Parotoplana mastigophora, Delogu & Casu & Curini-Galletti, 2008
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publication ID |
https://doi.org/ 10.1080/00222930701840696 |
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persistent identifier |
https://treatment.plazi.org/id/8D5587EB-FFF4-AE5E-1982-FD3D9C554988 |
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treatment provided by |
Felipe |
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scientific name |
Parotoplana mastigophora |
| status |
sp. nov. |
Parotoplana mastigophora View in CoL sp. n. ( Figures 2C View Figure 2 , 4B View Figure 4 , 5 View Figure 5 )
Holotype. One whole mount (SMNH 6789).
Type locality. Spain. Benajarafe (lat. 36 ° 42954.380N, long. 4 ° 10949.950W); about 5 m deep, fine sand. October 2005 .
Etymology. The specific epithet refers to the peculiar stylet of the new species, shaped like a whip (Greek: mastix).
Description
A very small Parotoplana (the fixed holotype is about 1.2 mm long), slender and elongate. With a poorly-developed adhesive area at the caudal end. With large, elongate rhabdoids, arranged in few, irregular longitudinal rows. The median pharynx is collar shaped.
Male genital organs. With two rows of seven to eight testes each anterior to the ovaries. The male copulatory organ consists of an elongate seminal vesicle, an ovoid prostatic vesicle (67 Mm long, 25 Mm high), surrounded by a thick outer layer of circular muscles, and a sclerotized apparatus consisting of a stylet surrounded by 18 spines ( Figures 2C View Figure 2 , 4B View Figure 4 ). The stylet is an elongate, inverted cone, 122 Mm long. Its basis (diameter 15Mm) is gutter shaped. The edges of the gutter fuse at about one-third of the length of the stylet, and coalesce into a narrow, tubular structure about 2.5 Mm broad. The distal portion of the stylet narrows to about 1 Mm in diameter, and the apex is truncated.
The spines of the girdle sharply increase in size from those most proximal to the stylet (dorsal) to those ventral to the stylet. The five ventral spines are about 5 Mm long, and are provided with slender distal tips, with very elongate subterminal teeth ( Figure 2C View Figure 2 : 1). Dorsally, these are followed by five longer (up to 20 Mm) spines, with progressively longer subterminal teeth ( Figure 2C View Figure 2 : 2). In the eight most dorsal spines (46–75 Mm long) the distal tips are shorter, broader and distinctly recurvate, and the subterminal teeth become progressively smaller ( Figure 2C View Figure 2 : 3).
Female genital organs. With two ovaries anterior to the pharynx, and two rows of vitellaria extending posterior to the ovaries to anterior to the copulatory organ.
With a small, ovoid bursa, about 40 Mm wide, opening dorsally in the common atrium through a long bursal canal.
Remarks
Parotoplana mastigophora sp. n. belongs to the group of species with a central stylet. However, the morphology of its sclerotized apparatus is unique, and does not allow further inferences on its phylogenetic relationships (see Figure 5 View Figure 5 ). None of the known species of Parotoplana , in fact, has a similarly elongate, whip-shaped stylet, nor has girdle spines so markedly different in shape and morphology. The species thus appears very characteristic, and markedly distinct from congeners.
The single mature specimen found came from the only subtidal station sampled in southern Spain. Its distribution could therefore be wider than documented at present.
Diagnosis
Parotoplana with a sclerotized apparatus consisting of an extremely elongate central stylet, 122 Mm long, and a girdle consisting of 18 spines, ranging from 5 Mm (with elongate subterminal teeth) to 75 Mm (with comparatively small teeth, and recurvate apices) in length.
Parotoplana varispinosa sp. n.
( Figures 2B View Figure 2 , 4A View Figure 4 , 5 View Figure 5 )
Holotype. One whole mount (SMNH 6788).
Type locality. Spain. Playa del Pinillo , Marbella (lat. 36 ° 3090.650N, long. 4 ° 55948.100W); lower intertidal in the Otoplana -zone, medium sand between rocks. October 2005 .
Etymology. The specific epithet refers to the presence of different (Latin: varius) kinds of spines in the sclerotized apparatus.
Description
A large Parotoplana (the fixed holotype is about 2 mm long) with the general morphology of the body similar to most other species of the genus.
Male genital organs. With two rows of about six testes each, anterior to the ovaries. The male copulatory organ consists of an elongate seminal vesicle (about 60 Mm long), a tubular prostatic vesicle (45 Mm in length) and a sclerotized apparatus consisting of 11 spines. These are arranged into a central group made of two different types of spines ( Figures 2B View Figure 2 , 4A View Figure 4 ): 1) two larger spines, 49–51 Mm long, acutely pointed distally;
2) two smaller spines, 45–46 Mm long, with a more obtuse distal tip. This central group is partially surrounded by a girdle, consisting of seven spines, 40–45 Mm long ( Figure 2B View Figure 2 : 3). The morphology of the spines of the girdle varies: the most dorsal spines have slightly falcate apices, with a hint of a subterminal tooth; the most ventral spines are provided with more recurvate apices, and well-developed subterminal teeth.
Female genital organs. With two ovaries anterior to the pharynx, and two rows of vitellaria extending behind the ovaries to anterior to the copulatory organ.
Observations on the living specimen showed the existence of a small bursa, opening independently into the common atrium.
Remarks
Several species of Parotoplana have a sclerotized apparatus provided with a group of few spines, presumably acting as functional copulatory stylet, partially or completely surrounded by a girdle of spines. This morphology is plesiomorphic for the genus Parotoplana (see Figure 5 View Figure 5 ), and it is found in most genera and species of the Parotoplaninae (cf. Ax 1956). Species with these characters are often confusingly similar (cf. Ax and Sopott-Ehlers 1987). Our phylogenetic analysis ( Figure 5 View Figure 5 ) points to a sister species relationship of the new species with P. capitata Ax, 1956 , a species ranging from Baltic Sea south to the west coast of France (Arcachon) ( Ax 1956). The two species share the presence of a central group of four spines, and a gradual change in the morphology of the spines of the girdle. However, the four central spines are needle shaped in the new species, while one pair has falcate, recurvate distal tips, and is provided with distinct subterminal teeth, in P. capitata (see Ax 1956, Figure 140). The girdle differs in the number of spines: 16–19 in P. capitata and only seven in the new species. Furthermore P. capitata is provided with bursal spines, which are absent in P. varispinosa sp. n. Differences in morphology thus appear sufficient to warrant specific distinction of the Mediterranean specimen.
Diagnosis
Parotoplana with a sclerotized apparatus consisting of a group of four needle-shaped spines, 45–51Mm long, and a girdle of seven spines, 40–45 Mm long; those most proximal to the central group have slightly recurvate apices, progressively becoming more falcate and with more developed subterminal teeth in the distalmost (ventral) spines.
New records
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