Art. VI.—Notes on the New Zealand Squillidæ.
[Read before the Otago Institute, 13th October, 1890.]
During the early part of this year I obtained from Mr. W. M. Innes, of Port Chalmers, some very fine specimens of a Squilla, and, in endeavouring to identify them with the forms already described from New Zealand, I have been led to make the following notes, which are perhaps worthy of publication:—
In Miers's “Catalogue of the Stalk- and Sessile-eyed Crustacea of New Zealand,” published in 1876, two species of Squillidæ are given, both on the authority of Heller. These are Squilla nepa, Latr., and Gonodactylus trispinosus, White. It is doubtful, however, whether either of these really belongs to New Zealand. In a paper on the Stalk-eyed Crustacea of New Zealand, in the New Zealand journal of Science, vol. i, p. 263, Professor Hutton gives Squilla nepa in a list of species which he considers as “very doubtful,” but which he was not yet prepared to dismiss from the New Zealand Catalogue. Gonodactylus spinosus, he says, may possibly belong to the colony, but was not represented, so far as he knew, in any collection in the colony.
So far as I know, neither of these species is yet represented in any New Zealand collection, but there I fear the matter must be allowed to rest for the present, as it is desirable to hesitate long before removing any species from the list.
Squilla nepa is, according to Miers, * widely distributed in the Indo-Pacific region, and has also been recorded from Sydney and from Chili. Gonodactylus trispinosus is known from Western Australia, Fiji, &c.
Since the publication of Miers's New Zealand Catalogue, the additions to our knowledge of the New Zealand Squillidæ have been as follows: In 1878 Mr. T. W. Kirk described as a new species Squilla indefensa, from Chatham Islands and Kapiti, and also recorded the occurrence of Squilla armata, M.-Edw., in Wellington Harbour. In the same year Professor Hutton described as a new species Squilla lævis, from the Auckland Islands. In 1880 Mr. E. J. Miers identified Squilla indefensa, Kirk, with Coronis spinosa, Wood-Mason, under the name Lysiosquilla spinosa; but at the time of writing his paper “On the Squillidæ” had evidently not seen Professor Hutton's description of Squilla lævis. In 1881 Mr. G. M. Thomson described as a new species Squilla tridentata, from Stewart Island. Brooks's “Report on the ‘Challenger’ Stomatopoda,” published in 1886, added greatly to our general knowledge of the group, and especially of the larval forms, and in this respect largely completed the working-out of the larval history that had been commenced by Claus in his “Die Metamorphose der Squilliden,” which appeared in 1871. The number of adult forms in the “Challenger” collections was, however, small, and none of them were from New Zealand. It is to be noted, however, that Brooks places Gonodactylus trispinosus, White, in a new genus, Protosquilla, formed to include some new species and some previously put down toGonodactylus.
I am not acquainted with any other papers bearing on the New Zealand Squillidæ.
During this year I received two very fine specimens of a Squilla from Mr. W. M. Innes, of Port Chalmers, and, in working these out and comparing them with the descriptions of the different species described from New Zealand, I became convinced that Squilla indefensa, Kirk, S. lævis, Hutton, and S. tridentata, Thomson, represent but one species, and that my specimens also belong to this species; and it is chiefly with the object of establishing this fact that I am writing the present paper, as in any consideration bearing on the New Zealand fauna the apparent existence of three species of Squilla (instead of one, as is really the case) might easily lead to wrong conclusions.
Our list of New Zealand Squillidæ will therefore be as follows:—
[Footnote] * “On the Squillidæ,” Ann. and Mag. N.H., ser. 5, vol. v., p.1.
Squilla nepa, Latreille.
Miers, “On the Squillidæ,” Annals and Mag. Nat. Hist., ser. 5, vol. v., p. 25 (1880).
Brooks, “Report on the ‘Challenger’ Stomatopoda”, p. 25 (1886).
The further synonymy is given by Miers in the paper quoted.
Hab. Indo-Pacific region. Recorded from New Zealand by Heller, but New Zealand habitat doubtful.
Squilla armata, Milne-Edwards.
Miers, l.c., p. 26 (1880).
Kirk, Trans. N.Z. Inst., xi., p. 401 (1878).
