Placobdella sophieae, Oceguera-Figueroa & Kvist & Watson & Sankar & Overstreet & Siddall, 2010

Oceguera-Figueroa, Alejandro, Kvist, Sebastian, Watson, Sara C., Sankar, Dominic F., Overstreet, Robin M. & Siddall, Mark E., 2010, Leech Collections from Washington State, with the Description of Two New Species of Placobdella (Annelida: Glossiphoniidae), American Museum Novitates 2010 (3701), pp. 1-16 : 6-8

Placobdella sophieae , new species

Figures 7–13

MATERIAL EXAMINED: Eight specimens collected in Squires Lake, Washington, September 30, 2009, by Alejandro Oceguera-Figueroa and Sebastian Kvist. Collected from the legs of A.O.-F. and from the underside of submerged rocks and wood.

DESCRIPTION: External morphology based on eight specimens. Body dorsoventrally flattened, ovate-lanceolate, semitransparent tegument when alive, with three pairs of dorsal rows of brownish-pigmented spots on a2 of each somite, otherwise chromatophores randomly arranged on ventral and dorsal surfaces (figs. 7–8). Body brownish when fixed. Average body length 12.6 (11.0–14.1), average body width 4.8 (4.0–6.4). Complete somite triannulate. Somites I and II uniannulate; III–V biannulate; VI–XXIII triannulate; XXIV biannulate; XXV–XXVII uniannulate. Two pair eyespots on III in “placobdellid” arrangement (fig. 9). Oral sucker small, mouth pore on anterior border. Posterior sucker circular, separated from body by obvious constriction or pedicel (fig. 10). Anus on dorsal surface of XXVII (fig. 11). Male gonopore between XI and XII. Female gonopore at XII a2/a3; 2 annuli between gonopores.

Internal morphology based on three dissected specimens. Proboscis short, in membranous sheath extending posteriorly to IX, unlooped when retracted. Diffuse salivary glands dispersed dorsolaterally from VII to XIII, connecting to base of proboscis through well-developed bundles of ductules (fig. 12). Esophagus large, folded, with one pair cecate mycetomes at X. Crop with seven pairs foliaceous caeca, last pair forming well-developed postcaeca (diverticula) extending posteriorly to XXV. Intestine with four pairs simple caeca in XX–XXIII. Male reproductive system with well-developed atria and highly coiled ejaculatory ducts. Six pair intersegmental testisacs from XIII/XIV to XVIII/XIX. Ovisacs without common oviduct, anteriorly bilobed, extending posteriorly to XVIII, ovisac bifurcation at XIII. Anterior lobe very short extending only to XII (fig. 13).

HOLOTYPE: Undissected, fixed in ethanol. 15.0 length, 5.8 maximum width. Collected by Alejandro Oceguera-Figueroa on September 30, 2009 ( AMNH 5529 ).

TYPE LOCALITY: Squires Lake , Whatcom County, Washington , 48°39′ 36.98″N; 122°20′ 02.76″W.

PARATYPES: Seven specimens (3 dissected and 4 undissected), fixed in ethanol. Collected by Alejandro Oceguera-Figueroa and Sebastian Kvist , Squires Lake , Whatcom County, Washington, on September 30, 2009 ( AMNH 5530 ) .

ETYMOLOGY: The species is named after Sophie Alice Burgess in honor of her birth.

REMARKS: The morphological characteristics found in P. sophieae , n. sp., are consistent with synapomorphies of the genus ( Siddall et al., 2005; Siddall and Bowerman, 2006). The presence of a small pedicel (peduncle) separating the posterior sucker from the rest of the body, present in P. sophieae , n. sp., has been recorded in at least two other Placobdella species , Placobdella pediculata Hemingway, 1908 , and Placobdella cryptobranchii ( Johnson and Klemm, 1977) , as well as in Actinobdella inequiannulata Moore, 1901 , and Actinobdella annectens Moore, 1906 . Placobdella sophieae , n. sp., is distinguished from species of Actinobdella , in that the latter have several retractile digitate processes on the rim of the caudal sucker; absent in the new species. In addition to the presence of a small pedicel, P. pediculata and P. cryptobranchii also have diffuse salivary glands like those of P. sophieae , n. sp. However, P. sophieae , n. sp., is distinguished principally by its external morphology, which contrasts with the absence of prominent papillae, white patches or colored dots in P. pediculata and P. cryptobranchii . Moser et al. (2008) described two paramarginal rows of metameric spots on the dorsal surface as well as white patches (typically 3) between white cephalic and caudal somites for P. cryptobranchii , in any case, the pattern corresponds with that of P. sophieae , n. sp. Furthermore, Hemingway (1908) recorded the anus at XXIII/XXIV in P. pediculata , whereas in P. sophieae , n. sp., the same structure is situated in XXVII. The diffuse salivary glands of Placobdella sophieae , n. sp., connect to the base of the proboscis through well-developed common bundles. These structures were not recorded by Johnson and Klemm (1977) for P. cryptobranchii . Placobdella pediculata and P. cryptobranchii were described as permanent parasites of the fresh-water sheepshead ( Aplodinotus grunniens ) and the Ozark hellbender ( Cryptobranchus alleganiensis ) respectively. Hemingway (1908) and Johnson and Klemm (1977) reported that the leeches were always found attached to their host, never free living, which contrasts with our findings of Placobdella sophieae , n. sp. In addition to P. pediculata and P. cryptobranchii , discussed above, Placobdella phalera (Graff, 1899) , Placobdella michiganensis (Sawyer, 1972) , and Placobdella picta (Verrill, 1872) also possess diffuse salivary glands, yet are easily distinguished from P. sophieae , n. sp., based on external pigmentation. Placobdella phalera and P. michiganensis have white patches together with a white nuchal ring on the dorsal surface. Placobdella picta has a dark greenish-brown dorsum and a thin median line. These characters contrast with the semitransparent tegument of P. sophieae , n. sp.

Figures

FIGURES 7–13. Placobdella sophieae, n. sp. 7. Holotype, dorsal view. 8. Holotype, ventral view. 9. Eyespots showing characteristic “placobdellid” arrangement. 10. Posterior sucker showing the pedicel (peduncle). 11. Posterior sucker showing dorsal papilla. 12. Proboscis (p) and bundle of ductules (d), dorsal view; mycetomes not shown. Diffuse salivary glands indicated by arrows. 13. Dorsal view of the male and female reproductive systems. Scale bars = 3 mm.