Centrorhynchus pitangi, R. & Smales, 2013

Smales, Lesley R., 2013, Acanthocephala including the descriptions of new species of Centrorhynchus (Centrorhynchidae) and the redescription of Lueheia inscripta (Westrumb, 1821) (Plagiorhynchidae) from birds from Paraguay South America, Revue suisse de Zoologie 120 (2), pp. 175-202 : 189-192

Centrorhynchus pitangi n. sp. Figs 28-37

MATERIAL EXAMINED: MNHG-INVE-82722; holotype male from Pitangus sulfuratus (Linnaeus, 1776), small intestine: Paraguay, Arroyo Agua-Pey, 26.10.1986 . – MNHG-INVE- 82723; paratype (allotype) female from Pitangus sulfuratus (Linnaeus, 1776), small intestine: Paraguay, Arroyo Agua-Pey, 26.10.1986 . – MNHG-INVE-38406; paratypes, from Pitangus sulfuratus (Linnaeus, 1776), small intestine: Paraguay, Arroyo Agua-Pey, 26.10.1986 . – MNHG- INVE-38448; voucher specimens, 1 female, from Pitangus sulfuratus (Linnaeus, 1776), small intestine: Paraguay, Arroyo Agua-Pey, 26.10.1986 . – MNHG-INVE-38447; 1 juvenile, from P. sulfuratus small intestine: Paraguay, Arroyo Tagatiya- Guiazu 17.10. 1983 .

ETYMOLOGY: The species name is taken from the genus name of the host.

DESCRIPTION

General: (based on 2 males, pieces of 2 males, 5 females, and pieces of 5 females) Trunk spineless, elongated; more or less cylindrical in female, dilated anteriorly in region of testes in male. Neck shorter than broad. Proboscis in 2 parts, with constriction at insertion of proboscis receptacle, at about 62% of distance from apex to proboscis base, anterior proboscis slightly expanded above constriction. Proboscis armed with 28-30 longitudinal rows 18-20 hooks. Anterior 7-8 hooks with large simple roots, first 4 also with manubria, blades hooks 1, 13.2, 39.6 long, hooks 2, 46.2, 49.5 long, hooks 3, 42.9 long, hooks 4, 39.6, 42.9 long, hooks 5, 36.3-39.6 long, hooks 6, 33- 36.3 long, hooks 7, 33 long, hooks 8, 26.4, 29.7 long; next hook with reduced root and manubrium, blade 27 long; following 3 transitional hooks with manubria, blades 33-39.5 long; posterior 7-8 hooks spiniform, blades 10-30 long, inserted on posterior part of proboscis. Neck spineless, shorter than broad. Proboscis receptacle double walled. Lemnisci tubular, inserted at base of neck, extend posteriorly beyond proboscis receptacle. Cerebral ganglion located at mid region of proboscis receptacle, posterior to neck.

Male: (based on two specimens) Trunk 9, 11 mm long, 1360 at widest part. Proboscis 1005, 1020 long, 280, 301 wide. Neck 268, 402 long, 670, 735 wide at base. Proboscis receptacle 1360, 1307 long, 201-306 wide; lemnisci 2800 long. Testes oval, tandem, contiguous, in anterior third of trunk; anterior testis 1700, 1105 long, 476, 731 wide; posterior testis 1870, 1105 long, 510, 782 wide. Cement glands, 3, elongated, tubular, begin immediately posterior to end of posterior testis, 5100 long; Saefftigen’s pouch 1200 long. Genital pore subterminal. Entire male system occupies about 85% trunk length.

Female: (Based on 5 specimens) Trunk 16-19 (18) mm long, 1190-1615 (1465) wide. Proboscis 804-1020 (946) long, 301-368 (320) wide. Neck 335-402 (370) long, 470-670 (570) wide at base. Proboscis receptacle 1394-1615 (1495) long, 238-295 (252) wide. Lemnisci 2200 long. Reproductive tract, uterine bell to genital pore, 2000 long. Genital pore subterminal. Eggs oval, external shell thick, ridged, 56.0-66.3 (58.8) long, 26.4-32.3 (27.9) wide.

COMMENTS: Centrorhynchus pitangi sp. n. conforms to the diagnosis of the genus given by Golvan (1956, 1960). In the key to the Neotropical species of FIGS 28-37

Centrorhynchus pitangi sp. n. (28) Male. (29) Egg. (30) Proboscis hooks, longitudinal row 4 transitional hooks. (31) Proboscis hooks, longitudinal row true hooks 1-8, 4 with manubria. (32) Female genital tract, dissection. (33) Proboscis hooks, longitudinal rows 8 spiniform hooks. (34) Female anterior end. (35) Female posterior tip of trunk, ventral view. (36) Female posterior tip of trunk, lateral view. (37) Male posterior tip of trunk, bursa inverted, ventral view. Scale bars: 28, 32, 1 mm; 29, 30, 31, 33, 25 µm; 34, 500 µm; 35, 36, 37, 100 µm.

