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A new bathynellacean, Camachobathynella meghalayaensisn. gen., n. sp., is described from a hyporheic habitat in Meghalaya, a northeastern Indian state. This is the first Palearctic bathynellacean from India. It has very little in common with the hitherto known tropical Bathynellidae Grobben, 1905 of India and other Gondwana landmasses, but it shows some close morphological relationships with the Palearctic members of the subfamily Bathynellinae Grobben, 1905. It has a unique of constellation of characters: antennule 7-segmented, with 5 setae on segment 7; antennary endopod 5-segmented and perpendicular to antennule, and exopod without medial seta; mandible sexually isomorphic with 3-segmented palp and distinct gnathobase; maxilla 4-segmented, setal formula 6-4-6-4; Th I-VII with 4-segmented endopod; male Th VIII penile region consisting of 3 lobes, none of them denticulate, basis armed with 2 setae on inner margin, exopod bent outwards and armed with 5 setae, and endopod absent; female Th VIII with large, biarticulate epipod, exopod and endopod 1-segmented, with 2 setae each; pleopod I 2-segmented, with 6 setae on distal segment; uropodal sympod with 5 equal spines; caudal furca with 4 spines; and pleotelson with 2 dorsal moderately strong setae. Of these characters, the male Th VIII lacking endopod and the caudal furca having only four spines can be considered the autapomorphies of the new genus within in the subfamily Bathynellinae. The position of the new taxon in Bathynellidae is discussed, and a brief note on its ecology and biogeography is also added.

A new bathynellacean, Indobathynella prehensilis n. gen., n. sp., is described from farm bores in southeastern India. This is an aberrant species, possessing such a unique combination of plesiomorphic and apomorphic characters that it cannot be assigned outright to any of the three known families of the order Bathynellacea, viz., Bathynellidae, Parabathynellidae, and Leptobathynellidae. And yet, it is provisionally placed in Bathynellidae pending reconstruction of the phylogenetic relationships within Bathynellacea. This decision is based mainly on the following plesiomorphies: 1) antennule is 7-segmented; 2) antenna has exopodal segment; 3) mandibular palp is 3-segmented; and 4) male thoracopod VIII has a basal penile lobe. The new taxon also displays some close apomorphic affinities with Parabathynellidae such as a 3-segmented prehensile maxilla, a lobe-like female thoracopod VIII, and a 1 -segmented pleopod I. The other spectacular apomorphies of the new species, some of them suggesting its po...

The stomatopod body plan is highly specialized for predation, yet the Superorder Hoplocarida originated from something other than the "lean, mean, killing machine" seen today. The fossil record of the group indicates that it originated early on from a non-raptorial ancestor, with the specialized predatory morphology developing much later. The Recent Hoplocarida have been variously positioned within the Malacostraca, from a Subclass equal in rank to the Eumalacostraca (= Caridoida) to being placed as a Superorder within the Eumalacostraca. Consideration of the early fossil morphology, especially of the form of the carapace, of the position and functioning of the articles in the last three pairs of thoracopods, and of other features, suggests that hoplocarids are early derivatives of a basal eumalacostracan stock that was "shrimp-like" in form. The enhancement of an abdominal respiratory system most likely allowed the development of the anterior thorax into the specialized raptorial system present today. We want to build a phylogenetic tree that presents the actual evolutionary his

The lacinia mobilis of the Crustacea Malacostraca is a more or less spine-like movable appendage of the medial mandibular edge, inserted near the base of the incisor process. It occurs in two or possibly three eumalacostracan superorders but is retained in the adult stage only in the Peracarida. The lacinia has been interpreted as the distal member of the spine-row found in many adult Malacostraca and/or their larvae, or alternatively as a derivative of a certain cusp (‘cusp b’) of the biting edge of the primitive lophogastrids. The distribution, ontogeny and function of the lacinia were studied in a variety of Eumalacostraca. There is great variability in the guiding and locking mechanisms involved in biting, within the subclass and even within single orders. A lacinia-based guiding and locking system is likely to function only in weak mandibles. New evidence is produced in favour of derivation of the lacinia from the spine-row, and the ‘cusp b’ derivation hypothesis is rejected, ‘cusp b’ being only a highly specialized lacinia. Doubt is cast upon the unity of the superorder Peracarida mainly because the place of the order Amphipoda within it is regarded as insecure.

