Periscolex malibu, Celis, Liliana V. & Rangel-Ch, Orlando, 2015

Celis, Liliana V. & Rangel-Ch, Orlando, 2015, Two new earthworm species (Oligochaeta: Annelida) of the Caribbean region of Colombia, Zootaxa 3974 (1), pp. 106-114 : 108-111

Periscolex malibu sp. nov.

Figure 2 , Table 1

Periscolex sp. nov.: Celis & Rangel.-Ch. 2013: 488f., fig. 268.

Material examined. Holotype: L.V.Celis002, clitellate specimen; Colombia, Department of Cesar, San Martin, Terraplen, El Congo wetland (73°38'42.6''W 7°52'48.7''N), 58 m asl; L.V. Celis, 30 August 2011. Paratypes: L.V.Celis004, seven specimens (6 adults, 1 juvenile); Colombia, Department of Cesar, San Martin, Terraplen, El Congo wetland, 44–56 m asl; L.V. Celis, 31 August 2011.

Description. Body cylindrical, color soft reddish. Body dimensions, holotype: length 100.8 mm; diameter 2.5 mm in preclitellar region, 2.35 mm in clitellum region, 1.95 mm in postclitellar region (segment xl). 305 segments, no intersegmental furrows; paratypes: length 100.8–140.5 mm, diameter 2.3–2.6 mm, 330–340 segments. First segment invaginated, shape of prostomium not determined. Setae in perichaetine distribution with about 45 setae per segment, on all the circumference, visible from segment ii. Setae sigmoid, node in proximal region, length about 250 Μm. No genital setae differentiated. Clitellum annular, located in segments xiv–xxiii, tubercula pubertatis in segments ⅔ xviii– ⅔ xxiii ( Fig. 2 A). Male pores microscopic, within tubercula pubertatis in intersegment 21/22; female pores in posterior part of segment xiv. Nephridiopores visible from intersegment 5/6, close in line laterodorsal. Five pairs of spermathecal pores in intersegments 6/7–10/11, in line with nephridiopore line.

Internal anatomy. Septa thin, as delicate membranes. Gizzard in cavity of segment vi, with strong muscles, prolonged towards anterior region (i.e., longer than wide). One pair of calciferous glands, opening into esophagus in segment vii. Each gland oval-shaped, tubular in structure. Transition esophagus–intestine in intersegments 16/ 17. Typhlosole a thin, crescent-shaped lamina occupying 1/5 of intestine diameter, visible from segment xxii (xxiii) to xl. No caeca observed in posterior segments ( Fig. 2 B). Three pairs of thin lateral hearts in segments vii–ix, two pairs of voluminous intestinal hearts in segments x and xi. One pair of vesicular holonephridia in each segment, with intertwining bands distributed on one face and above the bladder. Nephrostome conspicuous and it has thickwalled and heart-shaped ( Fig. 2 C).

Two pairs of testicular sacs and male funnels in segments x and xi (holandric). Testicular sacs and male funnels each continued into ducts that project laterally inside ventral body wall, and merge into a single visible deferent duct that superficially penetrates body wall. Deferent ducts of each side open to male pore in intersegment 21/22. Testicular sacs continue in a pair of seminal vesicles, projecting toward posterior part on dorso-lateral sides of intestine, one band on each side, reaching segments xliii–xlv; bands with strong, irregular intersegmental constrictions ( Fig. 2 B). One pair of ovaries and female infundibula ventrally in segment xiii. Oviducts located in posterior part of segment xiv. Five pairs of spermathecae in line with nephridiopore at intersegments 6/7–10/11. Spermathecae all of same size, with duct as long as ampulla ( Fig. 2 D).

Etymology. The species is named in honor of the Malibu indigenous people who live around the Zapatosa wetland in the department of Cesar, Colombia.

Habitat characteristics. Periscolex malibu was only found in El Congo wetland (59 m asl), in two physiognomic types of vegetation: highly transformed areas and savanna with trees ( Celis & Rangel 2013). Of the 15 species of the genus Periscolex six species are found in the Colombian Andes at altitudes of 2600 m asl or higher: P. columbianus Michaelsen, 1900 ; P. fuhrmanni Michaelsen 1913 ; P. longituberculatus Zicsi, 1989 ; P. muisca , P. s a l i b a, and P. sicuani Feijoo, 2008 . The other nine species are found below 1000 m: P. vi al i s Michaelsen, 1913 and P. coreguaje Feijoo & Celis, 2012 , both recorded in Colombia, P. ecuadoriensis Zicsi, 1992 and P. profugus Cognetti, 1904 in Ecuador, P. nevoi Czudi & Pavlíček, 2009 , restricted to the Guadeloupe Island, P. brachycystis Cognetti, 1905 and P. mirus Cognetti, 1905 , found in Panama, P. guayaramerinensis Zicsi & Csuzdi, 1999 in Bolivia, and P. yu y a Righi & Römbke, 1987 in Peru ( Feijoo & Celis 2011).

Species Length Clitellum Tubercula pubertatis Posterior extension of Spermathecal

(mm) seminal vesicles pores

P. coreguaje 35.5 xiv–xxii ⅓ xvii–xxii 2nd pair to lvi–lx 6/7–8/9 Feijoo & Celis, 2011 (9 segments) (5 ⅓ segments)

Annular

Comments. Within the genus, Periscolex malibu sp. nov. shares the perichaetine setae distribution with P. coreguaje Feijoo & Celis, 2012 , P. fuhrmanni Michaelsen, 1913 , P. longituberculatus Zicsi, 1989 , P. vi al is Michaelsen, 1913, P. m i r u s Cognetti, 1905, P. n ev o i Csuzdi & Pavlíček, 2009 and P. yuya Righi & Römbke, 1987 . Among these, the new species is similar to P. fuhrmanni in the position of both clitellum and tubercula pubertatis, but differs from it in the extension of the clitellum (10 segments vs. 9 in P. fuhrmanni ) and the presence of 5 pairs of spermathecae in intersegments 6/7–10/11 (vs. 3 in intersegments 6/7–8/9). A comparison of perichaetine species of Periscolex is given in Table 1.

Figures

FIGURE 2. Periscolex malibu sp. nov. A. Lateral view of ventral region. B. Internal dorsal view (G, gizzard; Cg, calciferous glands; Sv, seminal vesicle; Ts, testicular sacs; Mp, male pores; Dd: deferent duct). C. Nephridium. D. Spermathecae.