Amynthas Kinberg 1867

Aspe, Nonillon M. & James, Samuel W., 2016, NeW species OF Pheretima, Amynthas, Polypheretima, and Pithemera (Clitellata: MegascOlecidae) FrOm MindanaO and assOciated islands, Philippines, Zoological Studies 55 (8), pp. 1-33 : 20-24

Genus Amynthas Kinberg 1867

Type species: Amynthas aeruginosus Kinberg

1867.

Generic diagnosis

Body circular in cross section, with numerous setae regularly arranged equatorially around each segment; setae absent on first and last segments. Male pores paired and superficial, opening on xviii. Spermathecal pores small or large, usually paired (bithecate) but occasionally numerous (polythecate) or single (monothecate). Spermathecal pores positioned either intersegmental or intrasegmental between 4/5 and 8/9. Clitellum annular, covering three segments (xiv to xvi). Single female pore midventrally on xiv. Genital markings present or absent. If genital markings present, variable in number and forming complex pattern on segments near male pores. Esophageal gizzard usually originating in viii; esophageal bursae lacking; pair of caeca originating in xxvii, extending forward. Ovaries and funnels free in xiii. Male sexual system holandric, metandric, or proandric. Spermathecae a single pair, multiple pairs, sometimes single and located midventrally, or sometimes lacking. Nephridia on spermathecal duct lacking. One pair of prostate glands, racemose. Copulatory bursae lacking.

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Amynthas dinagatensis n. sp. ( Fig. 4A , Table 4 ) urn:lsid:zoobank.org:act:3151BD49-87AF-40F3-B22B-5112CBCD992D

Material examined: Holotype: preclitellate ( NMA 4595 ), Brgy Boa , municipality of Cagdianao, Dinagat Province, (10°05'53"N, 125°39'42"E), 250 m asl, Dinagat Island, Philippines, coll. N. Aspe, J. Adeva, 23-26 Apr. 2004 . Paratypes: two preclitellate individuals (NMA 4611); three preclitellate individuals (ZRC.ANN 0064), same collection data as for holotype.

Etymology: The species is named for Dinagat Island.

Diagnosis: Purplish brown worm, body dimension 240 mm x 7-9 mm (longest preclitellate specimen among samples); ventrum pale; equators non-pigmented, making the body appear striped; spermathecal pores and spermathecae lacking; 20 setae between male pores; intestinal origin in xiii; caeca long, from xxvii to xxi; prostate glands small, rudimentary, confined to xviii.

Description: Purplish brown dorsum, lighter ventrum, equators non-pigmented, making the body appear striped. Large preclitellates with length 223-240 mm (n = 6 individuals); diameter 6.5-9 mm at x, 6-7 mm at xx; body circular in cross-section, tail tapering; 163-167 segments. First dorsal pore at 12/13, spermathecal pore

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absent. Female pore single in xiv, openings of male pores paired in xviii, distance between pores 6 mm (0.27 circumference apart ventrally), 20 setae between pores. Setae irregularly distributed around equators in some segments; 35-48 setae on vii, 70-73 setae on xx, dorsal setal gaps present, no ventral gaps. Genital markings lacking.

Septa 5/6/7 membranous, 7/8 and 10/11- 12/13 muscular, 8/9/10 lacking. Dense tufts of nephridia on anterior faces of 5/6 and 6/7; nephridia of intestinal segments located mainly on body near septum/body wall junction. Large gizzard in viii-x, esophagus with low vertical lamellae x-xii, intestinal origin in xiii, caeca simple originating in xxvii, extending forward to xxi; typhlosole originating in xxvi, simple fold, about 1/5 lumen diameter, intestinal wall with 43 longitudinal blood vessels. Hearts in x to xiii, esophageal; commissural vessels in vi, vii, and ix lateral; those in viii extend to gizzard.

Ovaries and funnels free in xiii. Spermathecae lacking. Male sexual system holandric, testes and funnels enclosed in paired sacs in x, xi; seminal vesicles xi, xii, each with short spherical dorsal lobe; vesicles of xi enclosed in testes sac; vasa deferentia slender, free from body wall on way to ental end of prostatic ducts; racemose prostates small, rudimentary, confined to xviii.

