Andiorrhinus (Amazonidrilus) duseni ( Michaelsen, 1918 )

Feijoo, Alexander, Brown, George G. & James, Samuel W., 2017, New species of Andiorrhinus Cognetti, 1908 (Oligochaeta: Rhinodrilidae) from Venezuela and Brazil, Zootaxa 4363 (1), pp. 55-78 : 62-64

Andiorrhinus (Amazonidrilus) duseni ( Michaelsen, 1918)

( Figure 3A–D )

Rhinodrilus duseni Michaelsen, 1918: 190 . Righi 1971: 16, figs 17–22; 1974: 101; 1985: 236; Zicsi & Csuzdi 1999: 130.

Material examined. 2 complete clitellate specimens (one of them longer than the other), 1 clitellate lacking tail segments ( MZUSP 0005 ), Itapeva, SP. Collection date: 01/01/1968. Collector: José Maria Margarido. —2 clitellate specimens, one of them much larger than the other ( MZUSP 1430 ), Curitiba, PR. Collection date: 1983 (no day or month specified on the label). Collector: Chang (the label has no more information on it, but it was most probably sent by Dr. Yong-Chiang Chang, professor of the Federal University of Paraná, who worked with earthworms).— Clitellate specimen ( COFM BRSP0072 ), in shallow rocky soil above stream under forest with Araucaria angustifolia at Itapeva Experimental Station , Itapeva, SP (24°04'09.8"S, 49°03'54.5"W) . Altitude: 715 m a.s.l. Collection date: 16/02/2010. Collector: Jamil de Morais Pereira. — Clitellate specimen ( COFM BRPR0410 ), in yard private city residence surrounded by forest with A. angustifolia, Curitiba , PR (25°25'10.3"S, 49°13'31.8"W) . Altitude: 917 m a.s.l. Collection date: 13/04/2012. Collector: Klaus D. Sautter.—6 clitellate specimens, 1 juvenile ( COFM BRPR0047 ), in red Latossol under Pinus sp. trees at Humanitas Philanthropic Association, São Jerônimo da Serra , PR (23°43'47"S, 50°44'04.5"W) . Altitude: 843 m a.s.l. Collection date: 27/03/2003. Collector: George G. Brown.—4 clitellate specimens, 3 juveniles, 1 cocoon ( COFM BRPR0059 ), in wet black grassland Organossol above small stream at Embrapa Produtos e Mercado , Rodovia do Talco Km 6, Ponta Grossa , PR (23°43'47"S, 50°44'04.5"W) . Altitude: 944 m a.s.l. Collection date: 11/04/2003. Collector: George G. Brown.—1 complete clitellate specimen, 2 clitellate specimens lacking posterior segments, 2 subadults (COFM BRPR0579), in dark brown grassland soil at Morro do Getúlio, Parque Estadual do Pico Paraná, Campina Grande do Sul, PR (25°14'10.3"S, 48°50'24.7"W). Altitude: 1450 m a.s.l. Collection date: 20/04/2012. Collectors: Guilherme Borges Xarão Cardoso, Alexander Feijoo, Victor Tedeschi, George G. Brown.—2 clitellate specimens (COFM BRSP0031), in wet grassland organic-rich dark soil above Rio Verde, Itaberá, SP (24°05'02.5"S, 49°11'59.9"W). Altitude: 638 m a.s.l. Collection date: 17/01/2003. Collector: George G. Brown.—1 clitellate specimen (COFM BRPR0154), in soil under Mimosa sp. trees at Embrapa Forestry, Colombo, PR (25°19'35.1"S, 49°09'49.9"W). Altitude: 918 m a.s.l. Collection date: 29/09/2010. Collector: Wilson Maschio. —1 clitellate specimen, 8 juveniles, 1 subadult with anterior portion only ( COFM BRPR0578 ), in grassland soil near banks of River Imbituvão, Fernandes Finheiro, PR (25°24'34.6"S, 50°32'30.8"W) . Altitude: 796 m a.s.l. Collection date: 17/01/2012. Collectors: George G. Brown, Marie Bartz, Samuel James, Seana Davidson, Hong Yong.—4 clitellate specimens, 1 cocoon ( COFM BRPR0577 ), in roadside ditch next to soybean field on private property, close to Faxinal-Mauá county border, Faxinal, PR (23°54'41.2"S, 51°12'05.1"W) . Altitude: 1034 m a.s.l. Collection date: 23/01/2004. Collectors: George G. Brown and Cassio Yutaka Matsumura.—1 clitellate specimen ( COFM BRPR0210 ), in Cambissol with grass vegetation cover under an open Pinus elliotti plantation at Embrapa Forestry, Colombo, PR (25°20'08.3"S, 49°09'27.2"W) . Altitude: 921 m a.s.l. Collection date: 30/08/2011. Collector: George G. Brown.—4 clitellate specimens ( COFM BRSP0209 ), in wetland soil with grasses on private property of Sr. Ettori de Lucca, neighboring the Capão Bonito National Forest, Capão Bonito, SP (23°53'51.9”S, 48°32' 11.4”W) Altitude: 600 m a.s.l. Collection date: 21/05/2012. Collectors : Harold Drake , Kristin Schulz , Alexander Feijoo , George Brown. —1 clitellate specimen ( COFM BRSP0077 ), bought from fish bait vendor along SP189, at bridge across River Paranapanema in Campina do Monte Alegre , SP. According to the seller, this worm had been collected from the topsoil of a grassland site near the Paranapanema River , about 2 km distance from his house.

