Pyura vittata (Stimpson, 1852), 2005

Rocha, Rosana M. & Counts, Bailey Keegan, 2019, Pyura (Tunicata: Ascidiacea: Pyuridae) on the coasts of Panama, Zootaxa 4564 (2), pp. 491-513 : 509-512

Pyura vittata (Stimpson, 1852)

( Figures 15–17 )

Pyura vittata: Van Name, 1945 (part): 321, fig 213 (upper figures); Monniot C., 1983: 1024, fig. 2, and synonymy; Monniot F., 2018: 423 , fig 21–23; not Monniot F., 2016: 237 , fig. 29 (= P. beta ).

Material Examined: DZUP PYU-76 , Isla Pastores , Bocas del Toro, 9°14'N 82°20'W, leg. R. M. Rocha, 10.08.2003 ; DZUP PYU-77 , Isla Pastores , Bocas del Toro, 9°14'N, 82°20'W, leg. R. M. Rocha, 10.08.2003 ; DZUP PYU-78 , Solarte , Bocas del Toro, 9°17'30”N 82°10'20”W, leg. R. M. Rocha, 11.08.2003 ; DZUP PYU-79 , Isla Pastores , Bocas del Toro, 9°14'N, 82°20'W, leg. R. M. Rocha, 10.08.2003 ; DZUP PYU-80 , Crawl Key , Bastimentos , Bocas del Toro, 9°15’2.6”N 82°07’38”W, leg. R. M. Rocha, 03.08.2003 ; DZUP PYU-81 , Isla Pastores , Bocas del Toro, 9°14'N 82°20'W, leg. R. M. Rocha, 10.08.2003 ; DZUP PYU-82 , STRI Point , Isla Colon , Bocas del Toro, 9°21’08”N, 82°15'35.2”W, leg. R. M. Rocha, 10.08.2003 ; DZUP PYU-83 , Isla Pastores , Bocas del Toro, 9°14'N, 82°20'W, leg. R. M. Rocha, 10.08.2003 ; DZUP PYU-106 , Solarte , Bocas del Toro, 9°16'38.9”N 82°12'24.1”W, leg. R. M. Rocha, 19.06.2014 ; DZUP PYU-136 , Isla Pastores , Bocas del Toro, 9°14'19.92”N 82°19'58.08”W, leg. R. M. Rocha, 17.08.2006 ; DZUP PYU-148 , 8 individuals, Punta Galeta , Colon 9°24'15”N 79°51'49”W, leg. R. M. Rocha, 06.01.2009 ; DZUP PYU-149 , Isla Pastores , Bocas del Toro, 9°14'19.92”N

82°19'58.08”W, leg. R. M. Rocha, 17.08.2006; DZUP PYU-165 , Isla Pastores, Bocas del Toro, 9°14'19.92”N 82°19'58.08”W, leg. R. M. Rocha, 15.08.2006.

Description. Animals can reach 5.5 cm at the longest length. The tunic is leathery and rough with numerous organisms encrusting the brown or light brown surface ( Fig. 15 ). The tunic is white inside and has a yellowish soft membrane. In the field, the siphons show four small triangular lobes, the oral siphon is usually apical and the atrial more lateral. There are long spines (~160 µm) lining both siphons with a very distinctive shape: narrow with a round enlargement in the middle and at the posterior extremity ( Fig. 16C, D ). Iridescent spots of blue, green or yellow color caused by the reflection of light by the enlarged areas of the spines are seen against a brown or reddish background ( Fig. 15 ). After long fixation, the tunic turns light brown. Often, a tinge of red can still be seen around the siphons.

The body wall has many longitudinal muscles radiating from the siphons; they form thin bands that cross each other making a musculature net. Circular muscles densely surround both siphons. The U-shaped right gonad and the enlarged secondary loop of the alimentary canal on the left side are visible through the transparent body wall ( Fig. 16A, B ).