Remarks: The main distinguishing characters that separate Amynthas from Pheretima are the absence of nephridia on the spermathecal ducts page 21 of 33

and the absence of copulatory bursae in Amynthas ( Sims and Easton 1972) . Despite having no spermathecae to determine if nephridia is present on the spermathecal ducts or not, we assign A. dinagatensis n. sp. in Amynthas on the basis of the absence of copulatory bursae. Even at preclitellate stage, the spermathecae and the copulatory bursae in thecate Pheretima species should already be evident.

Prior to the last decade, seven Amynthas species had been reported from the Philippines, all from Luzon Island: A. albobrunneus Beddard 1912 ; A. americanorum Beddard 1912 ; A. orientalis Beddard 1912 ; A. pauaiensis Beddard 1912 ; A. sodalis Beddard 1912 ; A. robustus Vaillant 1889 ; and A. corticis Kinberg 1867 . However, due to the lack of information on the location of the caeca on Beddard’s (1912) five Amynthas species, and because the types of these species could not be located ( Reynolds and Cook 1976), Hong and James (2004) proposed that placement of these species in Amynthas be considered provisional. Furthermore, Beddard’s (1912) Amynthas species have share some features with Philippine Pithemera ( James et al. 2004) , leading Hong and James (2004) to suspect that the four species might actually be Pithemera .

Since all the A. dinagatensis specimens collected were preclitellate, we provisionally assign the new species to the A. illotus group of Sims and Easton (1972), which includes Amynthas

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species without spermathecae. Tsai et al. (2002) acknowledged five species in this group: A. hohuanmontis Tsai et al. 2002 ; A. illotus Gates 1932 ; A. assacceus Chen 1935 ; A. sheni Chen 1935 ; and A. oyuensis Ohfuchi 1937 . Blakemore (2007) eliminated this species group, with species assigned to it either considered have doubtful identity (given the status species inquirenda) and in need of further investigation, or synonymized with other species. Amynthas dinagatensis , despite having no clitellate specimen, differs markedly from other Philippine Amynthas in its relatively large size (240 mm × 7- 9 mm; adult body dimensions of other species range from 32- 48 mm × 2.7-3.5 mm ( A. mindoroensis Hong and James, 2004 ) to 84-111 mm × 4.6-5.8 mm ( A. heaneyi James 2004 ); in having numerous setae (20) between male pores (6-9 in A. isarogensis Hong and James 2004 ; 4-7 in A. malinaoensis Hong and James 2004 ; 2-6 in A. heaneyi James 2004 ; and 0 in A. philippinensis Hong and James 2004 , A. mindoroensis and A. halconensis Hong and James 2004 ); in having the intestinal origin in xiii (in xv, xvi, or xvii in the others); and in having longer caeca (xxvii-xxi) than the others (xxvii-xxv, xxiv, or xxiii). Although A. dinagatensis is similar in size to A. americanorum (200 mm × 8 mm) and A. robustus (113-244 mm × 5.6-7.5 mm), in contrast, the new species appears to have stripes because the segmental equators don’t have pigmentation, whereas the equators are pigmented in A. robustus while A. americanorum has pale brown coloration. The new species also lacks genital markings around the spermathecal pores, while the latter two have, and the genital markings are especially numerous in A. americanorum . The intestinal origin of A. dinagatensis is in xiii while it is in xiv or xv in A. robustus and A. americanorum . Also, the caeca is long, covering seven segments, extending from xvii-xxi, while it only covers three segments in the latter two. In addition, the prostate glands are small, rudimentary, and confined to xviii in A. dinagatensis , but these are larger in A. americanorum (xvi-xxii) and A. robustus (xvi-xx or xxi).