Centrorhynchus by Lunaschi & Drago (2010) C. pitangi falls close to C. giganteus Travassos, 1926 in the form of the true hooks, both species having true hooks with manubria as well as transitional hooks with manubria. The two species differ in proboscis armature C. pitangi having 28-30 longitudinal rows of 18-20 hooks compared with 24-26 rows of 27-28 hooks for C. giganteus . Further the blades of the true hooks of C. pitangi are shorter than those of C. giganteus (13.5-43 compared with 100-150). Travassos (1926) does not use the term transitional hooks to describe hooks with manubria but no roots, separating the hooks only into 16-17 hooks and 11 spines in each row. His plate 9, figure 22, of hook types, however, shows at least one spine in each row was a transitional type, with manubrium and without a root. Therefore in comparing numbers of hook types in this instance, transitional hooks should be counted as true hooks. Accordingly C. pitangi would have 11-12 hooks and 7-8 spines compared with 16-17 hooks and 7-8 spines for C. giganteus . Centrorhynchus pitangi can be further distinguished from C. giganteus as a smaller worm (females 16-19 compared with 37-55mm long) with a shorter proboscis (up to 1020 long, compared with 1870), shorter lemnisci (2200-2800 compared with 5200 long) and smaller testes (up to 1870 compared with 3000 long) ( Travassos, 1926).

Although not recognized by Lunschi & Drago (2010) C. tumidulus , as described and figured by Travassos (1926, see p. 68 and fig. 5) also has true hooks with manubria. Centrorhynchus pitangi can be distinguished from C. tumidulus by the number of hooks of the proboscis armature (28-30 rows of 18-20 hooks compared with 26 rows of 20-21 hooks) and in having transitional hooks which C. tumidulus lacks. Further C. pitangi is a smaller worm with larger testes, longer lemnisci, shorter cement glands and larger eggs than C. tumidulus (Table 3).

Centrorhynchus albidus and C. polymorphus are the other species from South America having a proboscis armature of up to 30 longitudinal rows of hooks ( Lunaschi & Drago, 2010). Centrorhynchus pitangi differs from both species in form of the true hooks. Centrorhynchus pitangi further differs from C. albidus in the total number of hooks per row (18-20 compared with 20-22 hooks) and the numbers of each type of hook, as interpreted above (7-8 true hooks, 4 with manubria + 1-2 true hooks with reduced root and manubrium + 2-3 transitional hooks + 7-8 spiniform hooks compared with 7-8 true hooks + 1 hook with reduced root and manubrium + 3 transitional hooks + 10-11 spiniform hooks) ( Schmidt & Neiland, 1966). Centrorhynchus pitangi has larger testes and larger eggs than C. albidus (Table 3).

Centrorhynchus pitangi further differs from C. polymorphus in proboscis armature, the total number of hooks per row (18-20 compared with 17) and the number of each type of hook in each row (8-9 including true hooks with manubria + 2-3 + 7-8 compared with 7+3+7) ( Travassos, 1926), as well as in body length and shape, cylindrical not claviform, the length of the proboscis, proboscis receptacle, cement glands and Saefftigen’s pouch and the size of the testes and eggs (Table 3).

Centrorhynchus pitangi differs from all other species found in Paraguay, C. guira , C. geranoaeti and C. millerae in proboscis armature, both in the morphology and the numbers of true hooks and spines. Centrorhynchus guira has 32 rows of 18-19 hooks, 4 being transitional hooks with lateral alate processes and 6 spiniform hooks. Centrorhynchus geranoaeti and C. millerae have females with and males without transitional hooks in 30, 30-32 rows of 22-24 and 16-20 hooks including 9-11 and 9-14 spiniform hooks respectively.

Centrorhynchus pitangi can be distinguished from C. opimus by the number of longitudinal rows of proboscis hooks (28-30 compared with 24) and by having true hooks 8-9 with reduced roots and manubria. Travassos (fig. 27, plate 11, 1926) shows anterior true hooks with manubria and transitional hooks but not hooks with reduced roots and manubria. Centrorhynchus pitangi has a shorter trunk (9-11 compared with 12-16 for males) longer lemnisci (2200-2800 compared with 2000) and longer cement glands (5100 compared with 2700) than C. opimus .

Centrorhynchus simplex , found in Brazil, can be distinguished from C. pitangi by the proboscis armature. Similarly C. pitangi can be differentiated from each of the four species of Centrorhynchus found only in North America by a combination of the characters of the proboscis armature; numbers, arrangement, morphology and sizes of hooks as detailed for C. geranoaeti above.