NEOROSSlA N.G. PRO ROSSlA (ALLOROSSlA) CAROLl JOUBIN, 1902, WITH REMARKS ON THE GENERIC STATUS OF SEMIROSSIA STEENSTRUP, 1887 (MOLLUSCA: CEPHALOPODA)
S. VON BOLETZKY Laboratoire Arago, Associe au C. N. R. S., Banyuls-sur Mer, France
ABSTRACT Rossia caroli Joubin is placed in a new genus, Neorossia, characterized by reduction of the ink sac and anal valves to apparently functionless rudi- ments. This is the first record of a decapodous cephalopod devoid of a functional ink sac. In the present study, the original generic status of Semirossia Steenstrup is reestablished.
INTRODUCTION A male specimen belonging to the sepiolid subfamily Rossiinae, captured off the Azores in 1901, was described by Joubin (1902a) as the type of a new species, Rossia caroli. In his revision of the Sepiolidae, published in the same year, Joubin listed this new species in the subgenus Franklinia created by Norman in 1890. The name Franklinia, preoccupied for a genus of birds, was changed to A llorossia by Grimpe (1922). Rossia caroli has been captured at several stations in the northern mid- Atlantic, tropical eastern Atlantic (Voss, manuscript), and, in large num- bers, in the Mediterranean Sea. In 1963, Mangold-Wirz redescribed the species and discussed its systematic position, distribution, and biology. When working on the collection of Rossia material in the U.S. National Museum, Washington, D.C. (Boletzky, 1970), I encountered a single, undissected male specimen of R. caroli from the coast of Algeria; it had been identified by Dr. W. Adam (Institut Royal des Sciences NatureIles, Bruxelles, Belgium). In this specimen, I found no ink sac, completely reduced anal valves and a small papilliform organ beside the kidney papilla of one side (the other side was damaged, so I was unable to recognize there the corresponding organ). The investigation of more specimens obtained by bottom trawling at depths between 400 and 800 m off the coast of Catalonia proved that the above-mentioned specimen was not aberrant, but that the species has no functional ink sac and no anal valves. It is therefore removed from the genus Rossia and placed in a new genus that is given the name Neorossia. I am deeply indebted to Dr. Katharina Mangold for allowing me to in- vestigate specimens of N. caroli of her collection, for valuable discussions and for reading the manuscript. I also thank Dr. Gilbert L. Voss for read- ing the manuscript and for giving valuable comments and information. 1971] v. Boletzky: Neorossia n. g. 965
MATERIAL In addition to one male specimen from the coast of Algeria (collection of U.S. National Museum), three female and 11 male specimens of Neoros- sia caroli captured in the Mediterranean off the coast of Catalonia, Spain and France, were investigated.
INTESTINAL COMPLEX AND "EPIRENAL BODIES" OF Neorossia caroli The intestine of Neorossia caroli ends in an externally very simple, rather short rectum. The anal valves are represented by two inconspicuous in- tegumental elevations on either side of the anus (Fig. 1, C, D). The absence of an ink sac is readily recognized if one looks at fresh specimens still having translucent tissues. Carefully performed dissections and histological sections reveal the presence of an extremely reduced rudiment in the shape of a narrow tube that ends in a small bulb contain- ing several globular chambers (Fig. 1, D); the latter probably represents the rudiment of the ink gland. There is no trace of ink secretion. The reduction of both ink sac and anal valves (as in abyssal Octopoda such as the Bathypolypodinae) suggests that these organs are functionally related to each other. It can be imagined that valves serve for avoiding formation of whirls around the anal opening when ink is discharged. The "dummy" structure (pseudomorph) of the ink cloud would probably not be so distinct if the ink (because of whirls) were mixed with the water ejected through the funnel. Small organs of unknown function that lie beside the kidney papillae are present only in males of N. caroli (Fig. 1, A). They are smaller in size than the kidney papillae; they are not connected with the latter. The structure of these organs is similar to that of the accessory nidamental glands. They contain ampullae of different sizes, formed by a single layer of ciliary cells, each communicating with the outside by a narrow duct. Organs in a similar position have been described by Chun (] 915) in the male of Rossia mastigophora. They are also present in males of R. bullisi (Boletzky, 1970). Naef (1923: 575) considered the organs described in R. mastigophora as rudiments of accessory nidamental glands, their position being analogous. But Sasaki (1920: pI. XVI) figured similar organs in a female specimen of R. bipapillata; they lie between the kidney papillae and the fully de- veloped accessory nidamental glands. Since these organs most likely correspond to the organs found in males of R. mastigophora, R. bullisi, and N. caroli, it is-despite the structural similarity-somewhat daring to consider the latter as rudiments of accessory nidamental glands. The entire complex comprising these organs, the accessory nidamental glands, and the light organs in Semirossia (Boletzky, 1970) needs to be rein- 966 Bulletin of Marine Science [21 (4)
r
eb p
kp lomm
A
r~_av ~ C
o FIGURE J. Neorossia caroli: A, mantle cavity of mature male (ML 38 mm), showing rectum (r) devoid of anal valves, epirenal bodies (eb) situated beside kidney papillae (kp), penis (p); B, visceral mass of mature female (ML 40 mm) with accessory nidamental glands (an), but no epirenal bodies; C, anterior view of rectum with anus and relics of anal valves (av); D, terminal part of intestine (i) with rudiment of ink sac (is) running into the rectum. The dissection figured shows the ink sac rudiment lifted off the intestine to which it normally adheres. 1971] v. Boletzky: Neorossia n. g. 967 vestigated. I therefore refer to the organs in question as "epirenal bodies," which term will not interfere with any functional or morphological relation that further studies may reveal.
