Pithemera suwastikai Fahri, Amaliah & Atmowidi

Fahri, Fahri, Amaliah, Rizki, Suryobroto, Bambang, Atmowidi, Tri & Anh D. Nguyen,, 2018, Three new " caecate " earthworm species from Sulawesi, Indonesia (Oligochaeta, Megascolecidae), ZooKeys 805, pp. 1-14 : 3-4

Pithemera suwastikai Fahri, Amaliah & Atmowidi sp. n. Fig. 2

Material examined.

Holotype. 1 mature (MZB Oli. 062), yards (00°53'05"S, 123°17'50"E), elevation of 5 m a.s.l., Lomba village, Banggai district, Central Sulawesi, Indonesia, 26 March 2016, coll. Mihwan Sataral, Sofyan Ladjatang, Endang Prasetyawati Wahyunigsih, and F. Fahri. Paratypes. 4 matures (MZB Oli. 063) and 3 matures (UNTAD Oli. 008), same data as for holotype.

Diagnosis.

Medium size, length 135-165 mm, diameter 4.5-5.5 mm at x and 4.5-6.5mm at xx, segments 110-127. Prostomium epilobous. First dorsal pore in 12/13. Setae 27-38 in v, 33-49 in vii, 38-54 in viii and 64-74 in xxv, and 7-12 between male porophores in xviii. Spermathecal pores arranged in four pairs, 5/6-8/9. Male pores paired, discharging directly onto surface of xviii. Genital markings absent. Holandric. Intestinal caeca originating from xxii, paired laterally.

Etymology.

The species is named after Dr I Nengah Suwastika, head of the Biology Department of Tadulako University for his kind support of our study on Sulawesi earthworms.

Description.

External characters. Body generally cylindrical. Medium size, length 135-165 mm, diameter 4.5-5.5 mm at x and 4.5-6.5mm at xx, segments 110-127. Brownish red on dorsum, dark brown around clitellum and yellowish white on ventrum, especially in living specimens (Fig. 2A). After fixation, coloration brownish red on dorsum and whitish on ventrum.

Prostomium epilobous. First dorsal pore in 12/13. Setae regularly distributed around segmental equators: 27-38 in v, 33-49 in vii (Table 1), 38-54 in viii and 64-74 in xxv,7-12 between male porophores in xviii; setae distance aa=1-1.2ab, zz=1-3zy. Clitellum annular, xiv–xvi, smooth without setae and dorsal pores. Female pore single, mid-ventral in xiv.

Spermathecal pores small, slightly rounded, lateroventrally paired in 5/6-8/9 (Fig. 2A). No genital markings in the spermathecal region (Fig. 2B).

The openings of male pores small, on the setal ring of xviii, paired and discharging directly onto surface of xviii (Fig. 2E); ventral distance between male pores approx. 0.2x body circumference. Genital markings absent in the male region.

Internal characters. Septa 3/4/5/6/7/8 thick, 8/9 absent, 9/10/11/12/13 thin. Gizzard round within viii-x. Last hearts in xiii. Intestine origin at xv; caeca originating at xxii, extending anteriorly to xx, simple and paired laterally (Fig. 2F). Esophageal pouches absent. Typhlosole simple.

Four pairs of spermathecae paired in vi–ix. Ampulla round; duct enlarged, stout, approx. 1/4-1/2 as long as ampulla; no nephridia on spermathecal ducts. Diverticulum cylindrical, longer than ampulla, attached to base of ducts (Fig. 2C). No accessory glands.

Holandric. Testes sacs paired in x–xi, small, separated, ventral, yellowish. Seminal vesicles in xi–xii. Ovaries paired on xiii. Prostate gland racemose paired within xvi–xx or xvii–xx. Prostatic ducts long and U–shaped (Fig. 2D). No accessory glands.

Habitat and ecology.

Specimens were collected in yards at Lomba village, Banggai district, Central Sulawesi, Indonesia at 5 m a.s.l. The species was found in sandy soils at depths of 0-10 cm, around the roots of banana trees planted 1-2 m away from houses. No other specimens were collected despite continued collecting effort. The specimens were collected at an elevation of 50 meters above sea level. When collected, earthworms were moving actively on the ground.

Remarks.

This new species belongs to the Pithemera pacifica group characterized by having the first spermathecal pores in 5/6 and four thecal segments ( Sims and Easton 1972). This group currently consists of three species, P. pacifica (Beddard, 1899) from New Guinea and Samoa, P. dahli (Ude, 1905) from New Guinea, and P. donvictorianoi (Aspe & James, 2015) from the Philippines. Although Pithemera suwastikai sp. n. is classified into Pithemera pacifica group because of the presence of four thecal segments (5/6-8/9), the new species is totally differentiated from P. pacifica (Beddard, 1899) in having larger size (length 135-165 mm vs. up to 56 mm), holandric (vs. metandric), a single female pore (vs. a pair of female pores (see James et al. 2004)), clitellum in xiv–xvi without setae (vs. in xiv–xv /xvi with setae), absence of genital markings (vs. presence of genital markings).

The new species has similar characters to P. donvictorianoi Aspe & James, 2015, e.g., in the number of spermathecal pores, but different in clitellum ( xiv–xvi vs. xiv–xv), setae on vii (33-49 vs. 42-48). P. suwastikai sp. n. also has different length with P. donvictorianoi (135-165 mm vs. 41-58 mm) and diameter (4.5-5.5 mm vs. 2.5-3.0 mm). In addition, P. donvictorianoi is a white worm, with small, narrow, oval spermathecal ampulla; ducts short, slender; diverticulum stalk short, attached to ducts, terminating in short ovate receptacle. In contrast, P. suwastikai sp. n. has brownish red pigment on dorsum, dark brown around clitellum and yellowish white on ventrum; ampulla rounded; ducts enlarged, approx. 1/4-1/2 as long as ampulla; diverticulum cylindrical, longer than ampulla, attached to base of ducts.

This new species is also similar to P. dahli (Ude, 1905) by having spermathecal pores in 5/6-8/9 and dorsal pore in 12/13. However, it differs from P. dahli in larger size (length: 135-165 mm vs. 70 mm; diameter 4.5-6.5 mm vs. 2.5 mm), absence of genital markings (vs. genital markings in x, xi, xvii–xxi), holandric (vs. metandric), and prostate glands in xvi–xx or xvii–xx (vs. in xvi–xxii). P. suwastikai sp. n. has also similar characters to P. pacifica (Beddard, 1899) in spermathecal pores (5/6-8/9) and dorsal pore (12/13), but it is totally different in absence of genital markings (vs. present in x, xi, xvii–xxi) and holandric (vs. metandric). The comparison of the four species is presented in Table 1.