Traditional views of eumalacostracan phylogeny are not in accord with current understanding of the fossil record. Another approach results from identification of basic morphotypes upon which radiations were built in the course of eumalacostracan history. Random association of characters (absence or varying conditions of the carapace, biramous or uniramous thoracopods, and presence or absence of subthoracic brood pouch of some form) yields an array of 16 morphotypes, of which 10 are recognized in the fossil and Recent record. The resultant "paper animals" combined with an analysis by cladistic methods yield six possible phenograms of eumalacostracan phylogeny. An evolutionary uncertainty principle precludes definitive choice among these patterns to produce a cladogram and taxonomy. However, a taxonomic system is advocated with the subjectivity associated with uncertainty clearly acknowledged. Perhaps one of the greatest noncontroversies in crustacean evolution has been the phylogeny and interrelationships of the Eumalacostraca. Since Calman (1904, 1909) it has been taken for granted that the higher malacostracans could be classified as discreet superorders which were derived from an ancestral type neatly delineated by a set of characters known as the caridoid facies. However, Calman's synthesis was the result of several decades of debate over how malacostracan groups were related. Boas (1883) visualized a single line arising from the phyllopods and giving off the malacostracan groups at successive levels. Claus (1885) envisioned three branches arising from a "eumalacostracan" stock: leptostracans, stomatopods, and "urschizopods," and this was essentially Grobben's (1892) position as well, except that Grobben had the stomatopods as the earliest offshoot from the "urschizopods.' Haeckel (1896) derived his "proschizopods" from the Leptostraca and in turn treated these as an ancestral stock for five lines: mysids, cumaceans, other "peracarids," "eucarids," and stomatopods. Calman's caridoid concept, however, exerted a stablizing influence on all succeeding speculations on higher malacostracan phylogeny, with the result that subsequent phyletic schemes for these groups have been essentially similar (Giesbrecht, 1913; Grobben, 1919; Balss, 1938; Siewing, 1956, 1963; and Brooks, 1962). Of these, Siewing came to be a focus of a certain school (viz., Fryer, 1964; Hessler, 1969) which essentially holds that all eumalacostracan superorders arose from a central stem. Schram (1969a, b) recently suggested that the Hoplocarida had nothing to do with other Eumalacostraca, but rather had an independent origin separate from the Eumalacostraca sensu stricto. This latter position was objected to by Burnett and Hessler (1973) but supported by Reaka (1975), Bowman and Abele (in press), and Kunze (personal communication). Through all this, the essential stability and supposed interrelationships of the Eumalacostraca sensu stricto, viz., syncarids, eocarids, peracarids, pancarids, and eucarids has remained relatively constant. The Eocarida and Syncarida were interpreted as near the base of the eumalacostracan line; and supposedly from somewhere within the eocaridan stock the Eucarida and Peracarida were derived, with the Pancarida seeming to bear some relationships to peracarids (some authors placing them as a separate superorder and others as an order of peracarids). This traditional arrangement of orders is outlined in Fig. 1.

Schram, F. R. (Dept. of Zool., Eastern Ill. U., Charleston, lll. 61920) 1974. Convergences between Late Paleozoic and modern caridoid Malacostraca. Syst. Zool. 23:323-332.-Study of the Middle Pennsylvanian, Mazon Creek, Essex fauna Crustacea (Johnson and Richardson, 1966; and Richardson and Johnson, 1971) of northeastern Illinois has prompted an examination of the entire Late Paleozoic radiation of caridoid malacostracans. Members of this radiation bear several gross anatomical similarities to Mesozoic-Cenozoic eucarid forms, yet are totally and completely distinct taxonomically from them. This convergent phenomenon affords a rare look at the evolution of a major taxonomic category extending over a period of some 300 million years. The comparison also bears on general theoretical considerations of diversity and convergence in evolutionary theory. [Convergence; Malacostraca; Diversity models.] The malacostracan crustaceans have been present in the fossil record since Cambrian time. The earliest and more primitive forms have been the Phyllocarida, forms with seven segments in their abdomens. In Devonian time a more advanced array of malacostracans apparently evolved from the phyllocarids. These forms, the Hoplocarida and the Eumalacostraca, are characterized by having six segments in the abdomen and a great variety of tagmatic and appendicular specializations that enabled them to more effectively dominate their environments. The Late Paleozoic radiation of advanced malacostracans was composed of hoplocaridans, syncaridans, and primitive eumalacostracans variously termed Eocarida (Brooks, 1962), caridoids, or schizopods. The Hoplocarida almost completely died out at the close of the Paleozoic except for the specialized Stomatopoda or "mantis shrimp." The caridoids persisted and formed the basis of the modern malacostracan radiation. The caridoids are all characterized by an array of features first elucidated by Calman (1909): two flagella on the first antenna, two segments in the thoracic protopod, five segments in the thoracic endopod, annulate and natatory thoracic exopods, thoracic epipodite gills, thorax and abdomien subequal, thorax containing viscera and covered by a carapace, abdomen developed with a special musculature for the distinctive backward-swimming caridoid escape reaction. These primitive caridoids gave rise to the groups which are the dominant malacostracans today, the Eucarida and Peracarida. The Peracarids have developed a brooding habit for protecting the young, and morphologically have a tendency to lose the carapace and greatly modify the body regions so as to diverge markedly from the caridoid morphotype. The evolution of the peracarids proper must remain the subject of another paper. The Eucarida have more closely retained the caridoid facies and are the dominant caridoid types today. The only living peracarids that can be termed "caridoid" are the Mysidacea. PERIPATETIC TAXONOMY The taxonomic affiliations of the Late Paleozoic caridoid malacostracans have been realigned several times. Huxley (1857) termed Pygocephalus cooperi an early form of decapod (Brooks, 1969, has since assigned this species to the genus Crangopsis). Huxley's designation influenced subsequent workers to categorize their fossil species as "macrurous decapods" as in Etheridge's (1877) description of some specimens of Anthrapalaemon and Wood