Redescription. Endo-anecic species. Its body is cylindrical and pointed at both extremes, beginning with a tiny fine tip that gradually increases in diameter until it reaches a maximum width in segments 18–22, after which its diameter decreases until it becomes flattened after segment 82, ending in a lanceolate tip. The species is characterized by a blue-violet dorsum and clitellum and a green-colored ventral region, corresponding to the respective color code numbers 537, 542, and 435 ( Seguy 1936). The length of the clitellate specimens varies depending on collection location, ranging from close to 130 mm (MZUSP 0 0 0 5 and MZUSP 1430) up to 401 mm (COFM BRPR 0410). Diameter of specimens also varies depending on overall size. Larger specimens such as that from Itapeva (COFM BRSP0072) have diameter of 16.7 mm in the preclitellar region, 11.8 mm in the clitellum, and 9.8 mm in the postclitellar region. The number of segments of fully clitellate and complete specimens is normally over 200 (253 in COFM BRSP0072 and 225 in BRPR0410). The first two segments are invaginated and the prostomium is only visible from the inside in the form of an elongated whitish lobe, measuring 1.6 mm in length. Four pairs of setae are visible as of segment 5. The hook-shaped common setae measure 1.38 mm (COFM BRPR0410). The distance between setae in segment 24 is aa:ab:bc:cd:dd = 4.8:1.0:10.2:0.4:17.2 and, in the posterior region in segment 204, 2.0:1.0:4.7:0.2:9.8 (measures on COFM BRPR0410). Setae of segments 7–9 and 18–23 are modified as genital setae, which measure 2.97 mm ( Fig. 3A ).

The clitellum lies in segments 16, 17–25, 26 (=10, 11) and the tubercula pubertatis are located on segments 20– 22 (=3). Three deep cavities are observed in the region next to the tubercula pubertatis, becoming more pronounced from the edge of the tubercula pubertatis through the mid-ventral region ( Fig 3B ). The male pores are located in segment 18, and female pores were not recognized. The nephropores are aligned with setae d. Three pairs of spermathecal pores were observed in intersegments 6/7, 7/8, and 8/9, aligned with setae c and d.

