Taxonomic review of Copella (Characiformes: Lebiasinidae) with an identification key for the species

A taxonomic review of Copella is presented based on the analysis of the type material of all nominal species and extensive material from South American drainages. Six out of ten nominal species are recognized as valid: Copella arnoldi, C. callolepis, C. compta, C. eigenmanni, C. nattereri, and C. vilmae. Copella carsevennensis is a junior synonym of C. arnoldi, C. nigrofasciata and ‘Nannostomus’ stigmasemion are junior synonyms of C. callolepis, C. metae is junior synonym of C. eigenmanni, and C. meinkeni is junior synonym of C. nattereri. Species of Copella occur in the rio Amazonas and Orinoco basins, and coastal drainages of Guyana, French Guiana, Surinam, and Venezuela. An identification key is provided.


Introduction
Fishes of the neotropical family Lebiasinidae occur in Central America (Costa Rica and Panama) and all South American countries, except Chile [1]. The family includes 75 valid species [2]. distributed in two subfamilies, Lebiasininae and Pyrrhulininae, and seven genera: Copeina Fowler, Copella Myers, Derhamia Géry & Zarske, Lebiasina Valenciennes, in Cuvier & Valenciennes, Nannostomus Günther, Piabucina Valenciennes, and Pyrrhulina Valenciennes [1]. Members of the family can be recognized by having a rather elongate, cylindrical body, large scales, laterosensory canal of head and body reduced, anal fin short-based, no frontal or parietal fontanels [1], and the absence of the metapterygoid-quadrate fenestra [3].
Examination of a large amount of material of Copella from the Amazon and Orinoco basins, and coastal drainages of Brazil, Guyana, French Guiana, Suriname, and Venezuela, as well as type material of all nominal species, made possible the most-comprehensive taxonomic revision of the genus. A dichotomous identification key and distribution maps are also presented.

Material and methods
Counts and measurements follow Fink & Weitzman [8], with the addition of depth at dorsalfin origin, pectoral to pelvic-fin origin, pelvic to anal-fin origin, and anal-fin base length, measured point to point. Additional meristic data are the first longitudinal scale row on body, the fourth longitudinal scale row, which is the mid-lateral scale series including the first three small scales posterior to opercle, the longitudinal scale rows between dorsal-fin origin and pelvic-fin origin, and longitudinal scale rows between dorsal-fin origin and anal-fin origin. Principal caudal-fin rays include all branched rays plus one unbranched ray in each lobe, following Hubbs & Lagler [9] and Lundberg & Baskin [10]. Teeth and anterior unbranched anal-fin ray counts were taken from clear and stained material (c&s), which was prepared according to Taylor & van Dyke [11]. Count of maxillary teeth of C. vilmae was made on specimens preserved in alcohol by transparency, because insufficient material was available for c&s preparations. Teeth were only counted in adult specimens, since juveniles have fewer teeth that are difficult to detect. Meristics of the holotype of 'Nannostomus' stigmasemion were not taken due to the poor condition of the specimen.
In species descriptions, counts are followed by their frequencies in parentheses. Asterisks indicate counts of holotype, lectotype, or syntypes. Measurements are given as percents of standard length (SL), except for subunits of the head given as percents of head length. Counts of vertebrae were made in c&s specimens and through x-rays. Vertebrae of the Weberian apparatus were counted as four elements and the fused PU1+U1 of the caudal region as a single element. Color in alcohol description does not follow the nomenclature proposed by Weitzman [12] for Nannostomus to avoid problems of homology (the longitudinal mid-lateral stripe on body, defined as "primary stripe", does not seem to correspond to the same melanophore pattern within Copella). In the color in life section, description of colors are based on observation of freshly collected specimens of C. arnoldi, C. eigenmanni, and C. nattereri and on photographs of live specimens for the remaining species. Species citations or characterized in Aquarium magazines are not included in the synonym list, except when the articles contain important taxonomic considerations (e.g. description of Pyrrhulina nigrofasciata).
For sexual determination, the anal-fin inclinator muscle of the last pterygiophore was used. This structure is thicker and inserted more distally in the last anal-fin ray of males than of females of several lebiasinids, especially Copella. This was confirmed by examination of the gonads of one male and one female of Copella arnoldi (MZUSP 105776), C. eigenmanni (MZUSP 81443), C. nattereri (MZUSP 87426), and C. stigmasemion (MZUSP 101933). The anal-fin inclinator muscle is considerably thicker even in early developmental stages of males, before other external secondary sexual features appear, such as dimorphic coloration or elongate fins. Therefore, this structure was used to sex Copella. Due to the impossibility to unambiguously distinguish female and immature males (fem/imm), they were treated together. has similar pattern of external sexually dimorphic features found in other lebiasinids concerning modifications on the anal fin. The rays are anteroposteriorly thickened and longer in males than in females [14], having thickened membranes, and well-developed erector and depressor muscles [16] (Fig 3). Some species of Copella have sexually dimorphic coloration. Other sexual dimorphic features are described in the "Sexual dimorphism" section under species descriptions.
