JOURNAL OF BIOLOGY, 17(4): 695-715, 1997

PHYLOGENETIC ANALYSIS OF THE STOMATOPODA ()

Shane T Ahyong

ABSTRACT The stomatopods or mantis shrimps are malacostracan of the subclass Hoplocarida. All extant hoplocarids belong to the order Stomatopoda and suborder Unipeltata. The Unipeltata comprises the extinct, stem-lineage sculdids, and the crown-group which includes the 19 extant fam- ilies with more than 400 species. A cladistic analysis of all 20 families of the Unipeltata, rooted with four fossil outgroups, resulted in a single, fully resolved topology. The results largely support the existing five-superfamily classification. The Squilloidea, not the Bathysquilloidea, were the earliest derived crown-group superfamily. The Lysiosquilloidea and Erythrosquilloidea are derived as sister groups, which together are sister to the gonodactyloids. The Bathysquilloidea and Gon- odactyloidea, however, were not monophyletic, supporting the erection of new superfamilies for the extinct Sculdidae and the extant Parasquillidae. The Bathysquilloidea is restricted to the Bathysquillidae and Indosquillidae, but, owing to in- complete fossil data, a new taxon is not erected for the sculdids. Instead, the Sculdidae is consid- ered incertae sedis until more fossil data become available. The superfamilial affiliation of the Parasquillidae is also considered uncertain pending further research. Monophyly of the Het- erosquillidae sensu Manning (1995) was unsupported. Paracoridon, presently a heterosquillid, is transferred to the Coronididae. Further study of coronidid relationships is necessary and may sup- port the removal of both Acoridon and Paracoridon. The Tetrasquillidae and Heterosquillidae, as restricted here, are recognized as sister taxa, but further study may require their synonymy. Char- acters based on the modified male first pleopod are informative at superfamily level and further study may reveal characters useful down to the specific level.

Stomatopods are among the most aggres- proposed that the hoplocarids and eumala- sive and behaviorally complex crustaceans. costracans were sister taxa, and included the All are active predators and mark one of the malacostracan phyllocarids with several non- very few radiations of obligate carnivores malacostracan groups in the Class Phyl- within the Crustacea (Schram, 1986). Char- lopoda. Although the sister relationship of the acteristic features of stomatopods are the hoplocarids and eumalacostracans is well sup- large and powerful raptorial appendages. Prey ported, Schram's concept of Phyllopoda is is captured by "spearing" or "smashing," de- now discounted (Martin and Christiansen, pending on whether the dactyl is extended or 1995). Three major radiations from an an- kept folded during the strike. The two meth- cestral malacostracan stock appear to have ods of prey capture distinguish two broad occurred: the Phyllocarida, the Hoplocarida, functional groups, the "smashers"-and the and the 'ifher Eumalacostraca. "spearers" (Caldwell and Dingle, 1976). Presently, the fossil record is relatively These two groups comprise the order Sto- poor, but apparently the hoplocarid ancestors matopoda, the only living representatives of diverged from other malacostracans during the subclass Hoplocarida (Schram, 1986). the Devonian. Three hoplocarid orders are The phylogenetic status of the hoplocarids recognized by Schram (1986): Aeschronec- has been subject to much speculatian tida, Pa+aeostomatopoda, and Stomatopoda. (Schram, 1969). Burnett and Hessler (1973) Fossil aeschronectids and palaeostomatopods considered the hoplocarids to be eumalacos- are known from North America and Europe tracans on the basis of "caridoid facies" (Cal- where they occupied near-shore, shallow-wa- man, 1909). Many characters, however, also ter habitats (Schram, 1977). The aeschronec- occur in other groups (Kunze, 1981). On the tids were the least specialized, whereas the basis of functional morphology, Kunze (1981) palaeostomatopods possessed small, sub- concluded that the hoplocarids evolved from chelate, raptorial claws. Two suborders of the a phyllocarid-like ancestor, distinct from the Stomatopoda are recognized: Archaeosto- eumalacostracans. Conversely, Schram (1986) matopoda and Unipeltata (containing the ex- 696 JOURNAL OF CRUSTACEAN BIOLOGY, VOL. 17, NO. 4. 1997 tant stomatopods). The archaeostomatopods previously assigned tentatively to the Ly- first appeared in the Carboniferous family siosquilloidea. Nineteen families and five su- Tyrannophontidae and are believed to link the perfamilies are currently recognized by Man- Palaeostomatopoda with the Unipeltata. ning (1995) for living taxa, containing more The Unipeltata comprises the Jurassic fam- than 100 genera and 400 species. The many ily Sculdidae and the extant superfamilies, genera, each containing relatively few species, usually termed Recent (Manning, 1980, have been considered to exhibit relict distri- 1995). The term Recent is used variously in bution patterns consistent with the antiquity of different contexts, but usually means Holo- the Stornatopoda (Reaka and Manning, 1987). cene to the present. Since the fossil record Certainly, many apparently closely related taxa suggests that extant superfamilies have Cre- exhibit restricted distributions which are con- taceous origins (Schram, 1986; Reaka and sistent with a former Tethvan distribution. To Manning, 1987), they are here referred to as date, however, cladistic biogeographic analy- the crown-group (Jeffries, 1979). The Uni- ses have not been conducted with stomatopods peltata is here considered to be the total-group to test such hypotheses. These, of course, re- and therefore the extinct sculdids comprise quire prior knowledge of phylogeny. the stem-group or better, the stem lineage Although stomatopods are remarkably uni- (Ax, 1985). The crown-group stomatopods form in general structure, much morpholog- are up to 100 million years old, displaying lit- ical diversity exists within the group. Previ- tle morphological divergence since then. All ous classifications were based on intuitive es- fossil stomatopods since the Cretaceous may timates of phylogeny. Relationships between be assigned to extant families (Schram, 1986). a few genera or families have been discussed Over the past three decades, the or implied in the classification (e.g., Manning, of the Stomatopoda has been revised exten- 1963, 1969c; Manning and Camp, 1993). For sively, principally through the work &Man- more than a century, however, no formal phy- ning (1963, 1968, 1980, 1995). Prior to his logeny of the Stomatopoda has been pro- work, only the single family, Squillidae, was posed, and there are no studies based on recognized for crown-group taxa. Giesbrecht cladistic principles. This analysis of the (1910) proposed several subfamilies based on Unipeltata, therefore, provides a framework larvae, but his work was largely ignored by for further study. those working with adults (Manning, 1968). In the most comprehensive work of its time, MATERIALSAND METHODS Kemp (1913) recognized only 126 species in six genera, in the single family Squillidae. Taxa Included.-All 20 families of the Unipeltata are rep- resented by their respective type genera, or genera re- Using larval, maxillipedal, and telson mor- garded as closely related (if material was unavailable or phology, Manning (1968) recognized 37 gen- published descriptions were insufficient). The Proto- era in four families: Squillidae, Lysiosquilli- squillidae is thus represented by Haptosquilla Manning dae, Bathysquillidae, and Gonodactylidae. (formerly Protosquilla Brooks) and Parasquillidae by Faughnia Serkne (formerly a subgenus of Parasquilla These four families were considered to rep- Manning). Where the family was relatively heteroge- resent distinct lineages within the Stomato- neous, several taxa from that family were included to rep- poda. Although the general aspect is often resent morphological diversity. The Squillidae was rep- sufficient to distinguish the four groups, the resented by Squilla Fabricius and Levisquilla Manning. telson and maxillipedal morphology appear The Nannosquillidae was represented by Hadrosquilla Manning and Acanthosquilla Manning. The Heterosquil- to be fundamental and conservative charac- lidae was represented by Manning, Het- ters, appearing also in larvae where known erosquilloides Manning, and Paracoridon Moosa. The (Manning, 1968). Giesbrecht's subdivisions, Coronididae was represented by Coronida Brooks and based on larvae, correspond to the familial Acoridon Adkison, Heard, and Hopkins. The Tetrasquil- lidae was represented by TetrasquillaManning and Chace lineages recognized by Manning (1968). and Tectasquilla Adkison and Hopkins. Manning (1980), in a further review of stp- Characters were polarized using multiple outgroups matopod classification, recognized four su- (Maddison et al., 1984), thus making no a priori as- perfamilies: Squilloidea, Lysiosquilloidea, sumptions of plesiomorphy or apomorphy. Insofar as the Bathysquilloidea, and Gonodactyloidea. Man- purpose of this study was to resolve relationships among living stomatopods, only fossil taxa were available as out- ning and Camp (1993) recognized in a-new groups. Outgroups included four extinct hoplocarid superfamily, the Erythrosquilloidea, Eq- groups outside of the Unipeltata. Whereas the cladogram throsquilla megalops Manning and Bruce, can be rooted with only a single outgroup, multiple out- AHYONG: PHYLOGENETIC ANALYSIS OF THE STOMATOPODA 697 groups were selected in order to better represent mor- Gonodactylidae and Odontodactylidae) (Fig. phological diversity among the fossil taxa. Three taxa rep- lC, D). The cornea of bathysquilloids, though resenting the Perimecturidae (Palaeostomatopoda) were included: Perimecturus Peach, Bairdops Schram, and Ar- much reduced, is also subspherical. Many chaeocaris Meek. The Tyrannophontidae was represented corneal characters are useful at generic and by its type Tyrannophontes Schram. specific level, but at the level of this analy- Material Examined.-The character states were scored sis, fewer characters are informative. from published descriptions and material in the collec- Recently, the value of the central band of tions of the Australian Museum, Queensland Museum, ommatidia has been recognized as an impor- Northern Territory Museum of Arts and Sciences, and the tant taxonomic character (Manning et al., Smithsonian Institution. Appendix 1 lists material exam- ined from the genera included in the analysis, but is by 1984a, b). Bathysquilloids possess no central no means restricted to the total material examined. band of ommatidia. Squilloids possess two bands of central ommatidia. Gonodactyloids Analytical Methods.--The final character matrix included 30 taxa and 43 characters (Appendix 2). Characters were and lysiosquilloids possess six bands of om- unordered (nonadditive), missing data were scored un- matidia in the central band but the ommatidial known, and polymorphic characters were scored as such facets differ in shape. The absence of a cen- rather than assuming the plesiomorphic state. Uninfor- tral band of ommatidia in bathysquilloids may mative characters were excluded to avoid artificially in- be an artifact of living at considerable depth, flating the consistency indices. Since character polarity was determined by outgroup comparison and character since the corneal facets are absent or ill-de- states were unordered, the number given to each charac- fined and the neural connections to the eyes ter state (i.e., 0, 1, 2) implies nothing about apomorphy are degenerate (Manning et al., 1984b). In or plesiomorphy. Characters and their states are listed in contrast, the fundamental differences in the Appendix 3. Trees weregenerated in PAUP 3.1.1 (Swofford, 1993) central band in the other superfamilies sug- using the heuristic search option (MULPARS, tree-bi- gest that the currently recognized lineages section-reconnection, 10 replications with random input were differentiated early in the history of the order). In PAUP, analyses were run so that the outgroups group (Manning et al., 1984b). The central formed a basal polytomy with the ingroup, and separate band ommatidia of Erythrosquilla appears to analyses were run with the outgroups constrained as monophyletic (the ingroup topology, of course, remained be absent (Manning, 1995). unchanged). Character changes were studied in MacClade Character 1: cornea strongly bilobed 3.04 (Maddison and Maddison, 1993). (0); bilobed (1); subspherical or faintly bi- Relative stability of clades was assessed using boot- lobed (2). strap (Felsenstein, 1985) and decay analyses (Bremer, 1988, 1994). Bootstrapping was based on 100 replicates Character 2: central band of ommatidia ab- of random input order. Decay analysis was conducted by sent (0); with two rows (1); with six rows (2). relaxing parsimony step by step until clades on the most Character 3: central band ommatidia parsimonious tree were no longer unequivocally sup- hexagonal (0); rectangular (1); absent (2). ported on suboptimal trees. Character 4: facets of the cornea well de- fined (0); poorly defined or absent (1). Eyes Antenna1 Protopod Vision in stomatopods has received con- The antennal protopod carries the antenna siderable attention in recent years (e.g., and the antennal scale (scaphocerite). Several Cronin and Marshall, 1989). Corneal mor- characters are informative at family level and phology is diverse and exhibits discernible three are considered here. The protopod of- taxonomic trends. Except in bathysquilloids, ten bears ventral and mesial papillae. Ven- the cornea is bisected by a central band of tral papillae are present in squilloids, most ly- ommatidia. The cornea is often bilobed and siosquilloids, most bathysquilloids, erythro- set transversely or obliquely on the stalk (Fig. squilloids, and some gonodactyloids. Mesial 1A). In erythrosquilloids, most squilloids, and papillae are present in most lysiosquilloids. lysiosquillids, the cornea is considerably An articulated plate (antennal plate), aris- broader than the peduncle and strongly bi- ing from the dorsal margin of the antennal lobed (Fig. 1B). The broad cornea is thought protopod, is present in the gonodactyloid fam- to increase parallax, thereby improving the ilies Pseudosquillidae, Eurysquillidae, Hemi- precision of stereoscopic rangefinding (Cald- squillidae, and Odontodactylidae (Fig. 1C). well, 1991). In most gonodactyloids and some The antennal plate is absent in all other sto- lysiosquilloids (e.g., Nannosquillidae), the matopods (Fig. lA, B). In takuids, gonodac- eyes are subcylindrical or subspherical (e.g., tylids, protosquillids, and alainosquillids, a 698 JOURNAL OF CRUSTACEAN BIOLOGY, VOL. 17, NO. 4,1997

