Raymond B. Manning

STRUCTURE AND OPTICS OF OMMATIDIA FROM EYES OF STOMATOPOD CRUSTACEANS FROM DIFFERENT LUMINOUS HABITATS

Shapes and sizes of ommatidia in six genera of stomatopods from different luminous habitats are described. Cornea-cone apertures and acceptance angles have been calculated. The ommatidia belong to the apposition type with fused rhabdoms as in most Malacostraca, but the spindle-shaped cone and the transparent wedges under the cornea are acquisitions of stomatopods. The same is true for rhabdom specializations, especially the thin undulated rhabdoms in ommatidia of the six-row middle band of the Gonodactyloidea, that divides the eye in two halves. Several regions can be distinguished in stomatopod eyes by differences in shapes, sizes, and proportions of their ommatidia and by the skewing pattern along the columns of ommatidia. As more light becomes available in the habitat, apertures and acceptance angles seem to decrease mainly by increasing the lengths of the cones.

CORNEA SHAPE AND SURFACE STRUCTURE IN SOME STOMATOPOD CRUSTACEA

ABSTRACT Three types of eyes have been observed in three different lineages of the Stomatopoda. In the Gonodactyloidea and the Squilloidea, the cornea is divided into two halves by a line of specialized ommatidia, the middle band. This band is two facets wide in the squilloids, and occupies a small portion, about 4 per cent, of the surface area of the cornea. In gonodactyloids the band is six facets wide and occupies much more of the surface area of the cornea, between 15 and 38 per cent. The middle band appears to be absent in the bathysquilloids. The greater development of the middle band in the gonodactyloid lineage than in the other lineages may be related to binocular vision and the strike of the raptorial appendage, light available in the habitat, and/or the complex behavioral patterns developed by some members of this group.

Possible monocular range-finding mechanisms in stomatopods from different environmental light conditions

Abstract 1. 1. Stomatopods have double eyes. 2. 2. In the middle band dividing the two halves of the eye ommatidia are perpendicular to the cornea. 3. 3. Rows of ommatidia parallel to the middle band have divergent optical axes. 4. 4. In the columns across the middle band the optical axes of ommatidia near the middle band are convergent between the two halves of the eye. 5. 5. From the fifth to tenth ommatidium towards the sides optical axes on each side are parallel to each other and to those in the middle band. 6. 6. This results in a strong overlap of visual fields between ommatidia with parallel optical axes in each half of the eye and with the fields of the skewed ommatidia from the opposite half of the eye. 7. 7. We postulate this as the morphological basis for a range-finding and motion measuring device along the columns, repeated around the eye along the rows. 8. 8. We hypothesize that this device may measure distances by the amount and pattern of overlap of visual fields at each point in space. 9. 9. Species from bright light habitats show less skewed ommatidia and similar patterns of overlap are shifted to longer distances than in dim light species.

An Attempt to Correlate Pseudopupil Sizes in Stomatopod Crustaceans with Ambient Light Conditions and Behavior Patterns

Abstract 1. 1. The distribution of pseudopupils in the eyes of representatives of five genera of Stomatopoda has been studied. 2. 2. A triple pseudopupil is seen when the eye is viewed perpendicularly to the specialized middle band on the cornea, but a double pseudopupil appears when the direction of viewing is moved five degrees away from the vertical, as a result of the skewing of ommatidia adjacent to the middle band. 3. 3. Skewed ommatidia near the middle band constitute a monocular range-finder. 4. 4. Species with the most complex behavior patterns have the most complex skewing patterns of ommatidia.