Distribution. Species of Copella occur in the rio Amazonas basin in Brazil, Colombia, Guyana, Peru, and Venezuela, the Orinoco basin in Colombia and Venezuela, and coastal drainages of Guyana, French Guiana, Surinam, and Venezuela. Ecological notes. Copella mostly inhabits still to slow-flowing forest streams and minor tributaries or flooded forest in the wet season. We have also collected specimens in small marginal ponds, poorly connected to main streams, along with species belonging to the family Rivulidae. They are most often found in moderately acid black water, frequently associated with macrophytes and partially submerged plants, where they find food and protection. The species  are usually seen in the water surface along the shoreline of small streams, eating allochthonous food and small insects with their upturned mouth [5]. Copella callolepis and C. nattereri are known to deposit eggs on submerged vegetation, which are guarded by the male during incubation. Copella arnoldi presents a very uncommon reproductive behavior commented under Remarks on this species.
Key to the species of Copella. 1a. Procurrent caudal-fin rays hyaline; darkly pigmented area extending from posteroventral portion of dentary to ventral portion of eye; brilliant white spots usually present on body scales, in live or preserved male specimens. Copella arnoldi (Regan, 1912) Tables 1 and 2 Pyrrhulina filamentosa. -   Diagnosis. Copella arnoldi can be distinguished from all congeners, except some specimens of C. nattereri, by having the procurrent caudal-fin rays hyaline (vs. black). It can be distinguished from C. nattereri by the absence of a black mark on each body scale (vs. presence). Additionally, it is distinguished from all congeners by having a pigmented area extending anterodorsally from ventral tip of the dentary to ventral portion of the eye (vs. absent). Some males of Copella arnoldi are unique among congeners in having brilliant white spots on scales of the third, fourth, fifth, and sixth longitudinal scale rows.
Description. Morphometrics in Table 1, meristics of types in Table 2. Largest examined male 42.3 mm SL, female 32.5 mm SL. Greatest body depth slightly anterior to vertical through pelvic-fin origin. Body cylindrical, slightly compressed laterally. Dorsal profile of body straight or slightly convex from tip of snout to end of supraoccipital, straight or slightly convex from that point to dorsal-fin origin, posteroventrally inclined along dorsal-fin base and straight along caudal peduncle. Ventral profile of body convex from anterior tip of dentary to vertical through anterior margin of orbit, straight from that point to vertical through pectoral-fin origin, slightly convex from that point to pelvic-fin origin, straight from pelvic-fin origin to analfin origin, posterodorsally inclined along anal-fin base and straight along caudal peduncle.
Color in alcohol. Overall ground coloration of body beige. Dark stripe extending from anterior tip of dentary to posterior tip of opercle (Figs 5 to 7). Dark pigmentation extending anterodorsally from posteroventral portion of dentary to ventral portion of eye (Fig 8). Thin predorsal dark stripe, frequently wider over second and third scales. Faint dark pigmentation at base and at posterior border of body scales (Fig 5). Ventral region clear. Small dark blotch behind opercle on males and females. Males with blur dark stripe of variable extension and intensity, extending from opercle to, at most, vertical through end of anal-fin base (Figs 5A-5E, 6A, 7). Dorsal fin with black round spot above smaller white one. Remaining fins hyaline. Pelvic and anal fins usually with dark edge, more intense in males. Some specimens from Surinam and mouth of rio Orinoco with distal portion of first pelvic-fin ray conspicuously black. Some males with brilliant white spots on scales of third, fourth, fifth, and sixth longitudinal scale rows, mainly restricted to median portion of body (Figs 5A to 5C, 6A and 7). Males with very long dorsal fin bearing elongated black spot extending to fin tip. Color in life. Dark stripe extending from anterior tip of dentary to posterior tip of opercle. Upper and lower jaws yellow to pale red. Overall body coloration light brown or beige, ventral portion clear. Fins yellow to orange. Dorsal fin with black spot dorsal to small, white round spot. Some males with brilliant white spots on scales of third, fourth, fifth, and sixth longitudinal scale rows, mainly restricted to median portion of body. Some males with dark stripe extending from opercle to, at most, vertical through end of anal-fin base, of variable intensity. Males with base of dorsalmost rays of upper caudal-fin lobe, and tip of basalmost rays of lower caudal-fin intense red (Figs 6 and 7).
Sexual dimorphism. Males with more numerous maxillary teeth than females (see description above). Pectoral, pelvic, dorsal, and anal fins distinctly longer in males than in females (Fig 9). Tip of pectoral fin sometimes extending beyond pelvic-fin origin in males, but never to that point in females. Tip of adpressed pelvic fin reaching to two-thirds length of caudal peduncle in males, but only to level of anus in females. Tip of adpressed dorsal fin reaching to one-half length of median caudal-fin rays in males, and approximately to one-half length of caudal peduncle in females. Tip of adpressed anal-fin reaching to level of first ventral procurrent rays in males, and to two-thirds length of caudal peduncle in females. Upper caudal-fin lobe longer than lower, especially in males. Sexually dimorphic color pattern described in "Color in alcohol" section.
Behavioral notes. Copella arnoldi is widely known among aquarists by its unique breeding behavior and parental care (see Krekorian & Dunham [28], [29], [30], Krekorian [31]). The male and the female line up side by side at the surface of the water and jump together out of the water, to spawn. Fertilized eggs are laid on the underside of an emergent leaf and the male then splashes them with its tail for about three days until they hatch, hence the popular name "Splash tetra".