Fig. 1. Anterior region of selected stomatopods. A, Levisquilla jurichi (Squillidae); B, Heterosquilloides insignis (Heterosquillidae); C, Pseudosquilla ciliata (Pseudosquillidae); D, Gonodactylus platysoma (Gonodactylidae). ap = antennal plate, as = anterolateral spine, c = cornea. long, slender, dorsal spine is present (Fig. ID). last three maxillipeds are longer than broad In other taxa, a small tooth may be present. (Fig. 2A-C). In contrast, the maxillipedal Character 5: ventral papillae absent (0); propodi of lysiosquilloids and erythrosquil- present (1). loids are broader than long, bearing ventral Character 6: mesial papillae absent (0); ribbing or beading (Fig. 2D). In most coro- present (1). nidids, the propodi are broad, but the ventral Character 7: dorsal margin of antennal beading is reduced. These maxillipedal forms protopod unarmed or with small tooth (0); are characteristic of both adults and known with articulated plate (1); with slender, fixed larvae (Manning, 1963). spine (2). In most stomatopods, the distal margin of the propodus of the fifth maxilliped bears Maxillipeds a dense brush of grooming setae (Bauer, The structure of the propodi of the third to 1987). This setal brush is vestigial in some fifth maxillipeds is recognized as fundamen- gonodactyloids and present, but reduced, in tal in delineating the superfamilies (Manning, bathysquilloids. 1968, 1980, 1995). In bathysquilloids, squil- In the Archaeostomatopoda and Palaeo- loids, and gonodactyloids, the propodi of the stomatopoda, the relative lengths of the max- AHYONG: PIIYLOGENETIC 4N4LYSIS OF THE STOMATOPODA