The tentacles project at the level of a strong muscular sphincter, the number ranging between 16–29. They are flat, very wide at the base and ramifying two or three times, with primary ramifications projecting along the posterior margin ( Fig. 16E, F ). The third order ramifications are minute and only appear in the largest tentacles that can reach 7 mm in length. The peritubercle region forms a deep V with the dorsal tubercle has U- or C-shaped aperture with enrolled ends. The dorsal lamina is divided in numerous thin and long densely packed languets.

The pharynx has six folds per side and is orange when fresh ( Fig. 16G ), but quickly loses coloration after fixation. The number of longitudinal vessels range from 305 to 410. Longitudinal vessels fray toward the base of the animal, making languets around the esophageal opening. Parastigmatic vessels are present.

Endocarps are present along the intestine, especially along the descending limb ( Fig. 17B ). Both gonads have large endocarps on each lobe, particularly the distal ones ( Fig. 17C ).

Identification Key

This tabular key includes all of the Pyura spp. that are known from the shallow waters on the Pacific and Atlantic sides of Panama. The table is based on

observed and literature characteristics.

1. Distribution: A. Atlantic; P. Pacific

2. Maximum length of specimen including tunic

3. Color in living specimen (tunic or siphons): B. Brown; Dr. Dark Red; O. Orange; P. Pink; Pu. Purple; R. Red; Y. Yellow; W. Wine color

4. Color inside of the tunic: B. Brown; O. Orange; R. Red; W. White; Y. Yellow

5. Presence of spinules: P. present; A. absent

6. Maximum length of spinules (Μm)

7. Position of the siphons: C. Close to each other; D. Distant from each other (opposite sides); I. Intermediate distance (atrial siphon in half the distance between oral and posterior region)

8. Total number of longitudinal vessels

9. Number of oral tentacles

10. Degree of tentacle ramification: F. First order; S. Second order; T. Third order

11. Number of gonad lobes on the right side

12. Number of gonad lobes on the left side

13. Margin of the anus: L. Lobed; S. Smooth

14. Presence of endocarps: B. Body wall; G. Gonads; I. Intestine

15. Peculiar characteristics: E. numerous endocarps on the body wall; F. Enlarged siphon vellum forming a flap in atrial siphon; I. Enlarged intestinal pouch; T. Extremely thick tunic; V. Ventral right gonad.

The alimentary canal occupies 2/3 of the left side. The primary loop does not reach the peripharyngeal groove, forms a close curve with a vertical descending limb that forms another close second loop with the ascending rectum ( Fig. 17A ). The intestine is not isodiametric; the secondary loop and rectum are enlarged. The anus is lobed. The digestive gland is dark green and forms lobes connected by long tubes as in a cauliflower. It has two main connections to the stomach. On the left side, the gonad completely fill the space within the primary intestinal loop, the number of gonad lobes ranging from 30–47. The right side of the animal is occupied by a large characteristic Ushaped gonad with 26 to 42 gonadal lobes. The gonoducts are long, the oviduct slightly longer than the sperm duct, both opening at the level of the anus.

Remarks. This is one of the most common species both in mangrove and reefs around Bocas del Toro province ( Rocha et al. 2005) and also found in Colon region but it has not been found on a survey of the Pacific coast ( Carman et al. 2011). The specimens from Panama agree well with the description of P. vittata from Guadeloupe and Martinique ( Monniot, C. 1983; Monniot, F. 2018). We believe that P. vittata reported by F. Monniot (2016) from French Guiana is actually P. beta Skinner, Rocha & Counts, 2019 .

Figures

FIGURE 15. Pyura vittata (Stimpson 1852). A–D. Animals in the field. Scale bar = 1 cm.

FIGURE 16. Pyura vittata (Stimpson 1852). A. Right side of animal with the tunic removed. B. Left side of animal with the tunic removed. C. Internal view of oral siphons with spinules. D. Oral siphonal spinules. E. Detail of anterior region (stained). F. Detail of oral tentacles (stained). G. Dissected view with pharynx. Scale bars: A = 1 cm; D = 100 µm.

FIGURE 17. Pyura vittata (Stimpson 1852). A. Dissected view, showing the digestive tract (enlarged intestinal pouch) and left gonad. B. Detail of primary intestinal loop with endocarps. E. Detail of the left gonadal lobes with endocarps.