Eukerria ibicatuensis James, Bartz & Brown 2023, sp. nov.
Creators: name: James, Samuel W.
name: Bartz, Marie L. C.
name: Brown, George G.
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Annelida
Clitellata
Haplotaxida
Ocnerodrilidae
Eukerria
Eukerria ibicatuensis

description: Eukerria ibicatuensis James, Bartz & Brown, sp. nov. (Fig. 2a, b)
Holotype. BRPR1851, one adult, Ibicatú State Park, Ibicatú, Paraná state, Brazil, S22.786°, W51.488°, 331 m asl, in wet seepage area near small river; 29 April 2004, G. Brown and S. James, colls.
Paratypes. BRPR0555, two adults, one of them amputated, same data as holotype.
Other material. BRPR1962, one subadult, two juveniles, same data as holotype.
Etymology. The species name is based on the location of the collection in the Paraná state park of Ibicatú.
Description. Dimensions 68-81 mm by 2-2.3 mm at segment x, 1.9-2.4 mm at xxx, 2.3-2.6 mm at clitellum; body cylindrical throughout, segments 160, 188 (of which 18 appear to be regenerated). Setae closely paired throughout, CD sub-lateral; setal formula AA:AB:BC:CD = 4.5:1.2:4:1 at xxx, DD> ½ circumference. Setae A present unmodified in xvii, xix; AB lacking in xviii; B lacking in xvii, xix. Prostomium epilobous open; segments without secondary annulations. Unpigmented, no dorsal pores, spermathecal pores large in 7/8, 8/ 9 in CD. Ovipores in xiv faint slits just behind 13/ 14 in B line. Male pores in seminal grooves in xviii; prostatic pores at ends of grooves slightly lateral to B in xvii-xix; prostatic porophores bearing small cleft papillae at ends of seminal grooves. Seminal grooves, prostatic pores on longitudinal elevated pads aligned lateral to ½ AB in xvii-xix; pads slightly constricted at xviii equator. Clitellum xiii-xxi, saddle-shaped, only present dorsally in xii, xxi, no other genital markings (Fig. 2a).
Anterior septa 5/6-8/9 thickly muscular, 9/10-11/12 less so. Alimentary canal with gizzard in vii; esophagous valvular in xi, intestinal origin in xii; no typhlosole or other differentiation of intestine. Calciferous glands blunt sagittate with ascending duct, paired in ix, attached latero-dorsally to esophagus. Glands with thick wall, irregular central lumen formed by longitudinal, radial projections of glandular tissue towards the center (Fig 2b); each gland with blood vessel from anterior end to extra-esophageal vessel, blood vessel from posterior face of gland to supraesophageal vessel. Holonephric, tubular nephridia bound within membranous covering to form flat, transparent ribbon, first nephridia in xii.
Vascular system with ventral trunk, single dorsal trunk, lateral vessels in v-ix, latero-esophageal hearts in x, xi.
Fan-shaped ovaries, with funnels in xiii; paired spermathecae in viii, ix, each an irregular sac ampulla on long broad duct, no diverticulum; sperm chambers visible within duct near body wall.
Male sexual system proandric, testes and funnels in x free, vas deferens superficial on body wall from 10/11 to xviii terminating without enlargement, seminal vesicles in ix with several long stalked branches, placed laterally on body wall, large and post-septal in xi; tubular prostates folded under intestine within xviii-xxi; prostatic ducts ectally enlarged, muscular, enter dome-shaped circular copulatory bursae, no penial setae.
Remarks. Eukerria contains two taxa in which the prostatic porophores merge antero-posteriorly to form a longitudinal bar, rather than the situation in which the porophores of a segment encroach towards one another to form a merged, or nearly merged, transverse bar across each of xvii and xix. Eukerria garmani garmani (Rosa, 1898) and E. g. argentinae Jamieson, 1970 are these two other taxa which have the longitudinal merger. Compared to the former subspecies, E. ibicatuensis sp. nov. lacks genital markings in xiii, has a larger gizzard, has more dorsally located spermathecal pores (CD vs. mid-BC), the calciferous glands are dorso-laterally attached to the esophagus (vs. ventro-laterally), the seminal vesicles of xi are larger than those of ix (vs. equal), prostates are confined to xviiixxi, prostate ducts enter small bursae (vs. not), and the spermathecal ducts are longer than the ampulla (vs. shorter). The differences from E. g. argentinae are fewer and as follows: the first nephridia are in xii (vs. xi), and there are distinct seminal grooves rather than a very glandular porophore and male field area marked by numerous transverse and longitudinal folds. Other species are excluded by the structure of the calciferous glands and positions and/or forms of genital pores. Eukerria cuca has similarly placed spermathecal pores but they are accompanied by genital markings and internal genital marking glands; it also has a simpler lumen of the calciferous glands, shorter clitellum and lesser male field development.
DNA barcodes for this species are GU013976 and GU013977. Calculations based on the K2P 14% criterion (conservative) and the ASAP algorithm (Puillandre et al. 2020) both separated this species from all other known ocnerodrilid barcode sequences.
description: Published as part of James, Samuel W., Bartz, Marie L. C. & Brown, George G., 2023, New Ocnerodrilidae genera, species and records from Brazil (Annelida: Crassiclitellata), pp. 235-269 in Zootaxa 5255 (1) on pages 238-239, DOI: 10.11646/zootaxa.5255.1.22, http://zenodo.org/record/7744817