Eight individuals of Copella arnoldi, five males and three females (MZUSP 105770), were kept and observed in aquarium. Territoriality was performed by two males, that usually chased other males and displayed parallel to each other, opening their fins and mouths widely. These two males were slightly larger than the others and had extremely long fins. They were more colorful, with more brilliant white spots, and a darker black stripe on body, compared to the other males. The remaining males were smaller, without exuberant coloration, some of them with color similar to the females. Only one of the largest males had access to the mature female, whose abdomen was orange and full of ovocytes. These observations bring the question of whether the differences in coloration among males of Copella arnoldi in the same shoal are somehow related to the hierarchical position in the group. However, this deserves further studies.
Just before lining up to jump out of the water toward the upper glass of the aquarium, the female follows the male, touching her abdomen at the anterodorsal portion of the male several times, swimming agitatedly. This seems to be the same behavior described by Zarske ([35]; fig  30), but interpreted as an attempt of the female to push the male down to the bottom. He proposed such breeding behavior as one of the differences between Copella arnoldi and C. carsevennensis. However, as he pointed out, the couple never spawned to confirm his hypothesis.
Remarks. Regan [20] described Copella arnoldi (rio Amazonas) and C. carsevennensis (Carsevenne, French Guiana = rio Calçoene, coastal drainage of Amapá, Brazil) based on the position of the dorsal fin that would distinguish C. arnoldi by having "the dorsal-fin origin nearer to base of caudal than to head" (vs. "origin of dorsal fin equidistant from head and base of caudal, or a little nearer head"). Géry [5] diagnosed both species also by the number of longitudinal scales (23-24 vs. 26) and Planquette et al. [32] by the presence of a black stripe in a low position on body reaching the level of the anal fin in C. arnoldi contrasting with an uniform coloration, except for the presence of a small stripe that does not surpass the level of the pectoral fin, in C. carsevennensis. Zarske [35] also distinguished Copella arnoldi from C. carsevennensis (Zarske [35]: tab. 8) by occasionally having a black stripe on the anterior half of body (vs. absence), presence of series of brilliant white spots at the posterior half of the body (vs. absence), and having the distal edge of dorsal, pelvic, and anal fins black (vs. fins never with a conspicuous black border). Zarske [35] observed that males of C. arnoldi have two color patterns that could be related to sexual activity (Zarske [35]: figs 15 and 16, 18 and 19). Interestingly, the "sexual inactive" males (Zarske [35]: figs 15 and 19) have the same color pattern of the supposed males of C. carsevennensis (Zarske [35]: figs 28 to 30). Furthermore, some diagnostic features of C. arnoldi (white spots on the posterior half of the body and distal edge of fins black) can be seen in the figure of the supposed C. carsevennensis (see Zarske [35]: fig 30]. In the present analysis, data taken from type and non-type material from several localities in Brazil, French Guiana, Surinam, Guyana, and Venezuela (Fig 36) did not reveal any morphological feature that could effectively separate the two species. Morphometric and meristic data (including those related to dorsal-fin position and longitudinal scale counts) largely overlap among the populations examined. Likewise, no color differences were observed that could justify the maintenance of two names. Indeed, there is color pattern variation in males (see Color in alcohol). However, males with exuberant coloration, presenting a longitudinal dark stripe, having brilliant white spots were syntopically collected with males that have similar coloration of females, and lack dark stripe and white spots on the body. Furthermore, males with intermediate coloration are always present (Fig 5B to 5D). If color variation among males is related to hierarchical position, sexual activity, or environmental influences, this should be further investigated through studies using different approaches. The features presented in the literature to distinguish the aforementioned Copella arnoldi from C. carsevennensis are herein interpreted as variation within a single species. Thus, Copella carsevennensis is considered a junior synonym of C. arnoldi, as previously proposed by Fowler [22].
Zarske [35] stated that the type locality of Copella arnoldi is Ilha do Arapiranga, near Belém, Pará, which according to him is a collecting site area explored by German aquarists in the past. However, this is highly speculative. Based on the distribution of C. arnoldi given as the "Amazon", the only possible inference is that the types might have come from anywhere in the lower Amazon basin.
Eigenmann [18] listed Pyrrhulina filamentosa from several localities in Guyana. One of us (MM) had the opportunity to analyze only part of this material: the paralectotypes of Copeina eigenmanni from the rios Aruka and Lama, and one specimen from rio Demerara, Kumaka (CAS 227312), and were identified as Copella arnoldi, but the identification of the remaining material could not be confirmed.
Kenny [41], Weitzman & Weitzman [1] and Phillip et al. [42] listed Copella arnoldi for Trinidad and Tobago but this could not be confirmed in the present study.
Material examined of Copella arnoldi in S1 Appendix.
