INTRODUCTION
The Red Sea is one of the most understudied bodies of water in terms of biodiversity (Terraneo et al., Reference Terraneo, Berumen, Arrigoni, Waheed, Bouwmeester, Caragnano, Stefani and Benzoni2014), including the polychaete fauna (Faulwetter et al., Reference Faulwetter, Chatzigeorgiou, Galil and Arvanitidis2011). For this reason, the Red Sea Research Center at the King Abdullah University of Science and Technology (KAUST) in Jeddah, Saudi Arabia launched a project to describe and catalogue the biodiversity of the Red Sea off the coast of Saudi Arabia. An international team of taxonomists have been participating in this project. In this paper I am describing the polychaetes of the family Ampharetidae that were sampled at the Al Fahal reef off Thuwal and deposited at the Florida Natural History Museum at the University of Florida.
Previously only three species of ampharetid polychaetes have been recorded from the Red Sea: Ampharete acutifrons (Grube, Reference Grube1860), Amphicteis gunneri (M. Sars, Reference Sars1835), and Isolda pulchella (F. Müller, Reference Müller1858) (Wehe & Fiege, Reference Wehe and Fiege2002). The identification of Isolda pulchella, a species originally described from Brazil, by Kiseleva (Reference Kiseleva and Vodyanitzkii1971) was only tentative. The records of Ampharete acutifrons and Amphicteis gunneri, both species described from arctic and subarctic seas, are based on species lists without any kind of descriptions. Both records seem doubtful to me. In addition to the three Red Sea records, Samytha storchi Reuscher & Wehe in Wehe, Reference Wehe2009 was described from the adjacent Gulf of Aqaba. This species was also found in the Red Sea samples of the present study. Additionally, a new species, Amphicteis fiegei sp. nov., is described here.
MATERIALS AND METHODS
The specimens examined in this study were collected by hand during scuba dives at the Al Fahal coral reef off Thuwal, Saudi Arabia (Figure 1) in March 2013. They were relaxed in magnesium chloride, fixed in 10% formalin and preserved in 75% ethanol.
Study site. (A) Sampling location within the Red Sea; (B) Aerial view of the Al Fahal Reef and the sampling location.
Preserved specimens were examined with Olympus SZX7 and Wild Heerbrugg M8 stereo microscopes and Leica DMLB and Olympus CX41 compound microscopes. Pencil drawings were made using camera lucidas, attached to the Wild Heerbrugg M8 and Leica DMLB microscopes.
The drawings were digitized with a Wacom Intuos drawing tablet and Adobe Illustrator, according to the methods of Coleman (Reference Coleman2003). Shadings were added in Adobe Photoshop. The ‘ID cards’ were prepared in Adobe Illustrator.
All specimens are deposited in the Florida Natural History Museum at the University of Florida (UF).
SYSTEMATICS
Ampharetidae Malmgren, Reference Malmgren1866
Ampharetinae Malmgren, Reference Malmgren1866
Amphicteis Grube, Reference Grube1850
TYPE SPECIES
Amphitrite gunneri Sars, Reference Sars1835
SYNONYMS
Crossostoma Gosse, Reference Gosse1855
GENERIC DIAGNOSIS
Prostomium with paired longitudinal glandular ridges and oblique or transverse nuchal ridges. Buccal tentacles smooth. Four pairs of cirriform branchiae. Notochaetae in segment II present and usually developed as paleae. Seventeen thoracic chaetigers with capillary chaetae-bearing notopodia from segment III. Notopodia with tuberculate ventral cirrus. Elevated or modified notopodia absent. Fourteen thoracic uncinigers with uncini-bearing neuropodial tori from segment VI. No intermediate uncinigers. Abdominal uncinigers with rudimentary notopodia and uncini-bearing pinnules with dorsal cirrus. Usually one pair of anal cirri present, inserted laterally in pygidium. Thoracic uncini with single row of teeth.
Amphicteis fiegei sp. nov. (Figure 2A–H)
Amphicteis fiegei sp. nov.: (A) Anterior end of holotype, frontal view; (B) Same, lateral view; (C) Species ‘ID Card’; (D) Branchiostyle with transverse rows of cilia, illustrated is the side with cilia; (E) Palea; (F) Posterior end of holotype, lateral view; (G) Thoracic uncinus, lateral view; (H) Abdominal uncinus, lateral view.
SPECIMENS EXAMINED
Holotype: UF 3572, Saudi Arabia, southern point of Al Fahal reef, off Thuwal, 22.2227°N 38.9677°E, 12 m, 20 March 2013. Paratype: UF 3554, Saudi Arabia, sheltered side of offshore reef Al Fahal, off Thuwal, 22.2227°N 38.9677°E, 18 m, 19 March 2013.
