Tiny Species Research Articles

Studies on the Crustacea of the Turks and Caicos Islands, British West Indies I. Four New Marine Isopod Crustaceans from the Vicinity of Pine Cay

Four undescribed species of shallow-water marine isopods were recently collected in the vicinity of Pine Cay in the western Caicos Islands. These are described and include the anthurid Licranthura tuberculata, possessing a tuberculate third article of the antenna and a rounded distolateral angle of the uropodal exopod; the anthurid Mesanthura spongicoia, which has a distinctive color pattern, distinctly attenuated body, and 5-7 spines on the third article of the mandibular palp; The paranthurid Califanthura minuta, a tiny (1.6 mm) species having a reduced, triangular uropodal exopod; and the stenetriid asellote Stenetrium caicosensis, which has a pronounced lobe on the merus of pereopod 1 in the male.

Topographic analysis of the retinal ganglion cell layer and optic nerve in the sandlance Limnichthyes fasciatus (Creeiidae, Perciformes).

The sandlance or tommy fish Limnichthyes fasciatus (Creeiidae, Perciformes) is a tiny species that lives beneath the sand with only its eyes protruding and is found throughout the Indopacific region. The retina of the sandlance possesses a deep convexiclivate fovea in the central fundus of its minute eye (1.04 mm in diameter). A Nissl-stained retinal whole mount in which the pigment epithelium had been removed by osmotic shock was used to examine the retinal topography of the ganglion cell layer. There was a foveal density of between 13.0 x 10(4) cells per mm2 (S.D. +/- 1.8 x 10(4) cells per mm2), counted in the retinal whole mount, and 15.0 x 10(4) cells per mm2, counted in transverse sections, which diminished to a peripheral density of 4.5 x 10(4) cells per mm2 (S.D. +/- 0.8 x 10(4) cells per mm2). The total population of axons within the optic nerve was assessed by electron microscopy. Optic axon densities ranged from 2 x 10(6) axons per mm2 in the caudal apex to over 16 x 10(6) axons per mm2 within a specialized region of unmyelinated axons in the rostral apex. The topography of the proportion of unmyelinated axon population (26%) follows closely that of the total population of optic nerve axons. There was a total of 104,452 axons within the optic nerve compared with 102,918 cells within the retinal ganglion cell layer. A close relationship is revealed between ganglion cell soma areas and axon areas where the organization in the optic nerve and retina may reflect some functional retinotopicity.

Characteristics of a Mammalian Fauna from Forests in Patagonia, Southern Argentina

Diet, reproduction, age structure, body size, sex ratio, and home range are described for nine species (eight genera) of small mammals living in Patagonian forests. Litter size and home range tend to be smaller in Patagonian species than in forest species of comparable body size in the Northern Hemisphere, but other life history characteristics are similar. Compared with the mammalian fauna of a similarly cool, wet forest on the Olympic Peninsula, Washington, the Patagonian fauna has relatively few species of carnivores, no tiny species such as shrews, few scansorial, and no arboreal species. Compared with the fauna of a Panamanian rain forest, the Patagonian fauna has more species of small mammals, more semifossorial species, and a much lower biomass because of the absence of middle-sized and arboreal species that contribute so much to biomass in Panama.

Coleopterocoris, an Interesting New Genus of the Subfamily Potamocorinae (Naucoridae: Heteroptera)

In 1941 Doctor Robert Usinger set up the new Subfamily Potamocorinae for Potamocoris parvus Hungerford, which was described in the same issue of the Annals of the Entomological Society of America, Vol. XXXIV, pp. 1–4, Plate I. This tiny species, only 2.8 mm. long, appeared to be a most interesting discovery, and remarkably smaller, and structurally different from any Naucorid known. Recently there has come to my attention another new species of about the same size, but with characters that place it in another genus and add strength to the suggestions of Doctor Usinger and Mr. W. E. China2,3 that there is some close relationship between the Naucoridae and the Helotrephidae.

Illustrations of Fungi—XV

Pileus thin, fleshy, convex to expanded, irregular or depressed at times, gregarious, I-2.5 cm. broad; surface glabrous, subrugose, ochraceous to orange; margin inrolled at first, entire or repand; context thin, pallid, mild, at length faintly peppery; lamellae decurrent, distant, very narrow, often forking, but seldom anastomosing, concolorous or somewhat paler; spores ovoid, somewhat one-sided, smooth, hyaline with a faint yellowish tinge, 8-9 X 4-5 /A; stipe slender, cylindric, equal, glabrous, shining, slightly striate at times, concolorous, usually solid, 2-5 cm. long, 2-4 mm. thick. This tiny bright-colored species is known to occur on the ground in deciduous woods from Massachusetts to Alabama in the eastern United States and is reported from a few localities in the middle west. Lepiota procera (Scop.) Quel. PARASOL MUSHROOM