Copella callolepis (Regan, 1912)  Copella eigenmanni.-Géry [5]: 141 [misidentification of unnumbered figure pg. 141 labeled "possibly C. eigemmanni"].  Description. Morphometrics in Table 3 and meristics of types in Table 4. Largest examined male 37.6 mm SL, female 30.4 mm SL. Greatest body depth slightly anterior to vertical through pelvic-fin origin. Body cylindrical, slightly compressed laterally. Dorsal profile of body straight to slightly convex from tip of snout to end of supraoccipital, slightly convex from that point to dorsal-fin origin, posteroventrally inclined along dorsal-fin base and straight along caudal peduncle. Ventral profile of body convex to posteroventrally inclined from anterior tip of dentary to vertical through anterior margin of orbit, straight from that point to vertical through Color in alcohol. Overall ground coloration of body beige to brown. Dorsal portion of body dark. Thin predorsal dark stripe, frequently wider over second and third scales. Scales on middorsal portion of body with posterior border dark, forming slight reticulate pattern; some specimens with small dark spot at posterior border of scale on that region (Fig 12). Black stripe extending from anterior tip of dentary to end of caudal peduncle, along fourth and fifth  (Fig 12A and 12B). Rarely, specimens with clear spot also on each scale of third to fifth longitudinal scale rows (Fig 12C). Ventral region of body clear. Dorsal fin with black round spot. Remaining fins hyaline. Pelvic and anal fins usually with dark edge, more intense in males. Some males with distal tip of dorsal fin dark. Some specimens with base of middle caudal-fin rays faint dark. Dorsal and ventral procurrent caudal-fin rays dark, forming black triangle at base of lower caudal-fin lobe. Dorsal procurrent caudal-fin rays hyaline and ventral procurrent caudal-fin rays faint dark in juveniles.
Color in life. Dorsal portion of body beige to gray. Black stripe extending from anterior tip of dentary to end of caudal peduncle, along fourth and fifth longitudinal scale rows (Fig 13A). Black stripe rarely faded (Fig 13B), only on courtship or when frightened (T. Christoffersen,  (1), MPEG 13775 (7), MPEG 15917 (6), MPEG 16249 (6), MPEG 17409 (5), MZUSP 23510 (7), MZUSP 85603 (8) (Fig 13). Rarely, specimens with red spot on each scale of second to fifth longitudinal scale rows. Ventral portion of body white. Fins yellow to orange. Basal portion of dorsal fin red. Some specimens with base of longest upper and lower caudal-fin rays red. Sexual dimorphism. Males longer than females. Males with more numerous maxillary teeth than females (see description above). Pelvic, dorsal, and anal fins longer in males than females (Fig 14). Pectoral fin apparently not sexually dimorphic. Tip of adpressed pelvic fin reaching to base of third branched anal-fin ray in males, and to anterior margin of anus in females. Tip of adpressed dorsal fin reaching caudal-fin base in males and approximately to one-half length of caudal peduncle in females. Tip of adpressed anal-fin reaching level of first ventral procurrent rays in males, and to two-thirds length of caudal peduncle in females. Upper caudal-fin lobe longer than lower, more evident in males.
Distribution. Copella callolepis is known in the Amazon basin from the rio Ucayali and Putumayo drainages in Peru, rio Amazonas and rio Madeira in Brazil, to the Amazon estuary in Pará State, Brazil (Fig 15).
Remarks. The analysis of type material of Copella callolepis revealed that Regan [20] used two distinct species to describe it. One of them (BMNH 1909.4.2.27), although faded colored, has a longitudinal dark band and three longitudinal rows of clear spots on the body. The abdominal region, as well as other remaining portions of body, is devoid of series of black spots characteristic of the spotted tetra C. nattereri (Fig 11A). The other specimen (BMNH 1909.4.2.28) clearly corresponds to the spotted tetra C. nattereri, with clear marks close to the posterior edge of the body scales, posteriorly bordered with dark spots. Hence, Copella callolepis has long been considered synonym of C. nattereri (see synonym list). However, Zarske & Géry [7] erected as lectotype of C. callolepis the specimen from BMNH 1909.4.2.27, linking the name C. callolepis to the species with a black longitudinal band on body, long known as the black-banded C. nigrofasciata. Nannostomus (= Copella) stigmasemion was described by Fowler [43] from the rio Madeira basin near Porto Velho, based on a single juvenile specimen 10.8 mm SL. This specimen was

Lectotype Largest syntype
Dorsal-fin rays ii8 ii8 Pectoral-fin rays i8 i9 Pelvic-fin rays i7 i7 Anal-fin rays iii9 iii9 Predorsal scales 13 12 First longitudinal scale row 12 12 Fourth longitudinal scale row 22 24 Longitudinal scale rows dorsal to pelvic 5 6 Longitudinal scale rows dorsal to anal 5 5 Circumpeduncular scale rows 10 10 Total vertebrae 34 -Meristic data of Nannostomus stigmasemion was not taken due to the poor condition of the material. not cited by Weitzman & Weitzman [1], but inside the jar with the holotype there is a label written by S. Weitzman: "This specimen described by Fowler as Nannostomus stigmasemion is a juvenile of Copella nattereri". Although poorly preserved, it was possible to notice that the specimen is indeed a Copella, not a Nannostomus species. However, it lacks the characteristic pigmentation of Copella nattereri, that is one black spot on each scale; instead it has a black longitudinal band on body (Fig 11B), similar to that present in C. callolepis. This could be confirmed by the drawing of the holotype in the original description ( Fig 11C). Additionally, according to our study, Copella nattereri only occurs near the mouth of the rio Madeira, far from the surroundings of Porto Velho. The only species occurring in the rio Madeira basin near Porto Velho is Copella callolepis. Therefore, C. stigmasemion is herein considered synonym of C. callolepis. Meinken [24] originally described Pyrrhulina nigrofasciata based on three aquarium specimens, two males and one female, said to be imported from the Peruvian Amazon, sent by J. All specimens correspond to the same species referred here as Copella callolepis. By comparing the measurements of a fully grown male and a female (37.2 mm SL and 31.0 mm SL respectively) given by Meinken [24] to the measurements taken from the probable syntypes, most of the data match with those of the male ZMH 1211 (35.8 mm SL) (Fig 11D) and the female ZMH 1212 (29.6 mm SL), which are the largest male and the largest female of the possible syntypes. However, the lot ZMH 1212 is represented by three specimens, more than what Meinken had in his hands. It is not possible to know whether one specimen was incorporated to ZMH 1212 after Meinken's description, but based on the data available, it is most likely that the original syntypes of Pyrrhulina nigrofasciata are those belonging to the ZMH collection.