DESCRIPTION OF THE HOLOTYPE
Length 11 mm, width 1.6 mm. Mature female, with eggs visible in abdomen. Paired prostomial longitudinal glandular ridges, bulbous anteriorly, not separated by median gap (Figure 2A). Paired prostomial nuchal ridges separated by median gap, arranged at wide angle to each other, crescent shaped, thick, and elevated from prostomium. Several small brown eyespots located in front of nuchal ridges and one or two brown eyespots located at right and left prostomial margins, respectively. Buccal tentacles smooth, with shallow ventral groove. Lower lip with longitudinal furrows (Figure 2B). Four pairs of smooth cirriform branchiae in 2 transverse rows in segments III and IV; both groups of branchiae separated by median gap of twice the branchial width; innermost pair of branchiae in posterior transverse row connected by dermal fold; innermost branchiae of anterior transverse row (pair 1) originating from segment II, outermost branchiae of anterior transverse row (pair 2) originating from segment III, innermost branchiae of posterior transverse row (pair 3) originating from segment IV, outermost branchiae of posterior transverse row (pair 4) originating from segment V (Figure 2C); branchiostyles of fourth pair present, others broken; three detached cirriform branchiae present, one of which with numerous transversal rows of cilia, surrounding about half of branchial perimeter (Figure 2D). Segment II with 5 paleae on either side, not reaching anterior end of prostomium; paleae slightly curving and tapering to very fine tips (Figure 2E). Notopodia with capillary chaetae from segment III, present in 17 chaetigers; anterior notopodia small, increasing in size from first to fifth pair (Figure 2B); tuberculate notopodial cirri commencing in segment VII. Neuropodial tori with uncini and tuberculate dorsal lobe from segment VI, present in 14 thoracic uncinigers. Continuous ventral shields conspicuous to thoracic unciniger 11, faint in thoracic unciniger 12. Elevated or modified notopodia absent. Intermediate uncinigers absent. Fifteen abdominal uncinigers with club shaped rudimentary notopodia (Figure 2F). Pinnules with tuberculate dorsal cirrus. Pygidium with terminal anus and paired long, lateral, cirriform anal cirri. Thoracic uncini with 4 teeth in 1 vertical row over basal prow and rostral tooth, lacking subrostral process (Figure 2G). Abdominal uncini with 3 teeth in 1 vertical row over basal prow and rostral tooth, lacking subrostral process (Figure 2H).
REMARKS
The paratype specimen is a mature male. It measures 7.5 mm in length, but is broken after abdominal unciniger 12. Branchiae of the paratype specimen are missing.
Only three other species of the genus Amphicteis were described with a combination of short (too short to reach the anterior end) and few (less than 10) paleae: A. dalmatica Hutchings & Rainer, Reference Hutchings and Rainer1979, A. midas (Gosse, Reference Gosse1855), and A. trichophora (Hartman, Reference Hartman1965). The latter species differs from A. fiegei sp. nov. by the lack of eyespots, different branchial arrangement, and the very long ‘threadlike processes’ in the last four thoracic parapodia. In A. midas the branchiae lack transversal rows of cilia and the paleae are much sturdier than in the new species. Most similar to the new species is Amphicteis dalmatica from Australia. It differs from the new species by its distinct spotted pigmentation pattern, the smaller gap between branchial groups, and the lack of transverse rows of cilia in any of its branchiae.
To my knowledge, branchiae with transversal rows of cilia have not been described for any other Amphicteis species. Unfortunately, the ciliated branchia was detached from the holotype specimen. Therefore, it is impossible to determine if it belongs to the first, second or third pair.
The nuchal ridges are elevated from the prostomium. This is quite unusual because other Amphicteis species have relatively flat nuchal ridges that are not elevated from the prostomium. It is possible, however, that this may be caused by fixation artifacts, rather than morphological differences.
The uncini of A. fiegei sp. nov. lack a subrostral process, in contrast to the majority of Amphicteis species (Reuscher et al., Reference Reuscher, Fiege and Imajima2015). However, this character has often been neglected in species descriptions. In many cases its presence or absence has only been documented in accompanying drawings, if at all. Few other species also seem to have uncini without a subrostral process, including A. dalmatica and A. trichophora. In A. midas the presence of a subrostral process is unknown.
Two species of Amphicteis, A. gunneri (M. Sars, Reference Sars1835) and A. posterobranchiata Fauvel, Reference Fauvel1932, have been recorded from the seas surrounding the Arabian Peninsula, according to the checklist of Wehe & Fiege (Reference Wehe and Fiege2002). The only species that has been identified from the Red Sea is A. gunneri (Wehe & Fiege, Reference Wehe and Fiege2002). The latter species differs from A. fiegei sp. nov. by the higher number of paleae. In his redescription of A. gunneri, Hartley (Reference Hartley1985) examined type material and additional specimens and determined the range of the number of paleae in adults to be 11–23. The paleae in A. gunneri are also longer than in the new species. Furthermore, the nuchal ridges in A. gunneri are flat and not elevated from the prostomium. Amphicteis posterobranchiata differs from the new species by the longer and more numerous (20–25) paleae, the fourth pair of branchiae located in segment V, and the lower number of abdominal uncinigers (13).