Ghost Shrimps of the Genus Lepidophthalmus from the Caribbean Region, with Description of L. Richardi, New Species, from Belize (Decapoda: Thalassinidea: Callianassidae)

ABSTRACT Lepidophthalmus jamaicense, originally described in limited detail on the basis of two male type specimens from Montego Bay, Jamaica, is redescribed and fully illustrated in the course of our examination of the original types, a large series of recently collected male and female topotypes, and recent collections from the southeastern Caribbean Sea. Comparative morphological studies of all the known western Atlantic species serve to distinguish materials from Belize, which are herein recognized as L. richardi, new species. Included in these comparisons and descriptions are detailed studies of ventral cuticular armor in the anterior abdominal somites, an apparent apomorphic character of particular value in segregating tropical western Atlantic populations. The occurrence of L. jamaicense in southeastern Cuba is confirmed from reexamination of museum material, and the range of the species is extended to Tobago and coastal Venezuela in the extreme southeastern Caribbean. While there appears to be strong potential for regional endemism in western Atlantic species of the genus Lepidophthalmus, the widely separated insular populations of L. jamaicense in the Antillean region appear to be undifferentiated. Reproductive history and potential for larval dispersal in this species remains unknown and may not conform to the abbreviated life histories reported for its western Atlantic congeners.

DESCRIPTION OF A UNIQUE CRUSTACEAN EYE

ABSTRACT The deeply scalloped cornea of Meiosquilla oculinova (Glassell, 1942) appears to be unique among crustacean eyes in overall shape, facet curvatures, and skewing of ommatidia.

Biogeography of deep-sea stomatopod Crustacea, family Bathysquillidae

Abstract One family of stomatopod crustaceans, the Bathysquillidae, occurs exclusively on outer shelf and upper slope habitats, in depths between about 200 and 1500m. Stomatopoda otherwise are largely restricted to shallow water habitats. The bathysquillids include four species in three genera. Bathysquilla microps occurs in both Atlantic and Pacific oceans, B. crassispinosa is found across the Indo-West Pacific from Japan to South Africa, Altosquilla soelae is known only from the northwestern coast of Australia, and Indosquilla manihinei , originally reported from the western Indian Ocean, is here reported from the Mariana Islands in the Pacific Ocean. The bathysquillids, with a fossil species in the Eocene, represent the oldest extent stock of Stomatopoda. The structure of the uropod in Indosquilla manihinei is intermediate between that of the fossil family Sculdidae and the Recent stomatopods.

Epulotheres Angelae, New Genus, New Species, a Pinnotherid Crab From the Caribbean Sea (Decapoda: Pinnotheridae)

ABSTRACT The monotypic genus Epulotheres is erected with E. angelae, new species, from Barbados, as its type species. Epulotheres resembles Ostracotheres Milne Edwards, 1853, and Calyptraeotheres Campos, 1990, in having a 2-segmented palp on the third maxilliped. It differs in that feature from most species of Pinnotheres Bosc, 1802, sensu lato, and other pinnotherid genera which have a 3-segmented palp on the third maxilliped. Epulotheres differs from Ostracotheres in being much smaller, in having a hexagonal rather than subcircular carapace, and in having a much slenderer and shorter propodus on the third maxilliped, with its apex rounded and narrowed rather than having a broad, spatulate propodus that is longer than the carpus. Epulotheres differs from species of Calyptraeotheres in lacking both sharp lateral edges and anterior longitudinal sulci on the carapace.

FIRST STAGE LARVA OF CORONIS SCOLOPENDRA LATREILLE (STOMATOPODA: NANNOSQUILLIDAE)

ABSTRACT The first larval stage of Coronis scolopendra is an antizoea with 5 pairs of biramous thoracic appendages; abdominal appendages are absent. This is the first larval stage of a nannosquillid to be identified with certainty and only the second lysiosquilloid for which the first larva is known. Instead of attaching their eggs to the walls of their burrows like other stomatopods, females of C. scolopendra carry their egg masses.

Research on the coast of Somalia. Crustacea Stomatopoda

Seventeen species of gonodactyloid stomatopods representing nine genera and four families are recorded from shore habitats in Somalia. All but one are new records for Somalia. Mesacturoides brevisquamatus (Paulson 1875) is recorded from below Djibouti for the first time. Two new genera are erected for species previously assigned to the genus Pseudosquilla Dana 1852, Pseudosquillana for P. megalophthalma Bigelow 1893, Pseudosquillisma for P. oculata (Brulle 1837) and two other species. A new host, Mesacturoides fimbriatus (Lenz 1905), is reported for the parasitic gastropod, Caledoniella montrouzieri Souverbie 1869.