As no description of this species has as yet appeared in any New Zealand publication, I transcribe the following from Miers's paper “On the Squillidæ:”—”
“The carapace is narrowed anteriorly, with the cervical suture very faintly defined in its posterior portion, and the lateral longitudinal carinæ obliterated, except on the postero-lateral lobes; the spine at the antero-lateral angles is small but distinct. The rostral plate is somewhat elongated and narrowed distally, with a very slight median elevation. The lateral spines of the antennulary segment are prominent and curved forward; and in front of these are two smaller spines on the ocular segment. The lateral processes of the first exposed thoracic segment are narrow, straight, and acute; those of the two following segments are broader and rounded laterally, with a spinule at their postero-lateral angles. There is a small median carinule or tubercle on the 3rd to 5th post-abdominal segments; on the 4th and 5th segments the lateral carinæ, and on the 6th segment all the carinæ end in spinules; the terminal segment is armed with a few tubercles near its base, with a longitudinal median carina, on either side of which is a lateral longitudinal series of very small tubercles; there is a rather deep median fissure between the submedian marginal spines, but no denticles; between these and the first lateral marginal spines there are on each side ten or eleven very small denticles or spinules. The distal prolongation of the base of the uropoda ends in two very unequal spines, the inner of which bears a small tooth on its outer margin. Length of the larger individual 5 ⅙in.”—[Miers.]
Hab. Chili; Auckland Islands (Miers). Recorded from Wellington by Mr. T. W. Kirk. There is a specimen (much damaged) in the Dunedin Museum labelled “Dunedin.” Mr.
Kirk informs me that the “Mantis shrimps,” dredged in Wellington Harbour, and exhibited by Mr. McIntyre at the meeting of the Wellington Philosophical Society on 2nd July 1890,* also belong to this species.
Mr. Kirk very kindly lent me a fine spirit specimen (female) and two dried specimens (males) for examination. The female is 4 ¼in. in length; the males are smaller. The “small median carinule or tubercle on the 3rd to 5th post-abdominal segments” is but slightly represented on the large female specimen, and is barely distinguishable in the smaller male specimens, and the “lateral longitudinal series of very small tubercles” on the sides of the median carina of the telson are also absent in all specimens; but in all other respects the specimens agree very closely with Miers's description. As the male specimens are dried, I have not been able to examine the structure of the terminal joint of the 1st abdominal appendage in this species.
Protosquilla trispinosa, White.
Miers, l.c., p. 121, pl. iii., fig. 10 (1880).
Brooks, l.c., p. 71 (1886).
Further synonymy is given by both Miers and Brooks.
Hab. West Australia, Fiji, Ceylon, &c. Recorded from New Zealand by Heller, but New Zealand habitat doubtful.
Lysiosquilla spinosa, Wood-Mason.
Wood-Mason, Proc. Asiatic Soc. Bengal, p. 232 (1875).
Kirk, Ann. and Mag. Nat. Hist., ser. 5, ii., p. 466 (1878).
Kirk, Trans. N.Z. Inst., xi., p. 394 and p. 401 (1879).
Hutton, Trans. N.Z. Inst., xi., p. 340 (1879) (not Hess).
G. M. Thomson, Trans. N.Z. Inst., xiv., p. 230 (1882).
Miers, “On the Squillidæ,” Ann. and Mag. Nat. Hist, ser. 5, v., p. 12, pl. i., figs. 10–12, and p. 125 (1880).
Of this species I have been able to examine Professor Hut-ton's type-specimen of Squilla lævis, and another specimen labelled “Squilla indefensa, Kirk”, in the Dunedin Museum; Mr.
[Footnote] * Monthly Review, ii., p. 427.
G. M. Thomson has kindly lent me his type of Squilla tridentata and a specimen obtained at Waipapa Point by J.F. Erecson; and Mr. T. W. Kirk has been good enough to send me specimens of his Squilla indefensa. I am thus able to give the synonyms mentioned above with perfect confidence: indeed, this might almost have been done from the descriptions alone, as there is little difference between them, except with regard to the number of teeth on the dactylos of the raptorial limbs; and this is evidently subject to some variation, as Miers has already pointed out in some other species. One of my specimens, a male 3.68in. in length, has twelve teeth (without the terminal spine) on the left side and thirteen on the right; the other specimen, a female, has lost the raptorial limbs. Squilla lævis, Hutton (type-specimen), has twelve teeth (exclusive of the extremity); Squilla indefensa, Kirk (type-specimen), has nine (exclusive of the extremity); Coronis spinosa, Wood-Mason, is described as “ten-toothed,” while Miers describes Coronis tricarinata, Gray, which I have no doubt belongs to this species, as having nine teeth including the terminal spine. Thomson's type-specimen of Squilla tridentata has only three teeth (four if we include the terminal spine); but it is very small—only 0.75in. long—and is evidently a young form: in the structure of the telson and in all other points it agrees closely with the other specimens.
