each premaxilla with 4 small scalpelloid teeth attached to its distal tip and disposed in peculiar parallel and aligned arrangement, forming comb-like structure in ventral view of cleared and stained preparations ( Figs. 4L ) and CT scan images ( Fig. 43 ). Scalpelloid teeth progressively larger mesially, deeply hidden in labial tissue and impossible to expose in preserved specimens without damaging soft tissue. One or two large conical teeth at angle at midlength of premaxilla, directed posteroventrally, with tip gently curved posteriorly ( Figs. 4L , 43 ). Upper lip very broad, continuous with ventral surface of snout. Median premaxilla large, with 11 teeth disposed in two irregular curved rows, anterior one with three teeth on each side (separated by median gap) and posterior one with two teeth on each side and one in middle ( Figs. 4L , 43 ). All teeth posteriorly oblique to ventral surface of median premaxilla at base and curved further posteriorly at distal pungent portion, those on lateral regions of median premaxilla also with lateral component. Basal portion of all median premaxillary teeth strongly compressed laterally.Three to five replacement tooth caps posterodorsally to mature dentition. Median premaxillary velum absent or very reduced. Hypodontal pad of median premaxilla broad, occupying most of internal surface of upper jaw. Lower jaw narrow, composed mostly of narrow and elongated dentary lobes, often adpressed at midline, round and slightly divergent anteriorly, continuous with mental region posteriorly. Jaw cleft short and strongly directed posteriorly, its lateral portion almost parallel to longitudinal axis. Dentary diastema narrow and well-defined, angulate. Dentary teeth 4, closely packed at mesial end of dentary and disposed as two ventral and two dorsal ones,not exactly aligned ( Figs. 4L , 43 ). Dentary teeth very long, their axis anteriorly-directed at base, but strongly curved dorsally at distal half.

Branchiostegal velum forming large, continuous, round and posteriorly concave, free fold across whole of mental region. Dorsal portion of branchial membrane reaching,but not covering,anterior margin of pectoral-fin base. Branchial openings small, spanning approximately area between ventral margin of opercular odontodophore and mid-depth of interopercular oontodophore. Maxillary barbel long and thin, reaching middle of interopercular odontodophore or beyond in some specimens (shorter in some individuals, but evidently due to damage). Posterior point of its base anterior to vertical through anterior margin of eye in lateral view. Mesial (or ventral) part of maxillary-barbel base inserting directly onto corner of mouth without intervening membranous outgrowth. Rictal barbel small but well-differentiated, located mesially to base of maxillary one and approximately one-fifth of its length. Nasal barbel vestigially represented by posterior elongated portion of fold around anterior naris described above, with double internal elastin core.

Lateral line short and straight, extending alongside dorsal margin of anterior portion of axillary gland. Terminal lateral-line pore immediately dorsal to axillary gland opening. Very short secondary branch splitting off ventrally from proximal portion of main canal, with corresponding pore opening anteriorly to midlength of main canal. Single lateral-line tubule straight, poorly calcified, extending for more than half of main canal posterior to bifurcation.

In individuals 15 mm SL and larger, pectoral fin long, aproximately equal to HL, with pointed shape resulting from steep decrease in fin-ray length posteriorly. First ray extending beyond fin margin in few specimens. Margin of fin irregular at close range. In individuals smaller than 15 mm SL, pectoral fin short (approximately 70% of HL) and round, with similar-sized rays or with first slightly shorter than rest. Pectoral-fin rays i + 5, its base on ventral side of body. Pelvic fin very small, close to each other at base, with i + 4 rays. Pelvic splint present. Origin of pelvics close to origin of anal fin, well anterior to vertical through origin of dorsal-fin, entirely covering anus and urogenital papilla and extending posteriorly to origin of anal fin. Posterior margin of pelvic fin round. Dorsal fin small, elongate, roughly rectangular, with roundish edge and gently convex distal margin. Dorsal-fin rays ii + 6 or ii + 7, plus 5 procurrent ones. Anal fin small, similar in shape to dorsal fin, with ii + 5 rays, plus 4 or 5 procurrent ones. Origin of anal fin at or slightly posterior to vertical through origin of dorsal-fin. Anal fin with same size, slightly smaller or slightly larger than dorsal one. Caudal fin truncate with round edges, slightly convex in most specimens (one specimen with concave fin, apparently from damange), less deep than maximum depth of caudal peduncle. Principal caudal-fin rays 5 + 6 or 6 + 6 (one specimen with 6 + 7, seemingly due to abnormal branchimg pattern). Procurrent caudal-fin rays 22 to 27 dorsally and 21 to 25 ventrally.

Vertebrae 40 (n = 3), 41 (n = 3) or 42 (n = 2). First dorsal-fin pterygiophore subsequent to neural spine of vertebra 21 (n = 2), 22 (n = 4), or 23 (n = 2). First anal-fin pterygiophore subsequent to haemal spine of vertebra 21 (n = 1), 22 (n = 5), or 23 (n = 2). Dorsal-fin pterygiophores 7 (n = 1) or 8 (n = 7). Anal-fin pterygiophores 6 (n = 8). Branchiostegal rays 3 or 4 (5 on one side of one specimen).