Fig. 2. Stomatopodd. A-D, Propodi of maxilliped 3: A, Oratosq~rillir~astephensoni (Squillidae); B, Bathysquilla cras- sispinosa (Bathysquillidae): C, Gonodacty1u.r platy.rorna (Gonodactylidae); D, Lysiosquilla hoevenii (Lysiosquillidae). E-G. raptorial claw: E. Heterosquilla fricarinara (Heterosquillidae); F. Hemisquilla ensigera a~rstraliensis(Heinisquil- lidae); G, ~onodr~chlusplatysoma (Gonodactylidae). H-L. endopod of the first male pleopod (A, B. D, E, right an- terior, C, left anterior): H, Faughnia serenei (Parasquillidae); I, Oratosquilli~iasrephensoni (Squillidae);J, Barhysquilla cmssispinosa (Bathysquillidae); K. Gonodachlus plahsom~(Gonodactylidae): L, Lysiosquilla sp. (1,ysiosquillidae). c = carpus. d = dactylus, i = ischium. h = hooked process. 1 = lateral lobe. (J redrawn after Bruce (1988)). 700 JOURNAL OF CRUSTACEAN BIOLOGY, VOL. 17, NO. 4. 1997 illipedal segments differ from those of crown- present in bathysquillids (one on each side group stomatopods. The propodi of maxil- of the propodus) and one row is present in lipeds 3-5 are all relatively large, elongate, harpiosquillids (on the outer side only). Man- and similar in size (Schram, 1969). This con- ning (1969a) and Bruce (1988) considered the trasts with the crown-group stomatopods, spined propodus in bathysquillids and har- where most maxillipeds are reduced, com- piosquillids to be convergent, since the ma- pared to the outgroups, and the second max- jor spines arise on different sides of the illiped is specialized as a large raptorial claw. propodus. In contrast, the outer row of spines Character 8: propodi of third to fifth max- in harpiosquillids and bathysquillids may be illipeds very elongate (0); slender (1); broad homologous despite their size, and the inner and ventrally ribbed (2); broad with ribbing row a bathysquillid synapomorphy. In the reduced (3). gonodactyloid smashers, the ventral margin Character 9: propodus of maxilliped 5 with of the propodus is smooth or faintly pectinate, setal brush present (0); vestigial (1); reduced (2). except in the Hemisquillidae. The ischiomeral articulation of the rapto- Raptorial Claw rial claw relates to the type of raptorial ap- Unlike the archaeostomatopods and palaeo- pendage and may be terminal or subterminal. stomatopods, the second maxilliped of crown- In spearers, the ischiomeral articulation is ter- group stomatopods is specialized as a rapto- minal (Fig. 2E, F). In most lysiosquilloids the rial claw. Apparently, in crown-group stomato- ischium is relatively long in proportion to the pods, maxillipeds 3-5 have become reduced merus. In Heterosquilla tricarinata, for ex- in size, while maxilliped 2 has become spe- ample, the ischium is approximately half the cialized. The condition in the sculdids is merus length (Fig. 2E). The relatively long presently unknown. ischium in the lysiosquilloids appears to fa- In all squilloids, bathysquilloids, eryth- cilitate increased reach of the raptorial claw rosquilloids, most lysiosquilloids, and some from the burrow entrance. gonodactyloids, the dactylus is armed with a The subterminal ischiomeral articulation series of serrated teeth used to impale prey. (Fig. 2G) appears to be a specialization for On the basis of ontogeny, fossil evidence, and smashing and is present in the most special- behavior, the spearing claw (Fig. 2E) is prob- ized smashers (Protosquillidae, Odonto- ably plesiomorphic (Caldwell, 1991). dactylidae, Gonodactylidae, and Takuidae). In smashers, the dactyl is basally inflated This condition may have arisen from en- and heavily calcified (Fig. 2F, G). The inner largement of the muscle blocks in the merus, margin of the dactyl is unarmed in the Pro- allowing a more powerful smashing strike. tosquillidae, Gonodactylidae, and Hemisquil- The ischiomeral articulation is terminal in all lidae (Gonodactyloidea). In Coronididae outgroups. (Lysiosquilloidea) and Odontodactylidae Character 10: maxillipeds subequal in size (Gonodactyloidea), the inner margin of the (0); second maxilliped considerably larger dactylus is armed with teeth. than others (1). The dorsal surface of the raptorial carpus Character 11: raptorial dactylus with long bears a stout tooth in most crown-group taxa. serrated teeth (0); teeth small, triangular (1); In the squilloids, however, the carpus is car- teeth absent (2). inate (which may be tuberculate) or un- Character 12: raptorial dactylus basally un- adorned. inflated (0); inflated (1). The raptorial propodus in most spearers is Character 13: raptorial carpus unadorned pectinate and armed proximally with a series (0); carinate (1); with obsolete projection or of up to four movable spines. In most coro- tooth (2); with stout tooth, usually acute (3). nidids, the propodus is pectinate only for the Character 14: number of movable spines on proximal two-thirds, except in Acoridon. In propodus absent (0); 1 (1); 2 (2); 3 (3); Acoridon, the propodus is pectinate for nearly 4 (4). its full length, as in Tectasquilla, for exam- Character 15 : outer inferior propodal mar- ple. In the bathysquilloids and harpiosquil- gin with fixed spines (0); pectinate (1); lids, the propodus is also armed with a se- smooth (2); pectinate for part of length (3). ries of evenly spaced, erect spines, presum- Character 16: fixed spines on inner inferior ably to aid prey retention. Two rows are margin of propodus present (0); absent (1). AHYONG:PHYLOGENETIC ANALYSIS OF THE STOMATOPODA 701

Character 17: ischiomeral articulation of arating lysiosquillids from pseudosquillids. raptorial claw terminal (0); subterminal (1). The genera of Ingle (1963), however, now Character 18: ischium length relative to correspond to families and superfamilies. merus very short (0); long (1). Thus, the assertions of Ingle still hold when interpreted at a higher taxonomic level. Carapace Two characters are used in this study: the The carapace of crown-group stomatopods structure of the hooked process and the pres- is broad and shieldlike. In most squilloids, the ence or absence of a large, lateral lobe on the carapace bears anterolateral spines (Fig. 1A). distal margin of the endopod (Fig. 2K). In A well-defined cervical groove is present lysiosquilloids, the hooked process is usually across the dorsum of the carapace in squil- short and the apex is always produced to a loids, bathysquilloids, and parasquillids. In blunt, round hook (Fig. 2L). The hooked other taxa, the cervical groove is absent or process in bathysquilloids resembles the ly- only faintly indicated laterally on or near the siosquilloid condition (Fig. 25). In squilloids gastric grooves. and gonodactyloids, the hooked process is In all crown-group stomatopods, the cara- elongate terminating in a sharp, crochet hook pace lacks ventrally produced lateral margins, (Fig. 2H, I, K). A broad, nonsetose lobe is permitting free movement and accommodat- present distolaterally on the endopod of gon- ing the massive raptorial claws. In the out- odactyloids (Fig. 2K) and absent in other groups, the lateral margins of the carapace taxa, including Faughnia (Parasquillidae) continue ventrally, partially enclosing the oral (Fig. 2H). Some bathysquilloids bear a notch field. in the margin, but no lobe or evidence of a In the Tyrannophontidae and all crown- lateral expansion, as in the gonodactyloids, is group stomatopods, the last three thoracic present. somites are fully exposed. In the Palaeosto- Character 23: endopod of male first pleo- matopoda, the thoracic somites are largely pod lacking lateral lobe (0); with lobe (1); concealed by the carapace. margin with a notch (2). Character 19: carapace largely concealing Character 24: hook process elongate (0); thoracic somites (0); posterior thoracic short (1). somites fully exposed (1). Character 20: carapace lateral margins pro- Pereiopods duced ventrally (0); lateral margins not pro- Malacostracans typically walk on the en- duced ventrally (1). dopods of the thoracic pereiopods. In sto- Character 2 1: anterolateral spines present matopods, the pereiopods consist of a 3-seg- (0); absent (1). mented protopod, a 2-segmented outer branch Character 22: cervical groove present (0); and a 1- or 2-segmented inner branch. Sto- absent (1). matopods walk on the outer branch. The outer branch is usually termed the exopod and the Male First Pleopod inner branch the endopod on the basis of spa- Stomatopods possess five pairs of gill- tial position (Holthuis and Manning, 1969). bearing pleopods. The distal segment of the Nevertheless, the endopod and exopod of the endopod of the first male pleopods undergoes stomatopods may not be homologous with the secondary sexual modification (Fig. 2H-L). caridoid endopod and exopod (Kunze, 1983). The precise function of the petasma is un- The shape of the pereiopodal endopods is clear, but it appears to have reproductive util- used as a diagnostic character in lysiosquil- ity as in other malacostracans. The mor- loids. The endopods vary from elongate (ly- phology of the petasma may be used to siosquillids) (Fig. 3A) to oval (tetrasquillids, broadly delineate lineages at a superfamilial coronidids, and heterosquillids) (Fig. 3B) to level. Further study may indicate generic and subcircular (nannosquillids) (Fig. 3C). The specific level differences, although Manning roundness of the pereiopodal endopods cor- (1969b) found no specific differences in Gon- relates with body size. Lysiosquillids, in odactylus. Ingle (1963) believed that the which the pereiopodal endopods are elongate, form of the petasma bears useful generic are also the largest. The nannosquillids, which characters. Specifically, he identified the mature at the smallest sizes, have subcircu- form of the "hook" process as useful for sep- lar pereiopodal endopods. 702 JOURNAL OF CRUSTACEAN BIOLOGY, VOL. 17, NO. 4, 1997