Thus, according to the analysis of the lectotype of C. callolepis, of possible types of 'Pyrrhulina' nigrofasciata, and of the type of 'Nannostomus' stigmasemion, along with considerable amount of freshly collected material listed herein, we consider them to be conspecific. Following the principle of priority, and that the senior synonym was described before 1899, 'Nannostomus' stigmasemion and 'Pyrrhulina' nigrofasciata are considered junior synonyms of Copella callolepis.
One of the paralectotypes of Pyrrhulina nattereri (NMW 56974), is probably Copella callolepis, but this could not be confirmed due to the poor condition of the material.
Material examined of Copella callolepis in S1 Appendix.
Copella compta (Myers, 1927) [23][24][25]. Males of C. compta can be distinguished from the males of C. vilmae by the absence of rows of conspicuous dark scales irregularly arranged on body (vs. presence); females of C. compta can be distinguished from the females of C. vilmae by the absence of a dark longitudinal band on body (vs. presence). Copella compta is the largest species of the genus, the males reaching 68.9 mm SL and the females 48.1 mm SL (vs. less than 55.5 mm SL and 44.2 mm SL, respectively, in the congeners).
Description. Morphometrics in Table 5 and meristic of holotype in Table 6. Largest examined male 68.9 mm SL, female 48.0 mm SL. Greatest body depth at vertical through pelvic-fin origin. Body cylindrical, slightly compressed laterally. Dorsal profile of body straight or slightly convex from tip of snout to end of supraoccipital, straight or slightly convex from that point to dorsal-fin origin, posterioventrally inclined along dorsal-fin base and straight along caudal peduncle. Ventral profile of body convex from anterior tip of dentary to vertical through anterior margin of orbit, straight from that point to vertical through pectoral-fin origin, straigth to

Dorsal-fin rays ii8
Pectoral-fin rays i9 Pelvic-fin rays i7 Anal-fin rays iii9 Caudal-fin rays - Dorsal fin with black round spot. Pectoral, pelvic, anal, and caudal fins hyaline; distal profile of pelvic and anal fins and tip of largest dorsal-fin rays frequently dark (Fig 16).

Color in life.
Unknown. Sexual dimorphism. Males longer than females. Males with more numerous maxillary teeth than females (see description above). Pectoral, pelvic, dorsal, and anal fins only slightly longer in males than in females (Fig 17). Tip of pectoral fin reaching to vertical through 12 th scale of first longitudinal row in males, and through nineth scale in females. Tip of adpressed pelvic fin reaching to vertical through bases between first and fourth branched anal-fin rays in males, and to anal-fin origin in females. Tip of adpressed dorsal fin reaching to caudal-fin base in males, and approximately to two-thirds length of caudal peduncle in females. Upper caudalfin lobe longer than lower, especially in males. Color pattern differences described in "Color in alcohol" section. Breeding tubercles on head and body of some male specimens.
Remarks. Myers originally described Copeina compta based on the holotype ("type") IU 17693 (now CAS 60496) ( Fig 16A) and two lots of paratypes IU 17694 (now CAS 60497) and MCZ 31568, with no specification of the number of specimens in each lot. The lot SU 18070 has the same data as those cited by Myers and the corresponding specimens are considered paratypes, probably splitted from the original lots after the description. SU 18070 had originally 11 specimens [49] but now there are nine specimens in alcohol (five were analyzed), one c&s, and one transferred to MHNG 2200.038.
Material examined of Copella compta in S1 Appendix.
Copella eigenmanni (Regan, 1912)  Diagnosis. Copella eigenmanni can be distinguished from all congeners by having the middle caudal-fin rays dark (vs. hyaline or with a small dark patch at base of middle caudal-fin rays on Copella callolepis). Additionally, it can be distinguished from C. arnoldi by having the procurrent caudal-fin rays black (vs. hyaline), from C. compta by having 14-15 scales on the first longitudinal scale row (vs. [16][17], from C. nattereri by the absence of a black spot on the posterior portion of each body scale (vs. presence), from C. callolepis by the absence of a series of conspicuous clear spot on each scale of the fourth longitudinal scale row (vs. presence), from males of C. vilmae by the absence of discontinuous longitudinal series of dark scales on body (vs. continuous), and from females of C. vilmae by the absence of a small dark spot at the base of the upper caudal-fin lobe (vs. presence).
