Glandulocaudini

Menezes, Naéreio A. & Weitzman, Stanley H., 1990, TWO NEW SPECIES OF MIMAGONIA TES (TELEOSTEI: CHARACIDAE: GLANDULOCAUDINAE), THEIR PHYLOGENY AND BIOGEOGRAPHY AND A KEY TO THE GLANDULOCAUDIN FISHES OF BRAZIL AND PARAGUAY, Proc. Biol. Soc. Wash. 103 (2), pp. 380-426 : 383-386

Key to the Species of the Glandulocaudini

Although this key employs many characters that are apparently synapomorphic at their level of use, the key is not a hypothesis of phylogeny for any of the included taxa except for the Glandulocaudini diagnosed in the first half (la) of the first couplet. Because the primary purpose of this key is to identify species, we use any appropriate character that either clusters and/ or distinguishes species. Thus, except for couplet la where the characters are synapomorphies, a given character may be either a plesiomorphy, a synapomorphy or an autapomorphy at its point of use. At this time we lack corroborated polarity hypotheses for many of the characters that are not associated with the secondary sexual features of adult males and our hypotheses for the secondary sexual characters cannot be considered well-supported. Homoplastic characters are used where they serve the purpose of the key. The reader should note that when using couplet 4, many maturing males of species of Mimagoniates that have a well-developed caudal pump chamber when fully mature, will key to 4a rather than 4b (where they belong) because of the incomplete development of the specimen’s caudal fin-ray pump. This will often be the case in relatively small and some moderate sized specimens even in the presence of apparently active testes.

1a. Adult males and females with modified caudal-fin squamation extending posteriorly onto caudal fin from base of ventral portion of dorsal caudal-fin lobe; principal caudal-fin rays ll and 12 of adult males somewhat bowed or curved ventrally, these and adjacent rays modified into a chamber or support for a chamber of a fin-ray pump organ in some species (compare Figs. 2-6 ). Glandulocaudini (2)

1b. Adult males and females without modified caudal-fin squamation or, if such scales present, then these derived from both caudal-fin lobes, only from ventral caudal-fin lobe or primarily from terminal lateral-line scale; principal caudal-fin rays ll and 12 of adult males straight or if modified, not bowed ventrally (as in Fig. 6 ) or modified into a fin-ray pump organ (as in Figs. 2-5 ) although they may provide origins for muscular and ligamentous attachments to a scale-diaphragm pump mechanism other tetragonopterine or glandulocaudine characid groups

2a. Caudal fin-ray pump absent in all sexes at all ages (see Fig. 6 ); hypertrophied glandular tissue widespread along caudal-fin rays, especially those of ventral caudal-fin lobe, but most dense along proximal portions of rays 11 and 12; more than 1 hook on each anterior anal-fin ray that bears hooks Glandulocauda (3)

2b. Caudal fin-ray pump present in mature males, modified primarily from caudal-fin rays 10- 12, sometimes relatively simple and represented by expanded, fiattened anterior portions of ray halves, sometimes by an anterior fin-ray pump chamber; hypertrophied glandular tissue confined to area immediately around and on caudal pump region of gland (see Figs. 2 , 5 ); no more than 1 hook on any anal-fin ray that bears hooks. Mimagoniates (4)

3 a. Branched anal-fin rays 20-23; perforated lateral line scales 11-21; scale rows between dorsal-fin on'- gin and anal-fin origin 14- 17; scale rows around caudal peduncle 17- 18, usually 18; dorsal-fm origin somewhat anterior to vertical line drawn from anal-fin origin. Glandulocauda melanogenys Eigenmann (upper rio Tietê, in São Paulo, Brazil)

3 b. Branched anal-fin rays 15- 18; perforated lateral-line scales 4-6; scale rows between dorsal-fin origin and anal-fin origin 11- 13; scale rows around caudal peduncle 16; dorsal-fin origin somewhat posterior to vertical line drawn from anal-fin origin Glandulocauda melanopleura Eigenmann (upper rio Iguaçu, in Paraná and Santa Catarina, Brazil)