Amynthas cagdianaoensis n. sp. ( Fig. 4B , Table 4 ) urn:lsid:zoobank.org:act:BBE85AA1-A978-4733-BBCE-8E5DF196C183

Material examined: Holotype: adult, amputee ( NMA 4596 ), Brgy Boa, municipality of Cagdianao , Dinagat Province, (10°05'53"N, 125°39'42"E),

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250 m asl, Dinagat Island, Philippines, coll. N. Aspe, J. Adeva, 23-26 Apr. 2004.

Etymology: The species is named for the municipality of Cagdianao, Dinagat Province, where this species was collected.

Diagnosis: Brown worm, body width 2.6- 3 mm; closely paired spermathecal pores at intersegment 8/9; first dorsal pore 11/12; spermathecal pores and male pores 0.12 and 0.11, respectively; 3 setae between male pores; genital markings lacking; proandric male sexual system.

Description: Brown dorsum, pale ventrum, equators pigmented. Length> 52 mm (n = 1, adult amputee); diameter 2.6 mm at x, 3 mm at xx; body circular in cross-section. First dorsal pore at 11/12, paired spermathecal pores closely paired at 8/9, distance between spermathecal pores 1 mm (0.12 circumference apart ventrally). Female pore single in xiv, openings of male pores paired in xviii, distance between pores 1 mm (0.11 circumference apart ventrally), 3 setae between pores. Clitellum annular, from xiv to xvi. Setae irregularly distributed around equators in some segments; 40 setae on vii, 39 setae on xx, dorsal setal gaps present, ventral gaps lacking. Genital markings lacking.

Septa 4/5-7/8 and 10/11-13/14 thin, 8/9/10 lacking. Dense tufts of nephridia on anterior faces of 5/6 and 6/7; nephridia of intestinal segments located mainly on body near septum/body wall junction. Large gizzard in ix-x, esophagus with low vertical lamellae x-xiii, intestinal origin in xv; caeca simple, originating in xxvii, folding upward in xxv, extending for two segments; typhlosole originating in xxvi, simple fold, about 1/4 lumen diameter, intestinal wall with 24 longitudinal blood vessels. Hearts in x to xiii, esophageal; commissural vessels in vi, vii, and ix lateral; those in viii extend to gizzard.

Ovaries and funnels free in xiii. Spermathecae paired, postseptal in ix, no nephridia on ducts. Each spermatheca with pyriform ampulla; short, slender, muscular duct; single stalked diverticulum attached to ectal portion of right face of duct of right spermatheca, and on left face of duct of left spermatheca; stalks long and convoluted, terminating in sausage-shaped receptacle. Male sexual system proandric, testes and funnels enclosed in paired sacs in x; seminal vesicles xi, each with short spherical dorsal lobe; vasa deferentia slender, free from body wall on way to ental end of prostatic ducts; prostates in xv to xix; each prostate a dense, racemose mass with four lobes; stout U-shaped muscular duct from lateral margin of prostate widens toward body wall, then

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narrows slightly just before body wall.

Remarks: Amynthas cagdianaoensis n. sp. belongs to the A. supuensis group of Sims and Easton (1972), characterized by having a pair of spermathecal pores at 8/9. Four species are assigned to this group: A. antefixus Gates 1935 and A. supuensis Michaelsen 1896 (both described from Halmahera, Indonesia), and A. dinghumontis Zhang et. al, 2006 and A. liaoi Zhang et. al, 2006 (both described from Guandong, China). The new species is smaller than A. antefixus (85-120 mm × 3.5-5 mm) and A. supuensis (115 mm × 6 mm) and lacks genital markings, whereas A. antefixus has the genital markings at the midventral line on iii, iv and v, and A. supuensis has them around the spermathecal and male pores. The first dorsal pore is at 11/ 12 in A. cagdianaoensis , but at 12/ 13 in A. antefixus and A. supuensis . Also, the male pores in A. antefixus are distantly spaced and located towards the lateral margins, while in A. cagdianaoensis , the male pores are much closer, (1 mm, 0.11 circumference apart ventrally). Moreover, the spermathecal diverticulum in A. antefixus has short stalk while in the new species it is long and convoluted. Amynthas cagdianaoensis is larger than A. dinghumontis (13-60 mm x 0.6- 2 mm) and A. liaoi (55 mm x 1.1-2 mm), and although A. dinghumontis lacks genital markings like A. cagdianaoensis , the spermathecal and male pores of the former are more widely spaced (0.25 and 0.17-0.25, respectively). Amynthas liaoi differs from A. cagdianaoensis in having genital markings around the spermathecal and male pores, and more setae (8) between male pores. No Philippine congener closely resembles A. cagdianaoensis n. sp.