Character 25: 1,2 pereiopodal endopods elongate protopod, unsegmented endopod, elongate (0); ovate (1); subcircular (2). and 2-segmented exopod. Unlike caridoids, stomatopods do not use the telson and Abdomen and Thorax uropods for backward propulsion as in the The dorsal ornamentation, structure, and "caridoid escape reaction." Rather, the articulation of the thoracic and abdominal uropods and telson usually function to sup- somites are particularly informative at super- port the abdomen and hold the pleopods family and family levels. The squilloid body (bearing gills ) off the substrate (Tirmizi and form is typically dorsoventrally depressed and Kazmi, 1984). A secondary use of the telson longitudinally carinate (Fig. 3E). The degree and uropods is in offense and defense, par- of carination varies and is a useful generic ticularly among gonodactylids. The uropods character. Bathysquilloids also have dorso- are rich in diagnostic characters below fam- ventrally depressed, carinate bodies, though ily level but are less similar between families. the carinae are much reduced. All lysiosquil- Three characters are considered here. The loids have flattened, noncarinate abdomens segmentation of the uropodal exopod is sig- (Fig. 3D) and somites are usually loosely ar- nificant. The uropodal exopod may be 1- or ticulated. In the Coronididae, Tetrasquillidae, 2-segmented. In most crown-group taxa, the and Heterosquillidae, the thoracic and ab- exopod is 2-segmented. In most fossil taxa, dominal somites are more closely articulated, such as the Sculdidae, the exopod is l-seg- referred to as compact (although diagnosed mented. In Tyrannophontes the segmentation as "loosely articulated" by Manning (1995), is scored as polymorphic because of variation the articulation in all heterosquillids exam- in the family and uncertainty in one species ined appears to be compact). In eurysquillids (Schram, 1984). In the bathysquilloid In- and erythrosquillids, the body resembles Ly- dosquilla manihinei Ingle and Merrett the dis- siosquilla. tal segment is reduced and separated from the In the gonodactyloids, the abdomen is usu- proximal segment only by an indistinct di- ally subcylindrical and compact (Fig. 3F). aeresis. Although it has been speculated that This condition is typical of the Gonodactyli- the exopod of Indosquilla marks affinity with dae, Odontodactylidae, Protosquillidae, and the sculdids, I believe that the resemblance Pseudosquillidae. The abdominal form may is superficial, reflecting neoteny as seen in relate to the habitat that most species of these several other stomatopod larvae (Manning, families occupy, namely, rock and coral 1991). Where the exopod is 2-segmented, the crevices (Reaka and Manning, 198 1). Hemi- articulation of the uropodal exopod may be squillids and parasquillids are more dorsoven- terminal (Fig. 3G) or subterminal (Fig. 3H). trally flattened and depressed. The uropodal endopod of the lysiosquil- The fusion of the anterolateral plates of the loids bears a dorsolateral fold. In nan- first abdominal somite unites bathysquillids. nosquillids, the fold is strong (Fig. 31). In In the outgroups, the anterolateral plates are other lysiosquilloids, the fold is weak (Fig. absent and, in most ingroup taxa, they are ar- 35) and in other taxa, the fold is absent (Fig. ticulated. 3K). Character 26: abdomen depressed (0); sub- Character 30: uropodal exopod unseg- cylindrical (1); flattened (2). mented (0); with diaeresis (1); 2-segmented Character 27: abdomen dorsally carinate (2). (0); noncarinate (1). Character 3 1: articulation of uropodal exo- Character 28: abdominal articulation com- pod segments terminal (0); subterminal (1); pact (0); loose (1). absent (2). Character 29: anterolateral plates articu- Character 32: dorsolateral endopod fold ab- lated (0); fused (1); absent (2). sent (0); weak (1); strong (2). Uropodal Articulation Telson The uropods of stomatopods are broad and The telson bears diagnostic characters at all massive relative to those of other malacos- taxonomic levels. In all groups except the ly- tracans. The tail fan of the crown-group sto- siosquilloids, a distinct dorsal median carina matopods is far more elaborate than in the is present (Fig. 4A, B, D, E). The median ca- outgroups. It typically consists of a forked, rina is present in fossil groups and is proba- AHYONG: PHYLOGENETIC ANALYSIS OF THE STOMATOPODA

Fig. 3. Stomatopoda. A-C, first and second pereiopodal endopods (indicated by stippling): A, Lysiosquilla ho- evenii (Lysiosquillidae); B, Heterosquilloides insignis (Heterosquillidae); C, Acanthosquilla acanthocarpus (Nan- nosquillidae). D-F, abdominal cross-sectional form: D, flattened; E, depressed, F, subcylindrical. G-H, uropodal ex- opod: G, Pseudosquilla ciliata (Pseudosquillidae); H, Gonodactylus platysoma (Gonodactylidae). I-K, uropodal en- dopod: I, Acanthosquilla acanthocarpus (Nannosquillidae); J, Lysiosquilla hoevenii (Lysiosquillidae); K, Levisquilla jurichi (Squillidae). 704 JOURNAL OF CRUSTACEAN BIOLOGY, VOL. 17, NO. 4,1997 bly plesiomorphic. In lysiosquilloids, a low occur in some phyllocarids and eumalacos- median boss may be present (Fig. 4C). In tracans, but are considered absent in the most taxa other than squilloids, a pair of low, Stomatopoda (Kunze, 1983). A note of cau- distinct submedian carinae or bosses is pres- tion is appropriate here in interpretation of the ent on the dorsal surface, though the subme- caudal furcae, since further study of the fos- dian ornamentation is highly reduced or ab- sil record may suggest that the caudal furcae sent in many nannosquillids. In coronidids, and marginal spines are homologous. Until the entire surface of the telson is strongly such data become available, however, the in- sculptured or covered with closely spaced tu- terpretation of Kunze (1983) is followed here bercles (Fig. 4F). An unusual squilloid char- in considering the caudal furcae absent in the acter is the presence of a curved ventrolat- Unipeltata. Nevertheless, the ingroup topol- era1 carina originating behind the base of each ogy is unaffected even if the caudal furcae are uropod. The function of the ventral carinae scored as homologous with the marginal may be associated with sound production via spines of the telson in unipeltatans. In Peri- stridulation of the dorsal surface of the uro- mecturus and Bairdops, the telson terminates pod with the ventral surface of the telson (per- in a long, median spine. sonal observation; Kemp, 1913; Tirmizi and Character 33: ventrolateral carinae of tel- Kazmi, 1984). son absent (0); present (1). Most lysiosquilloids bear additional dor- Character 34: median carina of telson pres- sal ornamentation in the form of a false eave ent (0); absent (1); with raised posterior me- or additional rows of marginal spines. Such dian prominence (2). additional marginal ornamentation may ob- Character 35: dorsal surface of telson rel- scure the true marginal armature and effec- atively unadorned (0); entirely tuberculate or tively thickens the telson. In heterosquillids strongly sculptured (1). and tetrasquillids, a rounded to subquadrate, Character 36: submedian ornamentation ab- raised, median prominence is present on the sent (0); carina present (1); boss present (2). posterior margin. Character 37: additional marginal armature In most crown-group stomatopods, the tel- absent (0); present (1). son has three pairs of marginal teeth (more Character 38: marginal teeth of telson ab- in bathysquilloids) and the apices of these sent (0); all apices fixed (1); submedian teeth teeth may be fixed or mobile. In gonodacty- movable (2); all teeth movable (3). loids and erythrosquilloids, the submedian Character 39: marginal intermediate denti- teeth are mobile (Fig. 4D, E). In bathysquil- cles 4 or more (0); 2 or fewer (1); absent (2). loids, all marginal teeth bear movable apices Character 40: caudal furca present (0); ab- (Fig. 4B), but, in squilloids, the apices are sent (1). usually fixed (in more than half the genera, Character 41 : telson with long terminal me- and certainly in the majority of species) (Fig. dian spine present (0); absent (1). 4A). In lysiosquilloids, the submedian teeth may bear movable apices. In the outgroups, Larvae marginal teeth are absent. In sculdids, mar- Unfortunately, our knowledge of stomato- ginal teeth appear to be mobile (Holthuis and pod development is nowhere near as complete Manning, 1969). as our understanding of the adults. The lar- The intermediate marginal denticles are im- val stages of many stomatopods are still un- portant characters separating the current su- known or at least unrecognized. Known ly- perfamilies (Manning and Camp, 1993). In- siosquilloid larvae hatch at an early stage of termediate denticles are absent in bathysquil- development (Manning, 1963). Early larvae loids and the number varies in lysiosquilloids. of lysiosquilloids are antizoeae, bearing five In squilloids, four or more intermediate den- pairs of biramous thoracic appendages but no ticles are always present (Fig. 4A). In gon- abdominal appendages. The antizoea devel- odactyloids and erythrosquilloids, two inter- ops into the erichthus, with two or fewer in- mediate denticles, at most, are present (Fig. termediate denticles on the telson and 4D, E). pleopods appearing from front to rear. Squil- Small caudal furcae are present in all out- loids and gonodactyloids hatch as pseudo- groups except the Tyrannophontidae. Caudal zoeae with two pairs of uniramous thoracic furcae are the paired rami of the telson and appendages and four or five pairs of pleopods, AHYONG: PHYLOGENETIC ANALYSIS OF THE STOMATOPODA 705

