Henlea petushkovi, Rota & Martinsson & Erséus, 2018

Rota, Emilia, Martinsson, Svante & Erséus, Christer, 2018, Two new bioluminescent Henlea from Siberia and lack of molecular support for Hepatogaster (Annelida, Clitellata, Enchytraeidae), Organisms Diversity & Evolution (New York, N. Y.) 18 (3), pp. 291-312 : 295-301

publication ID	https://doi.org/ 10.1007/s13127-018-0374-6
DOI	https://doi.org/10.5281/zenodo.13171971
persistent identifier	https://treatment.plazi.org/id/03FD87E0-FFC6-FFF1-C932-2D65FC0AF5CA
treatment provided by	Felipe
scientific name	Henlea petushkovi
status	sp. nov.

Treatment

Henlea petushkovi View in CoL sp. n. ( Figs. 3–5 View Fig View Fig View Fig )

Holotype MCZR OLIGOCHAETA 0205 , whole-mounted specimen, fixed in Bouin Feb 2016.

Type locality Elovoye (56° 8′ 40.08″ N, 92° 32′ 27.97″ E), village near Yemelyanovo International Airport , 25 km NWof Krasnoyarsk, soil within and around greenhouse (loc. 4) GoogleMaps .

Paratypes MCZR OLIGOCHAETA 0206–0209 , four posteriorly amputated submature or immature specimens (vouchers CE31467 –CE31470) preserved in 85% ethanol from type locality (loc. 4), Apr 2017 ; posterior parts used for DNA extraction (COI Barcodes, Nuclear markers and GenBank nos. listed in Table 1). MCZR OLIGOCHAETA 0210 , mature specimen from forest soil by Kacha river (loc. 1), fixed in Bouin Oct 2001 , anterior 16 segments cross-sectioned, posterior body (49 segments) in ethanol. MCZR OLIGOCHAETA 0211 , submature specimen from same locality (loc. 1), fixed in Bouin Oct 2001 , anterior 20 segments sectioned longitudinally, posterior body (45 segments) in ethanol. MCZR OLIGOCHAETA 0212– 0213 , two mature specimens, whole-mounted, from forest soil along Mana river (loc. 2), fixed in 80% ethanol Aug 2003 . SMNH Type Collection 9076, one mature specimen, whole-mounted, from forest soil along Mana river (loc. 2), fixed in 80% ethanol Aug 2003 . SMNH Type Collection 9077–9078, two posteriorly amputated submature or immature specimens (vouchers CE31475 –CE31476) preserved in 85% ethanol from type locality (loc. 4), Apr 2017 .

Additional material Ten specimens (vouchers not preserved) from farmyard soil at Gladkoye (loc. 3), DNA-sequenced Mar 2015 (COI Barcodes, other markers and GenBank nos. listed in Table 1). Numerous specimens from loc. 1, 2, and 4 in first author’ s collection.

Etymology Named for Valentin N. Petushkov, researcher of the Russian Academy of Sciences, for his lifelong dedication and excellent accomplishments in the biophysical study of enchytraeid bioluminescence.

External Colour white-yellowish, emitting flashes of bluish light upon stimulation. Body wall opaque, rather stiff. Live body size: length 25–30 mm, width at V 720 μm, at clitellum 750–850 μm. Fixed dimensions can be much altered by body contraction: length 16–21 mm; width at V 800–1200 μm, at clitellum 900–1500 μm. Segments 61–70, average 65.5 (n = 8). Prostomium hemispherical, in a side view dorsally depressed, short, in vivo 240 μm from head pore to tip, 400 μm wide at base ( Fig. 3a, b, c, d View Fig ). Peristomium (segment I) in vivo 250–280 μm long, 550 μm wide ( Fig. 3a, b, c, d View Fig ); after fixation 190–200 μm long, 530–650 μm wide. Head pore as a transversal slit at 0/1. Epidermal gland cells irregularly shaped and sized, distributed in 4 transversal rows. Chaetae arranged in lateral and ventral bundles, straight, (1)2÷5 − 2÷5(6,7,8): (1)2÷6 – 2÷7(8) per bundle, most numerous in segments XL–L (Suppl. Fig. 1 View Fig ); the outer chaetae in a bundle larger than the inner ones (e.g., 115 μm vs 90 μm in segment XVII), length up to 150 μm (caudally), thickness up to 13 μm. Chaetae of XII missing in mature specimens. Clitellum ( Fig. 4g, h View Fig ) over 1/4 XI–3/4 XIII, moderately elevated, made of small gland cells, the hyaline cells somewhat larger than the granular ones, the two types irregularly arranged. Paired male pores ventral in XII, inside deep male bursae; clitellar gland cells absent between them. No copulatory glands. Paired spermathecal pores in lateral lines at 4/5.