Description. Morphometrics in Table 7 and meristics of types in Table 8. Largest examined male 56.4 mm SL, female 44.2 mm SL. Greatest body depth slightly anterior to vertical through pelvic-fin origin. Body cylindrical, slightly compressed laterally. Dorsal profile of body straight to slightly convex from tip of snout to the end of supraoccipital, straight to slightly convex from that point to dorsal-fin origin, posteroventrally inclined along dorsal-fin base, and straight along caudal peduncle. Ventral profile of body convex from anterior tip of dentary to vertical through anterior margin of orbit, straight from that point to vertical through pectoralfin origin, slightly convex from that point to pelvic-fin origin, straight from pelvic-fin origin to anal-fin origin, posterodorsally inclined along anal-fin base and straight along caudal peduncle.  Color in alcohol. Overall ground coloration of body beige to brown. Dark stripe from anterior tip of dentary to posterior tip of opercle. Dorsal portion of body dark. Thin dark stripe at predorsal region. Anterior portion of scales of third to sixth longitudinal scale rows dark, with apparently subjacent dark coloration on posterior portion of scales on fourth and fifth longitudinal scale rows of variable intensity, frequently forming conspicuous longitudinal dark band (Fig 20). Some specimens with longitudinal conspicuous clear stripe at third longitudinal scale row, contrasting with conspicuous dark band on fourth and fifth longitudinal scale rows, from opercle to caudal peduncle, (Fig 20B); some specimens with clear stripe on third longitudinal scale row and dark spots on anterior portion of scales of third to sixth longitudinal scale rows (Fig 20D and 20E); and some individuals with intermediate color pattern, with clear stripe on third longitudinal scale row, dark spots on anterior portion of third to sixth longitudinal scale rows, and subjacent, not conspicuous, dark band on fourth and fifth longitudinal scale rows (Fig 20A and 20C). Ventral region of body clear. Dorsal and ventral procurrent caudal fin rays black. Dorsal fin with black round spot; some males with tip of dorsal fin dark. Pectoral, pelvic, anal, and caudal fins hyaline; distal profile of pelvic and anal fins usually dark. Middle caudal fin rays dark, fading toward tips of rays.
Color in life. Dorsal portion of body gray. Upper portion of eye orange. Body with variable color pattern (see Color in Alcohol). Specimens with longitudinal black band on fourth to fifth longitudinal scale rows with conspicuous metallic gray to purple band above it, on third row,  (10) Taxonomic review of Copella and metallic green coloration mid-dorsally on caudal peduncle ( Fig 21A); specimens without longitudinal black band with lighter metallic grey to purple band on third row, and red pigmentation on fourth and fifth longitudinal scale rows on caudal peduncle (Fig 21B). Fins yellow to orange. Pink spot at dorsal-fin base and upper and lower portions of caudal fin lobes. Sexual dimorphism. Males longer than females. Males with more numerous maxillary teeth than females (see description above). Pectoral, pelvic, dorsal, and anal fins only slightly longer in males than in females. Tip of adpressed pelvic fin reaching to base of last branched anal-fin ray in males, and up to anus in females. Tip of adpressed dorsal fin reaching to caudal-fin base in males, and approximately up to one-half length of caudal peduncle in females. Upper caudal-fin lobe longer than lower one, especially in males. No sexual dimorphism in color pattern in Copella eigenmanni.
Distribution. Rio Orinoco basin, Colombia and Venezuela; upper rio Negro, Brazil and Venezuela and upper rio Putumayo drainage, Colombia, rio Amazonas basin (Fig 15).
Remarks. The original description of Copella eigenmanni was based on specimens designated as syntypes from several localities: Pará, Brazil, Guyana, and Bogotá, Colombia (probably collected near Villavicencio on the rio Meta, according to Weitzman & Weitzman [1]). Regan [20] mentioned color differences among specimens from Brazil, Guyana, compared to those from Colombia: "In the smaller examples there is sometimes an indistinct dusky band on the anterior part of the body and an indication of a pale stripe above the dark one on the head. In the larger ones, from Bogotá, a silvery stripe from eye to caudal fin separates a broad dark band below from the dark colour of the back", but considered all the same species. Eigenmann [52] described Copeina metae from the rio Meta and stated: "Regan records presumably this species from Bogotá [in reference part of the syntypes of C. eigenmanni]. His specimens were probably collected in the Meta, and some at least of those reported from Bogotá represent the present species [= C. metae]". Our findings agree with Eigenmann's conclusion that Copeina metae is conspecific with the type specimens of C. eigenmanni from Bogotá.
Zarske [35] designated as lectotype for Copella eigenmanni a specimen from Bogotá (Fig 19A), and by doing so synonymyzed Copella metae with C. eigenmanni and kept the old catalog number (BMNH 1869.7.25.6-7) for the lectotype, but apparently did not pay attention to the fact that the original lot was represented by two specimens which should be considered respectively lectotype and paralectotype. This situation is now resolved with designation of BMNH 1869.7.25.6 for the lectotype and consequently BMNH 1869.7.25.7 for paralectotype.

Lectotype Holotype
Dorsal-fin rays ii8 ii8 Pectoral-fin rays i9 -Pelvic-fin rays i7 i7 Anal-fin rays iii9 iii9 Caudal-fin rays -i8,7i Predorsal scales 15 15 First Description. Morphometrics in Table 9 and meristics of types in Table 10. Largest examined male 45.0 mm SL, female 40.5 mm SL. Greatest body depth slightly anterior to vertical through dorsal-fin origin. Body cylindrical, slightly compressed laterally. Dorsal profile of body straight to slightly concave from tip of snout to end of supraoccipital, straight to slightly convex from that point to dorsal-fin origin, posteroventrally inclined along dorsal-fin base and straight along caudal peduncle. Ventral profile of body convex to posteroventrally inclined from anterior tip of dentary to vertical through anterior margin of orbit, straight from that point to vertical through pectoral-fin origin, slightly convex from that point to pelvic-fin origin, straight from pelvic-fin origin to anal-fin origin, posterodorsally inclined along anal-fin base and straight along caudal peduncle.   Taxonomic review of Copella and ventral procurrent caudal-fin rays hyaline or dark (Fig 25). Pigmentation of procurrent caudal-fin rays more conspicuous in males than females and usually absent in juveniles. Adult specimens with hyaline procurrent caudal-fin rays only found in rio Negro basin (Fig 25B).