Fig. 4. Dorsal surface of the telson in Stomatopoda: A, Oratosquillirza stephensoni (Squillidae); B, Bathysquilla crassispinosa (Bathysquillidae); C, Lysiosquilla Izoellenii (Lysiosquillidae); D, Pseudosquilla ciliata (Pseudosquilli- dae); E, Eunsquilla galarheae (Eurysquillidae); F, Cororzida hradyi (Coronididae). i = intermediate denticles. st = submedian tooth. (E, F. redrawn after Manning (1977)). JOURNAL OF CRUSTACEAN BIOLOGY, VOL. 17, NO. 4, 1997

A, &Perimecturus Bairdops

: Archaeocaris I I ITyrannophonfes Sculda I I / SQUILLIDAE

2 I Harpiosquilla

Faughnia I I I

24 18 8 Lysiosquilla Acanthosquilla

Hadrosquilla

Coronida

Acoridon

Paracoridon

Tetrasquilla I TETRASQUILLIDAE Tectasquilla Heterosquilla

Heterosquilloides

Eurysquilla l EURYSQUILLIDAE 31 1 Alainosquilla I ALAINOSQUILLIDAE I I 1 13 1 Pseudosquilla PSEUDOSQUILLIDAE 2 0 1 28 26 26 -ti- Hernisquilla 1 HEMlSQUlUlDAE 0 1 0 I2 11 Odontodactylus ODONTODACTYUDAE 1 1 , ,- ~aptosqui~~a l PROTOSQU~LL~DAE 1 GONODACTYLIDAE 1 TAKUIDAE

Fig. 5. Single most parsimonious cladogram of the Stomatopoda. Length 118, Consistency Index 0.66, Homoplasy Index 0.41, Retention Index 0.85. Outgroups (Perimecturus, Archaeocaris, Bairdops, Tyrannophontes) constrained as monophyletic with respect to the ingroup. B, Bathysquilloidea; E, Erythrosquilloidea; G, Gonodactyloidea; L, Ly- siosquilloidea; S, Squilloidea. Unambiguous character changes are indicated. Character number is indicated above the branch. Character state is indicated below the branch.

