Brinkhurstia americanus
Creators: name: Jamieson, Barrie G. M.
name: Fragoso, Carlos
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Annelida
Clitellata
Alluroidida
Alluroididae
Brinkhurstia
Brinkhurstia americanus

description: Brinkhurstia americanus (Brinkhurst 1964) (See Figs 3 & 10)
Alluroides americanus nom. nud. Cernosvitov 1936: 19.
Alluroides americanus Brinkhurst 1964: 533–534. Figs.5–7.
Brinkhurstia americanus (Brinkhurst), Jamieson 1968: 80–81, Figs. 3, 12; Brinkhurst & Jamieson 1971: 716–717, Fig. 14.1E, F; Righi et al. 1978: 11–12, Figs. 11 –21; Stacey & Coates 1996: Tables 1 and 2; Omodeo and Coates 2001: 39–40, Fig. 1 A, B.
Length 24–30 mm, width 0.56–0.75 mm, segments 100–130. Prostomium short or large and rounded. Ventral setal couples of XIII replaced by a single penial seta on each side; in the ovarian segments aa:ab:bc:cd:dd =4.7:1:5:1.1:6.2; dd =0–25 u; length of a lateral seta from XI, base to node=87 µm. Clitellum annular, slightly less developed ventrally; segments 1/2XII–XV. Lateral lines present. Male pores ventrolateral in XIII. Female pores anterior in XIV. Spermathecal pore single, middorsal, anteriorly in IX.
Septum 3/4 excessively delicate and doubtfully complete; 4/5 and 14/15 hardly appreciably, 6/7–8/9 fairly strongly thickened (two tiers of muscle fibres) the remainder intermediate; 10/11 has one tier of muscle fibres and is not backwardly deflected. Septal glands in V–VIII. Alimentary canal expanding greatly in XVI but no definite transition from oesophagus to intestine. Gizzard, oesophageal diverticula and typhlosole absent. Perienteric blood sinus in IX posteriad, not appreciable in front of this. Testes discrete elongated tongues of tissue dependent from the anterior wall of X. Gonadial tissue absent from XI. Seminal vesicles absent or present in XI. Vas deferens running on body wall in XI and XII. Atria very thin much coiled tubes extending from mid–XIII into XIV; discharging in the close proximity of the corresponding vas deferens through the posterior wall of a globular non-muscular ectal chamber; a simple, straight, unornamented penial seta in a follicle approximately twice the length of the chamber, penetrates the anterior wall of the chamber. Each prostate has a cuboidal lining epithelium surrounded in turn by a very thin muscular sheath and an external layer of prostatic cells only one to a few cells thick, though considerable masses of prostatic cells are formed between adjacent coils. Width muscular tube of atrium (external) 28 µm; width ectal chamber 37 µm; length penial seta 115 µm; greatest width 18 µm. Ovaries dependent from the anterior wall of XIII and extending posteriad into ovisacs formed by the backward evagination of septum 13/14 through as many as 8 segments: diameter of the largest oocyte–nuclei 33 µm. First nephridia (from peritoneal masses) in IX or X. Spermatheca in IX a simple elongated pouch, 87 µm wide, with no distinct ampulla, lined internally by a short columnar epithelium invested in a single layer of circular muscle and an outer glandular? peritoneal sheath.
Distribution. Brazil; Saint Lucia (Caribbean); Argentina; Guyana.
description: Published as part of Jamieson, Barrie G. M. & Fragoso, Carlos, 2024, A monograph of the Oligochaete family Alluroididae, pp. 401-435 in Zootaxa 5529 (3) on pages 421-422, DOI: 10.11646/zootaxa.5529.3.1, http://zenodo.org/record/14022623