Figueiredo, José Lima de

Menezes, Naércio A.

English

Cadernos Espinosanos (E-Journal)

Papeis Avulsos de Zoologia Papeis Avulsos Zool., S. Paulo, vol. 24(15): 197-205 31.III. 1971 LONCHOPISTHUS MEADI, A NEW JAWFISH FROM THE COAST OF RIO GRANDE DO SUE, BRASIL (PISCES, OPISTHOGNATHIDAE) Naercio A. Menezes 1 Jose Lima de Figueiredo 2 Abstract A new species of the opisthognathid genus Lonchopisthus is described. Remarks are made on the genus Lonchistium Myers, which is shown to be a synonym of Lonchopisthus Gill. Introduction During the years 1968 and 1969 the research vessel "Prof. W. Besnard" of the Institute Oceanografico da Universidade de Sao Paulo made six exploratory cruises to the coast of the state of Rio Grande do Sul. This was a joint program (Institute Oceanografico da Uni- versidade de Sao Paulo and the Rio Grande do Sul state government through its Grupo Executive do Desenvolvimento da Pesca — GEDIP) to investigate the fishery resources of the Rio Grande do Sul conti- nental shelf. The fishes collected on these cruises are now in this Museum and among them we found 16 specimens of a new species of Lonchopisthus, which is described below. This work is the first of a series on the fishes collected during those cruises. It is with a great pleasure that we name this new species in honour of Dr. Giles W. Mead, curator of fishes of the Mu- seum of Comparative Zoology, Harvard University, in recognition of his unfailingly generous help and specifically of his contribution to the knowledge of the genus Lonchopisthus. Methods and Materials In all characters studied (meristic and body proportions), sexes were initially handled separately. Sex differences were found only with regard to orbital diameter; therefore in regression analysis where this character is involved, males and females are plotted separately. Measurements and counts were made on the loft side of the specimens. The measurements were taken with a micrometer to the nearest tenth of one millimeter, and the counts with the help of a thin needle, both under the stereomicroscope. 1. Museu de Zoologia, Universidade de Sao Paulo. Bolsista do Conselho Nacional de Pesquisas. 2. Estagiario do Museu de Zoologia, Universidade de Sao Paulo. 198 Papeis Avulsos de Zoologia Measurements Standard length — from tip of snout to caudal base. Head length — from tip of snout to posteriormost tip of opercle, including its membranous edge. Trunk length — standard length minus head length Body depth — from origin of dorsal fin to insertion of ventral fin spine. Predorsal distance — from tip of snout to origin of dorsal fin. Preanal distance — from tip of snout to origin of anal fin. Caudal peduncle depth — is the least depth of the caudal peduncle. Horizontal orbital diameter — is the maximum length of orbital dia- meter, measured horizontally inside the orbital ring. Vertical orbital diameter — is the maximum length of orbital diameter, measured vertically inside the orbital ring. Interorbital width — is the least width of bony interorbital. Maxillary length — this measurement was taken from the anterior tip of maxillary to the posteriormost tip of its expanded part. The anterior ascending maxillary process is not involved in this measurement. Premaxillary length — from anterior tip of premaxillary to posterior- most bony tip. Counts Dorsal fin — the last two close-set rays were counted as one. Anal fin — the last two close-set rays were counted as one. Caudal fin — only branched caudal rays were included in the counts. Gill rakers — this count includes the total number of gill rakers and rudiments on the first gill arch. Lateral line pores — this count refers to the number of pores along the lateral line. Scales above lateral line — is the number of scales in a vertical row from the origin of dorsal fin to lateral line. Scales below lateral line — is the number of scales in a vertical row from origin of anal to lateral line. Lonchopisthus meadi, sp. n. (Fig. 1) Holotype; MZUSP 8014, female. "Prof. W. Besnard" Cruise VI, Station n. 554, Rio Grande do Sul; 32012'S. lat., 50o12'W. long., March 9, 1969; 149 m. Paratypes: MZUSP 8015-17. "Prof. W. Besnard" Cruise VI, Sta- tion n. 554, Rio Grande do Sul; 32012'S. lat., 50o12'W. long.; March 9, 1969, 149 m. MZUSP 8018-19. "Prof. W. Besnard" Cruise V, Sta- tion n. 