DISCUSSION Until recently, there were various reasons for considering the subfamily Rossiinae as mono typic, with the genus Semirossia incorporated as a sub- genus (Joubin, 1902b). Semirossia differs from all other subgenera by having only one hectocotylus; this characteristic alone mayor may not justify a separation at generic level. The recent observation, however, that Semirossia has large light organs (Boletzky, 1970) leads back to the con- cept of Semirossia as a separate genus. This corresponds to the separation, among Sepiolinae, of the genus Sepietta, that has no light organs, from Sepiola and Rondeletiola that have them (N aef, 1923). As to the reduction of the ink sac, it is more difficult to decide at which taxonomic level a separation is correct. Since this is the first record of a decapod devoid of a functional ink sac (Voss, 1967), classification cannot be adjusted to a similar case in a closely related group. In Octopoda, the presence or (complete?) absence of the ink sac is listed among the char- acteristics of a genus at the least (Robson, 1932). Separation at a higher level in the case of Neorossia caroli would be exaggerated, despite its uniqueness among Decapoda, because this genus is, except for the reduc- tion of the ink sac and the anal valves, so similar to Rossia that N. caroli has even been considered as possibly being a geographical race of the same species as R. bullisi (Mangold-Wirz, 1963). Less than generic dis- tinction, on the other hand, would be inappropriate, because complete loss of an important function such as the production of ink is likely to be the result of a longer evolutionary process than the morphological modification of a fully developed organ, considered as a subgeneric or even generic characteristic (e.g., light organs of Sepiola and Rondeletiola; Naef, 1923). The question arises whether Neorossia caroli is really the only known species of Rossiinae devoid of a functional ink sac. At present, it cannot be answered definitely, but there is no doubt as to the following species, members of the three remaining subgenera of Rossia and of the genus Semirossia; I have found a well-developed ink sac in all of them: Rossia (Rossia) macrosoma and R. moiled; Rossia (Allorossia) bullisi, R. glaucopis, R. megaptera, R. mollicella, and R. tortugaensis; Rossia (Austrorossia) antillensis; Semirossia tenera, S. patagonica, and S. equalis. Our knowledge of Rossia is, as a matter of fact, still insufficient for a thorough revision of the genus, but I am confident that removing a species 968 Bulletin of Marine Science [21 (4) and a subgenus fram where they evidently do not belong will facilitate, rather than impede, working up the bulk of the remaining problems. Diagnosis of Neorossia n.g.- Typical Rossiinae with dorsal adhesive organ at the entirely free mantle border; buccal membrane with six lobes. Ink sac reduced to a narrow tube, no ink secretion in the rudiment of the ink gland. Anal valves completely reduced.
ARTIFICIAL KEY TO THE GENERA OF ROSSIINAE 1. No functional ink sac and anal valves Neorossia n.g. Ink sac and anal valves well developed 2 2. No light organs connected with ink sac; both dorsal arms of male hectoco tylized Ross ia Owe n Light organs connected with ink sac present; only left dorsal arm of male hectocotylized Semirossia Steenstrup
SUMARIO
Neorossia N.G. PRO Rossia (Allorossia) caroli JOUBIN, 1902, CON OBSERVACIONES SOBRE EL ESTATUS GENERICO DE Semirossia STEENSTRUP, 1887 (MOLLUSCA: CEPHALOPODA) Rossia caroli Joubin es colocada en un nuevo genera, Neorossia, caracterizado por la reducci6n del saco de la tinta y las valvulas an ales aparentemente a rudimentos sin funciones. Este es el primer reporte de un cefal6podo decapodo sin saco de tinta funcional. En el presente estudio el estatus generico original de Semirossia Steenstrup se reestablece.
LITERATURE CITED BOLETZKY, S. v. 1970. Biological results of the University of Miami Deep-Sea Expeditions. 54. On the presence of light organs in Semirossia Steenstrup, 1887 (Mollusca: Cephalopoda). Bull. Mar. Sci., 20: 374-388. CHUN, C. 1915. Die Cephalopoden. II. Teil: Myopsida, Octopoda. Wiss. Ergebn. dt Tiefsee-Exped. "Valdivia," 18(2): 405-552, pIs. 63-95. GRIMPE, G. 1922. Systematische Uebersicht der europaischen Cephalopoden. Sber. naturf. Ges. Lpz., 48: 36-52. JOUBIN, L. 1902a. Observations sur divers Cephalopodes. 6e Note: Sur une nouvelle espece du genre Rossia. Bull. Soc. zool. Fr., 27: 138-143. 1902b. Revision des Sepiolidae. Mem. Soc. zool. Fr., 15: 80-145. MANGOLD-WIRZ, K. 1963. Contribution a l'etude de Rossia caroli Joubin. Vie Milieu, 14: 205- 224. 1971] v. Boletzky: Neorossia n. g. 969
NAEF, A. 1923. Die Cephalopoden. Fauna Flora Golfo Napoli, Monograph No. 35, Teil I, Band 1, Lfg. 2: i-xiv, 149-863. NORMAN, A. M. 1890. Revision of British Mollusca. Ann. Mag. nat. Rist., Ser. 6, 5: 457- 484. ROBSON, G. C. 1932. A monograph of the Recent Cephalopoda. Part IT, The Octopod a (excluding the Octopodinae). London, pp. 1-359. SASAKI, M. 1920. Report on the cephalopods collected during ]906 by the U.S. Bureau of Fisheries Steamer Albatross in the northwestern Pacific. Proc. U.S. natn. Mus., 57: 163-203. STEENSTRUP, J. J. S. 1887. Notae Teuthologicae, 7. Overs. K. dansk. Vidensk. Selsk. Forh., ]887: 21-80 (67-126). Voss, G. L. 1967. The biology and bathymetric distribution of deep-sea cephalopods. Stud. trap. Oceanogr. Miami, No.5: 511-535.