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Studies on Thalassinid Crustacea (Decapoda, Macrura Reptantia) with a Description of a New Jaxea from New Zealand and an Account of its Larval Development
Part I — An Outline of the New Zealand Thalassinidea with Keys to the Genera of the Family Laomediidae and to Recent Adults of the Genus Jaxea Nardo, 1847
Part I
An Outline of the New Zealand Thalassinidea with Keys to the Genera of the Family Laomediidae and to Recent Adults of the Genus Jaxea Nardo, 1847
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1. The New Zealand Thalassinidea
In this account the laomediids and their thalassinid allies will be regarded as belonging to the supersection Macrura Reptantia and their relationship to the Anomura will not be considered.
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Order DECAPODA
Supersection MACRURA REPTANTIA
Section THALASSINIDEA
The seven families now regarded as belonging to the section (previously called tribe) Thalassinidea are the Callianassidae, Callianideidae, Upogebiidae, Axiidae, Axianassidae, Laomediidae and Thalassinidae. These are discussed in some detail and a key for their separation is given by Gurney (1938: 339–343). All are apparently burrowing forms characterised by:— a reasonably well calcified, compressed carapace; a symmetrical, extended, often feebly calcified abdomen terminating in a well developed tail fan; the first pair of legs chelate or subchelate, second chelate, subchelate or simple, and third legs always non-chelate.
The family Callianassidae is represented in New Zealand by at least two species. Callianassa (Trypaea) filholi A. Milne Edwards (see Chilton, 1907; de Man, 1928: 101) is a widespread burrower of intertidal sandy beaches and can be locally abundant; its first larval stage has been described by Lebour (1955) and by Wear (1965). The rarely collected Ctenocheles maorianus Powell, 1949, is known from both shallow water and the continental shelf, where it is often recognised merely from detached examples of its highly characteristic comb-like chelae (see also Glaessner, 1960: 13).
The minor family Calliandeidae presumably is represented in our waters since Callianidea typa H. Milne Edwards has been listed from New Zealand by de Man (1928: 30).
The Upogebiidae is represented by the subtidal and shallow water species Upogebia (Upogebia) hirtifrons (White) and U. (U.) danai (Miers)–see Chilton, 1907; de Man, 1928: 39–43.
The Axiidae is represented by at least three species on the New Zealand continental shelf and probably others as yet unrecognised. Axius (Axius) novaezealandiae Borradaile, 1916, has seldom been taken; Calocaris (Calocaris) macandreae Bell, "Indian form" has been recorded (Kirk, 1879; de Man, 1925: 8), and an undescribed Axiopsis (Axiopsis) n.sp. is quite common (see Griffin and Yaldwyn. 1965: 43).
The Axianassidae, Laomediidae and Thalassinidae complete the list of families included in this section. A single species of the family Laomediidae is described here, while the other two families have not yet been recorded from the New Zealand area. The family name "Axianassidae" used by Wear (1965: 13) for two species of axiid larvae from Wellington Harbour is a lapsus for Axiidae. One of these two larval species was provisionally placed in Iconaxiopsis, a subgenus of Axius.
2. The Family Laomediidae Borradaile, 1903
The laomediids are rather rare, burrowing decapods, macrurous in form, regarded by some authors as true Anomura in their systematic relationships. The family is at present represented by three genera and six described species.
Laomedia de Haan is known from one species, L. astacina de Haan, 1849, from Japan and Korea (see de Man, 1928; Sakai, 1962). The authors know a large undescribed adult laomediid from eastern Australian shallow waters which also appears to belong to the genus Laomedia.
Jaxea Nardo is known from one named species, J. nocturna Nardo, 1847, from the Mediterranean and North Atlantic (see Selbie, 1914; Bouvier, 1940), and from four, apparently specifically distinct, but unnamed species known only by their larvae—in New Zealand waters (Gurney, 1924), off Samoa (Gurney, 1938), off New South Wales (Dakin and Colefax, 1940) and from the Adriatic Sea (Kurian, 1956). In Part II of this paper we wish to report the finding of the adults and all the larval stages of the New Zealand species which we propose to name Jaxea novaezealandiae n.sp.
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The remaining genus, Naushonia Kingsley, is known from four species: N. crangonoides Kingsley, 1897, from off Massachusetts (Atlantic Coast of U.S.A.); N. portoricensis (Rathbun, 1901) from Puerto Rico, West Indies; N. perrieri (Nobili, 1904) from the Red Sea, and N. macginitiei (Glassell, 1938) from Southern California (see Chace, 1939). Larval stages referred to Naushonia have been described from off New South Wales (Dakin and Colefax, 1940) and, with less certainty in generic placing, from off Samoa and from the Great Barrier Reef (Gurney, 1938).
