Grania sperantia, Rota & Wang & Erséus, 2007
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publication ID |
https://doi.org/ 10.1080/00222930701391682 |
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persistent identifier |
https://treatment.plazi.org/id/FA09AD4F-FFE4-FFA4-2888-51CD9634195E |
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treatment provided by |
Felipe |
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scientific name |
Grania sperantia |
| status |
sp. nov. |
Grania sperantia sp. n.
( Figures 7A–H View Figure 7 , 8A, B View Figure 8 )
Type material
Holotype: WAM V 7320 , whole-mounted specimen, fully mature, from southeast of Cowerie Bay at Cheyne Point, 33 ° 56.919S, 122 ° 31.279E, subtidal, 0.5 m, heterogeneous sand with pebbles and coral, 19 February 2003 (Stn ES03-39 ) GoogleMaps . Paratypes: WAM V 7321–7326 , six specimens numbered in this order: one from type locality, one from Stn ES03-25 C, one from Stn ES03-28 A, one from Stn ES03-28 C, and two from Stn ES03-35 A. SMNH Type Coll. 6809–6817, nine specimens: six from Stn ES03-28 C and three from Stn ES03-35 A (two missing posterior segments). MCZR Oligochaeta 0150–0155, six specimens: three from Stn ES03-28 C (two missing posterior segments) and three from Stn ES03-35 A (two missing posterior segments). All fully mature except three just puberal from ES03-25 C, ES03-28 A, and ES03-35 A, and two subadult from ES03-28 C and ES03-35 A.
Description
Body 11.8–15.4 mm long (n 513), 0.30–0.35 mm wide at V, 0.38–0.42 mm at clitellum (n 520). Segments of complete adults 66–78 (n 514). Prostomium rounded ( Figure 7A, B View Figure 7 ), 80–108 mm long, 133–175 mm wide at 0/1 (n 520), epidermis just thinning at front (to 10– 15 mm). Chaetae beginning in VII ventrally, absent throughout laterally. Chaetal length 125–163 mm in preclitellar segments, 105–160 mm in postclitellar segments, larger in (VII) IX–XXV (XXX), then gradually decreasing towards tail. Chaetae ( Figures 7F View Figure 7 , 8A View Figure 8 ) stout, L-shaped, ectal tip blunt, shaft straight, progressively expanding entally (from up to 11 mm thick at mid-point to up to 14 mm across ankle), then curving into a short, slender foot with low instep and indistinct heel. Chaetal index 4.84, n 510, s 50.424. Sole of foot flat, tip of foot upturned. Epidermal gland cells inconspicuous. Thick layer of longitudinal body wall muscle fibres. Clitellum as much as 32.5 mm thick when fully developed, extending from the chaetae of XI to the whole of XIII, sometimes covering part of XIV ( Figure 7C, D View Figure 7 ); gland cells distributed into three main bands around body: a wider ‘‘middle band’’ of small (8–11 mm across), polygonal cells with two granulation types, hyaline and pale granular, interspersed in an irregular pattern—this middle band starts in the first half of XII; and an anterior and a posterior ‘‘border band’’, each of 14–16 regular transverse rows of cells, dominated by large rectangular (10 × 16–24 mm) hyaline cells. In closer view, the ‘‘border bands’’ indeed consist each of two sub-bands: one located at the (anterior or posterior) boundary of clitellum and comprising about 10–12 rows of merely hyaline cells, and the other, adjacent to the middle clitellar band, consisting of four to five rows of hyaline cells intermingled with few, very small (3–7 × 6 mm), refringent granular cells ( Figure 7D View Figure 7 ). Clitellum absent midventrally between male pores ( Figure 7C View Figure 7 ). Male pores ventrolateral in middle of XII. A small ‘‘copulatory gland’’ midventrally in XIV. Spermathecal pores ( Figure 8B View Figure 8 ) located in lateral lines at onethird of V.