Squillalævis, Hutton, has, of course, no connection with Squilla lævis, Hess., Archiv. f. Naturg., p. 170, pl. vii., fig. 22 (1865), which Miers puts down as a doubtful synonym of Squilla nepa, Latreille.
I have no doubt that the “Lysiosquilla tricarinata (Coronis tricarinata, Gray, ined. White List, Cr. Brit. Mus., p. 85, 1847)” mentioned by Miers* is identical with the species now under consideration. Miers compared it with Kirk's description of Squilla indefensa, and says it is “very probable that it belongs to the same species;” and, from the further description of the unique specimen that he gives, I have no doubt this identification is correct. The specimen was collected in the Antarctic expedition under Captain Sir J. C. Ross, but the locality has not been preserved. I am not able to find out whether White gave a description of it or not, and whether his name, therefore, has precedence over Wood-Mason's or not.
The species we are considering, though described by most of its authors under Squilla, was placed by Miers under the genus Lysiosquilla, Dana, the species of which differ from the more typical species of Squilla chiefly in the absence of the longitudinal ridges or keels on the carapace and abdomen. As no description of this genus has as yet been given in
[Footnote] *Loc. cit., p.12.
works on New Zealand Crustacea, I give here Brooks's diagnosis of it.
Generic Description.—“Stomatopoda with the 6th abdominal somite separated from the telson by a movable joint; the hind body depressed, loosely articulated and wide; the dactyli of the raptorial claw without a basal enlargement, but with more than 6 marginal spines; no more than 4 secondary spines, and often only 1 between the intermediate and submedian spines of the telson, which is usually wider than long, and the outer spine of the ventral prolongation from the basal joint of the uropod usually longer than the inner. The larva is an Erichthus or Squillerichthus with the ocular and antennulary somites covered by the carapace; the lateral edges of the deep carapace folded inwards over the ventral surface; the bases of the postero-lateral spines distant from the dorsal middle line; the hind body flat and wide; the telson wider than long, with a few spines, or only 1, between the intermediate and submedian spines, and the dactylus of the raptorial claw with numerous marginal spines.”—[Brooks.]
To this he afterwards adds: “The terminal joint of the exopodite of the 1st abdominal appendage of the adult male is subtriangular, with its large outer lobe separated by a suture from the very small inner lobe, and the fixed limb of the petasma very small and not ending in a book.”
Lysiosquilla spinosa, Wood-Mason.
Specific Diagnosis.—Whole dorsal surface quite smooth. Carapace with rostrum making up slightly more than one-fifth of the total length from tip of rostrum to the end of the telson. Eyes nearly cylindrical, corneæ somewhat expanded and wider than the peduncles. Rostrum triangular, sides slightly arched, acute in front. Raptorial claw usually with 12 spines on dactylos; inner edge of the propodos narrow and finely pectinated, with 3 stout movable spines and a few fine hairs near the base. Second thoracic segment produced on each side into a thin rounded projection compressed longitudinally so that when viewed from above it looks like a sharp spine; 3rd, 4th, and 5th thoracic segments rounded at the sides. Appendages of the pereiopods ovate, that of the 4th the largest, that of the 5th narrower than the others. Abdomen widening slightly posteriorly, 6th segment having the postero-lateral angles produced into sharp spines. Telson with the posterior margin semicircular, upper surface with a median and two submedian ridges ending posteriorly in sharp spines just above the level of the marginal spines; lateral portion of telson flat, expanded, ending posteriorly in the lateral spines; usually 1
secondary spine between the lateral and intermediate, and 2 or 3 between the intermediate and submedian spines; in the centre, between the submedian spines, the margin is notched, the portion on each side of the median notch being convex, and bearing 8–9 small secondary spines. Sixth abdominal appendages (uropods) large, the basal portion produced into a long flat spine, ridged below along the inner margin, and reaching nearly as far backwards as the endopodite; inside this spine the basal portion bears 2 small spines on posterior margin; on the upper surface it also bears a spine at the postero-distal angle. The endopodite is small and oval; the exopodite has the first joint nearly as large as the terminal joint, and bears 5–6 spines on the distal portion of the outer margin, the last two being long and curving outwards; terminal joint oval, with a ridge running along the centre of the upper surface.
Colour, male greyish, female with abdomen reddish. (For fuller details see below.)
Length of largest specimen examined, 3–68in.