respectively. Squilloid pseudozoeae develop into an alima larva with four or more inter- mediate denticles on the telson, whereas gon- Analysis of the data produced a single most odactyloid pseudozoeae develop into an parsimonious cladogram of length 118, con- erichthus larva (Tirmizi and Kazmi, 1984). sistency index (CI) 0.66 and retention index Character 42: early larva a pseudozoea (0); (RI) 0.85 (Fig. 5).The CI is the ratio between antizoea (1). the theoretical minimum number of steps and Character 43: late larva an alima (0); the actual number. Because the CI is inversely erichthus (1). related to the number of extra steps, it is a AHYONG: PHYLOGENETIC ANALYSIS OF THE STOMATOPODA 707 good measure of homoplasy (Goloboff, originally described the Erythrosquillidae in 1991). Homoplasy was thus relatively low. the Lysiosquilloidea. The broad maxillipedal The monophyly of the crown-group is sup- propodi (Char. 8), elongated ischium of the ported in 96% of bootstrap replicates. The raptorial claw (Char. 18), and similar male bootstrap statistics were relatively low at the pleopod structures (Char. 24) unite eryth- bases of some major clades, ranging from rosquilloids and lysiosquilloids. According to 60-96%. The bootstrap values at the bases of the analysis, the appearance of mesial papil- the gonodactyloid (G) and erythrosquil- lae (Char. 6), the presence of four proximal loid+lysiosquilloid (E+L) clades were 60% movable spines on the raptorial propodus and 62%, respectively. The squilloid (S) clade (Char. 14), the variously folded margin of the was supported in 8 1% of bootstrap replicates. uropodal endopod (Char. 32), and the absence The bathysquilloid (B) and lysiosquilloid (L) of a distinct median carina of the telson (Char. clades were the most highly supported of ma- 34) are synapomorphies of the Lysiosquil- jor clades with bootstrap values of 96% and loidea. 94%, respectively. In view of the relatively Lysiosquilla is derived earliest in the L small data set and conservatism of the boot- clade, followed by several subsequent clades. strap, the upper bootstrap values indicate ro- Hadrosquilla and Acanthosquilla form a dis- bust clades. The E and L clades were less well crete clade united unambiguously by the supported by the bootstrap and should be corneal morphology (Char. 1) and form of the viewed more cautiously if only bootstrapping uropodal endopod (Char. 32), corresponding is considered. to the Nannosquillidae. The other clades are The base of the ingroup clade decayed with united by the compact abdominal articulation two extra steps, but was retained in 99% of (Char. 28). Most heterosquillid genera (Het- suboptimal trees. The decay values for the erosquilla and Heterosquilloides) are derived bases of the crown-group and major ingroup as the sister to the tetrasquillids (Tetrasquilla clades (S, B, G, E+L, L) were all at least three and Tectasquilla). Paracoridon, originally de- extra steps. These decay values may well ex- scribed as a coronidid (Moosa, 1991) and ten- ceed three steps, but the "+3" run was aborted tatively transferred to the Heterosquillidae by owing to excessive processing time. Unlike Manning (1995), is derived as the sister to the some of the bootstrap values, the decay val- coronidids, represented by Acoridon and Coro- ues indicate well-supported clades giving nida. The analysis supports the monophyly of confidence to the topology produced. the Coronididae and the Tetrasquillidae. The Squilloidea is unambiguously united by The morphology of the pereiopodal en- four characters of which only two (Characters dopods is supported as a strong phylogenetic 33, 39; Appendix 3) are never reversed-the character. The pereiopodal endopods are slen- presence of lateroventral carinae and four in- der and elongate in the Lysiosquillidae, less termediate denticles on the telson. The early slender in the coronidid+tetrasquillid+het- derivation of squilloids implies early deriva- erosquillid clade, and least slender among tion of the strong dorsal carination of the body nannosquillids. The polarization of Char. 25 (Char. 27) and less specialized central om- clearly indicates that the styliform pereiopo- matidia of the cornea (Chars. 2, 3). The po- dal endopod is plesiomorphic. larization of Char. 27 clearly indicates a re- The Gonodactyloidea sensu Manning duction in dorsal carinae in successive clades. (1995) are polyphyletic in this analysis. Ex- The Bathysquilloidea, sensu Schram cluding Faughnia (Parasquillidae), the gon- (1986), comprising extant and Jurassic fam- odactyloids are derived as the sister to the ilies, was polyphyletic. The Jurassic sculdids E+L clade. Faughnia, which appears to bear were optimized as the earliest derived uni- both squilloid and gonodactyloid characters, peltatans, while extant bathysquilloid fami- is derived as the sister to the E+L+G clade. lies were derived after the squillids. The In Faughnia, the dorsal carinae and male monophyly of extant bathysquilloids was well pleopod form resemble the condition in squil- supported by six synapomorphies. loids. Furthermore, in material that I have ex- The Erythrosquilloidea is derived as the amined, the number of ommatidial rows in sister to the Lysiosquilloidea. The close rela- the central band of the cornea appears to re- tionship between these superfamilies is con- semble squilloids. The ommatidial characters, sistent with Manning and Bruce (1984) who however, were scored unknown, because the 708 JOURNAL OF CRUSTACEAN BIOLOGY, VOL. 17. NO. 4. 1997 preservation of available material made the sil attributed to Bathysquilla is from the lower ommatidia difficult to observe. Although the Eocene (Quayle, 1987), whereas squilloids corneal characters were scored as unknown, are known from the Cretaceous (Holthuis and the topology remains unchanged regardless of Manning, 1969). Furthermore, the material of whether they are scored as squilloid, gon- B. wetheralli Woodward studied by Quayle odactyloid, or absent. Manning (1963, 1969b) (1987) is incomplete and may not even rep- regarded the dorsal carination as convergent. resent Bathysquilla. Nevertheless, caution The exclusion of that character from the must be exercised when interpreting incom- analysis has no effect on the topology. plete fossil specimens. The derivation of The remaining gonodactyloids are united bathysquilloids after squillids suggests that by two synapomorphies (Chars. 3, 23). Eu- bathysquilloids formerly possessed good vi- rysquillids, derived first, exhibit the flattened sion and occupied shallow-water habitats. abdomen which typifies lysiosquilloids and The Bathysquilloidea, sensu Schram (1986), erythrosquilloids. Higher in the clade, taxa comprising extant and Jurassic families, was progressively become more subcylindrical in derived as polyphyletic. The Bathysquilloidea body form. A corresponding trend is also is restricted to the Bathysquillidae and the In- present with the narrowing of the cornea and dosquillidae, and the Sculdidae is here con- derivation of the smashing claw. Hemisquilla, sidered incertae sedis. with a raptorial claw intermediate between The squilloid clade is unambiguously the spearing and smashing taxa, is derived as united by four characters, two of which are such, between Pseudosquilla and Odonto- never reversed. Stronger apomorphic support dactylus. for squilloids will probably result from com- The gonodactyloid smashers are united by plete data in surrounding clades. Larval char- four unambiguous characters, most relating to acters, for instance, are unknown in the out- the raptorial claw. Gonodactylus and Taku groups, sculdids and bathysquillids. The (formerly in the Gonodactylidae) are most maxillipedal morphology and number of in- closely related and together form a sister termediate denticles in larvae are conserved clade to the protosquillids. in adults. If larval types can be predicted from adult characters, the larvae of the aforemen- tioned taxa may be dissimilar to the squillids. Bathysquillids were considered to be the Although the monophyly of the squilloid fam- most ancient of crown-group stomatopods on ilies is supported, the present analysis is not the basis of their apparent relict, upper-slope sufficiently detailed to suggest trends within distributions paralleling various ancient fish the superfamily. More than 40 genera are species, and the segmentation of the uropo- presently included in two families. The rela- dal exopod (Manning and Struhsaker, 1976). tionships within the superfamily will be stud- All known bathysquillids are restricted to up- ied in an analysis of the squilloid genera per-shelf habitats, but new distribution (Ahyong, in preparation). records are regularly appearing (e.g., Bruce, Kemp (19 13) considered the squilloids to 1985, 1988; Manning et al., 1990; Moosa, represent the most ancient lineage of extant 1986; and unpublished Australian records, stomatopods, a view supported here. It should, Ahyong, in preparation). The segmentation of however, be noted that the earliest known the uropodal exopod (Char. 30) and its rela- crown-group fossil, Palaeosquilla brevicoxa tion to the condition in the Sculdidae (dis- Schram, from the Middle Cretaceous, is be- cussed in the character analysis) may not be lieved to be a gonodactyloid (Schram, 1968). homologous or derived. Indosquilla bears With few exceptions, squilloids burrow in characters that closely resemble last-larval level, soft substrates and forage nocturnally characters of Bathysquilla crassispinosa re- for all types of soft-bodied prey. They are the ported by Manning (199 1). The unsegmented most cosmopolitan of known stomatopods. uropod and more pronounced dorsal and lat- Manning (1995) separated the Het- eral spines in Indosquilla imply neoteny, as erosquillidae from the Tetrasquillidae, based postulated by Ingle and Merrett (1971). Lit- on abdominal articulation (loose and com- tle a priori justification exists for consider- pact, respectively) and the number of teeth on ing bathysquilloids to be the earliest derived the raptorial claw (four in tetrasquillids and crown-group taxa. The earliest reported fos- more than four in heterosquillids). The ab- AHYONG: PHYLOGENETIC ANALYSIS OF THE STOMATOPODA 709 dominal articulation in taxa of both families, of Acoridon and Paracoridon, in which case however, is compact. When Paracoridon is the Coronididae could be defined by at least excluded from the Heterosquillidae, the ab- four strong synapomorphies (Chars. 6, 8, 14, sence of mesial papillae (Char. 6) becomes a 15). heterosquillid synapomorphy. The genera of Lysiosquilloids are well adapted for life in the two families are otherwise very similar. burrows. The flattened, lightly sclerotized Characters distinguishing heterosquillids body permits great flexibility within the bur- from tetrasquillids vary within genera of other row confines. The elongated ischium of the families. Most species of both families were raptorial claw may be an adaptation for in- included in the single genus Heterosquilla by creasing reach from the burrow entrance. Manning (1963, 1969b). The independent sta- Coronidids are the only lysiosquilloids which tus of the Heterosquillidae (excluding Para- may also occupy preformed coral cavities coridon) and the Tetrasquillidae is not dis- (Reaka and Manning, 1981). Based on field puted in this analysis, but the absence of observations, lysiosquilloids rarely leave their strong characters for their separation may fa- burrows and often live in colonies (Caldwell, vor their synonymy. The Heterosquillidae is personal communication). According to presently restricted to Acaenosquilla Man- Reaka and Manning (1987), rates of mor- ning, Heterosquilla Manning, Heterosquil- phological evolution inversely relate to body loides Manning, Heterosquillopsis Moosa, size. More than 40 species of nannosquillids and Kasirn Manning. are known, compared with fewer than 15 spe- The analysis supports the removal of Para- cies of lysiosquillids. The smaller lysiosquil- coridon from the Heterosquillidae and sup- loids appear to be undergoing active radiation ports the original inclusion by Moosa (1991) (Reaka and Manning, 1987). Lysiosquilloids of Paracoridon in the Coronididae. Para- appear to have evolved in conjunction with coridon is derived as the sister to the coro- soft substrates and are specialized for life in nidids, principally on the basis of the dorsal burrows unlike the well-armored squillids ornamentation of the telson (Char. 35). Man- which actively forage. ning (1995) recognized five coronidid genera: The close relationship between lysiosquil- Acoridon Adkison, Heard, and Hopkins, loids and gonodactyloids has been implied in Coronida Brooks, Neocoronida Manning, the literature through the discovery of the eu- Parvisquilla Manning, and Mortensenenus rysquillids (e.g., Ingle, 1963) and Ery- Manning. Acoridon is atypical among the throsquilla (e.g., Manning and Camp, 1993). coronidids in bearing mesial papillae, the The eurysquillids bear the flattened habitus of maxillipedal propodi are strongly beaded ven- lysiosquilloids and Erythrosquilla bears char- trally, and there are four instead of three mov- acters considered diagnostic of both ly- able spines proximally on the raptorial propo- siosquilloids and gonodactyloids. Members of dus which is pectinate for most of its length. the G clade are readily distinguished from the All of these characters are also found in Para- E+L clade by male pleopod characters. coridon. Therefore, the most important char- The taxonomic significance of the endopod acter excluding Paracoridon from the Coro- of the male first pleopod is mentioned by var- nididae is the uninflated raptorial dactylus ious workers (e.g., Ingle, 1963; Brooks, (Char. 12). That character, however, is an un- 1886), but has hardly been used to study re- reliable coronidid synapomorphy. For in- lationships within the Stomatopoda. The lat- stance, the raptorial dactylus in Parvisquilla eral lobe on the endopod was previously un- is relatively uninflated. Parvisquilla is oth- recognized and appears to be an extremely erwise a "typical" coronidid (Chars. 6, 8, 14, useful gonodactyloid synapomorphy. Further, 15) suggesting the definition of the Coroni- male pleopod characters are useful in distin- didae requires review. Pending further re- guishing the superfamilies and further study search, however, Paracoridon is included in of the pleopods will likely yield several more the Coronididae. Presently, the elaborate dor- informative characters which may be useful sal ornamentation (Char. 35) will distinguish down to the specific level. the Coronididae from other lysiosquilloids. In Manning (1962) noted that parasquillids many respects, Acoridon appears to be more were morphologically intermediate between similar to Paracoridon than to other coroni- squillids and gonodactylids. In all subsequent dids. Further study may support the removal higher classifications, parasquillids were 710 JOURNAL OF CRUSTACEAN BIOLOGY. VOL. 17. NO. 4. 1997

GONODACMCIDEA LYSIOSOUILLOIDEA SQUlUOlDEA SOUILLOIDEA LYSlOSOUlLLOlDEA CWDACMOIDEA

Fig. 6. Phylogeny of Brooks (1886): A, reinterpreted as a cladogram; B, re-rooted using the squilloids