The family Laomediidae, as now constituted, consists of those Thalassinidea having:— a linea thalassinica (a transverse, hinged groove along each side of the carapace) present; 1st pereiopods subequal, and chelate or subchelate; 2nd pereiopods subchelate or simple, never chelate; no appendix interna on pleopods; uropod with transverse suture on both endopod and exopod; podobranchs on at least 2nd and 3rd maxillipeds and 1st and 2nd pereiopods, and epipods on 1st to 4th pereiopods.
| 1 (4) | First pereiopods chelate, 5th pereiopods subchelate; antennal scale (scaphocerite) rudimentary or absent (Laomediinae) | |
| 2 (3) | First pereiopods with stout and heavy chelae (hand length less than 2½ times hand width and less than carapace length), 2nd pereiopod subchelate or simple*; peduncles of both antennule and antenna short (penultimate segment of antennal peduncle subequal with ultimate)† | Laomedia de Haan, 1849 |
| 3 (2) | First pereiopods with relatively heavy but elongated chelae (hand length three or more times hand width and subequal with or greater than carapace length); 2nd pereiopod subchelate; peduncles of both antennule and antenna elongated and relatively slender (penultimate segment of antennal peduncle at least four times ultimate)† | Jaxea Nardo, 1847 |
| 4 (1) | First pereiopods subchelate, 2nd and 5th pereiopods simple; antennal scale well developed (Naushoniinae) | Naushonia Kingsley, 1897 |
Genus Jaxea Nardo, 1847
Laomediids with a firm, white exoskeleton covered with a densely crowded fur of very short setae. The linea thalassinica of the carapace is distinct and well
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developed. The eye is reduced and hidden under the rostrum in dorsal view and the pigmentation of the cornea is reduced. The peduncles of both the antennules and antennae are greatly elongated and relatively slender. The scaphocerite is rudimentary but distinct. First maxilliped with flagellum on exopod but no podo-branch. First pereiopods subequal, with enlarged and elongate chelae, 2nd and 5th pereiopods subchelate. A single arthrobranch on 1st maxilliped and two on 2nd and 3rd maxillipeds and on 1st to 4th pereiopods. Podobranch present or absent on 3rd pereiopod. Male 1st pleopods absent, female 1st pleopods reduced and uniramous, 2nd to 5th pleopods biramous and similar in both sexes.
The type of the genus is Jaxea nocturna Nardo, 1847 (of which Calliaxis adriatica Heller, 1863, is a synonym) known from the British Isles and Irish Sea (Selbie, 1914), the Mediterranean coast of Spain (Zariquiey, 1946), the Adriatic (numerous authors), and apparently more abundant in the eastern Mediterranean, including the coasts of Israel and Egypt, than in the western Mediterranean (Holthuis and Gottlieb, 1958).
A fossil from the Miocene of the Vienna Basin has been described as Jaxea kuemeli Bachmayer, 1954 (corrected from kümeli). It can be distinguished at once from the two named recent species in this genus by the position of the cervical groove in the adult stage. In the fossil form this groove is situated distinctly posterior to the midpoint of the carapace, exclusive of the rostrum.
| Hand between 1 and 1½ times length of carapace and rostrum; fingers more than 1½ times length of palm. Anterolateral margin of carapace with several small teeth below origin of line a thalassinica and sometimes several minute "thorns" above. Third maxilliped with ischium armed medially with a crest of about 14 to 16 strong teeth | J. nocturna |
| Hand subequal in length to carapace and rostrum; fingers a little longer than palm. Anterolateral margin of carapace with single small tooth immediately above origin of line a thalassinica and sometimes several minute "thorns" below. Third maxilliped with ischium armed medially with a crest of about 12 to 14 (usually 13) strong teeth | J. novaezealandiae |
* The 2nd pereiopod of Laomedia astacina is described as "simple" (see Borradaile, 1903: 540, under generic name only) or implied to be so (Sakai, 1962: 30 and fig. 19. Note that Sakai calls this limb "fifth pereiopodite", apparently regarding the 1st maxilliped as equivalent to his "first pereiopodite"), but the 2nd pereiopod of an undescribed Laomedia from eastern Australian waters must be termed "subchelate". In this species the dactyl closes against part of the prodopus and can be regarded as subchelate, just as in the 2nd pereiopod of Jaxea novaezealandiae.
† The 1st maxilliped of Laomedia astacina is described as having "no lash to the exopodite nor podobranch", while that of Jaxea nocturna is described as having "a lash to the exopodite and a podobranch" (see Borradaile, 1903: 540–41, under generic names only). These features do not appear to be good generic differences as Sakai (1962: 31 and fig. 11) clearly figures a flagellum on the exopod of the 1st maxilliped (= his "first pereiopodite") of L. astacina and lists, but does not figure, a rudimentary podobranch on this appendage. The eastern Australian Laomedia, Jaxea nocturna (see Selbie, 1914: 99 and Pl. XV, fig. 6) and J. novaezealandiae all have a flagellum on the exopod of the 1st maxilliped, with a podobranch recorded, though not figured, in J. nocturna only (Selbie, 1914). Caroli (1924) denies the presence of this podobranch in J. nocturna, and from personal examination neither Jaxea novaezealandiae, nor the undescribed Laomedia, have any trace of a podobranch on this appendage.