ETYMOLOGY
This new species is dedicated to Dieter Fiege (Senckenberg Forschungsinstitut und Naturmuseum Frankfurt), who introduced me to the ‘world of polychaetes’.
DISTRIBUTION
Only known from the Al Fahal reef off Thuwal (Saudi Arabia).
I suspect that some of the A. gunneri records from the Red Sea and other seas surrounding the Arabian Peninsula may actually belong to A. fiegei sp. nov. The records of A. gunneri from the Red Sea are based simply on species lists (Kiseleva, Reference Kiseleva and Vodyanitzkii1971; Amoureux, Reference Amoureux1983). Fauvel (Reference Fauvel1932) provided a short description of A. gunneri from the Gulf of Oman. However, this description is insufficient to determine if the identification was correct.
Samytha Malmgren, Reference Malmgren1866
TYPE SPECIES
Sabellides sexcirrata Sars, Reference Sars1856
GENERIC DIAGNOSIS
Prostomium without glandular ridges, with middle lobe encircled by surrounding lobe. Buccal tentacles smooth. Three pairs of cirriform branchiae. Segment II without chaetae. Thorax with 17 chaetigers and 14 uncinigers. Modified or intermediate segments absent. Abdomen with glandular pads above pinnules.
Samytha storchi Reuscher and Wehe in Wehe, Reference Wehe2009 (Figure 3A–G)
Samytha storchi. (A) Anterior end, frontal view; (B) Same, lateral view; (C) Species ‘ID Card’; (D) Last two thoracic and first three abdominal uncinigers, lateral view; (E) Thoracic uncinus, lateral view; (F) Thoracic uncinus, frontal view; (G) Abdominal uncinus, frontolateral view.
SPECIMENS EXAMINED
UF 3573, Saudi Arabia, southern point of Al Fahal reef, off Thuwal, 22.2227°N 38.9677°E, 12 m, 20 March 2013.
DESCRIPTION
Length 11 mm, width 1.7 mm, broken after abdominal unciniger 7. Mature female with eggs in coelomic cavity. Prostomium with paired black eyespots, without glandular ridges (Figure 3A); posterior prostomium with median lobe, delimited by groove from surrounding lobe. Lower lip smooth (Figure 3B). Buccal tentacles extended, with ventral groove, smooth. Three pairs of cirriform branchiae, arranged in one transverse row in segments II and III, without median gap; branchiae fused basally; second outermost branchiostyle in left group missing; second outermost branchiae of transverse row (pair 1) originating from segment II, outermost branchiae of transverse row (pair 2) originating from segment III, innermost branchiae of transverse row (pair 3) originating from segment IV (Figure 3C). Segment II without chaetae. Notopodia with capillary chaetae from segment III, present in 17 chaetigers; notopodia increasing in size from first to third pair, without cirri (Figure 3C). Neuropodial tori with uncini from segment VI, present in 14 thoracic uncinigers; tori without cirri. Continuous ventral shields conspicuous to thoracic unciniger 9. Elevated or modified notopodia absent. Intermediate uncinigers absent. Abdominal uncinigers with glandular pads above pinnules, but without cirriform rudimentary notopodia (Figure 3D). Pinnules without dorsal cirrus. Pygidium unknown. Thoracic uncini with nine teeth in two alternating vertical rows above rostral tooth, small subrostral process, and basal prow (Figure 3E, F). Abdominal uncini with five teeth in two alternating vertical rows above rostral tooth and basal prow (Figure 3G).
REMARKS
The specimen described here differs from the original description by the possession of small eyespots. This may be caused by fixation artifacts or intraspecific variation.
DISTRIBUTION
Samytha storchi was originally described from the Gulf of Aqaba (Wehe, Reference Wehe2009). This is only the second specimen found. It is a new record from Saudi Arabia.
ACKNOWLEDGEMENTS
I am grateful to Gustav Paulay (Florida Museum of Natural History) for providing the specimens for this study. Arthur Anker (Museu de Zoologia da Universidade de São Paulo), Camrin Braun (King Abdullah University of Science and Technology), Jenna Moore and Patrick Norby (both Florida Museum of Natural History) collected the polychaetes. Jenna Moore also provided more information on the sampling stations and procedures. I am indebted to Richard D. Kalke and Fabio Moretzsohn (both Texas A&M University – Corpus Christi) for lending me their camera lucidas.
FINANCIAL SUPPORT
Financial support was provided through the Texas Research Development Fund Post-Doctoral Support Program, awarded to my supervisor Paul A. Montagna by the Division of Research, Commercialization and Outreach at Texas A&M University – Corpus Christi.