Pigmentation in preservative: Most specimens with body almost entirely white. Posterior half of neurocranium with irregular dark brain pigment seen by transparency. Few isolated chromatophores scattered between eyes and nostrils, on opercular odontodophore and anterolateraly to eyes. Small dark spot on dorsal corner of hypural plate. Few specimens with irregular bilateral series of dark spots along dorsal midline, until dorsal fin, and sometimes an irregular row of markings along anterior half of longitudinal skeletogenous septum, until approximately vertical through middle of pelvic fin. One population (INPA 31551) with specimens particularly darkly-pigmented, following pattern above but with dark chromatophores larger and denser than in other samples, resulting in strikingly different superficial aspect.

Etymology: From the Slavic (treated as Latin) wampir, a blood-sucking ghost or demon, and glanis, Greek word for catfish. Used as an adjective.

Geographical distribution: Paracanthopoma vampyra is an eastern Amazon form from Brazil, so far recorded in smaller tributaries to rio Preto da Eva, rio Uatumã, rio Trombetas and lower rio Tocantins ( Fig. 45 ). The occurrence in the latter, rather disjunct from remaining records, indicates that the species is likely to occur more widely than so far recorded.

Remarks: The heavy dark pigmentation on the body of specimens in INPA 31551 distinguishes them from all other available samples of Paracanthopoma vampyra . In fact, they are the darkest form of any Paracanthopoma yet known. They also have slightly shorter snouts on average than those in other samples of Pc. vampyra . Such differences might at first sight be seen as indicative of a distinct species. However, closer examination does not support such conclusion. The dark markings of specimens in MZUSP 31551 actually match the pattern in other populations of Pc. vampyra , differing only in the number and size of dark chromatophores.Besides,specimens intermediate in pigmentation exist in some samples (e.g., MZUSP 31306; see Fig. 44 ). Lot MZUSP 31306 also shows some correlation between intensity of dark pigmentation and size, with largest specimens being darkest and smallest ones almost totally white. Finally, snout length in MZUSP 31551 is only slightly shorter than, and broadly overlaps with, values in other samples of the species. Those facts, plus the lack of any additional discrete differences in internal or external anatomy which might further support specific differentiation, indicate that INPA 31551 is a populational variant of Pc. vampyra .

Figures

Figure 4. Comparative chart of jaws and anterior portion of head of Paracanthopoma species, cleared and stained specimens, ventral views: (A) Pc. ahriman FMNH 105525;(B)Pc.alleynei MZUSP 103052;(C) Pc.cangussu MZUSP 86250;(D)Pc.capeta MZUSP 29154;(E) Pc.daemon MZUSP 95597;(F)Pc.irritans INPA 20529; (G) Pc.malevola MCP 36217;(H) Pc.parva MZUSP 30400;(I) Pc.saci MZUSP 125626; (J) Pc.satanica MZUSP 100149;(K) Pc.truculenta MZUSP 30404;(L) Pc.vampyra MZUSP 100138. Scale bars = 500 μm. Pc.carrapata not shown.

Figure 42. Paracanthopoma vampyra, n. sp., holotype,MZUSP 86953, 14.6 mm SL.Brazil, Amazonas, Rio Preto da Eva, Igarapé Sucuriju.(A) Lateral view of body; (B) Dorsal view of head;(C) ventral view of head.

Figure 43. Paracanthopoma vampyra, holotype,MZUSP 86953,CT scan images of head skeleton,(A) Lateral;(B) Dorsal;(C)Ventral.

Figure 44. Paracanthopoma vampyra, INPA 31551,intraspecific variation inpigmentation pattern.

Figure 45. Map of northern South America showing geographical distribution of Paracanthopoma saci (square); Pc. satanica (5-tip star); Pc.truculenta (dot); and Pc. vampyra (10-tip star). Open symbols represent type localities. Some symbols may represent more than a single locality or lot of specimens.

Tables

Table 13. Morphometric data of Paracanthopoma vampyra. Ranges, mean and SD include holotype. Head subunits were obtained with an ocular micrometer and therefore as projections. Abbreviations: min = minimum value; max = maximum value; n = number of specimens; SD = standard deviation.

	n	holotype	min	max	mean	SD
Standard length (mm)	6	15.14	12.8	22.7	16.7
Percentages of SL
Total length	6	1.1	1.1	1.1	1.1	0.0
Body depth	6	12.1	11.5	14.2	12.6	0.9
Caudal peduncle length	6	20.7	20.1	21.7	20.8	0.8
Caudal peduncle depth	6	8.6	6.9	8.6	8.1	0.6
Predorsal length	6	69.0	69.0	74.2	71.3	2.3
Preanal length	6	69.8	67.9	73.0	70.7	1.8
Prepelvic length	6	62.1	62.1	64.9	63.9	1.1
Dorsal-fin base length	6	10.3	6.3	10.4	8.7	1.7
Anal-fin base length	6	9.5	6.3	9.5	8.1	1.2
Pectoral-fin length	6	17.2	12.3	19.3	15.0	2.8
Head length	6	19.0	19.0	20.2	19.5	0.5
Percentages of HL
Head width	6	65.6	58.3	70.1	65.2	4.0
Head depth	6	37.5	30.1	37.5	33.3	2.7
Pectoral-fin length	6	85.4	56.4	93.8	72.9	14.5
Interorbital	6	12.5	11.5	14.5	12.5	1.1
Eye diameter	6	15.6	14.5	16.1	15.4	0.6
Snout length	6	35.4	35.3	37.6	36.2	0.9
Mouth width	6	14.6	14.6	25.4	21.4	4.4
Anterior internarial width	6	16.7	15.6	17.6	16.5	0.8
Posterior internarial width	6	6.3	5.2	6.3	5.7	0.4