Hab. New Zealand and neighbouring islands. Also recorded from the Andamans (Wood-Mason). In New Zealand this species is evidently widely distributed: Kirk records it from the Chatham Islands, Kapiti, and Waikanae; Hutton's type-specimen was obtained at the Auckland Islands; Thomson's was from Port Pegasus, in Stewart Island, and in his collection there is also a specimen from Waipapa Point; I have specimens from Port Chalmers, and there is also a specimen in Dunedin Museum from Otago Harbour. At the meeting of the Hawke's Bay Philosophical Institute on 13th May, 1889, Mr. Hamilton exhibited specimens of this species* from the Napier district.
In his report on the “Challenger” Stomatopoda, Brooks has called special attention to the complicated structure on the endopodite of the 1st abdominal appendage of the male, and says that “if each description of a new species contained a figure of this structure, the tracing-out of the generic relation between the species would be greatly simplified” (p. 13). I therefore give a description and also figures of this appendage in Lysiosquilla spinosa. From these it will be seen that in most respects it pretty closely resembles the corresponding appendages of Lysiosquilla maculata and L. excavatrix, as described and figured by Brooks, though his figures—especially that of the former—are too small to allow of satisfactory comparison in detail.
In Lysiosquilla spinosa the endopodite of the 1st abdominal appendage of the male (see Pl. X., fig. 1) has the basal joint
[Footnote] * Trans. N.Z. Inst., vol. xxii., p. 551.
subtriangular; the inner edge is sinuous, being convex in proximal half, and afterwards slightly concave, the whole of it being densely fringed with long, very finely plumose setæ; these be come somewhat smaller towards the distal end, but there is a tuft of longer ones again at extremity of the joint; the outer edge is curved, and fringed with setæ similar to those on the inner margin; towards the base these setæ are short, more spiniform, and not so numerous. This basal joint is divided into two parts by an oblique suture running from the outer corner of the base across the joint to the inner distal angle. It would appear that the outer distal portion thus separated off is to some extent movable, as three narrow muscular bands arising from the same muscle that supplies the movable limb of the forceps extend as far as the suture. There is a small tuft of 5–6 simple setæ on the surface of the joint on the proximal side of the suture. The terminal joint, B, of the appendage is divided from the basal joint by a nearly transverse suture; it consists of the inner lobe, b, and the outer lobe, a. The latter is considerably longer than the former, from which it is completely separated, and is very different from it in shape, but is not larger; it is subtriangular, articulating to the basal joint by a very narrow base; it expands distally, and has the end regularly rounded; the outer edge is smooth, but the end and inner margin are densely fringed with long plumose setæ, the outer ones being the longest. The inner joint is partially overlapped by the outer, and is irregularly circular in outline. The retinaculum is distinctly marked, it ends acutely, and has nearly the whole of the inner margin densely covered with the characteristic curved setæ. The movable limb of the forceps, f, is long, curved outwards, and ending acutely in two points; the fixed limb, e, is small, rounded at the end, and apparently curving outwards from the joint, but not hooked.
Secondary sexual differences between the sexes appear to be rare among the Stomatpoda, though Brooks records slight differences in Lysiosquilla maculata. Differences in colour are more common. Brooks states that the male of Pseudo-squilla ciliata is said to be more brilliantly coloured than the female, and that the female of Lysiosquilla excavatrix is larger and darker than the male. Of Lysiosquilla spinosa I have seen one female only, all the rest being males; but, as the males were all closely alike in colour, and differed markedly from the female, I am inclined to think that the difference is normal: and it is worthy of note that in this species, unlike Pseudosquilla ciliata, it is the female that is more brilliantly coloured. In this specimen the thorax and abdomen are also slightly broader in proportion than in the male (see measurements below); but whether this is accidental or normal I can-
not say. The raptorial claws were missing in my single female specimen, but Mr. Hamilton tells me that those of the female differed to some extent from those of the male in his Napier specimens. The males are greyish in colour, the general surface of the body being of a semi-transparent white, and varyingly covered with dark spots, so as to give a grey appearance. There is generally a well-marked line of these along the posterior margin of the segments of the thorax and abdomen, and a much broader but lighter band along the anterior margin. The carapace, raptorial limbs, and uropods are more sparingly marked with dots; the telson is much darker, but has white stripes along the median and submedian ridges, and the margins are also white. In most of these respects the female is similar-coloured, but the carapace is darker, and the grey colour is more distinct on the sides of the thorax and abdomen, and does not extend across the centres of the segments so much as in the male; the grey portions, which are rather darker than in the male, have also a slight greenish tint; and, in addition to this, the whole of the central part of the segments of the abdomen is coloured a bright red. This description of the colours of the animals was taken originally from fresh specimens, but very little change has as yet taken place in the spirit specimens, the bright red of the female in particular being just as brilliant as in the fresh specimen.