aligned with the gonodactyloids, with the form from flattened to subcylindrical corre- squilloid characters considered convergent. lates with increased dorsal armor and the de- The present analysis optimizes parasquillids velopment of the smashing claw. Thus, the outside of the Gonodactyloidea and suggests general trends in gonodactyloid phylogeny that a new superfamily should be erected for are consistent with specialization corre- the Parasquillidae. The pleopod structure and sponding to increasing exploitation of hard- the number of ommatidial rows suggests that bodied prey and coarse substrates, such as the squilloid facies of parasquillids may mark rock and coral reefs. squilloid affinity. Whether or not the squilloid The only overall phylogenetic scheme to facies are in fact homologous must be deter- be explicitly proposed (other than that im- mined by further study and the present result plied by classifications) was that of Brooks should be accepted with caution. Therefore, (1886), when fewer than 10 genera were rec- superfamilial affinity of the parasquillids is ognized. The topology of Brooks (1886) dif- presently considered uncertain. This analy- fers markedly from the present analysis and sis nevertheless supports the familial status of is interpreted as a cladogram in Fig. 6A. The parasquillids recently recognized by Manning weaknesses of his scheme were reviewed by (1995); parasquillids were previously in- Manning (1963). Though the classifications cluded with the pseudosquillids (Manning, of Manning (1968, 1980, 1995) and this 1977, 1980). cladogram lend no support to Brooks (1886), My analysis strongly supports the view that some points are noteworthy. If Fig. 6A is re- the smashing claw (Odontodactylidae, Gon- rooted with the squillids (Squilla and odactylidae, and Protosquillidae) is derived Clorida), the topology resembles the present from a spearing ancestor (Caldwell, 1991). analysis and differs chiefly in the position of Hemisquillid raptorial claws are morpholog- Coronida (Fig. 6B). Thus, the most important ically intermediate between the spearers and difference between the present analysis and smashers, and the analysis optimizes them as that of Brooks is in his identification of Pro- such. In gonodactyloids, the change in body tosquilla as the earliest derived group. This AHYONG: PHYLOGENETIC ANALYSIS OF THE STOMATOPODA 71 1 result points to some broader issues in phy- ciently detailed to suggest trends within the logenetic systematics-the importance of Squilloidea, but a more detailed study of the identifying reliable characters and distin- squilloid genera is in progress. guishing between plesiomorphies and apo- The Erythrosquilloidea, Lysiosquilloidea, morphies. According to this analysis, Brooks and Squilloidea are each supported as mono- misinterpreted his characters. Brooks (1886) phyletic. Monophyly of the Gonodactyloidea was confident of his phylogeny and proba- and Bathysquilloidea was unsupported and bly never imagined the diversity in the Sto- the analysis supports erection of new super- matopoda. Our knowledge of stomatopods families for the Sculdidae and Parasquillidae. has vastly increased in the century since The sculdids are excluded from the Bathy- Brooks, but it is always possible that future squilloidea. Owing to incomplete fossil data, discoveries, particularly from the fossil however, the Sculdidae are considered incer- record, may significantly alter our concepts tae sedis until more fossil data are available. of stomatopod relationships. The superfamilial affinity of the Parasquilli- From the cladogram, a broad picture of dae is also considered uncertain pending fur- stomatopod evolution may be drawn. The ear- ther research. liest of the crown-group stomatopods were The Heterosquillidae sensu Manning probably dorsally carinate, generalist spear- (1995) is polyphyletic. Paracoridon is re- ers with a broad flat telson. Squillids and moved from the Heterosquillidae and trans- bathysquillids appeared earliest and both now ferred to the Coronididae. The Coronididae occupy soft, level substrates. Bathysquillids requires reevaluation and more detailed were restricted to deep water leading to de- analyses may support the removal of Acori- generate vision, while the cosmopolitan squil- don and Paracoridon to new taxa. Characters lids exploited shallower waters. The E+L+G separating the Heterosquillidae, as restricted clade, derived as the sister to parasquillids, here, from the Tetrasquillidae are weak, vary- has diverged in two broad directions. In the ing within genera of other families. Further E+L clade, dorsal armature is lightly calci- analysis will likely favor their synonymy. fied, the elongated ischium facilitates spear- The E+L clade forms the sister group to the ing prey from the vertical burrow entrance, G clade. Lysiosquilloids show a trend toward and the flattened body form permits maxi- general reduction in body size, which correlates mum flexibility in the burrow confines. Taxa with the shape of the pereiopodal endopods and appear well adapted to a sedentary habit on increasing numbers of species. Apparently they soft, level substrates. have diverged to exploit soft, level substrates. In the G clade, the general reduction in Evolution of gonodactyloids correlates with ex- body size, stronger dorsal body armor, and ploitation of coarse substrates. development of the subcylindrical body form Characters derived from the pleopods, es- and smashing claw appear more suited to oc- pecially the first male pleopod, appear to be cupy and forage on coarse substrates. Perhaps extremely useful phylogenetic characters. the most extreme specialization is the smash- Further study of pleopod morphology is in ing claw which permits exploitation of the progress and will likely yield further infor- hard-bodied prey common on coarse sub- mative characters. strates. Thus, today there are the cosmopoli- tan squilloids, deep-water bathysquilloids, ly- siosquilloids occupying vertical burrows in CLASSIFICATIONOF THE STOMATOPODA soft substrates, and gonodactyloids occupy- Extinct taxa are indicated (*). ing hard substrates. Phylum, Subphylum, or Superclass Crustacea Class Malacostraca The analysis supports the monophyly of the Subclass Phyllocarida Packard, 1879 Subclass Eumalacostraca Grobben, 1892 Unipeltata and largely supports the current Subclass Hoplocarida Calman, 1904 five superfamily classification of Manning Order Aeschronectida Schram, 1969 (*) (1968, 1980, 1995). The purported ancient Order Palaeostomatopoda Brooks, 1962 (*) derivation of the Bathysquillidae (Manning et Family Perimecturidae Peach, 1908 Order Stomatopoda Latreille, 18 17 al., 1990), however, was unsupported. Rather, Suborder Archaeostomatopoda Schrarn, 1969 (*) the Squilloidea is the earliest derived crown- Family Tyrannophontidae Schram, 1969 group superfamily. The analysis is not suffi- Suborder Unipeltata Latreille, 1825 JOURNAL OF CRUSTACEAN BIOLOGY, VOL. 17, NO. 4, 1997

Superfamily Lysiosquilloidea Giesbrecht, Bruce, A. J. 1985. Altosquilla soelae, new genus, new 1910 species, a bathysquillid stomatopod from the Australian Family Tetrasquillidae Manning and northwest shelf.-Journal of Crustacean Biology 5: Camp, 1993 468-475. Family Heterosquillidae Manning, 1995 . 1988. Two mantis shrimps new to the Australian Family Coronididae Manning, 1980 fauna (Crustacea: Stomatopoda: Bathysquillidae).- Family Nannosquillidae Manning, 1980 The Beagle 5: 87-95. Family Lysiosquillidae Giesbrecht, 1910 Burnett, B. R., and R. R. Hessler. 1973. Thoracic Superfamily Erythrosquilloidea Manning and epipodites in the Stomatopoda (Crustacea): a phyloge- Bruce, 1984 netic consideration.-Journal of Zoology 169: Family Erythrosquillidae Manning and 381-392. Bruce, 1984 Caldwell, R. L. 1991. Stomatopods: the better to see you Superfamily Gonodactyloidea Giesbrecht, with my dear.-Australian Natural History 23: 1910 696-705. Family Takuidae Manning, 1995 ,and H. Dingle. 1976. Stomatopods.-Scientific Family Gonodactylidae Giesbrecht, 1910 American 234: 80-89. Family Protosquillidae Manning, 1980 Calman, W. T. 1909. Crustacea.-In: R. Lankester, A Family Odontodactylidae Manning, 1980 treatise on zoology, Part 7. Adam and Charles Black, Family Hemisquillidae Manning, 1980 London, England. Family Pseudosquillidae Manning, 1977 Cronin, T., and N. J. Marshall. 1989. Multiple spectral Family Alainosquillidae Moosa, 1991 classes of photoreceptors in the retinas of gonodacty- Family Eurysquillidae Manning, 1977 loid stomatopod crustaceans.-Journal of Comparative Superfamily Bathysquillidoidea Manning, Physiology A 166: 261-275. 1967 Felsenstein, J. 1985. Confidence limits on phylogenies: Family Bathysquillidae Manning, 1967 an approach using the bootstrap.-Evolution 39: Family Indosquillidae Manning, 1995 783-791. Superfamily Squilloidea Latreille, 1803 Giesbrecht, W. 1910. Stomatopoda.-Fauna und Flora Family Harpiosquillidae Manning, 1980 des Golfes von Neapel, 33: i-vii, 1-239. Family Squillidae Latreille, 1803 Goloboff, P. A. 1991. Homoplasy and the choice among Superfamily uncertain c1adograms.-Cladistics 7: 15-232. Family Sculdidae Dames, 1886 (*) Holthuis, L. B., and R. B. Manning. 1969. Stomato- Family Parasquillidae Manning, 1995 pods.--In: R. C. Moore, ed., , Treatise on invertebrate paleontology, part R, 4: 535-552. Geo- logical Society of America and University of Kansas, ACKNOWLEDGEMENTS ~awrence,~aisas. Ingle, R. W. 1963. Crustacea Stomatopoda from the Red Thanks are due to Drs. I. M. Suthers (University of Sea and Gulf of Aden (Contributions to the knowledge New South Wales), C. J. Quinn (University of New South of the Red Sea, Number 26).-Bulletin, Sea Fisheries Wales), and G. D. Wilson (Australian Museum) for en- Research Station (Haifa) 33: 1-69. couragement, much helpful criticism, and assistance with , and R. N. Merrett. 1971. A stomatopod crus- the cladistic analysis. Drs. Suthers and Wilson provided tacean from the Indian Ocean, lndosquilla manihinei useful comments on the draft. I thank Dr R. B. Manning gen. et sp. nov. (Family Bathysquillidae) with remarks (Smithsonian Institution) for providing data on Eryth- on Bathysquilla crassispinosa (Fukuda, 19lO).-Crus- rosquilla, the loan of material, and assisting in numer- taceana 20: 192-198. ous other ways. I also thank Ms. K. Coombes (Northern Jeffries, R. P. S. 1979. The origin of the chordates-a Territory Museum), Mr. P. Davie (Queensland Museum), methodological essay.-In: M. R. House, ed., The ori- and Dr. P. B. Berents (Australian Museum) for access to gin of major invertebrate groups. Pp. 443-447. Aca- stomatopod collections. This study was supported by an demic Press, London, England. Australian Postgraduate Award. Kemp, S. 1913. An account of the Crustacea Stomato- pods of the Indo-Pacific region, based on the collec- tion in the Indian Museum.-Memoirs of the Indian LITERATURECITED Museum 4: 1-217. Ax, P. 1985. Stem species and the stem lineage con- Kunze, J. C. 1981. The functional morphology of sto- cept.-Cladistics 1: 279-287. matopod Cmstacea.-Philosophical Transactions of the Bauer, R. T. 1987. Stomatopod grooming behavior: func- Royal Society of London B 292: 255-328. tional morphology and amputation experiments in Gon- , 1983. Stomatopoda and the evolution of the odacrylus oerstedii.-Journal of Crustacean Biology 7: Hop1ocarida.-Crustacean Issues 1: 165-188. 414-432. Maddison, W. P., and D. L. Maddison. 1993. MacClade, Bremer, K. 1988. The limits of amino acid sequence data version 3.04.-Sinauer Associates. Sunderland, Mas- in angiosperm phylogenetic reconstruction.-Evolution sachusetts. 42: 795-803. , M. J. Donoghue, and D. R. Maddison. 1984. . 1994. Branch support and tree stability.- Outgroup analysis and parsimony.-Systematic Zool- Cladistics 10: 295-304. ogy 33: 83-103. Brooks, W. K. 1886. Report on the Stomatopoda col- Manning, R. B. 1962. A new species of Parasquilla lected by H.M.S. Challenger during the years (Stomatopoda) from the Gulf of Mexico, with a re- 1873-76.-The Voyage of the H.M.S. Challenger, Zo- description of Squilla ferussaci Roux.-Crustaceans 4: ology, 16: 1-16. 180-190. AHYONG: PHYLOGENETIC ANAl ..YSIS OF THE STOMATOPODA 713