449, Rio Grande do Sul; 32o01'S. lat., 50o05'W. long.; Dec. 7, 1968; 161 m. MZUSP 8020. "Prof. W. Besnard" Cruise II, Station n. 306, Rio Grande do Sul; 320S. lat., 50o05'W. long.; June 24, 1968; 178 m. MZUSP 8021-29. "Prof. W. Besnard" Cruise V, Station n. 437, Rio Grande do Sul; 30o23'S. lat., 48037'W. long.; Dec. 4, 1968; 199 m. Diagnosis D. XI+ 12; A. Ill+ 12; P. 20-21; V. 1 + 5; 11-12 branched caudal fin rays; 26-29 pores in the lateral line; 5 scales above lateral line, 14-16 below; 14-15 + 27-28 gill rakers on first gill arch. Vol. 24 (15), 1971 200 Papeis Avulsos de —0— Description Body small (S. L. 50,5-62,8 mm) and compressed. Dorsal outline slightly more curved than ventral. Maximum depth of body at the beginning of dorsal fin. Head anteriorly rounded. Mouth terminal, lower jaw projecting slightly when mouth is open. Eyes large, much larger than snout, about one third as long as head; the upper part of the eye enters into dorsal profile of the head. Interorbital very narrow, its least width much shorter than orbital diameter. Two nostrils, the anterior tubular and smaller than the posterior, which is situated above and Closer to the anterior border of the orbit. Premaxillary slightly pro- tractile, its posterior bony part not reaching posterior margin of orbit; each premaxillary with 18-25 irregularly spaced pectinate teeth. Maxil- lary nearly straight, posteriorly expanded and notched, reaching and in some specimens surpassing posterior margin of the orbit. There are 18-22 irregularly spaced pectinate teeth on each dentary and two additional teeth behind the normal row of teeth in some specimens. Vomer and palatines edentulous. Opercle with a spine on its upper part. This spine is largely cover- ed by skin and does not reach the opercular membrane which ends in a prominent angular flap. 14-15+27-28 gill rakers on first gill arch. Scales cycloid, imbricate, embedded in the skin. Head naked, ex- cept for a patch of scales on the preopercle and another on the upper part of opercle. Body, base of pectoral and base of caudal fins scaled. Lateral line incomplete, beginning above upper part of opercle, running very close to the back and extending to below the fourth or fifth dorsal fin ray. 26-29 pores along lateral line. 5 scales from dorsal fin origin to lateral line, 14-16 from lateral line to origin of anal fin. Origin of dorsal fin much nearer to tip of snout than to caudal base. Last dorsal fin rays reaching beyond caudal fin base when 21- 20- 18' © • males ofemales Trunk length 32 34 36 38 40 42 Fig. 2, Linear regression of head length on trunk length. Vol. 24 (15), 1971 201 0) (O TJ 74 ' i -f-; X! i— O M o X ® males o females 18 19 Head length "20" 21 22 • males CD 0 females CD E (0 "O "id 0 la O 0 ro 0 • 1— 0) > 0 Head length 18 19 20 ' 21 22 Fig. 3, Linear regression of horizontal orbital diameter on head length. Fig. 4, Linear regression of vertical orbital diameter on head length. Papeis Avulsos de Zoologia TABLE 1 Measurements (mm) A B C D E F G H I J K L 8014 58.8 20.3 38.5 18.2 20.8 35.4 7.3 7.5 6.8 1.8 10.4 8.5 8015 62.5 21.5 41.0 19.0 21.3 39.3 7.4 8.0 7.2 1.9 11.3 9.7 8016 51.3 18.0 33.3 15.2 18.1 31.0 6.7 6.5 6.2 1.5 8.8 8.1 8017 53.6 19.0 34.6 16.0 19.1 34.0 6.8 7.0 6.7 1.7 10.0 8.7 8018 56.1 19.5 36.6 16.5 19.0 35.0 6.0 7.0 6.5 1.8 10.0 8.7 8019 52.6 18.3 34.3 15.2 17.9 31.8 6.1 6.5 6.0 1.5 10.0 8.2 8020 56.6 20.0 36.6 17.0 20.0 35.0 7.1 7.4 6.9 1.8 10.7 9.4 8021 62.8 21.5 41.3 18.8 21.7 38.6 8.0 7.3 7.0 2.0 11.9 10.0 8022 62.0 21.4 40.6 18.1 20.4 37.4 7.5 6.9 6.8 1.9 11.3 9.2 .8023 60.1 20.8 39.3 18.6 20.8 37.0 7.6 6.9 6.4 1.9 10.8 9.3 8024 58.7 20.3 30.4 16.8 20.0 36.8 6.9 6.8 6.6 1.8 11.0 8.8 8025 55.8 19.5 36.3 16.0 18.8 34.3 7.0 6.6 6.3 1.9 10.3 8.5 8026 52.6 18.8 33.8 15.4 18.8 32.8 6.4 6.8 6.4 1.8 9.5 8.4 8027 50.5 17.7 32.8 14.6 18.0 30.6 6.3 6.7 6.1 1.8 9.3 8.1 8028 51.7 18.4 33.3 14.5 19.0 32.2 5,8 6.7 6.1 1.7 9.2 7.8 8029 54.2 18.8 35.4 15.3 19.4 33.0 6.7 6.8 6.4 1.8 9.7 8.7 A - Standard length E B Head length F C - Trunk length G D - Body depth H - Predorsal distance - Preanal distance - Caudal peduncle depth - Horizontal orbital diameter I - Vertical orbital diameter J - Interorbital width K Maxillary length L - Premaxillary length TABLE 2 Counts A B C D E F G K I 8014 XI+12 111+12 20 1+5 12 14 + 27 28 5 15 8015 XI+12 111+12 21 1+5 11 14+28 26 5 16 8016 XI+12 111+12 21 1+5 12 14+27 28 5 16 8017 XI+12 111+12 21 1+5 12 15+28 29 5 16 8018 XI+12 111+12 20 1+5 11 14+27 27 5 14 8019 XI + 12 111+12 20 1+5 12 14+27 26 5 - 8020 XI+12 111+12 21 1+5 12 14 + 27 29 5 14 8021 XI+12 111+12 20 1+5 12 15+27 26 5 16 8022 XI+12 111+12 21 1+5 12 14 + 27 26 5 14 8023 XI+12 111+12 21 1+5 12 14 + 27 26 5 15 8024 XI + 12 111+12 21 1+5 12 14+27 27 5 15 8025 XI + 12 111+12 20 1+5 12 14 + 27 25 5 15 8026 XI + 12 111+12 20 1+5 12 15+28 28 5 14 8027 XI+12 111+12 20 1+5 12 14 + 27 26 5 15 8028 XI+12 111+12 21 1+5 12 14 + 28 28 5 14 8029 XI+12 111+12 20. 