Nothing is known as yet of the habits of this species. Although widely distributed, it is, probably owing to its habits, not very often taken, and most of the specimens known have been taken from the stomachs of fish. Both my specimens, one of Mr. Thomson's, and Professor Hutton's, were obtained in this way, Professor Hutton's being from the stomach of Notothenia microlepidota. Most species of the group are burrowing animals; and Lysiosquilla excavatrix, the habits of which have been fully described by Brooks, lies in wait for prey in its burrow, and seldom ventures far from the burrow.
Much interest attaches to the larval forms of the Squillidæ. These are transparent pelagic animals, very different in appearance and in habits from the adults; but nothing special is as yet known of the larval forms of Lysiosquilla spinosa.
For convenience of comparison I have appended a table of measurements of both male and female, similar to those given by Brooks for Lysiosquilla excavatrix. I have made these measurements as carefully as possible; but it must be borne in mind that some of the parts are not easy to measure accurately, and that they may vary to a considerable extent even on the two sides of the one specimen: thus, in the male specimen
measured, the scale of the 2nd antenna was 0.28in. long on one side, but only 0.20in. on the other.
[The section below cannot be correctly rendered as it contains complex formatting. See the image of the page for a more accurate rendering.]
|Measurements.||In Hundredths of an Inch.||In Thousandths of Total Length.|
|Total length on middle line||3.68||3.21||1.000||1.000|
|Total length of rostrum and carapace||0.80||0.70||0.218||0.218|
|From posterior edge of carapace to that of 2nd thoracic segment||0.12||0.12||0.032||0.037|
|From posterior edge of 2nd thoracic segment to that of 3rd||0.20||0.14||0.054||0.044|
|From posterior edge of 3rd thoracic segment to that of 4th||0.22||0.20||0.059||0.062|
|From posterior edge of 4th thoracic segment to that of 5th||0.22||0.20||0.059||0.062|
|Length of 1st abdominal segment||0.30||0.25||0.082||0.078|
|" 2nd "||0.30||0.26||0.082||0.081|
|" 3rd "||0.30||0.26||0.082||0.081|
|" 4th "||0.30||0.26||0.082||0.081|
|" 5th "||0.38||0.32||0.103||0.097|
|" 6th "||0.22||0.22||0.059||0.069|
|Total length of hind body||2.88||2.51||0.782||0.780|
|Width of carapace at anterior end||0.50||0.40||0.136||0.125|
|Greatest width of carapace||0.80||0.70||0.218||0.218|
|Width of 2nd thoracic segment||0.35||0.36||0.095||0.112|
|" 3rd "||0.55||0.50||0.150||0.156|
|" 4th "||0.60||0.56||0.163||0.174|
|" 5th "||0.60||0.58||0.163||0.181|
|Width of 1st abdominal segment||0.68||0.65||0.185||0.202|
|" 2nd "||0.70||0.66||0.190||0.206|
|" 3rd "||0.72||0.67||0.196||0.208|
|" 4th "||0.73||0.67||0.198||0.208|
|" 5th "||0.74||0.68||0.201||0.212|
|" 6th "||0.65||0.62||0.176||0.193|
|Greatest width of telson||0.60||0.56||0.163||0.174|
|Length of 1st antenna, from tip of rostrum to tip of longest flagellum||0.62||0.48||0.168||0.149|
|Length of appendage of 2nd antenna||0.63||0.58||0.171||0.181|
|Length of scale||0.28||0.25||0.076||0.078|
|Length of eye||0.18||0.16||0.049||0.050|
|Total length of swimmeret||0.62||0.52||0.168||0.162|
Descriptin of Plate X.
Fig. 1.Lysiosquilla spinosa. Endopodite of first abdominal appendage of male, posterior side: A, basal joint; B, terminal joint, with outer lobe a, and inner lobe b. (Enlarged.)
Fig. 2.Terminal joint, B, of same, anterior side: d, retinaculum; e, fixed limb of forceps; f, movable limb of forceps. Other letters as in fig. 1. (Enlarged.)
Fig. 3. Portion of the retinaculum, highly magnified, showing the curved setæ.