Internal Brain concave anteriorly, deeply indented posteriorly, slightly longer than wide, ca. 170 μm wide and 180 μm long ( Fig. 3a, d View Fig ). Septa 6/7–8/9 thickened ( Figs. 4a, b View Fig , and 5b View Fig ). Oesophageal appendages adhering to gut wall and, through VI and beginning of VII, forming frilled ridges giving off numerous branched extensions into the coelom dorsally and ventrally ( Fig. 4a View Fig , arrows). Intestinal diverticula forming a multitubular tulip-shaped structure surrounding gut and occupying much of the coelomic cavity in VIII ( Figs. 4a View Fig , and 5a–c View Fig ); tubules arising from intestine in posterior of VIII, extending forwards while branching, ending blindly to make the frontal border of the organ ( Fig. 4a, b View Fig ). The mass of tubules adheres to gut but anteriorly is extensively anchored to septum 7/8 ( Fig. 4b View Fig ), thus, the diverticula appear evenly expanded along anterior half (in vivo maximum diameter ca. 490–520 μm, length 360–410 μm), and the frontal border appears doubly paired, with diverging anterior tips (middorsally and midlaterally the anterior outline appears concave; Fig. 5a, b, c View Fig ). Chloragogen cells from IV, small, forming a dense olivebrown tissue from X; in vivo granules irregularly distributed and cells appearing more aggregated in places, so as to make the tissue not uniformly opaque. Dorsal vessel originating in IX ( Figs. 4a View Fig , and 5a View Fig ), with heart-like expansions in IX, VIII and VII; lateral commissures seen in IV (2 pairs) and V (1 pair) ( Fig. 4a, d, e View Fig , arrowheads); cell nuclei seen on the inner wall of all vessels. Preclitellar nephridia 6 pairs, in 5/6–10/11, efferent ducts arising anteroventrally ( Fig. 4a View Fig ). Coelomocytes abundant, with evenly fine-granulated cytoplasm, opaque when accumulated ( Fig. 5b, c View Fig ), discoid, 60–85 μm across both in vivo and fixed (and regardless of worm’ s maturity), longer than half the largest outer chaetae ( Fig. 5d View Fig ); live coelomocytes often showing a peripheral annular wrinkle ( Fig. 5d View Fig ), but no cell sculpture remains evident in whole-mounts or sections ( Fig. 4a, d, f View Fig ). Seminal vesicles paired, extending to X ( Fig. 4f View Fig ). Sperm funnels cylindrical, slightly narrowing entally to ectally, in vivo ca. 400 μm long and 120 μm wide (fixed: 375 by 150 μm); collar low, wider than ental end of funnel body ( Fig. 4f View Fig ), often with upturned border. Heads (i.e., nuclei) of spermatozoa about 48 μm long. Vasa deferentia confined to XII, long, forming regular loops, relatively thin (in vivo ca. 12 μm thick) ( Fig. 4f View Fig ). Penial bulbs simple, of lumbricilline-type (i.e., with a compact glandular body surrounded by muscles). Spermathecae one pair, in V. Three or four large accessory gland cells around each spermathecal pore; glands elongate, club-shaped, attached by their narrower ends to ectal pore, 100–140 μm long and 40 μm in max width ( Fig. 4c View Fig ). Ectal ducts stout, in vivo 300– 350 μm long and 60 μm wide, thick-walled (ca. 20 μm), with inner canal expanding markedly (from 10 to ca. 35 μm) from pore to spermathecal midcourse; at junction with ampulla, duct canal forms a bell-shaped cavity 50 μm across, merging with ampullar lumen ( Fig. 4d View Fig ). Ampullae oval, 140 μm wide, not clearly demarcated from sac-like ental ducts, total length of ampulla and ental duct 250–300 μm, entally merging into a short common chamber communicating with oesophagus in posterior of V ( Fig. 4a, e View Fig ). Spermatozoa present all along the ectal ducts, in the lumen and walls of ampulla and in ental ducts ( Fig. 4a, d, e View Fig ).

Taxonomic relationships Henlea petushkovi sp. n. belongs to a non-monophyletic subgroup of Henlea discussed below, “ Hepatogaster ” (Suppl. Table 1), characterized by a multitubular gut outgrowing in VIII, brain posteriorly

indented, dorsal blood vessel from IX, conspicuous spermathecal ectal glands and nephridia from 5/6. As concerns the number of chaetae and body segments, the new species is most similar to H. tubulifera Welch 1914b , originally described from North America (Michigan). However, in Welch’ s species the coelomocytes were smaller (36–54 μm), the oeosophageal appendages ended posteriorly in VI and had only dorsal extensions into the coelom, the sperm funnels showed different size and shape, and so did the spermathecae. On the other hand, H. moderata Welch 1914a from Illinois resembles the new species in the size of coelomocytes (max length 85 μm), and the structure of the oeosophageal appendages (giving off branches in VII), but differs from the new species in its lower segment number, shorter sperm funnels, and differently shaped brain and spermathecae (see Welch 1914a). Neither of these named species was reported by Welch to be bioluminescent.

As shown and discussed below, H. petushkovi sp. n. is most closely related to H. rodionovae sp. n. described below, and there is genetic evidence that the two species are capable of hybridizing.