Brain indented posteriorly. Head organ housing four to six globular inclusions of uniform (4.8 mm) or different (2.5–6.4 mm) diameter ( Figure 7A, B View Figure 7 ); inclusions often showing a central hole (some specimens from ES03–28C and ES03-35A). Pharyngeal glands paired at 4/5–6/7, with ventral lobes in IV–VI; ventral lobes larger than dorsal ones in IV. Gut contents: small to large diatoms, fragments of thick sponge spicules, organic material mostly decomposed. Rectal ampulla not expanded ( Figure 7G, H View Figure 7 ). First nephridia at 7/8; nephridia conspicuous in posterior body half. Coelomocytes not seen. Dorsal blood vessel commencing in XXXIX–XLIX (n 512). Chloragogen cells reaching 16 mm above gut in anterior segments, more flattened (11 mm at most) behind clitellum. Sperm sac extending to XXII–half XXIX (n 56). Sperm funnels elongate, 62.5 mm wide, about 19 times longer than wide, occupying 3.5 segments [XIII–XV(XVI)], with a short (16–19 mm) hyaline portion below collar. Heads of sperm reaching 22–24 mm above collars. Vasa deferentia not very long, always less deep than sperm funnels inside sperm sac (coils only seen as far back as XIV); vas unmodified, ciliated throughout, proximally 17.5 mm wide, ectally narrowing to 10 mm as approaching penial apparatus from posterior side. Penial apparatus, a compact glandular bulb, oval in lateral view, 96–112 mm long, slightly off-centred to the rear of the male pore, flanked laterally by an aglandular sac pointing posteriorly; all parts of apparatus anchored by robust muscles to body wall ( Figure 7E View Figure 7 ). No stylets present (penial type‘‘3’’ sensu Coates 1984). Egg sac extending into XXIX–XXXII (n 54). Spermathecal ampullae large, oval, 88–112 mm wide, 104–128 mm long, with agranular walls, separately attached to oesophagus in posterior of V ( Figure 8B View Figure 8 ); about 30 sperm rings, maximally 19 mm wide, embedded in each ampulla. Ectal ducts 100–128 mm long, 32 mm wide at midcourse, narrowing at both ends; ducts S-shaped, proximally curved medially to enter ampullae laterally, distally bent at angle to reach external pores. Latter portion of ducts showing distinct muscle fibres.
Etymology
Named using the late Latin equivalent of ‘‘Espérance’’ (the French name for ‘‘Hope’’).
Remarks
This new species is easily distinguished by the complete lack of lateral chaetae, the multiple-banded pattern of the clitellum, the extremely long sperm funnels, and the intrasegmental location of the spermathecal pores. Remarkable also is the high number (and the hollowness) of the inclusions that can be found in the head organ of some specimens. The lack of coelomocytes, consistently observed in material from four stations, could be an artefact due to loss of these cells on fixation (thus representing at least a behavioural, if not physiological, trait of the species). The body size, the chaetal characters (size, shape, and distribution) and the proportions of the sperm funnels are strongly reminiscent of G. conjuncta Coates and Stacey, 1993 , another Western Australian species described (on a single specimen) from Rottnest Island, characterized by dorsally merging spermathecae and the lack of penial aglandular sacs. Grania sperantia , however, does not share such aberrant structure of the spermathecae and penial apparati, and is also readily distinguished from G. conjuncta by its regular number of pharyngeal glands, the occurrence of nephridia at 7/8, and a more posterior origin of the dorsal vessel.
Distribution and habitat
South coast of Western Australia (Esperance). In lower intertidal to shallow subtidal (2 m), medium to coarse sand.
Grania vacivasa Coates and Stacey, 1993
( Figures 8C View Figure 8 , 9A–E View Figure 9 )
Grania vacivasa Coates and Stacey 1993, p 400 –402, Figures 5A–D View Figure 5 , 6A–D View Figure 6 .
Material examined
WAM V 7327–7329 , three specimens, one of which ( V 7329 )missing posterior segments . SMNH Main Coll. 90237–90238, two specimens, one of which missing posterior segments . MCZR Oligochaeta 0156–0157, two specimens. All from Stn ES03-4 A and fully mature.