1+5 12 15+28 29 5 14 A - Dorsal fin D - Ventral fin G - Lateral line pores B Anal fin E - Branched caudal rays H Scales above lateral line C - Pectoral fin F - Gill rah ers I Scales below lateral line Vol. 24 (15), 1971 203 depressed. Spinous dorsal fin with 11 spines, lower than soft dorsal which has 12 rays, the last 8-10 branched. Anal fin with 3 spines and 12 rays, the last 8-10 branched, its origin under first dorsal fin ray. Last anal fin rays reaching beyond caudal fin base when depress- ed. Pectorals inserted a little behind opercular flap, posteriorly extend- ing to beyond anal fin origin. There are 20-21 pectoral fin rays, the uppermost and lowermost two simple, the rest branched. Caudal fin lanceolate, with 24 rays including the procurrent rays; 16 segmented caudal rays, 11-12 of which are branched. Color immediately after capture: silvery with scatered dark green blotches throughout the body. Opercle and pectoral fin bases pink. Top of head dark. Anal fin black, tip of anal fin rays blackier than the rest of the fin. Tip of dorsal fin rays, median caudal fin rays and inner rays of ventral fins black. Spinous dorsal fin and pec- toral fin with a coloration similar to that of the body. Ground color in alcohol light brown, top of the head and snout a little darker. Posterior part of soft dorsal, tip of median caudal fin rays and innermost ventral fin rays black. Anal considerably darker than the other fins, the tip of its rays black. Pectorals pale. The measurements of the specimens are shown in table 1 and the counts in table 2; the regression data in table 3 and figures 2-4. TABLE 3 Regression data Regression N b a r F Head length x trunk length 16 0.42 + 0.022 4.19 + 0.81 h.96 357.47 Body depth x standard length 16 0.35 + 0.027 -3.51+1.55 0.92 167.30 Predorsal distance x standard length 16 0.26 + 0.028 4.69+1.62 0.B5 83.93 Preanal distance x standard length 16 0.61 + 0.043 -0.10 + 2.44 0.93 203.47 Loriz. orbital diameter x head length (males) 6 0.18 + 0.O40 3.05 + 0.81 0.84 21.47 Koriz. orbital diameter x head length (females) 10 0.38 + 0.034 -0.40+0.66 0.94 126.07 Vertical orbital diameter x head length (males) 6 0.27 + 0.056 1.02+1.14 0.85 22.89 Vertical orbital diameter x head length (females) 10 0,30 + 0.036 0.76 + 0.70 0.89 68.47 Iloriz. orbital diameter x maxillary length (males) 6 0.35 + 0.047 3.01+0.51 0.93 55.26 Iloriz. orbital diameter x maxillary length (females) 10 0.59 + 0.051 1.19+0.51 0.94 131.95 Vert, orbital diameter x maxillary length (males) 6 0.51 + 0.049 0.90 +0.54 0.96 107.77 Vert, orbital diameter x maxillary length (females) 10 0.46 + 0.047 1.93 + 0.47 0.92 94.62 Masillary length x head length 16 0.64 + 0.061 -2.32+1.21 0.88 107.35 Caudal neduncle depth x bodv denth 16 0.34 + 0.040 1.12+0.67 0.83 72.23 M Number of specimens b - Regression coefficient + its standard deviation a - Regression constant + its standard deviation r2- The square of correlation coefficient F Variance ratio Discussion Mead (1959) reviewed the species of Lonchopisthus. According to him, four nominal species should be included in the genus: L. lindneri Ginsburg, L. micrognathus (Poey), L. vanderhilti Mowbray, and L. hig- mani Mead. He separates L. higmani from the others mainly because it is the only species with some caudal fin rays branched. Lonchopis- thus meadi, sp. n., has also branched caudal rays and in this respect it is closer to L. higmani than to any other species of Lonchopisthus. However, the number of branched rays in our species is much higher (11-12) and there is also a considerable difference in the number of 204 Pap6is Avulsos de Zoologia dorsal and anal fin rays and gill rakers, these counts being much lower