4 a. Caudal fin-ray pump little developed in males of completed sexual maturity and without obvious pump chamber enclosed by modified proximal portions of caudal-fin ray halves 1 1 and 12; ray halves of this region of these rays modified into expanded, flattened structures parallel to one another; these modified ray halves of each side of caudal fin developed so that a groove exists between them; groove and accompanying hypertrophied glandular tissue constitute a primitive pump organ (see Figs. 2 , 3 ) (5)

4b. Caudal fin-ray pump well-developed in males of completed sexual maturity, consisting of bilateral chambers, one on each side of fin and each chamber enclosed by fiattened expanded portions of ray halves of rays 11 and 12; pump chamber with an obvious posterior opening, lateral slit and anterior opening (see Figs. 4 , 5 ) (6)

5. Branched anal-fin rays 23-29, usually 25-27, rarely 28 or 29; scales in lateral series (including lateral line scales) 36-41, usually 37-40; scale rows between dorsal-fin origin and anal-fin origin 16- 18; dorsal-fin origin at vertical line drawn from base of second or third branched anal-fin ray; mid-lateral dark body stripe of adult males diffuse, poorly developed, often not apparent; body depth approximately 2.7 to 3.3 in SL Mimagoniates inequalis (Eigenmann) dos Patos and lagoa Mirim, in Rio Grande do Sul, Brazil and northeastern Uruguay)

5 b. Branched anal-fin rays 30-36; scales in lateral series 41-48; scale rows between dorsal-fin origin and anal-fin origin 13- 15; dorsal-fin origin at line drawn vertically from base of seventh to ninth branched anal-fin rays; lateral dark body stripe of adult males nearly black, clearly distinct; body depth at dorsal-fin origin about 4.0 to 4.5 times in SL. Mimagoniates barberi Regan (tributaries of rio Paraguay in parts of Brazil and Paraguay)

6 a. Hooks absent on all principal caudal-fin rays of adult males (see Figs. 3,11,12 ) (7)

6 b. Hooks present on at least principal caudal-fin rays 10 and 1 l of adult males, hooks also frequently present on ray 12 (see Figs. 5 , 21 ) (8)

7 a. Lateral series scales 49-56; scale rows between dorsal-fin and anal-fin origins 16- 18; body depth of adult males 3.4-3.8 in SL; in wild caught specimens body silvery blue, when black horizontal stripe present, located at and partly dorsal to mid-lateral region of body fiom tip of snout to central caudal-fin rays, stripe diffuse and broad and often obscured by silvery blue coloration posteriorly and by silvery pigment anteriorly; stripe rarely clearly defined M. sylvicola , new species (tributaries of Atlantic Ocean in southern Bahia, Brazil)

7 b. Lateral series scales 37-44; scale rows between dorsal-fin and anal-fin origins 12- 15; body depth of adult males 3.8-5.1 in SL; in wild caught specimens body mahogany brown, especially dorsally, with dark brown, nearly black, horizontal lateral body stripe below mid-region of body prominent and extending from tip of lower jaw, posteriorly ventral to eye, across opercle and body sides just ventral to mid body region onto caudal peduncle and across central portion of caudal fin Mimagoniates lateralis (Nichols) (tributaries of Atlantic Ocean from Santos, São Paulo south to Joinville, Santa Catarina, Brazil)

8 a. Branched anal-fin rays 23-29, usually 24-26; branched dorsal-fin rays 8-12, rarely 8; scale rows between dorsal-fin origin and anal-fin origin 17-22, usually 19-20; scale rows around caudal peduncle 19-23, usually 20-22; branched dorsal-fin rays 8-12, rarely 8; very small hooks on caudal-fin rays 1 1- 12 of fully adult males ( Fig. 21 ); dorsal-fin origin at vertical line drawn from anal-fin origin or from base of 2 to 4 rays posterior to anal-fin origin Mimagoniates rheocharis , new species (tributaries to Atlantic Ocean of southern Santa Catarina and northern Rio Grande do Sul, Brazil)