Color in life. Dorsolateral portion of body gray, ventral portion beige. Distal portion of scales on second or third to sixth longitudinal scale rows with red to purple spots, limited dorsally, posteriorly, and ventrally by dark pigmentation. Dark longitudinal band on fourth and fifth longitudinal scale rows. Fins yellow to pale red or hyaline (Figs 25 and 26).
Sexual dimorphism. Males longer than females. Males with more numerous maxillary teeth than females (see description above). Pelvic, dorsal, and anal fin of males longer than in females (Fig 27). Length of pectoral fin apparently not dimorphic. Tip of adpressed pelvic fin reaching to base of last branched anal-fin ray in males, and to anterior border of anus in females. Tip of adpressed dorsal fin reaching to one-half length of middle caudal-fin rays in males, and approximately to one-half length of caudal peduncle in females. Tip of adpressed anal-fin reaching to level of first ventral procurrent rays in males, and up to two-thirds length of caudal peduncle in females (Fig 27). Upper caudal-fin lobe longer than lower, especially in males. No evidence of sexual dimorphism related to color pattern in this species. Distribution. Rio Amazonas at Letícia, Colombia; rio Amazonas from mouth of rio Negro to mouth of rio Tapajós, Brazil; rio Negro basin, Brazil, Venezuela, and Guyana; upper and middle rio Orinoco basin, Venezuela (Fig 10).
Remarks. The description of Pyrrhulina nattereri by Steindachner [59] was based on syntypes from two localities: "Joh. Natterer collected the here-described species in many samples at the mouth of the Rio Negro and by Prof. Agassiz [= Thayer Expedition] at Ó bidos in a tributary of the Amazon". Possible types of Pyrrhulina nattereri are known to be deposited in the NMW, MSNG, ZMUC, and MCZ museums. Specimens deposited at NMW from the Thayer Expedition collected in Ó bidos are undoubtedly type material (NMW 56974, 57148 and 95055). However, the lot NMW 56973 from Codajás and Tabatinga, that are questionably marked as type material of Pyrrhulina nattereri, cannot be considered type since the locality does not match with those mentioned in the original description. Zarske & Géry [7] listed this same lot (NMW 56973) as paratypes of Copella meinkeni (= Copella nattereri) (Fig 23D).
Samples deposited in the Genova and Copenhagen museums are said to be from the rio Amazonas with no further information. The material from Genova (MSNG 9239, 1 specimen), and Copenhagen (ZMUC P241264 and P241265, 2 specimens) were donated by Steindachner in 30 Oct 1880 (G. Doria personal communication) and in 1876 (J. Nielsen personal communication), respectively, and therefore they should be considered paralectotypes of Pyrrhulina nattereri. Regarding the 57 specimens (MCZ 6259) collected during the Thayer Expedition in Ó bidos and deposited at MCZ, it is not clear whether Steindachner analyzed this material or not during his stay at MCZ from 1870-1871 (before he left to take part in Hassler's expedition from 1871 to 1872, according to Borodin [65]). Since this material has not been specifically designated we find no reason to consider it as types.
Despite Zarske's effort in searching the material from the mouth of the rio Negro, it was never found is considered as probably lost [7]. The lack of details on the origin of the samples deposited at MSNG and ZMUC raises the possibility that it could have come from that locality, but this was not confirmed.

Lectotype Holotype
Dorsal-fin rays ii8 ii8 Pectoral-fin rays i9 i9 Pelvic-fin rays i7 i7 Anal-fin rays iii9 iii9 Caudal-fin rays -i87i Predorsal scales 14 13 First longitudinal scale row -13 Fourth longitudinal scale row -21 Longitudinal scale rows dorsal to pelvic 5 6 Longitudinal scale rows dorsal to anal 5 5 In the present study, only types of Copella nattereri from the NMW museum could be examined. The lot NMW 56974 has five numbered paralectotypes. Numbers 1, 2, and 5 (28.8, 28.8, and 32.0 mm SL, respectively) represent, indeed, C. nattereri. Number 3, however, probably belongs to C. callolepis (28.9 mm SL) and number 4 (24.0 mm SL) is a specimen of Copella not precisely identified due to its poor condition. The lot NMW 57148 has four paralectotypes in poor conditions, the smallest (16.4 mm SL) is a Nannostomus sp. with a dark band on body and the remaining are Copella nattereri.