Description
Body 14–18 mm long (n 55), 0.32–0.36 mm wide at V, 0.32–0.37 mm at clitellum (n 57), comprising 70–87 segments (n 55). Prostomium dome-shaped (hemispherical) ( Figure 9B View Figure 9 ), 175–200 mm wide at base and 100–120 mm long (n 55), epidermis 7.5– 15 mm thick at front. Posterior margin of pygidium rounded ( Figure 9C, D View Figure 9 ). Chaetae lacking laterally, beginning in V (three specimens) or VI (four specimens) ventrally. Preclitellar chaetae 80–130 mm long, postclitellar chaetae 90–147 mm long. Size of chaetae reaching maximum at mid-body (around XXX – XL), progressively decreasing towards anterior and posterior body ends. Chaetae L-shaped or hooked, with shaft straight or slightly bent ectally (without preferential direction), thickest at mid-point, entally curving into a short foot with curved sole and slightly upturned toe ( Figures 8C View Figure 8 , 9A View Figure 9 ). Chaetal index 5.70, n 511, s 50.523. Body cuticle always thin (1 mm), or tightly adhering, over prostomium, peristomium, and pygidium; it may reach up to 4 mm over mid-body segments ( Figure 9A View Figure 9 ). Epidermal gland cells inconspicuous. Clitellum maximally 23– 27 mm thick, absent between male pores; both granular and hyaline gland cells small, irregularly shaped, intermingled; only granular cells occurring midventrally behind male pores and laterally to male pores. Spermathecal pores as conspicuous oval buttons in lateral lines, somewhat posterior to 4/5.
Brain indented posteriorly. Head organ absent ( Figure 9B View Figure 9 ). Septa 7/8–9/10 somewhat thickened. Gut contents: conspicuous sponge spicules (large needles, fragmented or entire, and spherical bodies) and coarse organic matter ( Figure 9E View Figure 9 ). Rectal ampulla distinctly dilated, occupying most of pygidial lumen ( Figure 9C, D View Figure 9 ). Nephridia not seen. Coelomocytes not seen. Dorsal blood vessel arising in XXXIV– XLVI (n 54). Chloragogen cells rounded, finely granular, forming a thin layer above gut in all segments. Sperm sac extending into XXV–XXXI. Heads of spermatozoa about 15 mm long. Vasa deferentia unmodified, showing conspicuous inner ciliation, about 11.0– 15.5 mm thick. Egg sac extending into XXXII–XXXVII. Spermathecae attached to oesophagus in posterior half of V. About 20 sperm rings, 16–22 mm in diameter, scattered throughout walls of each ampulla; spermatozoa often present (uncoiled) also inside canal of ectal duct.
Remarks
This large species, known so far from one station at Rottnest Island, is easily identified by the lack of lateral chaetae, the location of the largest chaetae at midbody, the midventral papillae in XIV and XV, the long sperm funnels (11–15 times longer than broad), and the unarmed penial apparati ( Coates and Stacey 1993; personal observation). Three additional diagnostic features, noted herein for the first time and essential to clearly separating it from the otherwise similar G. sperantia , are: the high chaetal index (the highest value recorded so far in the genus), the lack of head organ, and the characteristic external and internal appearance of the pygidium. The dorsal blood vessel appears longer in the specimens from Esperance than in the types from Rottnest Island. The lack of coelomocytes, a feature not specified in the original description, could be due to a recurrent behavioural artefact (loss of these cells on fixation). Coates and Stacey (1997) noted a strong similarity between G. vacivasa and the northwestern Australian G. integra Coates and Stacey (1997) , to the point that they suspected the two species might be identical other than in the presence of the penial stylet (in G. integra ). Our own observations on the two species (Rota et al. 2003; and present paper) confirm this discrepancy and add others: e.g. presence of abundant coelomocytes, confinement of the spermathecal ampullae to the anterior half of V, and no expansion of the rectal ampulla in G. integra . (The latter feature is possibly correlated with the kind of items found in the gut in G. vacivasa .) For the time being, however, the hypothesis of a close relationship between the two species should not be discarded.
Distribution and habitat
South (Esperance) and west (Rottnest Island) coasts of Western Australia. Subtidal to at least 11.5 m (new depth record), in medium to coarse sand.
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.
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Grania sperantia
| Rota, Emilia, Wang, Hongzhu & Erséus, Christer 2007 |
Grania vacivasa
| Coates KA & Stacey D 1993: 400 |