Hemienchytraeus wuhanensis, Chen & Schmelz & Xie, 2021
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publication ID |
https://dx.doi.org/10.3897/zookeys.1015.59019 |
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publication LSID |
lsid:zoobank.org:pub:C45FA298-10C5-4869-B478-8E8502521940 |
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persistent identifier |
https://treatment.plazi.org/id/D3137BCA-E1CC-4FC7-AA55-A88FA9ED06E6 |
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taxon LSID |
lsid:zoobank.org:act:D3137BCA-E1CC-4FC7-AA55-A88FA9ED06E6 |
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treatment provided by |
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scientific name |
Hemienchytraeus wuhanensis |
| status |
sp. nov. |
Hemienchytraeus wuhanensis sp. nov.
Holotype.
Fully mature, whole-mounted specimen, stained, HBO201904002.
Type locality.
Mount Shizi, litter layer of hardwood forest (30°28'42.57"N, 114°21'10.48"E; 44 m a.s.l.), Huazhong Agricultural University (Fig. 1 View Figure 1 ), Wuhan, Hubei Province, 6 April 2019, coll. Y. H. Ge.
Paratypes.
HBO201904003, HBO201904004 two whole-mounted fully mature specimens, HBO201904005-HBO201904007, three adult specimens, used entirely for DNA extraction; HBO201904008-HBO201904010 three adult specimens from the type locality maintained in 75% alcohol, same data as holotype. HBO201904001 one whole mounted fully mature specimen, HBO201904011-HBO201904012 two adult specimens used for extract DNA, and HBO201904013-HBO210904015 three adult specimens maintained in 75% alcohol from Mount Luojia, under a pine tree (30°32'05.39"N, 114°22'10.95"E; 31 m a.s.l.), Wuhan University, Wuhan, Hubei Province, 2 April 2019, coll. X. K. Jiang & J. J. Chen.
Etymology.
Named after the city where the species was found.
Distribution and habitat.
Mineral soil and organic layers under camphor trees near a narrow, tarred road at Mount Shizi, Huazhong Agricultural University; mineral soil and organic layers under pine trees at Mount Luojia, Wuhan University. The two hills are about 10 km apart, with little human disturbance.
Diagnosis.
This new species can be recognized by the following combination of diagnostic traits: (1) chaetae anteriorly and posteriorly of about the same size, not enlarged in caudal segments; (2) oesophageal appendage with tertiary branches; (3) three pairs of secondary pharyngeal gland ventral lobes in V, VI, VII, small in VII; (4) five pairs of preclitellar nephridia in 5/6-9/10; (5) dorsal vessel originating in clitellum segments; (6) clitellum girdle-shaped; (7) seminal vesicle absent; (8) spermathecae extending to VI-VII, not enlarged.
Description.
Length 6.5-9.3 mm (in vivo), diameter 0.3-0.4 mm (in vivo) at clitellum. Segment number 37-42. Two chaetae per bundle throughout, absent in XII in mature specimens. Chaetae straight with slight proximal bend; in anterior segments, slight distal bend in opposite direction of proximal bend, i.e., chaetae faintly sigmoid; in proximal segments, chaetae distally straight. Chaetae in preclitellar bundles 37.5-42 mm long, diameter 5 mm, 27.5-32.5 mm in postclitellar segments, diameter 5 mm. Head pore mid-dorsally on prostomium. Epidermal gland cells gray, three to four transverse rows per segment, the cells nearly rectangular and arranged in regular pattern (Fig. 3E View Figure 3 ). Clitellum in XII-1/2XIII, inconspicuous thickening, cells ca 5-9 mm high, girdle-shaped (Fig. 3I, J View Figure 3 ), hyalocytes and granulocytes in reticulate arrangement with hyalocytes taking larger proportion dorsally (Fig. 3I View Figure 3 ). Body wall 25-37.5 mm thick.
Brain about as long as wide (117 mm long, 93 mm wide, in vivo), slightly indented anteriorly, deeply incised posteriorly (Figs 2B View Figure 2 , 3A View Figure 3 ). Oesophageal appendage arising from mid-dorsal region of pharynx in III as an unpaired root with large proximal chamber; following section longer than proximal chamber, with thick, meandering canal; two primary branches, longer than root, with smaller canal; each primary branch bifurcating into two short, secondary branches; each secondary branch bifurcating into four or more tertiary branches, the latter difficult to distinguish. Secondary and tertiary branches of same diameter, thinner than primary branches (Figs 2E View Figure 2 , 3B, C View Figure 3 ). All three pairs of pharyngeal glands united dorsally, primary ventral lobes in V and VI. Three pairs of secondary pharyngeal gland lobes in V, VI and VII, small in VII (Figs 2D View Figure 2 , 3D View Figure 3 ). Dorsal vessel from XII-XIII, blood colorless.
Five pairs of preclitellar nephridia from 5/6 to 9/10 (Fig. 2A View Figure 2 ); each about 160 mm long and 60 mm wide (in vivo). Anteseptale globular, with minute and numerous brownish granules at periphery; funnel orientated obliquely ventrad, with small and narrow anterior projection; postseptale elongate, ca twice as long as anteseptale. Efferent duct originating from the middle of the postseptale (Fig. 3G View Figure 3 ).
Seminal vesicle absent, cysts dorsally in XI. Sperm funnels cylindrical, tapering distad, well developed, ca 150-250 mm long and 40 mm at collar (in vivo). Collar distinct, somewhat narrower than funnel body (Figs 2F View Figure 2 , 3K View Figure 3 ). Spermatozoa ca 140 mm long, heads ca 20 mm long (in vivo). Sperm ducts elongate, diameter ca 6 mm, loose or tight coils in XII-XIII (Fig. 3L View Figure 3 ). Male copulatory organs with distinct musculature, male glandular body globular, ca 85 µm in diameter (in vivo). No accessory copulatory glands (Fig. 3H View Figure 3 ).
Spermathecae free, not attached to oesophagus. Ectal pores laterally at 4/5, without ectal gland. Ectal ducts ca 400-500 mm long and 20-26 mm wide (in vivo), with distinct ampullar dilatation in V. Connecting tube between ampulla proper and ental reservoir thinner than ectal duct, extending into VI or VII, ending in a small, elongately ellipsoid ental reservoir of 88-128 µm length and 30-50 µm width (in vivo), empty or with spermatozoa (Figs 2C View Figure 2 , 3F View Figure 3 ). One mature egg or 3-4 immature eggs at a time.
Molecular results
COI sequences of five paratype specimens of H. wuhanensis sp. nov. were successfully acquired and submitted to GenBank with accession numbers. This is the fourth species of Hemienchytraeus of which DNA sequences are available (Table 1 View Table 1 ), the other three being H. quadratus , H. koreanus , and H. jeojunensis Dózsa-Farkas & Hong, 2010, all from South Korea. Clear genetic gaps were observed among the four species with high interspecific distances (7.0-21.9%) and low intraspecific distances (0%) among H. wuhanensis sp. nov. specimens based on the K2P distances of COI sequences (Table 2 View Table 2 ). Interestingly, among the three species from South Korea, the one with lowest genetical distance to H. wuhanensis sp. nov., H. koreanus , is also the one which is most similar morphologically to the new species (see below).
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