The topotypes under MCZ 6259 mentioned above as not representing type material is actually part of a mixture including other lots bearing MCZ numbers "6263+6300+6835+6836 +6837". Examination of the 78 specimens in this mixture revealed the presence of Copella nattereri (57 specimens, 18.3-30.7 mm SL), C. callolepis (9, 28.9-32.9 mm SL), Copella sp. Steindachner [59] originally described Pyrrhulina (= Copella) nattereri based on the presence of a bright spot close to the posterior edge of the body scales, bordered with dark brown pigmentation, except for its anterior edge. Steindachner also mentioned that a weak dark longitudinal band is not rare between the third and the fourth longitudinal scale rows (Fig 23A). Zarske & Géry [7] chose a lectotype for Copella nattereri discussing its identity, stating that it does not correspond to the same species that has been traditionally referred to by aquarists as Copella nattereri (the "spotted tetra"), but to what has been named Copella nigrofasciata (= Copella callolepis), species that has a black longitudinal band and one to three conspicuous longitudinal rows of clear spots on body (Fig 12), and made a new available name for the spotted tetra, Copella meinkeni (Fig 23C). The analysis of the lectotype of Pyrrhulina nattereri revealed that it clearly has the same color pattern described by Steindachner, not the characteristic coloration of Copella callolepis (see the presence of rows of dark spots on body in Fig 23B). Therefore, C. meinkeni is considered junior synonym of Copella nattereri, the valid name for the spotted tetra.
According to Zarske [35], there are two species with a series of black spots on body scales, C. meinkeni (= C. nattereri) and C. callolepis, the former being larger and with hyaline procurrent caudal-fin rays, and the later being smaller, with a black mark on the ventral procurrent caudal-fin rays. According to the present study, there are only one species of Copella with series of black spots on body scales, which is Copella nattereri (with C. meinkeni as its junior synonym). The lectotype proposed by Zarske & Géry [7] for C. callolepis has a black longitudinal band on body and clear spots, not corresponding to the same species (see Remarks under C. callolepis). The presence of a black mark on the ventral procurrent caudal-fin rays, mentioned by Zarske [35] is herein considered variable within Copella nattereri (see Color in alcohol section). Although both conditions (presence and absence of a dark mark on the procurrent caudal-fin rays) are only found in the adult specimens from the rio Negro basin (Fig 25) (adults of the remaining localities where this species occurs have dark procurrent caudal-fin rays and juveniles from all the localities usually lack a dark mark on procurrent caudalfin rays). Therefore, this feature was not found to be unambiguous to recognize a different species. Furthermore, dark procurrent rays can be even observed in some paratypes of C. meinkeni (NMW 56973: Fig 23D). No morphometric, meristic, osteological, or color features were found to justify considering more than one species in the populations of C. nattereri analyzed.
Zarske & Géry [7] listed "15 out of 30" specimens from the lot MHNG 2205.096 as paratypes of Copella meinkeni. Examination of this lot revealed there are actually a total of 41 specimens, a mixture of the 15 paratypes and other 26 non-types. Remaining type material of Copella nattereri and its synonym species that were not examined are: MSNG 9239 (1, often on fourth longitudinal scale row, but also on third and fifth rows, without fixed arrangement. Brown scales on anterior portion of body deep dark, gradually lighter posteriorly (Fig 28A to 28C). Females and juveniles with distinct colorations of males, consisting of inconspicuous wide brownish stripe on flank, on fourth and fifth longitudinal scale rows, extending from opercle to caudal peduncle, with clear longitudinal stripe above it (Fig 28D). Juvenile males with color pattern intermediate between those of adult males and females, with longitudinal wide stripe on flank and clear stripe above it, and series of dark brown scales on fourth longitudinal scale row. Dorsal fin with black round spot. Remaining fins hyaline. Pelvic and anal fins usually with dark edge, more intense in males. Dorsal and ventral procurrent caudalfin rays dark, darker in males. Females and juveniles with inconspicuous dark spot at base of upper caudal-fin lobe.

Dorsal-fin rays ii8
Pectoral-fin rays i9 Pelvic-fin rays i7 Anal-fin rays iii9 Caudal-fin rays i8,7i Color in life. Dorsal portion of body olivaceous, ventral portion pale yellow anteriorly and deep pink posteriorly. Males with series of brilliant green scales irregularly arranged, mainly on fourth longitudinal scale row. Base of dorsal fin, base of dorsalmost rays of upper caudal-fin lobe, and tip of basalmost rays of lower caudal-fin deep pink in males (Figs 29 and 30A). Females with metallic-green longitudinal band on body, extending from opercle to end of caudal peduncle (Fig 30B).
Sexual dimorphism. Males longer than females. Males with more numerous maxillary teeth than females (see description above). Pelvic, dorsal, and anal fins longer in males than in females. Pectoral-fin length apparently not sexually dimorphic. Tip of adpressed dorsal fin reaching to one-half length of upper caudal-fin lobe rays in males, and approximately to twothirds length of caudal peduncle length in females. Tip of pectoral fin sometimes extending beyond pelvic-fin origin in males, never in females. Tip of adpressed pelvic fin reaching base of last anal-fin rays in males, and to anus in females. Upper caudal-fin lobe longer than lower one, especially in males. Differences in color pattern between sexes described in "Color in alcohol" section.
Remarks. Géry [6] described Copella vilmae based on the holotype (Fig 28A) and 20 paratypes. Four paratypes were kept in aquarium and then deposited at SU. These four specimens are now under USNM 198135. Among the remaining 16 paratypes, 12 were said to be deposited at SMF 5967-78 and nothing was said about the other four paratypes. At SMF, we only analyzed 11 paratypes stored in a single jar under SMF 5967-77, separated by small glass tubes. The paratype SMF 5978 was not available and it was not possible to confirm whether it is missing. The remaining four paratypes cited in the description are deposited at MHNG 2200.018.
Material examined of Copella vilmae in S1 Appendix.