Internal anatomy. The anterior septa of segments 6/7–12/13 are thick, conical and funnel-shaped, gradually losing their thickness as of segments 12/13 and 13/14 until they become fine membranes. The round muscular gizzard and thick musculature are located in the cavity of segment 6. Three pairs of sac-shaped calciferous glands, with no appendage and with a lamellar internal structure, are present in segments 7–9, each gland with 28 nonparallel lamellae ( Fig. 3C ). The esophagus-intestine transition begins in segment 21/22 and the typhlosole begins in segment 23. There are no intestinal caeca. Three pairs of lateral hearts are present in segments 7–9 and four pairs of intestinal hearts in segments 10–13, with those of segments 12 and 13 being much larger. Both supraesophageal and subesophageal vessels are present. There is one pair of holonephridia per segment.

Two pairs of oblong testis sacs contain the testes in segments 10 and 11, and two pairs of seminal vesicles are present in segments 11 and 12. The two pairs of deferent ducts merge in segment 17 and open towards the male pore in segment 18. One pair of ovaries is present in the cavity of segment 13; the female pore is unrecognizable.

Three pairs of spermathecae are present in segments 7, 8 and 9 ( Fig. 3D ). The sperm duct is large—in some cases with creases—and separated from the long, rounded ampulla by numerous seminal chambers.

Remarks. The holotype of the species was collected by P. Dusen in Curitiba, Brazil, in 1910 and is deposited in the Zoological Museum of the University of Hamburg, Germany (ZMUH 8494). Michaelsen (1918) based the description on a single individual with a regenerating tail, and Righi (1971) provided further information on 10 individuals (being 8 adults and 2 juveniles), collected in Pilar do Sul (São Paulo), Brazil, in 1966. Additional specimens were reported on by Righi (1974, 1984) from Fátima do Sul (Mato Grosso do Sul) and Itapeva (São Paulo) and by Zicsi & Csuzdi (1999) from Quatro Barras (Paraná), near the type locality in Curitiba. Michaelsen (1918) described the structure of the calciferous gland as panicled-tubular (Rispenschlauchtaschen) with a slight variation of its borders. Righi (1971) also considered the structure of calciferous glands in Rhinodrilus duseni as composite-tubular in his samples from Pilar do Sul. However, the label of the vial ZU-75 with specimens from Itapeva had the following comment: " Há variação na forma das espermatecas e glândulas calcíferas ”, which translates "There are variations in the form of spermathecae and calciferous glands”. After examining the specimens of the MZUSP (0005 and 1430) and comparing it with samples collected in various locations throughout the states of São Paulo and Paraná, the structure was defined as corresponding to Lamellentaschen with the presence of 28 non-parallel lamellae, with three central divisions that form tube-like figures that could confuse taxonomists. However, after being examined in detail, these are observed to continue until the borders of the gland, conserving the lamellar-like structure ( Fig. 3C ). Therefore, Rhinodrilus duseni Michaelsen 1918 was relocated in the genus Andiorrhinus (Amazonidrilus) due to the lamellar-type (Lamellentaschen) structure of the calciferous gland (Table 1). In conclusion, the gland cavity lengthwise is divided into numerous parallel or entalwards diverging lamellae ( Righi 1995). A complete and detailed description of the vascular system of A. duseni can be found in Schroeder-Araújo (1978).

This species corresponds to Andiorrhinus (Amazonidrilus) sp. nov. 4 and Andiorrhinus sp. nov. 1, sp. nov. 2 and sp. nov. 3, as cited in Fragoso & Brown (2007), and to Andiorrhinus sp. 1, n. sp. 2, n. sp. 3, n. sp. 4, Andiorrhinus sp. and Andiorrhinus spp. in Brown & James (2006), and Sautter et al. (2006, 2007). More careful morphological examination of the individuals categorized as different species due to variations in size and coloration, in the fore-mentioned publications, resulted in them all being included in A. duseni .

Figures

FIGURE 3. Andiorrhinus (Amazonidrilus) duseni (Michaelsen, 1918). A. Genital seta b, segment 8. B. External, ventral view of clitellum.C. Cross-section of the calciferous gland from segment 8. D. Spermathecae of 7, 8, 9.