. 1963. Preliminary revision of the genera Pseu- logical comparison of the phyllopodous thoracic limbs dosquilla and Lysiosquilla with descriptions of six new of a leptostracan (Nebalia sp.) and a spinicaudate con- genera (Crustacea: Stomatopoda).-Bulletin of Marine chostracan (Leptestheria sp.), with comments on the Science of the Gulf and the Caribbean 13: 308-328. use of Phyllopoda as a taxonomic category.

Appendix 1. Material examined from genera included in the analysis. AM (Australian Museum), NTM (Northern Territory Museum of Arts and Sciences), QM (Queensland Museum), SI (Smithsonian Institution).

Squillidae Heterosquillidae Levisquilla jurichi (Makarov, 1979) AM Heterosquilla tricarinata (Claus, 187 1) AM Levisquilla inermis (Manning, 1965) NTM Heterosquilloides insignis (Kemp, 1911) NTM Squilla mantis (Linnaeus, 1758) AM Pseudosquillidae Harpiosquillidae Pseudosquilla ciliata (Fabricius, 1787) AM Harpiosquilla harpax (de Haan, 1844) AM Hemisquillidae Harpiosquilla annandalei (Kemp, 1911) AM Hemisquilla ensigera australiensis Stephenson, Bathysquillidae 1967 AM Bathysquilla crassispinosa (Fukuda, 1911) QM Odontodactylidae Bathysquilla microps (Manning, 1961) AM Odontodactylus scyllarus (Linnaeus, 1758) AM Parasquillidae Odontodac@lusjaponicus (de Haan, 1844) AM Faughnia haani Holthuis, 1959 AM Gonodactylidae Faughnia serenei Moosa, 1982 AM, QM Gonodac@lus chiragra (Fabricius, 1781) AM Lysiosquillidae Gonodactylus platysoma (Wood-Mason, 1895) AM Lysiosquilla sulcirostris Kemp, 1911 SI Gonodactylus smithii Pocock, 1893 AM Lysiosquilla tredecimdentata Holthuis, 1941 Takuidae AM, QM Taku spinosocarinatus (Fukuda, 1909) AM Lysiosquilla hoevenii (Herklots, 185 1) SI Protosquillidae Nannosquillidae Haptosquilla glyptocercus (Wood-Mason, 1875) AM Acanthosquilla acanthocarpus (Claus, 1871) AM Haptosquilla trispinosa (Dana, 1852) AM Acanthosquilla multifasciata (Wood-Mason, 1895) AM Hadrosquilla perpasta (Hale, 1924) AM

Appendix 2. Input data matrix of 43 characters and 30 taxa. Multistate characters are indicated by (I) and missing data (?).Outgroups are the last four listed (Perimecturus, Archaeocaris, Bairdops, and Tyrannophontes).

1 1 1 1 I I I I 1 12 2 222222 22 3 3 33333 3334444 I234567890123 4 567890 1234567 89 0 123456 7890123 Levisquilla 11000001010OlL23 1 OO01lcylOOOOOO 00 2 001000 0201100 Squilla 0100100101001 3 1 0001 1 0000000 00 2 0 01000 0 101100 Harpiosquilla 0100100101000 3 0 00011 0000000 00 2 0 01000 0101100 Bathysquilla 2021100111003 4 0 10011 1021000 11 2 000001 03211?? Indosquilla 2021000111003 4 0 10011 10??000 11 1 000001 03211?? Erythrosquilla 0020100201003 3 100111 1101021 102 00?001 02111?? Lysiosquilla 0200110201003 4 100111 11 01021 10 2 0 10102 0111111 Acanthosquilla 2200110201003 4 100111 1101221 10 2 020102 1201111 Hadrosquilla 2200110201003 4 100111 11 01221 10 2 020100 1211111 Coronida 1200100301013 3 3 00011 1101121 00 2 0 10112 1211111 Acoridon 1?00110201013 4 100011 11??121 00 2 010112 12111?? Paracoridon 0?00110201003 4 1 00011 11 ??l 21 00 2 0 10112 12211?? Tetrasquilla 1200110201003 4 100111 11 01121 00 2 0 10202 12011?? Tectasquilla 1200110201003 4 100111 1101121 00 2 0 10202 12111?? Heterosquilla 2200100201003 4 1 00111 11 011 21 00 2 0 10202 1211111 Heterosquilloides 0?00100201003 4 100111 1101121 002 010202 1201111 Alainosquilla 2210002101002 1 100011 11 ??021 10 2 10?001 02111?? Eurysquilla 1210100101003 3 1 00011 11 10020A10 2 0 00001 021 ll?? Gonodactylus 2210002121210011 2 01011 11 1001 100 2 100001 0211101 Haptosquilla 2210002121210 1 2 01011 11 1001 100 2 000001 0211101 Hemisquilla 2210001101212 2 1 00011 11 10001 00 2 000001 0211101 Odontodactylus 2210001121110 0 201011 1110011002 000001 0211101 Faughnia 0??0100101003 3 100011 1000000 00 2 0 00001 02111?? Pseudosquilla 2210001101002 3 1 00011 11 1001 1 00 2 0 00001 021 1101 Taku 2210002121210 0 2 01011 11 1001 100 2 100001 02111?? Sculda ??????O?????? ? ? ???lo 10???20 02 0 2 00000 03?11?? Perimecturus ??????OO?OOOO ? ? OO?OO l????2 0 02 0 2 ??0000/l0200?? Bairdops ??????OO?OOOO ?0/200?00 l????I 0 02 0 2 ??OOO 10200?? Archaeocaris ??????OO?OOOO ? 0 OO?OO 1????11020 2 ??lo0 00201?? Tyrannophontes ??????00?0000 ? 0 00?10 l???? 11 02W1 0/2??000 0021 I??