Amynthas talaandigensis n. sp. ( Fig. 4C, 4D , Table 4 ) urn:lsid:zoobank.org:act:D9356AF7-E305-43E9-9D7F-FEDCA398816F

Material examined: Holotype: adult ( NMA 4597 ), Brgy Songco , municipality of Lantapan , Bukidnon Province, Mt. Kitanglad Range (8°05'47"N, 124°55'21"E), 2200 m asl, Mindanao Island, Philippines, coll. N. Aspe, 27-31 Oct. 2012 . Paratypes: one adult (NMA 4613); two adults (ZRC. ANN 0066), same collection data as for holotype.

Etymology: The species is named for the Talaandig indigenous tribe of Mt. Kitanglad.

Diagnosis: Brown worm, adult length 85- 110 mm; pair of spermathecal pores on small protrusions at intrasegments anterior of setal page 23 of 33

equators of 6, 7, 8, 9; first dorsal pore at 13/14; genital markings lacking; intestinal origin in xvi, prostate glands small, confined to xviii.

Description: Brown dorsum, pale ventrum, equators non-pigmented. Length 85-110 mm (n = 4 adults); diameter 3.2-4.5 mm at x, 3.7-4.5 mm at xx; body circular in cross-section, tail tapering; 85-105 segments. First dorsal pore at 13/14, paired spermathecal pores on small protrusions at intrasegments anterior of setal equators of 6, 7, 8, 9; spermathecal pores inconspicuous on 6; distance between spermathecal pores 1.8 mm (0.13 circumference apart ventrally). Female pore single in xiv, openings of male pores paired in xviii, distance between pores 2.8 mm (0.20 circumference apart ventrally), 12-13 setae between pores. Clitellum annular, from xiv to xvi. Setae irregularly distributed around equators in some segments; 32-37 setae on vii, 40-45 setae on xx, dorsal and ventral setal gaps present. Genital markings lacking.

Septa 4/5-6/7 and 12/13/14 thin, 7/8 and 10/11/12 muscular, 8/9/10 lacking. Dense tufts of nephridia on anterior faces of 5/6 and 6/7; nephridia in intestinal segments located mainly on body near septum/body wall junction. Large gizzard in viii-x, esophagus with low vertical lamellae x-xiii, intestinal origin in xvi; caeca simple, originating in xxvii, extending forward to xxiv; typhlosole originating in xxvi, simple fold slightly less than lumen diameter, intestinal wall with 27- 40 longitudinal blood vessels. Hearts in x to xiii, esophageal; commissural vessels in vi, vii, and ix lateral; those in viii extend to gizzard.

Ovaries and funnels free in xiii. Spermathecae paired, postseptal in vi, vii, viii and ix, nephridia on ducts lacking. Each spermatheca with pyriform ampulla; long, slender, muscular duct; single stalked diverticulum attached to the ectal portion of right face of duct of right spermatheca, and on left face of duct of left spermatheca; stalk long, terminating in ovate receptacle. Male sexual system holandric, testes and funnels enclosed in paired sacs in x, xi; seminal vesicles xi, xii, each with short, spherical dorsal lobe; vesicles of xi enclosed in testes sac; vasa deferentia slender, free from body wall on way to ental end of prostatic ducts; prostates very small, attached to wall in xviii; stout U-shaped muscular duct widens towards body wall, then narrows slightly just before body wall.