8 b. Branched anal-fin rays 26-33, usually 28- 31; branched dorsal-fin rays 7-9, rarely 9; scale rows between dorsal-fin origin and anal-fin origin 14- 17, usually 15- 16; scale rows around caudal peduncle 15- 18; numerous strong hooks on at least caudal-fin rays 11- 12 (sometimes 7-12) of fully adult males (see Fig. S); dorsal-fin origin at a vertical line drawn from base of branched anal-fin rays 5 or 6 Mimagoniates microlepis (Steindachner) (tributaries to Atlantic Ocean from southern Bahia south to northern Rio Grande do Sul, also in upper rio Iguaçu, Paraná)

Figures

Fig. 2. Mimagoniaıes barberi. unstained central basal region of caudal fin adjacent to caudal peduncle of a preserved adult male, lateral view. left side, anterior at left. SL 32.7 mm. UMMZ 205420, Paraguay, rio Aguarymi, tributary to rio Paraguay, San Pedro. Illustrates external features of a caudal gland without complex pump chamber. Darkly pigmented glandular groove between principal rays ll and 12 indicated by arrow. Modified dorsal caudal-fin lobe scales, although present, are transparent and not visible.

Fig. 3. Mimagoniates barberi, osteology of central basal region of caudal-fin skeleton, principal fin-rays 6- 15, of adult male, lateral views, left side, anterior at left. SL 35.6 mm, UMMZ 205420, same locality as Fig. 2. Principal ray 12 indicated by arrow. (A) Illustrates glandular groove between rays ll and 12. (B) Illustrates relationship ofmodified dorsal caudal-fin lobe squamation to glandular groove. Note that modified scales together with their epidermis form a movable flap just lateral to surface of rays and glandular groove. Free border of this flap occurs along ventral margin of ventral row of scales and at posterior edge of posterior scale of ventral scale row.

Fig. 4. Mimagoníates microlepis, unstained central basal region of caudal fin adjacent to caudal peduncle of a preserved adult male, lateral view, left side. anterior at left. SL 51.7 mm, USNM 279876, Brazil, Santa Catarina, rio Itapocú. Illustrates external features of a caudal gland with a complex pump chamber. Arrow at left indicates anterior intake opening. middle arrow indicates lateral slit ofchamber and arrow at right designates posterior exit opening of chamber. These openings surrounded by glandular tissue, especially exit opening. Modified dorsal caudal-fin scales appear as rather poorly focused "ghost" images in upper half of picture, above main body of pump chamber.

Fig. 5. Mimagoniates microlepis, osteology of central and basal region of caudal skeleton of adult male, lateral view, left side, anterior at left. SL 45.3 mm, USNM 236089, Brazil, Parana, rio Nhundiaquara at Morretes. Relationship of modified dorsal lobe caudal-fin squamation to caudal gland shown in inset at left. Distal regions ofventral and posterior scales and their epidermis form a flap partly covering intake openings of pump chamber.

Fig. 6. Glandulocauda melanogenys, osteology of central and basal region of caudal Skeleton of adult male, lateral view, left side, anterior at left. SL 40.2 mm, USNM 236093, Brazil, São Paulo, headwater stream of rio Tietê near Campo Grande (= Alto da Serra, type locality). about 3.5 km west of Paranapiacaba. Decurved principal caudal-fin rays l 1 and 12 are labeled and inset at left illustrates relationship of modified dorsal caudal- fin squamation to rays ll and 12. Note that modified caudal-fin squarnation of females of in all species of Glandulocauda and Mimagoniates is very similar to that illustrated here but may reach only about half the relative dimensions depicted here.

Fig. 21. Mimagoniates rheocharis. new species, paratype, anterior 13 anal-fin rays of an adult male, lateral view, anterior is at lefi. USNM 279879, SL 45.4 mm; Brazil, Santa Catarina, rio Jordão at Jordão Alto. For explanation see Description under M. rheocharis.