for L. meadi, sp. n. The opercular spot so characteristic of Mead's species is absent in specimens of L. meadi; sp. n. Myers (1935) described a new genus and species, Lonchistium le- mur, based on a single specimen caught in Puerto Rico off Punta Boca Juana; he characterized his new genus by having only 2 anal spines. Cervigon (1966) identified 4 specimens from the Islas Los Hermanos, Venezuela, as L. lemur, but having found 3 anal spines in all specimens, he suggested Lonchistium to be a synonym of Loncho- pisthus. He thinks the presence of a third spine could have escaped Myers' examination due to the small size of his specimen. We received, through the kindness of Dr. Stanley H. Weitzman, measurements and meristic data and an X-ray of Myers' holotype. The latter shows the presence of 3 anal spines, the first very small. We observed also that Lonchistium has the same basic number of vertebrae found in all the species of Lonchopisthus. The validity of Myers' genus therefore, seems to be untenable and we consider Lonchistium Myers, synonymous with Lonchopisthus Gill. Lonchopisthus meadi, sp. n., and L. lemur have the same number of dorsal and anal rays and spines but the number of pectoral rays and gill rakers is quite different. L. meadi, sp. n. has 20-21 pectoral rays and 14-15+27-28 gill rakers on the first gill arch. These counts for L. lemur are respectively 17-18 and 13+25. Unfortunately other important characters such as number of branched dorsal, anal and caudal fin rays and number of scales could not be compared since they are not mentioned in the original description. According to Myers (1935: 3) the single specimen on which the description is based had the fins broken and was almost without scales. Another feature that must be taken into consideration is that L. lemur and L. meadi, sp. n., were caught in different geographic areas which belong to two different zoogeographical regions. In the study of body proportions, the regressions of orbital dia- meter on head length (figs. 3 and 4) revealed a significant difference between males and females. The regression of head length on trunk length (fig. 2), on the other hand, did not show any sex differences, clearly indicating that the differences found are related exclusively to the proportional differences between orbital diameter and head. There seems to be then, sexual dimorphism within the species, the females having a larger eye. The regression lines for males and females in figure 3 (horizontal orbital diameter) are divergent and almost parallel in figure 4 (ver- tical orbital diameter), showing that there is a differential growth rate involving vertical and horizontal orbital diameters. This strongly suggests that not only size but also shape of the eye plays an important role in sex recognition. Further studies are needed to show if this kind of dimorphism occurs also in other species of Lonchopisthus. The known species of the genus Lonchopisthus are confined to the Western Atlantic: L. micrognathus (Poey), Cuba; L. vanderbilti Mow- bray, Cuba and Gulf of Mexico; L. lindneri Ginsburg, Gulf of Mexico and off Texas; and L. higmani Mead, Suriname and off Venezuela. The occurrence of L. meadi, sp. n., in Rio Grande do Sul represents the first record of the genus in the South Atlantic. We thank Dr. Stanley H. Weitzman of the United States National Museum for the data and the X-ray of the holotype of L. lemur, Miss Francisca C. do Val for the drawing of Lonchopisthus meadi, sp. n. and Drs. Giles W. Mead and Paulo E. Vanzolini who read and criticized the manuscript. Vol. 24 (15), 1971 205 References Cervigon, F. M. 1966. Los Peces Marinos de Venezuela, 2:637-642. Fundacion La Salle de Ciencias Naturales. Caracas. Mead, G. W. 1959. The Western Atlantic jawfishes of the opisthognathid genus Lonchopisthus. Studies cm the Fauna of Suriname and other Guyanas 2(18): 104-112. Myers, G. S. 1935. A new genus of opisthognathid fishes. Smithsonian Misc. Coll. 91(23): 1-5. 

Lonchopisthus meadi, a new jawfish from the coast of Rio Grande do Sul, Brasil (Pisces, Opisthognathidae)

https://www.revistas.usp.br/paz/article/download/210775/193220/619456

Lonchopisthus Meadi, a new jawfish from the coast of Rio Grande do Sul, Brasil (Pisces, Opisthognathidae)

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