Remarks: Amynthas talaandigensis n. sp. belongs to the A. rimosus group of Sims and Easton (1972), which is characterized by having

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intrasegmental spermathecae in 6, 7, 8, and 9. Sims and Easton assigned to this group A. rimosus rimosus (Gates 1931) and A. rimosus effeminatus ( Gates 1932) , both described from Myanmar. However, Blakemore (2007) suggested that the latter subspecies is probably a synonym of the nominal subspecies. The new species differs from A. r. rimosus in the location of the first dorsal pore (at 13/14, compared to 12/ 13 in A. r. rimosus ), the absence of genital markings or distinctly demarcated porophores around the male pores (Gates in 1931 described A. r. rimosus to have a pair of thickly crescent-shaped genital markings in xviii, but in 1972, he described the species to have distinctly demarcated porophores around the male pores instead of genital markings), the origin of the intestine (in xvi, compared to xv in A. r. rimosus ), and the size of the prostate glands (in xviii, compared to covering five segments from xv-xix in A. r. rimosus ). Another species with ventral intrasegmental spermathecal pores is A. monstriferus ( Kobayashi 1936) from Korea. This species is much larger (235 mm) than A. talaandigensis , has genital markings on viii, and has manicate intestinal caeca. Hong and James (2009b) included A. ani , also from Korea, in this species group; Amynthas ani is larger (164-171 mm × 7.8 mm) than A. talaandigensis , has more segments and more setae around segments vii and xx (125-130, 65 and 68, respectively), and has longer prostate glands (xvii-xx). Amynthas talaandigensis is the second Amynthas species described from Mt. Kitanglad Range, following Amynthas heaneyi (James 2004) .

Figures

Fig. 4. Schematic dorsal views of the internal morphology of the three Amynthas species described here. (A) A. dinagatensis n. sp.; (B) A. cagdianaoensis n. sp.; (C) A. talaandigensis n. sp. Scale bars: A-C: 5 mm. (D) Schematic ventral view of polythecal A. talaandigensis n. sp., showing the intersegmental spermathecal pores (sp). Abbreviations: s, spermatheca; h, heart; p, prostate gland; c, caecum; sp, spermathecal pores.

Tables

Table 4. Comparison of Amynthas, Polypheretima, and Pithemera species

Characters	A. dinagatensis n. sp.	A. cagdianaoensis n. sp.	A. talaandigensis n. sp.	P. bukidnonensis n. sp.	P. zamboangensis n. sp.	P. nolani n. sp.
Length	240	>52	85-110	131	223-306	143-159
Width x, xx	9, 7	2.6, 3	3.2-4.5, 3.7-4.5	5-6.5, 5.5-6.5	3.5-4, 4-5	3.5, 3.5
Dorsal pigmentation	Dark brown	brown	brown	brown	unpigmented	Reddish brown
Segment equator	unpigmented	pigmented	unpigmented	pigmented	unpigmented	unpigmented
Segments	163-167	?	85-105	147	227-248	100-114
1st dorsal pore	12/13	11/12	13/14	12/13	12/13	11/12
Setal gaps D, V	+, -	+, -	-, -	+, -	+, +	+, +
Spermathecal pores	-	Paired at 8/9	Paired at 6,7,8,9	Batteries at 5/6/7	-, paired at 5/6/7	Paired at 5/6
Sperm. pore distance	-	0.12	0.13	-	inconspicuous	0.19
Male pore distance	0.27	0.11	0.2	0.22	0.31	0.20
Setae between openings	20	3	12-13	6-7	8-9	9-11
Setae vii, xx	35-48, 70-73	40, 39	32-37, 40-45	39-45, 46-58	60-84, 69-70	34-36, 56-59
Genital markings	-	-	-	Paired in xix-xxi	Paired in xix-xxii	-
Gizzard	viii-x	viii-x	viii-x	viii-x	x-xi	viii-x
Intestinal origin	xiii	xv	xvi	xv	xvii	xiv
Caeca	xxvii-xxi	xxvii-xxiii	xxvii-xxiv	-	-	xxiii-xxi
Prostate	xviii	xv-xix	xviii	xvi/xvii-xix	xvi-xix	xvi-xx/ xv-xix
Copulatory bursae	-	-	-	-	-	xvii-xix